I am trying to install Ubuntu 18.04 but I get this error at the end of installation process!  I tried to create a partition with ext4 for \boot. also ext1 but non of them worked. Also I tried to choose the ntfs partition that my Windows 10 grub file is in that but didn't work too.  I also had Ubuntu 16.04 beside my Windows 10 on this Laptop, But when I tried to format the old Linux and install the new one, I get this error message!  (My Windows is installed on sda (Samsung ssd hard))  Edit: Screen shot didn't work and couldn't large the window to show off all the partitions, so I took 2 images:

I am installing Ubuntu 16.04 in an Intel NUC computer with UEFI enabled. I am using an SSD from another computer. During the installation I chose Erase the disk and make a new full install  At the end of the process I see:  grub-efi-amd64-signed failed installation /target/ Ubuntu 16.04    And the system does not boot.  I tried to use boot-repair but apparently it does not solve the problem.


I'm using System.DirectoryServices.DirectorySearcher for traversing Active Directory for users. In most cases, this works fine. The code is pretty much as follows:  Ldapconnection conn = CreateConnection(...); System.DirectoryServices.DirectorySearcher searcher = new System.DirectoryServices.DirectorySearcher(); searcher.SearchScope = System.DirectoryServices.SearchScope.Subtree;  foreach (System.DirectoryServices.SearchResult result in searcher.FindAll()) { }   For some reason, this doesn't always traverse the tree completely. If I specify the searchroot to point at a missing subtree, it does import that subtree.  Am I missing something?

I just noticed that the return list for results is limited to 1000. I have more than 1000 groups in my domain (HUGE domain). How can I get more than 1000 records? Can I start at a later record? Can I cut it up into multiple searches?  Here is my query:  DirectoryEntry dirEnt = new DirectoryEntry("LDAP://dhuba1kwtn004"); string[] loadProps = new string[] { "cn", "samaccountname", "name", "distinguishedname" }; DirectorySearcher srch = new DirectorySearcher(dirEnt, "(objectClass=Group)", loadProps); var results = srch.FindAll();   I have tried to set srch.SizeLimit = 2000;, but that doesn't seem to work. Any ideas?


I am starting to use Arch Linux / Mate, and Guake with it (last versions). I would like Guake can highlight the command prompt, like in . You can see the prompt is light green, and the other text is white.  Actually Guake is showing like , with no differences between prompt and the rest of the text.  My intention is to differ from the command prompt and the other text showed in Guake.  Is there a way or a theme to make this difference? Thanks.

I used several colors in my PS1 prompt such as   \033]01;31\] # pink \033]00m\]   # white \033]01;36\] # bold green \033]02;36\] # green \033]01;34\] # blue \033]01;33\] # bold yellow   Where can I find a list of the color codes I can use?  I looked at  but it didn't answer my question about a list of the actual codes.  It would be nice if there was a more readable form also.  See also


John: "I gave the waiter a $50 dollar tip and he gave me a dirty look. Maybe I should have given him more?" Bill: "No, $50 is enough, I would have thought." Should it be: "No, $50 was/would be enough, I would have thought"?

She has five kids. I can imagine how busy she would be.   Is the use of would be right in this sentence? What about      She has five kids. I can imagine how busy she is.   Are both correct? Do they mean different things?


I have a sphere and I want to make some cylindrical cavities on it's surface, which are tangent to the sphere's surface The cylinders wich which I should make the boolean difference should be disposed as a sea urchin, i suppose: with the bottom faces of the cylinders being on the same origin and the top faces spreading out radially.  Here are some images to give a better idea of what I should do:  This is a "flattened" version of what I want to acieve   How do I do the same thing on a sphere?  I need to get to the point where i get something like this but with the cylinders going all around the sphere orbiting around its Z-axis    Thanks in advance :D  Edit: Is there a versatile way of doing so on objects which have an elliptical/irregular shape?

We know that the there is an Object Offset option for Array modifier, but when trying to make a circular array with that offset object as the center of the array circle, it always doesn't behave quite like what's expected. So how to make a nice and controllable circular array?  P.S.: There is an old  about moving the object's origin. I wonder if there is any way to do this without changing the location of the origin. :)


Is it ok to use this font freely in a website you're creating for a school in the UK?

Basically I would like to use on website a "Norasi" font, that was bundled with Ubuntu, but I cannot find any license. Am I allowed to distribute that font through website? What is its license?


Why in regression analysis does the inclusion of a new variable make  statistically insignificant coefficients that previously were not? In model 3 length of contraception becomes insignificant when controlling for age. How to interpret this

I have what is probably a simple question, but it is baffling me right now, so I am hoping you can help me out.  I have a least squares regression model, with one independent variable and one dependent variable. The relationship is not significant. Now I add a second independent variable. Now the relationship between the first independent variable and the dependent variable becomes significant.  How does this work? This is probably demonstrating some issue with my understanding, but to me, but I do not see how adding this second independent variable can make the first significant.


When I attempt to test the catching of an exception with a spsecific message when a Queue is empty the test fails. Here is the Queue class: import time from multiprocessing import Lock, Process, Queue, Pool  class QueueFun():      def writing_queue(self, work_tasks, name):         while True:             print("Writing to queue")             work_tasks.put('1')             time.sleep(3)      def read_queue(self, work_tasks, name):         while True:             print("Reading from queue", work_tasks.empty())             if work_tasks.empty():                 raise ValueError('Queue should not be empty')             item = work_tasks.get()             time.sleep(1)  if __name__ == '__main__':     work_tasks = Queue()     queue_fun = QueueFun()     print('setup done')      write_queue_process = Process(target=queue_fun.writing_queue, args=(work_tasks, "write_to_queue_process"))     print('write_queue_process')      write_queue_process.start()      read_queue_process_1 = Process(target=queue_fun.read_queue, args=(work_tasks, "read_from_queue_process_1"))     read_queue_process_1.start()     read_queue_process_2 = Process(target=queue_fun.read_queue, args=(work_tasks, "read_from_queue_process_2"))     read_queue_process_2.start()      write_queue_process.join()     read_queue_process_1.join()     read_queue_process_2.join()  And here is the test: import unittest from queue import Queue  from playground.QueueFun import QueueFun   class QueueFunTests(unittest.TestCase):     def test_empty_queue(self):         q = QueueFun()         work_tasks = Queue()         self.assertRaises(ValueError('Queue should not be empty'), q.read_queue(work_tasks, "1"))  Test fails with :     raise ValueError('Queue should not be empty') ValueError: Queue should not be empty  Have I not implemented the test correctly ?

How does one write a unittest that fails only if a function doesn't throw an expected exception?


I'm a starting graduate student in math. Without a doubt I'm not a genius or even that smart, and that creates a serious problem: I often lose my nerve while doing research or studying other people's paper. I feel that some of those people (if not most) are just too good and I crack under the pressure to produce works of similar quality. I know the right thing to do is to be "brave" and power through and see where I end up. But this issue of "cowardice" has severely hurt my productivity. Do successful researchers have same problem or are they just totally engrossed with their work and do not care about anything else? How can I somehow be more disciplined with my emotions?

I am a third year (starting fourth year in the fall) PhD student in mathematics. I've passed all qualifying exams and am currently doing research. As far as I can tell, I am not doing poorly. I have the good fortune of having a great advisor, being in a very supportive department, and having friends and family who genuinely care about my success.   The fact is research is hard. It appears to consist primarily of staring at a problem for days and days and days without getting anywhere. Sometimes, rarely, I do figure something out and that feels wonderful, but the overwhelming majority of my time appears to be spent banging my head against a mostly figurative wall. I am not complaining about the material being hard, and I am not averse to putting in hard work, but I get frequently discouraged when I realize the vast volumes of mathematics that I yet know nothing about (and probably never will). It's very hard to quantify progress - in particular, there are too few tangible returns after too many hours worked. I find myself thinking along the lines of "Oh, if only someone actually smart were thinking about this problem they would have solved it in moments" and so on.   I've talked about this to some number of people; here is some advice I have received:   Take a day off. Putting in hours upon hours of trying things doesn't magically lead to a solution, particularly if the brain is tired and just wants to sleep. Have a hobby. Since math research doesn't exactly provide instant gratification, a hobby might provide some instead.  Talk to other graduate students. Realize that many graduate students go through this.   I'm interested to know how other folks have dealt with being discouraged as a graduate student. Does it get better with time and experience? Is this a sign that research is not for me and that I should seriously consider a life outside academia?


We know that summation is for discrete values, and integration is the generalization of summation so that it can be extended to continuous values.  We also have product for discrete value, what is its continuous counter part?

We know that continuous version of $\sum$ is $\int$, but, can there be a continuous version of $\Pi$?


I would like to prove that given an irreducible polynomial $g(X)\in \Bbb Z[X]$, then the ideal $\langle g(X) \rangle \trianglelefteq \Bbb Z[X]$ is not maximal.   One can think to prove $$\langle g(X) \rangle \subsetneq \langle p,g(X)\rangle \subsetneq \Bbb Z[X]$$ and maybe to use the ring isomorphism  $$\frac{\Bbb Z[X]}{\langle p,g(X) \rangle}\cong\frac{\Bbb Z_p[X]}{\langle \overline g(X) \rangle }$$ where $p$ is a prime number and $\overline g(X)$ is $g(X)$ with coefficients in $\Bbb Z_p$. But how could we proceed?   I face difficulty to prove $\langle p,g(X)\rangle \subsetneq \Bbb Z[X]$.  I know that this may be an easy question, but I have stuck. Also, any other ideas are welcome!

Let $f$ be a nonconstant element of ring $\mathbb Z[x]$. Prove that $\langle f \rangle$ is not maximal in $\mathbb Z[x]$.   Let us assume $\langle f \rangle$ is maximal. Then $\mathbb Z[x] / \langle f \rangle$ would be a field. Let $a \in \mathbb{Z}$. Then $a + \langle f \rangle$ is a nonzero element of this field, hence a unit. Let $g + \langle f \rangle$ be its inverse. Then $a g - 1 \in \langle f \rangle$, hence $ag(x)-1 = f(x)h(x)$ for some $h \in Z[x]$, hence $ag(0) + f(0)h(0) = 1$, thus $(a,f(0))=1$ for all $a \in \Bbb Z$, contradiction, hence the proof.  Is my argument correct? Is there any other method?


Why is the characteristic function of a probability distribution function uniformly continuous? This is from page151 of Chung's A Course in Probability Theory.  Specifically, why is the last inequality true? $|\phi(t+u)-\phi(t)|=\left|\int (e^{i(t+u)x}-e^{itx})dF(x)\right|\leq\int |e^{iux}-1|dF(x)$.

Defining the Characteristic Function $ \quad  \phi(t) := \mathbb{E} \left[ e^{itx} \right] $ for a random variable with distribution function $F(x)$ in order to show it is  uniformly continuous I say  $$ |\phi(t+u) - \phi(t)| = \left |\int e^{itx}(e^{iux} - 1) dF(x) \right| \le \\ \int 1 \cdot|e^{iux} -1|dF(x) \to 0 \quad as  \quad u\to0 $$  Now my question is, does the convergence I state in the last line follow directly, or do I need to be a little carful before I conclude it is true ? (i.e. can I directly use that $|e^{itu} -1| \to 0 ? )$


edit 1: my question was marked as duplicated but it is not answering my question, i don't want to merge but intersect bar in foo.. If bar holds extra properties, merging bar in foo will result in having foo with 3 properties. what i want is to copy the values of the properties of bar that are also presents in foo object.  I hold two objects  var foo = { id:8, name:"luke" } var bar = { id:9, name:"vador" }   the view keeps a reference on foo object, then foo=bar will not make the view updated as foo has a new reference to data.  Then my question is how can I intersect bar in foo as to keep foo's reference ?  something similar to   foo.id = bar.id foo.name = bar.name   but as foo and bar Object may have a lot of properties this would become tedious to write all manually.  What is the most proper way to intersect without any use of js frameworks ?

I need to be able to merge two (very simple) JavaScript objects at runtime.  For example I'd like to:  var obj1 = { food: 'pizza', car: 'ford' } var obj2 = { animal: 'dog' }  obj1.merge(obj2);  //obj1 now has three properties: food, car, and animal   Does anyone have a script for this or know of a built in way to do this?  I do not need recursion, and I do not need to merge functions, just methods on flat objects.


I'm trying to figure out whether or not to hyphenate a new medical-related phrase, "post birth control syndrome."  I know Post-traumatic Stress Disorder is hyphenated, but that seems to make sense because "post-traumatic" on it's own defines the state of the condition.  "Post-birth-control" doesn't feel right as "birth control" as a phrase isn't hyphenated.  So do I do "post-birth control syndrome" or "post birth control syndrome" and why?

For example, "file system" and "related". Is it "file system-related"? It will appear as if it is a compound of "file" and "system-related", won't it?


In Python 3 interpreter,   1//0.1 2//0.2 4//0.4   returns 9.0, but   5//0.5 3//0.3   returns 10.0. Is this rounding-off behavior correct?

Consider the following code:   0.1 + 0.2 == 0.3  ->  false   0.1 + 0.2         ->  0.30000000000000004   Why do these inaccuracies happen?


can you tell me a video or written tutorial to create a 3D character animation in Blender 2.80 beta and then export it as .fbx for Unity 2018.3.7?  I tried starting with a character downloaded from Mixamo (only the tpose) and then imported to Blender 2.80beta, so I tried to create the desired keyframe (in Blender it seems to be OK), but when I export it to Unity as .fbx, I don't I know why but the animation is not the same as that of Blender (the arms remain always extended along the shoulders and only part of the arm moves). The animation I wanted to create is that of the character who stretches his right arm to open a door.

Since asking for tutorials, videos, resources, links to other content or downloads is considered off topic here, this is a specifically created Community Wiki which gathers resources for Blender and it has been approved by the .  Just write in the appropriate answer/section. If you have concerns, questions, post a  question, so we don't clutter the comments, but you can link your meta question from the comments.  Questions regarding such resources are not allowed anymore, except for very specific and on topic requests (ask on  if you're unsure about your question). Follow the instructions made in the question about how to post, what can be posted, etc.  Learning             Assets    (also see: )   Reference Images/Blueprints (also see: )    Tools    (also see: )      Other   Special Interest ()     Also see the .


I am having trouble with an image in Latex. I am getting the error message:  Runaway argument? width=8cm][height=8cm]{IMG_0390.PNG} \end {figure} ! Paragraph ended before \Gin@iii was complete. <to be read again>                    \par   I have got the graphicx package on the file, my code for the image is;  \begin{figure} \includegraphics[width=8cm][height=8cm]{IMG_0390.PNG} \end{figure}   There are no other errors in the document and no errors when I cut this part out  The full error message with the display math is:   ! Missing $ inserted <inserted text>                 $ l.63 ...aphics[width=8cm,height=8cm]{IMG_0390.PNG}

\documentclass[a4paper,12pt]{article}  \usepackage[utf8]{inputenc} \usepackage[T1]{fontenc} \usepackage[french]{babel} \usepackage{amssymb} \usepackage{amsthm} \newtheorem{montheoreme}{Théorème}[] \newtheorem{monlemme}{Lemme}[] \newtheorem{mondem}{Démonstration}[] \newtheorem{moncorol}{Corollaire}[] \newtheorem{mondefin}{Définition}[] \newtheorem{chapter}{Chapitre} \newtheorem{monremarq}{Remarque} \newtheorem{monpropos}{Proposition} \newtheorem{monexpl}{Exemple} \usepackage{graphics} \begin{document}  \begin{Large}  \textbf{Biographie :} \end{Large} \\  \includegraphics[scale=0.1]{800px-Karl_Weierstrass.jpg} \textbf{Karl Theodor Wilhelm Weierstrass :} habituellement appelé Karl Weierstrass, orthographié Weierstraß en allemand, né le 31 octobre 1815 à Ostenfelde (Westphalie), mort le 19 février 1897 à Berlin, était un mathématicien allemand, lauréat de la médaille Copley en 1895.\\ Il a étudié les mathématiques à l'université de Münster et obtint une chaire à l'Université technique de Berlin. Il fut immobile les trois dernières années de sa vie et s'éteignit à Berlin à la suite d'une pneumonie.\\ Karl Weierstrass est souvent cité comme le « père de l'analyse moderne ». Il consolida des travaux de Cauchy sur les nombres irrationnels et leur amena une nouvelle compréhension. Ses travaux les plus connus portent sur les fonctions elliptiques.


Is there some way to search questions of users with low reputation or with high reputation?

There seems to be a deluge of questions by folks with rep of 1-10. Many of these questions are "homework" or questions that are annoying to me "please read my 500 line script and tell me whats wrong with it" Is there any way to filter questions by reputation?


I have this answer I did yesterday on SO:    And I got my tenth upvote today. So I got the Nice Answer badge an hour ago:    But I was a bit confused that why I didn't get the Enlightened badge. As in the badge page, the trigger for the badge is:  First to answer and accepted with score of 10 or more  I did that in that answer. But now just 5 minutes ago I was awarded the Enlightened badge.    But that is a big time difference between the time of awarding for the two badges. Why is it like that? Why is there a such a big time gap?

Do badges get calculated in real time, or do they get calculated by an external service? How long does it take for a badge to be awarded, once its requirements are met?  Does Stack Overflow use any external services to do things, like maintenance, e-mailing or badge calculation?


What I want to do is link/merge folders. The two folders I want to combine are  /home/user1/Pictures  /home/user2/Pictures   I want all these family photos to be stored in a single location and be easily accessible from every user account. I tried the ln command but it didn't work because owners of both folders are different, so there's no access permission via the symlink.

I need a shared folder. My wife and I need to exchange files on the same computer. How can we do that?


Would you help me understand and possibly fix the problem below?  If I do  \title{\input{toBeIncluded.tex}}  \begin{document}  \maketitle  \section{Test Section 1}  \section{Test Section 2}  \end{document}   I get exactly what I d expect (with no errors), whereas if I do  \title{Test Title}  \begin{document}  \maketitle  \section{\input{toBeIncluded.tex}}  \section{Test Section 2}  \end{document}   I get two errors, even though the pdf is still produced and looks perfect.  toBeIncluded.tex is a file with just one word ("Hello") in it.  Thanks a lot

I cannot figure out how to import a file in a chapter title:  \chapter{\input{"Introduction.txt"}} \chapter{\texorpdfstring{\input{"Introduction.txt"}}{Introduction}}   Both of these fail with      Use of \@chapter doesn't match its definition.   Any help will be greatly appreciated.


I was thinking about the following problem:    Let $A$ be an $n\times n$ matrix over real numbers such that $AB=BA,$ for all $n\times n$ matrices $B$.Then which of the following options is correct?     (a)$A$ must be zero,   (b)$A$ must be the identity,   (c)$A$ must be a diagonal matrix,   (d)$A$ must be either $0$ or the  identity.     I think the answer will be between $(c)$ and $(d)$. But i am not sure how to get the exact result.Can someone show me the right direction? Thanks in advance for your time.

The question is from Axler's "Linear Algebra Done Right", which I'm using for self-study.  We are given a linear operator $T$ over a finite dimensional vector space $V$. We have to show that $T$ is a scalar multiple of the identity iff $\forall S \in {\cal L}(V), TS = ST$. Here, ${\cal L}(V)$ denotes the set of all linear operators over $V$.  One direction is easy to prove. If $T$ is a scalar multiple of the identity, then there exists a scalar $a$ such that $Tv = av$, $\forall v \in V$. Hence, given an arbitrary vector $w$, $$TS(w) = T(Sw) = a(Sw) = S(aw) = S(Tw) = ST(w)$$ where the third equality is possible because $S$ is a linear operator. Then, it follows that $TS = ST$, as required.  I am, however, at a loss as to how to tackle the other direction. I thought that a proof by contradiction,  ultimately constructing a linear operator $S$ for which $TS \neq ST$, might be the way to go, but haven't made much progress.   Thanks in advance!


I wants to check all combination values which satisfy the conditions given in if statement   def drange(start, stop, step):     r = start     while r < stop:         yield r         r += step     for a in drange(0.1, 0.9,0.1):     for b in drange(0.1, 0.9,0.1):         for c in drange(0.1, 0.9,0.1):             if a+b+c == 1 and a>b>c:                 print a                 print b                 print c   It is working but doesn't give the all combinations.


I can't figure out how to get an item that is renamed using the /give command and I have tried the command I found here, /give @s stone 1 0 {display:{name:"name"}} but it keeps saying that I am missing a close bracket in line 1, column 2. I have as many closed brackets as I do open brackets. I want to know this because I am making a private server in Minecraft PE.

This question was recently split into different questions for each workaround. See   meta posts for more information.   Can you use NBT tags in commands? I’ve tried commands that normally work in Java Edition like: give @s minecraft:planks 30 1 {display:{Lore:["Wooden planks"]}} give @s stone_pickaxe{Unbreakable:1b} give @s item_frame{EntityTag:{Invisible:1b}} summon villager ~ ~ ~ {Offers:{Recipes:[{buy:{id:"emerald",Count:5b},sell:{id:"diamond_sword"}}]}} summon tnt ~ ~ ~ {Fuse:20s}


What is a formal word/phrase that describes a person who always searches to benefit from other people?  It is hard to recall the word in my own language to translate. So I decided to give it a try and ask here.  I prefer adjective

What would you call someone who isn't afraid to ask for money or any kind of favor or who misinterprets someone's generosity for a consistent resource for what they need?


As per the title, the task is to     Factor the RSA modulus $n = 3844384501$ knowing that $$3117761185^2 \equiv 1 \pmod{n}\text{.}$$   $n$ being an "RSA modulus" means that it is a product of two primes, i.e. $n = pq$.  The task is to find these two primes.  I can see that from what we're given, $$ (3117761185 - 1)(3117761185 + 1) \equiv 0 \pmod{n}\text{,} $$ but I do not know how to proceed from there on.  Any hints would be greatly appreciated.  N.B. It would seem that computing $\gcd(3117761184, n)$ and $\gcd(3117761186, n)$ would give me $p$ and $q$ but I have no idea why that would be justified.

The algorithm purposed to play a fair game of heads or tails over the phone given  claims that knowing the four solutions to  $$ x^2 \equiv a^2 \pmod n$$ would allow us to factor $n$ where $n$ is a product of two unknown primes $p,q$ and $\gcd(a, n) = 1$. However, I am not seeing why this would be true. Can someone please explain?


I've created an ArcGIS 10 Addin that consists of a toolbar containing one button and one tool. The button opens a form, and the tool is disabled until the user enters some information on the form.  This addin works great on my development computer and on other computers in my office. But when I deliver the addin to the client, toolbar is there with the button and tool, but when he clicks the button, nothing happens. Not knowing if this had something to do with the form, I added a third button to the toolbar which displays a simple message when the button in clicked. For the client, a click on this button also results in nothing happening. The addin was created using vb.net and Visual Studio 2010.  I've checked that he has the same ArcGIS 10 service pack installed that I have, and that he has the correct .net framework installed. What else could be missing on his computer?

I developed a user form that allows user to edit feature attributes in visual basic 2008. vb.net. The add-in's that I built work great on my computer, but when I tried it on another, it crashes ArcMap.  is this because the DeveloperKit is not installed on the other computer?    I manually add-in the tool (i.e., Customize, Add from file, etc) and it looks like it installs. ArcMap crashes when I click on the button though.  On my computer it work correctly using the same method.   I have uploaded the file to here:


Sir I was not able to see my login screen so I switched to shell. Whenever I enter my username and press enter, the cursor never stop or wait for me to enter password, so I can not enter my password. And a loop of login incorrect occurs for 4 times. When I am in recovery mode it's fine.

I upgraded from 16.04 to 18.04. When I press Ctrl+Alt+F3 I get the terminal which prompts for the username. When I type my username and press Enter, it doesn't wait for my password (its as if I pressed Enter without entering anything). Even if I enter something, the text shown in plaintext and then it keeps on saying my password is wrong. After few times, the screen is cleared and it prompts for my username again and the same loop goes on.


I am teaching someone basic real analysis. Working through the past exams, they've found the following problem:  Prove that $\tan x \geq x + \dfrac{x^3}{3}$ for $x \in \left[0, \dfrac{\pi}{2}\right)$.  What's the simplest way to prove it? I've found two possible solutions, but both seem too complex for the course level:   Use Taylor expansion of the $\tan$ function. While Taylor series were covered in the course, this specific one was not. Plug $x = \arctan y$, and prove that $f(y) = y - \arctan y - \dfrac{\arctan^3 y}{3}$ is monotonically increasing through derivation. This works, but it's also fairly tricky.   Is there a simpler solution that I am missing?

I proved as follows:  Let $f(x) = \tan x -  x - \frac{x^{3}}{3}.$ Then $f '(x) = \sec^{2}x - 1 - x^{2}$ and $f''(x) = 2\sec^{2}x\tan x-x > \tan x - x,$ since $\\tan x > x,$ $f''(x) > 0$ so $f'(x)$ is increasing. Since $f '(0) = 0,$ $f '(x) > 0$ for all $x \in (0, \frac{\pi}{2}).$ So $f(x)$ is increasing. since $f(0) = 0,$ $f(x) > 0$ for all $x \in (0, \frac{\pi}{2}).$  But my proof seems complex. Is there any simpler way to prove this?


I am trying to install Yeoman in my machine but i am getting the error  node outdated,when i checked my versions i got this.   node --version && npm --version  v0.10.37 1.4.28   if my versions are ok then why i am getting these error.Whats the cause for this.      Running sanity checks on your system  ✔ No .bowerrc file in home directory ✔ Global configuration file is valid ✔ NODE_PATH matches the npm root ✖ Node.js version  List item  Your Node.js version is outdated. Upgrade to the latest version: https://nodejs.org  ✔ No .yo-rc.json file in home directory ✖ npm version  Your npm version is outdated.  Upgrade to the latest version by running: npm install -g npm   Found potential issues on your machine :( npm WARN unmet dependency /usr/lib/node_modules/npm/node_modules/npm-package-arg requires semver@'4' but will load npm WARN unmet dependency /usr/lib/node_modules/npm/node_modules/semver, npm WARN unmet dependency which is version 2.3.0 npm WARN unmet dependency /usr/lib/node_modules/npm/node_modules/rimraf/node_modules/glob requires inflight@'^1.0.4' but will load npm WARN unmet dependency /usr/lib/node_modules/npm/node_modules/inflight, npm WARN unmet dependency which is version 1.0.1 npm WARN unmet dependency /usr/lib/node_modules/npm/node_modules/rimraf/node_modules/glob requires minimatch@'^2.0.1' but will load npm WARN unmet dependency /usr/lib/node_modules/npm/node_modules/minimatch, npm WARN unmet dependency which is version 1.0.0 npm WARN unmet dependency /usr/lib/node_modules/npm/node_modules/node-gyp/node_modules/glob requires inflight@'^1.0.4' but will load npm WARN unmet dependency /usr/lib/node_modules/npm/node_modules/inflight, npm WARN unmet dependency which is version 1.0.1

I have installed nodeJS on Ubuntu with following code   sudo apt-get install nodejs   Since I am a new user for ubuntu I also ran this code too  sudo apt-get install npm   Now when I type    nodejs --version   It shows   v0.6.19   I checked and saw latest nodeJS version is 0.10.26   How can I update my version of nodeJS to 0.10.26?  I tried with    sudo apt-get install <packagename>  sudo apt-get install --only-upgrade <packagename>   but no luck.


Was Daenerys' baby pronounced dead or was the body seen when it was dead? Also how does anyone that the body was Daenerys' baby? Couldn't the mid-wife have taken Daenerys' baby for her own or sold it and pretended that it died? If answered please give evidence, I already read the wikia, it didn't have a satisfactory answer.  Is there any canon evidence that either suggests that this is possible, or shows that this cannot be the case?

Did anyone read or see anything that might suggest that Daenerys' baby was not stillborn but was taken away to be raised by another since he was to be strong and a leader? There was never a sighting of this child and I wonder in the future books if this is ever brought up again or were her statements factual about his death. Also I know she had to kill her husband but I am disappointed he will not be in future seasons. A great couple!


Well I can Intuitively see that.  I am wondering If there is a neat way to prove that

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


I currently have a continuous distribution that's described as a series of trapezoids in two arrays xs and ys, which integrate to 1, as shown in the picture below.  I'm trying to find a simple way to get samples from this distribution, preferably using some special scipy function.

I have a pdf modelled as a piecewise linear function that I can represent as the sequence of pairs of real numbers standing for the points in the of the piecewise line: $\{(x_{1}, y_{1}), \dots, (x_{n}, y_{n})\}$ such that  each $x_{i}, x_{i+1}, i=1\dots n-1$ is a bin; the first two points are on the x axis, i.e. $y_{1}=y_{n}=0$, and the (trapezoid) area defined by the line is equal to 1 (it is a proper probability distribution function).  How can I procedurally sample from such a distribution? I feel like I can first determine one bin, e.g. $x_{s}, x_{s+1}$, by randomly selecting one with probability proportional to the trapezoid mass inside the bin, then how can I sample from the line defined by the two points $(x_{s}, y_{s}), ( x_{s+1}, y_{s+1})$?  Or shall I go through the cumulative distribution function? How can I derive it from the piecewise density representation of a sequence of points?


I am now freaking out about my 42-minute layover in Newark.  We are arriving at terminal C and have a flight to Quebec 42 minutes later in terminal A.  We do NOT want to have to go through security again. Since United allowed this booking, any chance I can make SURE we get to the next gate/terminal and get on our plane? Fastest Suggestions anyone. Thanks!!

We'll be arriving at Newark airport (with two kids under 7) at Terminal A and our flight connection is in Terminal C. Is that enough time to catch the connecting flight?  Update: both flights are on United.


I have the coordinates for the police stations in a city, they are grouped close together at the center and sparse towards the suburbs.  Since I do not have the shapefile for the jurisdiction of each station, I want to do a rough estimate of the area by defining non overlapping variable size and dimension polygons with the police station as the center.  Is there a standard function in R or any other open source toolkit which will do this?  If a standard function is not available what algorithms is best suited for this task?

For a point data set with temperature data I have, I want to create their Thiessen Polygons in R. So far, the only algorithm I have found is that of Carson Farmer (). I would like to know if there is a ready to use function that creates Thiessn Polygons?


I am new to stack overflow and i don't know how to add/mark reputation or points to those who answered a question in stack overflow. Can anyone give me steps? Thanks.

On Stack Exchange, users may gain a certain level of reputation.  What does reputation do? How can a user gain or lose reputation?   See also   in the Help Center  - Maximum amount of votes a user can use in a day and reputation requirements to vote.  - How to get an exact overview of the actions that got you your reputation.  - A full list of all privileges granted at each reputation level on all sites.


I am trying to write a unit test for the following method,  public static DateTime addBusinessDays(DateTime startDate, Integer numberOfDays, String businessHoursName){          Integer numberOfDaysTobeAdded = 8*3600000*numberOfDays;          BusinessHours bh = getBusinessHourSettings(businessHoursName);          Datetime endDate = BusinessHours.add(bh.id,startDate,numberOfDaysTobeAdded);          return endDate;     }      My questions are:          Why is the salesforce BusinessHours class doesn't support DML   operations?   How could I test a BusinessHours class functionality with unit   tests? (without querying the BusinessHours?)

I have written a class to calculate business hours for Case age in business hours.  The class works great my issue is when trying to write decent test code for the class.  In following testing best practices, I want to create all my own test data and not rely on existing data (seeAllDate=true).  I would assume that in order to test my different scenarios I would need to create and insert new business hours.  Normally, I would use something like the snippet below  BusinessHours newHours = new BusinessHours(     MondayStartTime = Time.newInstance(9, 0, 0, 0),     MondayEndTime = Time.newInstance(17, 0, 0, 0),     TuesdayStartTime = Time.newInstance(9, 0, 0, 0),     TuesdayEndTime = Time.newInstance(17, 0, 0, 0),     WednesdayStartTime = Time.newInstance(9, 0, 0, 0),     WednesdayEndTime = Time.newInstance(17, 0, 0, 0),     ThursdayStartTime = Time.newInstance(9, 0, 0, 0),     ThursdayEndTime = Time.newInstance(17, 0, 0, 0),     FridayStartTime = Time.newInstance(9, 0, 0, 0),     FridayEndTime = Time.newInstance(17, 0, 0, 0),     IsActive = true,     IsDefault = true ); insert newHours;   However, you cannot perform DML on business hours.  Is there a way to do this without having to use seeAllData=true?  I have searched and searched but can;t find much info on using the business hours class in test code.  Any help is much appreciated.


Sampling with replacement $N$ items from $K$, where $N \geq K$, what is the probability that each item in $K$ is selected at least once?  For example, from $10,000$ individuals, what is the probability that every birthday is represented? (assume each birthday $p = 1/365$)  I've been using simulations to work this out, but would like to know the general solution. Thanks!

Suppose Earth has been attacked by $n$ Martian spaceships and suppose that we have $m=k \cdot n$ missiles to release against the $n$ spaceships. The probability to hit and destroy each spaceship by each missile is $p$ (independent from the rest).  What is the probability to destroy all the spaceships if we release all the missiles at the same time but each missile will choose a spaceship at random?


With tools such as std::is_base_of, std::is_arithmetic, etc, is there a way we can, at run time, check if a function is available to a type?  e.g.  template<typename T> void function( T arg ) {     static_assert(std::has_function<T, "DoSomething">::value, "Type must have function DoSomething!");     arg.DoSomething(); }   Or something along those lines?

Is it possible to write a template that changes behavior depending on if a certain member function is defined on a class?  Here's a simple example of what I would want to write:  template<class T> std::string optionalToString(T* obj) {     if (FUNCTION_EXISTS(T->toString))         return obj->toString();     else         return "toString not defined"; }   So, if class T has toString() defined, then it uses it; otherwise, it doesn't. The magical part that I don't know how to do is the "FUNCTION_EXISTS" part.


I'm trying to find the Thevenin equivalent for this circuit. I'm confused how to do this, but my solution so far is:   Mesh 1: 0 = 2(I1) + 2(I0) - 2I0(volt source) Mesh 2: = ? Vth = Vab = I1 - I2 Rth = (2+4) * (2+4) / (2+4+2+4) = 3ohm    Is this in the right direction?

Well, I'm trying to find the Thevenin equivalent of this circuit:    As you can see, the only current source is a dependent source. However, the control variable is in a wire where, if nothing is connected between A and B, is \$i_\Delta = 0\$ A, and that makes the source 0 A. However, if I connect an impedance \$Z\$ to the circuit, I will have current, and a Thevenin equivalent. I don't know how to solve this problem. I've bee searching here for a while, and I found this:   . I can see how is solved that case. However, I still don't know how to apply that method to my circuit.  Any help about finding the Thevenin equivalent is appreciated n.n


I am trying to write a simple command line "word guessing game" with an Array of colors. The problem is that it won't break out of the do/while loop with my current IF statement even when the correct color is chosen.  import java.util.Random; import java.util.Scanner;  public class ColorGuess {      public static void main(String[] args) {          Scanner input = new Scanner(System.in);               String[] colors = { "red", "blue", "green", "yellow", "purple",                 "pink", "white", "black", "brown", "orange", "grey" };          String colorGuess;          Random rand = new Random();         int randColor = rand.nextInt(colors.length);         String color = colors[randColor];          System.out.printf("Guess the color: ");          do {             colorGuess = input.nextLine();             if (color == colorGuess) {                 break;             } else {                 System.out.printf("Sorry, try again: ");             }         } while (colorGuess != color);          System.out.println("You got it! The color was indeed " + color + ".");      }  }

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


I am trying to differentiate between first block and second block of code.  //first block  function xyz(){    this.callXyz=function(){      console.log('callXyz inner');    } } // second block xyz.prototype.callXyz=function(){      console.log('prototype function');    }

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


I am building a matrix calculator as a react app. I have implemented a method that shows the history of every single mathematical operation that the user used, like addition, substraction etc. The problem is that every time a new operation is called and the current matrices change than the previous ones, the history updates its content with the new values.  You can test the app on:   The matrix itself is a class, where is defined a 2d array and its size      this.matrice = [];      for(let i=0;i<arraySize;i++){         this.matrice[i]= [];         for(let j=0;j<arraySize;j++){             this.matrice[i][j]=0;         }     }      this.size = arraySize;   Then to introduce the data to the matrix I use a form:  <input   type='text'                  placeholder='0'   onChange={this.handleChange.bind(this, i, j)}   key={j}               />   The function:  handleChange = (i,j, event)=> {     event.preventDefault();     let x = event.target.value;     this.state.matriceA.setValue(i, j, value); }   By using this function, I insert the value to the matrix.  Now, every time an operation is requested, the matrices used, the operator and the matrix where the result is calculated are stored in an array. This is the function that does that:  var list = [         {             matrixA: matriceA,             operator: semn,             matrixB: matriceB,             matrixC: matriceC //result         }     ]      this.setState({         results: [...list, ...this.state.results]     })   So, the values are now stored in this.state.results and at the end I map through the entire array and display elements:  {this.props.rezultate.map((item, index) => {  ///useless stuff  })}   But the elements shown are not expected to be there, here is an example:    To see, what i am talking about, look to the bottom of the page  As you can see, the last operation, also updated the previous operations, even though it should not have done that.  I do not know what i am doing wrong at this stage, so i am looking forward to hearing from you a solution. Thanks!

What is the most efficient way to clone a JavaScript object? I've seen obj = eval(uneval(o)); being used, but . I've done things like obj = JSON.parse(JSON.stringify(o)); but question the efficiency.  I've also seen recursive copying functions with various flaws.  I'm surprised no canonical solution exists.


How to show that $\frac{\sqrt{2}}{2} \cdot \frac{\sqrt{2+\sqrt{2}}}{2}\cdot \frac{\sqrt{2+\sqrt{2+\sqrt{2}}}}{2}\cdot ... =\prod\limits_{n\in \mathbb{N}} \frac{1}{2} ~ \overbrace{\sqrt{2+\sqrt{2+...+\sqrt{2}}}}^{n}$ converges ? My approach : Let $A_n =\overbrace{\sqrt{2+\sqrt{2+...+\sqrt{2}}}}^{n}$ ; now $~~ \prod\limits_{n\in\mathbb{N}} \frac{A_n }{2} $ converges if and only if $\sum\limits_{n\in \mathbb{N}}\log \frac{A_n }{2} $ converges. By the ratio-test of the sum above we have : $\lim\limits_{n\to\infty} \bigg|\dfrac{\log \frac{A_{n+1} }{2}}{\log \frac{A_n }{2}}\bigg|=1$ which doesn't prove anything ,so how to continue from here ?

How is it possible to prove that the multiplication from 0 to n of $$\cos{(x/2^k)}$$ with $x=\pi / 4$ is $$\dfrac{\sqrt{2}}{2} \times \dfrac{\sqrt{2+\sqrt{2}}}{2} \times \dfrac{\sqrt{2+\sqrt{2 + \sqrt{2}}}}{2} \times  ...$$  I tried recurrence but got stuck


I need to query the database directly using php. I am getting my head around this an how to do this using the Drupal database abstraction layer (using db_select and db_query). I need to limit my query to nodes created in the current month. I know that the node table contains the date the node was created in the 'created' column and that this contains a date as a timestamp.   I am not sure how to get the current month and express it as a range of timestamps and return only nodes that were created between the two timestamps.  This code is working to return nodes limited by title:      $result = db_query("SELECT nid, title FROM {node} WHERE title = :title", array(':title' => $node->title));     foreach ($result as $record) {       // Do something with each $record       $mynode = node_load($record->nid);       dpm($mynode);     }   Going to the  I have tried to adapt that code to fit my query so I've ended up with:      $year_month = "2014-04";     $date = date_parse_from_format ("Y-m" ,  $year_month);     $num = cal_days_in_month(CAL_GREGORIAN, $date['month'], $date['year']);     $first_minute = mktime(0, 0, 0, $date['month'], 1, $date['year']);     $last_minute = mktime(23, 59, 59, $date['month'], $num, $date['year']);     $entity_type = 'node';     $result = db_query("SELECT nid, title FROM {node}  WHERE created = :created", array($first_minute, $last_minute), 'BETWEEN'));    foreach ($result as $record) {      // Do something with each $record      $mynode = node_load($record->nid);      dpm($mynode);    }   So I worked it out, but as this question has been marked as a duplicate i cannot provide this in an answer, but here we go:  I needed to get the syntax of the between part of the query correct. Working code is:       $year_month = "2014-05";     $date = date_parse_from_format ("Y-m" ,  $year_month);     $num = cal_days_in_month(CAL_GREGORIAN, $date['month'], $date['year']);     $first_minute = mktime(0, 0, 0, $date['month'], 1, $date['year']);     $last_minute = mktime(23, 59, 59, $date['month'], $num, $date['year']);      $args = array(':first_minute' => $first_minute, ':last_minute' => $last_minute);      $result = db_query("SELECT nid, title FROM {node} WHERE created BETWEEN :first_minute AND :last_minute", $args);        foreach ($result as $record) {          // Do something with each $record          $mynode = node_load($record->nid);          dpm($mynode);        }

I have a custom search form that I posts a year + month, such as 2014-04 I would like to get all nodes created that month, when I create the timestmap I use: "SELECT .......         AND changed >= 'strtotime($date)'"  This is the code for form date:  $form['aqar_date'] = array( '#type' => 'date_select',  '#title' => t('Date'), '#prefix' => '

Node date
', '#suffix' => '
',      '#date_format' => 'Y-m', '#default_value' => date('Y-m'), '#date_year_range' => '-4:+0',  );   This is the form submit:  $start_date = strtotime($date); $query = " SELECT `nid` FROM `node` WHERE  `type` = 'custom'  AND `changed` >= '$start_date'";   But I'm not getting, I need a way to specify to only this month period not this month and newer!  Thanks!


I have read that a standard way to do  is that the male and female are separated and the pigeon races to its mate.  My understanding that in these cases the roost is several miles away from the release point. How does the pigeon know how to find the roost?  I have heard that sometimes they will hold up the mate in the air, but at several miles away, how would that help.

Homing pigeons (Columba livia) have been prized for their navigational abilities for thousands of years. They’ve served as messengers during war, as a means of long-distance communication, and as prized athletes in international races. ()   Do all homing pigeons just pick a direction, and fly "straight" home, or do they all follow certain "tunnels" or "roads" to get closer to their home area, before heading home? (similar to cars getting on a highway between two regions)  Does any information about that exist? I'd be interested to know if pigeons released in the same area (with different target locations in one common direction) tend to do follow the same paths, or if it's just a chaotic crisscross.


So I installed it on a dual-boot on my Main drive, with the intention of this space being for the os and a few programs as this is my SSD with less space. I went back later and used GParted to make another partition for stuff I want to install on ubuntu on another hard drive, I have done this, and now I'm back in Ubuntu but I can't do anything to the drive as the owner is root.   I've looked online for help with this but all I can find is how to edit individual files on a root drive. how do I permanently become the owner?  if relevant the file system type is ext3/ext4

I have a number of drives internal and external. Some are partitioned. Most mount automatically at boot (all did at one point).    One partition is owned by root and therefore does not mount automatically. I know how to mount it as root.   I do not know how to take ownership of that partition as user X. I have tried changing permissions using the gui in Nautilus as root. They are not accepted and immediately revert.  The partition is NTFS. The other parition on that drive is owned by me as user and mounts automatically


I recently read about the false inductive proof that all horses are the same colour. There are some mathSE threads about this already (, ).  After reading this, I now realise I have never really understood mathematical induction. It seems obvious for sums, but when presented with this example I was stumped.  I have some questions:  Question 1. The inductive step   for all horses are the same colour goes roughly as follows:      Assume that there are n horses, numbered 1 to n. By induction horses 1   through (n-1) are the same colour, and similarly horses 2 through n   are the same colour. The overlapping sets H_0 = {1,2,...,(n-1)} and   H_1 = {2,3,...,n} imply that horse 1 and horse n are the same colour.   Thus all horses are the same colour.   I have an issue with one of the statements:      By induction horses 1 through (n-1) are the same colour, and similarly horses 2 through n are the same colour.   I understand why horses 1 through (n-1) are the same colour (by hypothesis), but why can we just say horse n is the same colour? It seems to imply the numbering is arbitrary to me, but then induction is completely invalid unless we can define an order?  Question 2. The base case:   If we grant the inductive step reasoning (of which I am unsure whether that is valid), the induction relies on the fact that for some k, two distinct k-1 subsets have shared elements, from which we can conclude they are all the same colour. So the base case should be n=2 (or should it be n=3?).   However the trick used in the inductive step seems to imply the numbering of the horses is arbritary (as I briefly mentioned above), so a subset of size n=2 would seem to require we prove all subsets of size 2 have horses which are the same colour, which makes the induction step redundant?  General Question 3.   How do we choose what inductive steps are valid, and what base cases are required? I realise this is poorly phrased, but is there a way in general, or a set of heuristics to enable a valid basis to be chosen?  A slightly modified version of Mathematical Induction that seems to me more intuitive  Perhaps my understanding of induction is incorrect. It seems to me mathematical induction is more intuitive when presented as follows:     For each positive integer n > n_0, Let p(n) be a statement.      Step 1. We first show that If p(k) then p(k+1) is true for every   positive integer k. To do this we choose an arbitrary k and show, by   direct proof usually, this implies (k+1)      Step 2. Choose a base case n_0 on which we induct on to all n > n_0.   Here we use the fact that we have shown that for an arbritrary k, k+1   is implied. Choosing a valid basis allows the "induction domino   effect" to work its magic.      Then we have shown p(n) is true for every positive integer n > n_0   That seems to me easier to understand. Although do we need to explicitly show our base case implies n_0 + 1?   I suppose this is a different way of asking the same question I asked above, namely how do we choose valid base cases?  Hopefully this question isn't too rambling. Please let me know if anything requires clarification.

I'm bugged by the following that's summarized on p. 109 of .     False theorem: All horses are the same color.      Proof by induction:      $\fbox{$P(n)$ is the statement: In every set of horses of size $n$, all $n$ horses are the same color.}$   $\fbox{Base Case or $P(1)$:}$ One horse is the same color as itself. This is true by inspection.   $\fbox{Induction Step:}$ Assume $P(k)$ for some $k \geq 1$.   $\fbox{Proof of $P(k + 1) :$}$   Since $\{H_1, H_2, ... , H_n\}$ is a set of $n$ horses, the induction hypothesis applies to this set. Thus, all the horses in this set are the same color.   Since $\{H_2, H_3, ... , H_{n+1}\}$ is also a set of $n$ horses, the induction step likewise holds for this set. Thus, all the horses in this set are the same color too.         Therefore, all $n +1$ horses in $\{H_1, H_2, H_3, ... , H_n , H_{n+1}\}$ are the same color. QED.   The issue the instructor was trying to point out is clearly valid. For the case $n = 1$, there is only ${H_1}$. So this case says nothing about possible overlapping elements of each set of $(n + 1)$, for instance $H_2$ in the above proof.    But it was proposed in the class discussion that this was the only problem. Had you been able to prove $P(2)$ true, then a proof of the above format would have been fine.    My interpretation is that yes, you could prove all horses are the same color, if you can prove that any set of two horses will be the same color. But this format would not work.  Why not? The problem I see is that the above proof is for the existence of at least one particular pair of sets of horses of sizes $n$ and $n + 1$, such that in each set, all horses are the same color.  Particularly when the set of size $n$ is a subset of the set of size $n + 1$.  In order to prove the induction step, don't you need to prove that sets of sizes $n$ and $n + 1$, do not necessarily contain the same, overlapping elements?  You could prove that any horse can be added to a set of 2 horses.  Take the last two, and they must be the same color, and so on.  Wwhatever color the first two happen to be, all other horses must thus be the same color.    Am I misinterpreting the example, or am I making a logical error? Thanks in advance.


The need we have is to pass encrypted messages but such that the encryption key can't be generated from the decryption key.  This sounds like with vanilla asymmetrical crypto I know, but in every schema I've seen, one can generate public key from the private key in a reasonable order of time.   Use case: we have a network processing daemon that we want to be able to decrypt encrypted traffic headers during routing but in the event the machine is hijacked/rooted/stolen, we want to mitigate the loss and not have an adversary have the ability to effectively author/encrypt anything.  Or perhaps there is a way to combine multiple schemas?  The daemon needs to have some kind of secret in order to decrypt the message headers -- so we're saying that secret gets leaked somehow. Unless what this question poses exists, the only choice would be to use a symmetric key, allowing all nodes on the system to be able read message headers. However, this would allow a rooted/stolen node to author fake messages -- not ok! Well, how about we add-on a signing scheme then... That means nodes would have individually-issued signing keys (that would be revoked/blacklisted when a node is known to be compromised). The problem is, in the mean time (seconds or days), a compromised node would still be able to author fake messages. This question is about a schema that is the "mirror" of canonical asymmetric encryption (where the "public" key can ONLY decrypt and the "private" key can only encrypt or do both).    Terminology accuracy note: I say the "public" key is used "only to decrypt", but it's obviously not public -- it's also held as a secret.  In the p2p node example, nodes would hold a set of "community" keys.  When a node is community decided to be compromised, a successor community key is generated and distributed using a traditional asymmetrical schema (except that the nodeID of the node that got stolen and of course not issued the successor key).  In effect, the compromised shared community key is no longer used and replaced with a new one.   ...or, the solution can be canonical asymmetric encryption, but it has to have the property that the encrypting key cannot be derivable from the decrypting key.  This is a far from trivial question and is why the "non-derivable" part of the question is so...key.  :\

I'm in the need of an inverse public-key encryption method where you encrypt with the private key and decrypt with the public key. In other words an asymetric encryption where you can't generate the encryption key from the decryption key. Does such encryption exist? If yes which, and which would be the fastest?  If nothing like that exists I would be glad if you helped me out with my situation:    I need to authenticate users logging in from my Java application in the way that the response from the server cannot be falsified and thus giving the user full access to the application. Using public key encryption was an obvious method, I would decrypt data received from the client to confirm the credentials. This won't work because if someone manages to decompile and get the private key from the code, they would be able to generate the public key, which would make them able to crack my application again. So any ideas how I can get this secure?


at work we have a lot of PHP based aplications and all of them runs at PHP 5.2, I'm making my wayt to update them all to PHP 7 but i come to problem as all queries were done via mysql method. I wanted to remade them into prepared statements, but my boss told me to just strip input from special chars and use regular queries. I want to ask if that aproach is secure enough.

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


Yoda is teaching a group of younglings in AotC:    Isn't that equivalent to handing them chainsaws without protection?

In learning to sword fight, Japanese samurai used wooden replica swords and medieval knights used blunt swords (which were safe enough to use on plate armour). However, lightsabers 'handle' very differently to a physical objects like sticks and swords; so how do Jedi (and Sith) learn and maintain their skills of lightsaber duelling?  Is there a non-lethal 'practice' lightsaber that can be used on a training partner safely? I know the movies backwards, and this is clearly not covered (apart from Luke training to block mini blaster shots from a floating droid, but that's a far cry from a lightsaber duel). On the other hand I have zero knowledge of any books and TV series. Is there is any of this material a clear depiction of Jedi (or Sith) learning to duel by 'sparring' in some way that emulates a real duel without the lethal danger?


Possible Duplicate:      I need a way to know the name of calling methods in C#.  For instance:    private void doSomething() { // I need to know who is calling me? (method1 or method2).  // do something pursuant to who is calling you? }   private void method1() {  doSomething(); }  private void method2() {  doSomething(); }

When logging in C#, how can I learn the name of the method that called the current method? I know all about System.Reflection.MethodBase.GetCurrentMethod(), but I want to go one step beneath this in the stack trace. I've considered parsing the stack trace, but I am hoping to find a cleaner more explicit way, something like Assembly.GetCallingAssembly() but for methods.


It used to be that when a question was flagged for closing, if the question was closed, the flag was automatically marked as "helpful." Since the recent closing overhaul, I have seen at least a couple questions that I have flagged get closed, without any action taken on the flag. Is this the intended behavior?  I am tagging this as a bug because I do not remember seeing any discussion of this behavior changing.  Example:  I flagged  for closing on Islam.SE. Nobody acted on my flag for a few hours. I mentioned it to one of the mods in chat, and he said that he never saw my flag, but after I linked to the question, he closed it. Currently, though, the flag still seems to be open in my list of flagged posts. The mod says that, as far as he can tell, nobody has taken action on the flag.

I flagged  five days ago because it seems off-topic to me. The question has been closed by a moderator few minutes after.  However my flag has not been marked as helpful (or declined, or disputed) in my flags summary page. It's just like the flag has not been taken into account (screenshot below).    Is a moderator can explain me?


I noticed this behavior on SO, this is the case:   A user opens a bounty for a question (let's say 300 points) This questions tends to be more difficult compared to a regular question The user get a good quality answers The user answers it's own question based on the answer he got from other people   According to this       half amount of bounty will be awarded to the answer that is given   after bounty is placed and has highest votes   so is there could be the case to get more votes on it's own answer and get the points back? to me that could considered as some way of cheating, is there any way to prevent this?

It's possible to offer and award bounties of reputation on questions.   What is a bounty? How can I find questions that have a bounty attached? How do I start a bounty? When can I start a bounty? Why is the system requiring me to choose a bounty amount that's higher than the minimum? Can I use Markdown formatting in the bounty remarks? Can I edit the remark? How long is the bounty period? How do I award a bounty? Can I award a bounty to my own answer? Can I award a bounty to an old answer? If I offer a bounty on someone else's question, can I award the bounty to their answer? After awarding the bounty, can I remove it or move it to another answer at a later time? What happens if there's no answer after the bounty period? What happens if I feel my question is still unanswered? What is automatic awarding? Are bounty awards exempt from the 200 points/day reputation limit? How does Community Wiki mode affect bounties? How does user deletion or post dissociation affect bounties? Can I award a bounty to an answer from a deleted user or one where the author was dissociated? Can I offer a second bounty after the first one has expired? Can I raise my bounty? What happens if a bounty question is closed or deleted? Why can't I vote to close or migrate a bounty question? What happens if I delete my account while I have an active bounty? Do I keep an awarded bounty when I delete my answer? What happens if a question where I awarded a bounty later gets deleted or migrated? Can I cancel my bounty? Can I affect / divide / share part of my bounty to two (or more) users? How many outstanding bounties can a single user have?      See also:  in the Help Center


I can understand there being a cost difference if you used gas vs electricity to heat your home.  But for heaters using the same energy source, how can they be more or less efficient than each other?  I always thought that heat is generally a product of inefficiency. A halogen lightbulb is wasteful because for it to be bright, it radiates a lot of heat.  But I often hear the claim that cheap heaters will consume more energy. For example, this website () claims "The cheaper the electric heater, the less efficient it's likely to be”.   This is not the only place I’ve heard this. People often recommend certain types of heaters or certain brands of heaters to save on heating costs.  So if this is true, how is this inefficency caused and where is the energy lost to?

How efficient is an electric heater?   My guess: greater than 95%. Possibly even 99%. I say this because most energy is converted into heat; some is converted into light and kinetic energy, and possibly other forms of energy.  Anyone other opinions? (This is not homework. I am just curious and I'm having a discussion with a friend who says an electric heater is horribly inefficient, less than 5%.)


i am pakistani national residing in oman. i am travelling to schengen area with my family, while coming back to oman from france we have to stay at heathrow airport for 21h 50m, can I get transit visa on heathrow air port?

Is there a website or some other way to find out if I need a transit visa for a short stop in the UK on my way somewhere else? Ideally this should give me the answer for all nationalities, and take into account any other visas I may have.


Square $ABCD$ has area $1cm^2$ and sides of $1cm$ each.  $H, F, E, G$ are the midpoints of sides $AD, DC, CB, BA$ respectively.  What will the area of the square formed in the middle be?  I know that this problem can be solved by trigonometry by using Area of triangle ($\frac{1}{2}ab\sin{c}$) but,  is there another method or visual proof?

If the lines intersect the vertices of the square. The area of the square is $1$ and the lines also intersect the midpoints of the square lines. How to find the area of shaded region?


My phone is bringing me tó write the google account which was previously synced into the phone but this was not mine í just bought it from someone.how can í do?

I won a Samsung Galaxy S6 Edge, signed into it with my Google account, played around with it, wiped it, and sold it.  Now the person can't get past setup because it's saying he must login with an account previously synced to the phone.   Is there anything I can do from my side to remove this lock?


I was recently reading some of the nice answers to the (related) question:   From many of the answers their appears to be a symmetry between:   A universe in which all matter-things (plus light) remain the same size, while the space between them expands. (The one we appear to live in) A universe where the space remains the same size and all objects in the universe shrink. Along with an appropriate change in physical length-scale constants. (One equally compatible with our observations?)   Said another way: At one point in time your ruler fit between those two galaxies $10^{50}$ times, now it fits between them $10^{51}$ times. This is usually explained as the space growing, I believe it could equally well be described by the ruler shrinking.  Is this symmetry obeyed? Are their any cosmological models presented in terms of matter shrinking?

Is there a physical reason why not to think that instead of space expanding, all physical constants and parameters are shrinking (including of course the instruments we use to measure the constants) and space is static, or is it a case of Occam's razor?


I recently noticed lots of questions have a typo in their content such as 'WodPress' instead of 'WordPress'. However, when I attempt to edit the typo, an error message is displayed on screen:     Edits must be at least 6 characters. Is there something else to   improve in this post?   What should I do if there is nothing else to improve? I'd still like amend the typo.

I just attempted to fix a typo on a question on cooking.stackexchange.com and saw this     Oops! Your edit couldn't be submitted because:         Your edit summary must be at least 10 characters   This edit is less than 6 characters; surely more can be improved with your edit?      So, misspelled words have to just be left misspelled?  That could prevent the post from being found in a search.


I am managing a small network of about 15 Windows 8.1 computers/users. None of these users have local admin rights (because I don't want to spend 24 hours a day removing viruses and malware from the computers)  We use a softphone for communication from a company called 8x8. The software is great and does NOT require admin rights to run, however, they do put out new releases about once a month or so. When this happens, in order to upgrade the software to the latest version, I have to physically go to the computer and use a local administrator password to allow the upgrade to occur.   I am hoping there is a way to essentially "trust" or "whitelist" a specific running program to allow that program to be upgraded directly from the local user account (who does not have admin access)  For what it is worth, this specific software does check for updates and starts the update from (what appears to me) to be inside of the program. Meaning, I do not have to go to a website, download a .exe file and run it. If this was the case, I can see where it might be harder, since I doubt there is a way to whitelist a certain .exe file by name or something like that.  Any ideas?

At my workplace, Windows 7 machines are being rolled out, and users are not being granted administrative privileges.  My department creates applications that run locally on the user's machine, and those are working normally (as far as we've seen).  One application, on the other hand, does not.  It's the application that updates the others (our 'Update Agent').  So, when the user runs the Update Agent, they're immediately stopped with an error, since that application was not able to write to C:\Program Files\our app\  We need a way for these Windows 7 machines to allow this application to be run as administrator or with admin rights when the user executes them.  Since these users will never be given the administrator password, 'Run As Administrator' is not an option.  The user will need to click on shortcut, and it run with enough permissions to modify that folder, write to the registry, etc.  What I'm hoping for is some kind of GPO or policy or something that can be configured on the domain level that will allow this to occur; or, something configured on the client machines once.  Our applications are .net Framework 1.1 and 2.0, and signed with a key.    Any insight would be appreciated.


I want to use wrapfigure in the enumerate environment. For example,   \documentclass[11pt, a4paper]{article} \usepackage{graphicx} \usepackage{float} \usepackage{wrapfig}  \begin{document} \normalsize {\bf Multiple Choice: } \begin{enumerate}     \item \begin{wrapfigure}{r}{4.5cm}           \includegraphics[scale=0.5]{Exam1_Fig1.jpg}           \end{wrapfigure}           As shown in the figure. This rock is phaneritic and contains quartz, K-feldspar, and plagioclase in nearly equal amounts. What is it? \\           (A) rhyolite \\           (B) basalt \\           (C) diorite \\           (D) ash-flow tuff \\           (E) granite \\ \end{enumerate} \end{document}   However, the figure inserted is not wrapped by the text, but put in a strange position. How to fix the problem?   Thank you!

is incompatible with the enumerate and itemize environments. Is there a typographical reason not to wrap a list around a figure or is it a technical limitation of LaTeX? If it is a technical limitation, is there any work (new packages or changes to LaTeX) currently being done to eliminate the limitation in the future?  Edit: To respond to some of the comments: I realize that there are "gymnastics" which can make this work. I do not have an example of the problem. Whenever I run into a problem with wrapfig because it is near an enumerate or itemize environment, I search for an easy solution, find none, and move the figure elsewhere. In the vast majority of cases, the cost of learning the complex solutions isn't worth the benefit of keeping the figure where I want it.


It seems very intuitive and simple, but how would I go about proving something like this? Thanks.

Show that every uncountable set of real numbers has a point of accumulation.


How to prove that $\lim_{(x,y) \to (0,0)} \dfrac{x^3y}{x^4+y^2} = 0?$   First I tried to contradict by using $y = mx$ , but I found that the limit exists.  Secondly I tried to use polar coordinates, $x =  \cos\theta $ and $y = \sin\theta$,  And failed .. How would you prove this limit equals $0$?

I have some trouble with this: Show that if $a, b \ge 0$, $c, d > 0$ and $\frac{a}{c} + \frac{b}{d} > 1$ then   $$\lim_{(x,y)\rightarrow (0,0)}\frac{\left|x\right|^a\left|y\right|^b}{\left|x\right|^c + \left|y\right|^d} = 0$$  we were not really shown how to evaluate multivariable limits other than trying different paths, which wouldn't work when the limit exists, or by applying the squeeze theorem which is my initial plan. Unfortunately I cannot find a proper bound for the denominator and so I am quite lost right now. Any help would be appreciated.


I'm stuck on this for 2 hours. Can't start with R.H.S also due to less no of variables.      Q. $(p \land q \land \neg r) \lor (p \land \neg q \land \neg r) \equiv p \land \neg r$   Here I started:       $(p \land q \land \neg r) \lor (p \land \neg q \land \neg r)$  $p \land (q \land \neg r) \lor p \land (\neg q \land \neg r)$ using Associative Law  $p \land (\neg q \land \neg r) \lor p \land (q \land \neg r)$ using Distributive Law    What else can we do with it? Any idea? Much appreciated.

The distributive property is very simple and it says p ∧ ( q ∨ r ) ≡ ( p ∧ q ) ∨ ( p ∧ r ), but here how is (p ∧ q ∧ ¬r) ∨ (p ∧ ¬q ∧ ¬r) ≡ (p ∧ ¬r) ∨ (¬q ∧ q) which someone told me is according to the distributive property, but I didn't get it.    In simple words, can someone please tell me in parallel & exactly how this proposition (p ∧ q ∧ ¬r) ∨ (p ∧ ¬q ∧ ¬r) ≡ (p ∧ ¬r) ∨ (¬q ∧ q) matches the distributive property p ∧ ( q ∨ r ) ≡ ( p ∧ q ) ∨ ( p ∧ r )? What each variable in distributive property means in that proposition. Million Thanks!


The question is basically about section 47. in Landau's Quantum Mechanics (non-relativistic theory)      everything is fine until the sentence (at the beginning of the second page) where he says: it is evident a priori that, as a result of passing...  My first question is how does he get that the second term dominates (if the contour goes over the upper half of the plane) that is that the first term dominates if we go through the lower part of the plane (what is the argument for this?)  secondly if we go in a semi-circle $x$ should be of the form $x=re^{i\phi}$   meaning if we make a semi-circle we should get  $$\frac{C}{2(2m(U(xe^{i\pi})^{1/4}}\exp{(-\sqrt{2m}/\hbar \int_a^{xe^{i\pi}}\sqrt{U(x')-E}dx')} $$  I see how he gets the $Ce^{\pm i \pi/4}$ but what happens with the $e^{i\pi}$ in the upper limit of the integral. Am I missing something? (I probably am because it is very unlikely that Landau is missing something and I  ain't)  Now that I think of it how does he get the $\pi$ factor anyway, It kind of makes sense because we are moving half-circle but I when I write it in the integral it doesn't seem to make sense.  I can't seem to comprehend what he is doing mathematically in this step  (note* I do have some understanding of complex analysis, It's not perfect but I know about branch cuts, the residue theorem and stuff like that)

Background of the question (see pp. 161, section 47 in Landau & Lifshitz's quantum mechanics textbook Vol3, 2nd Ed. Pergamon Press). We have the following potential well $$U(x)\leq E \quad\text{for} \quad x \leq a ,$$ $$U(x)>E \quad\text{for} \quad x>a .\tag{47.0}$$ The WKB solutions right and left to the turning point are $$\begin{align}\psi=&\dfrac{C}{2\sqrt{p}}\exp{\left(-\dfrac{1}{\hbar}\left|\int_a^x pdx\right|\right)} \cr &\quad \text{for} \quad x>a, \end{align}  \tag{47.1}$$ $$\begin{align} \psi= & \dfrac{C_1}{\sqrt{p}}\exp{\left(\dfrac{i}{\hbar}\int_a^x pdx\right)}\cr +&\dfrac{C_2}{\sqrt{p}}\exp{\left(-\dfrac{i}{\hbar}\int_a^x p dx\right)}\cr &\quad \text{for} \quad x<a,\end{align} \tag{47.2}$$ respectively. Most quantum mechanics textbooks determine the relation between $C$ and $C_i$'s by finding the exact solution near the turning point. And then let the exact solution match with the WKB solutions. However, in Landau & Lifshitz's quantum mechanics textbooks (vol3, section 47) they let $x$ vary in the complex plane and pass around the turning point $a$ from right to left through a large semicircle in the upper complex plane. Landau claims starting from +$\infty$, when arriving at $-\infty$ (left to $a$), there is phase gain $\pi$ in the denominator of prefactor in Eq.(2). From this we can determine $$C_2=\frac{C}{2}\exp\left(i\frac{\pi}{4}\right).\tag{47.4a}$$ They also claim the first term will exponentially decay along the semicircle in the upper half plane. Question is why? Can we show $$\Im{\left(\int_a^x pdx\right)},$$ where $\Im$ stands for the imaginary part, is positive?


Please advise me my excel files are not changing like previous version i had, now I am pressing alt + two times tab in excel for go back to my previous windows i tried my best to reach out from this but i found no solution regarding this matter , kindly check and give me any solution if available.

In other apps, when I hit Alt+Tab it switches to the previous app.  Before I actually release the Alt key I can see a list of windows as well and the previous windows is selected.  But in Excel 2010 (Professional Plus, if that makes any difference) hitting Alt+Tab and not releasing Alt shows Excel still selected, and in any case I have to hit Tab an extra time to switch to the previous application.  (Alt+Tab+Tab)  Furthermore, the iconized view showing my spreadsheet only takes up about 1/3 of the height available.  Needless to say this throws off my workflow because switching between Excel and another application is inconsistent, requiring an extra keystroke to switch away but not to switch back.  Is this a bug in Excel, or is there some option that I need to change to get the default behavior?  What's going on here?


Show that, if $S_1$ and $S_2$ are subsets of a vector space $V$ such that $S_1 \subseteq S_2$, then $span(S_1) \subseteq span(S_2)$.    A (hypothesis): $S_1$ and $S_2$ are subsets of a vector space $V$ such that $S_1 \subseteq S_2$.  B (conclusion): $span(S_1) \subseteq span(S_2)$  A1: Let $S_2 = \{x^n, x^{n - 1}, ..., x^0\}$  A2: $span(S_2) = \{a_nx^n + a_{n - 1}x^{n - 1}+ ... + a_0 : a \in F \}$  A3: Let $S_1 = \{w^n, w^{n - 1}, ..., w^0 \}$ where $w = a_nx^n + a_{n - 1}x^{n - 1}+ ... + a_0$.  $\therefore$ The elements of $S_1$ are linear combinations of $S_2$.  A4: $span(S_1) \subseteq span(S_2)$  $Q.E.D.$    I would greatly appreciate it if people could please take the time to review my proof for correctness. If there are any errors, then please explain why and what the correct solution is.

If X and Y are two sets of vectors in a vector space V, and if X $\subset$ Y, then is span X $\subset$ span Y? If so, why is or isn't the span of X a subset of the span of Y?  EDIT:  Thank you for the hints! Here is the proof I came up with; please let me know if it is correct.    The spanning set of X can be written as: Span(X) = {$a_1 x_1 + a_2 x_2 + ... + a_n x_n$} where all $x_i$ are vectors and all $a_i$ are scalars. Since X$\subset$Y then all $x_i$ are also in Y. Thus, Span(x) is a linear combination of vectors from Y So Span(x) $\subset$ Span(Y).


The anime Bleach has to do with soul reapers and stuff, but not actually Bleach. So, I'm not getting why it's called Bleach. Mind explaining, anyone?

The name "Bleach" seems to be having no relevance to the plot unlike most other series. Was it just chosen at Kubo-sensei's whim or does it have some significance? Maybe some cultural significance associated with shinigami, etc. that I am now aware of?


I have an issue with translation of custom labels...  How to translate custom labels into other(sweedish, german,.......) languages.. Default language for my org is ENG.  How to get the translation text for custom labels?? For Ex: i have one custom label  Online Help ... how to translate these custom label into german?????  Any one can help me how to translate????

I want to make my appexchange app available in multiple language like Spanish, dutch etc. so that depend on the language of the user they can access the app.  Is it possible in any way..  any help will be appreciated.. Thanks


I've got a problem with removing items from List in RecyclerView. It contains list of checked items. I want to uncheck one item of the list.   So, method removeGroupItem() removes item from list of checked items. Here it is:  private void removeGroupItem(String groupId) {     for (String group : pickedGroups) {         if (group.equals(groupId))             pickedGroups.remove(group);     } }   If I tap very fast 2-3 times on some item - it crashes.  Here is stacktrace:  java.util.ConcurrentModificationException         at java.util.ArrayList$Itr.next(ArrayList.java:860)         at com.camness.vidimguploadjun2016.trips.group_adapter.GroupsAdapter.removeGroupItem(GroupsAdapter.java:76)         at com.camness.vidimguploadjun2016.trips.group_adapter.GroupsAdapter.access$300(GroupsAdapter.java:16)         at com.camness.vidimguploadjun2016.trips.group_adapter.GroupsAdapter$GroupViewHolder.lambda$new$0$GroupsAdapter$GroupViewHolder(GroupsAdapter.java:65)         at com.camness.vidimguploadjun2016.trips.group_adapter.GroupsAdapter$GroupViewHolder$$Lambda$0.onClick(Unknown Source:2)         at android.view.View.performClick(View.java:6303)         at android.widget.CompoundButton.performClick(CompoundButton.java:134)         at android.view.View$PerformClick.run(View.java:24828)         at android.os.Handler.handleCallback(Handler.java:789)         at android.os.Handler.dispatchMessage(Handler.java:98)         at android.os.Looper.loop(Looper.java:164)         at android.app.ActivityThread.main(ActivityThread.java:6798)         at java.lang.reflect.Method.invoke(Native Method)         at com.android.internal.os.Zygote$MethodAndArgsCaller.run(Zygote.java:240)         at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:767)   Thank you all in advance for any help.

We all know you can't do the following because of ConcurrentModificationException:  for (Object i : l) {     if (condition(i)) {         l.remove(i);     } }   But this apparently works sometimes, but not always. Here's some specific code:  public static void main(String[] args) {     Collection<Integer> l = new ArrayList<>();      for (int i = 0; i < 10; ++i) {         l.add(4);         l.add(5);         l.add(6);     }      for (int i : l) {         if (i == 5) {             l.remove(i);         }     }      System.out.println(l); }   This, of course, results in:  Exception in thread "main" java.util.ConcurrentModificationException   Even though multiple threads aren't doing it. Anyway.  What's the best solution to this problem? How can I remove an item from the collection in a loop without throwing this exception?  I'm also using an arbitrary Collection here, not necessarily an ArrayList, so you can't rely on get.


let $A, B, C$ be sets so $B\cap C = \varnothing$. prove that $A^{B\cup C} \sim A^B\times A^C$.  I don't know how to start with solving this question. I know we need to define a function $A^{B\cup C} \to A^{B}\times A^{C}$ that is a bijective function but can't think of one. I'm looking for a simple function that can prove this theorem.

Let $A,B,C$ be sets, and $B \cap C=\emptyset$. Show $|A^{B \cup C}|=|A^B \times A^C|$ by defining a bijection $f:A^{B \cup C} \rightarrow A^B \times A^C$.  Any hints on this one?  Thank you!


I would like to turn a cylinder into a neon light tube with emission. My problem is, for the sake of realism I would like to be the inner part of the cylinder brighter than the outside. (like a neon tube light in rela life). So far I have tried to connect a gradient with a color ramp before the emission shader, but I can't get it right. I am working in Cylces btw.

I have been searching everywhere, and I can't find an answer so I'm coming here!  I'm trying to create a CFL Blacklight bulb. I've attached a couple images below of what I've tried to make. I'd love to have an effect like this:    Does anyone know how to recreate this? It seems like the color is affected by time as the bulb heats up, eventually being all white-ish. That would be fine, too, but I can't even seem to get the lighting effect of the pink glow around it and whatnot. I can post pictures of my node setup if you need it, though I think I made it necessarily complicated.  Thanks in advance!  UPDATE: This is what I have now:   I want to adjust the colors, but that isn't the issue now... The way I made this is a glass spiral that acts as the bulb. Inside of that bulb (that has a glass-like shader) is a purple material that I made that mimics the phosphor coating blacklight light bulbs have to filter light. Then, a separate mesh spiral is inside of that, and it has the emission stuff on it.   As Duarte suggested, I used the node setup he had for my emission, but used a transparent node instead of glossy. Why isn't the emission light from inside my glass causing the glass to be glossy? If I put a point light in the scene, it looks glossy.   Thanks in advance!


How do I calculate $A=UL$ factorization where $U$ is upper triangular matrix with 1's along the diagonal and $L$ is lower triangular matrix?   How is this similar to the $LU$ factorization?

Let $Q$ be the $n$x$n$ permutation matrix  $$Q= \begin{bmatrix} 0&0&...&0&1\\ 0&0&...&1&0\\ .& \\ .&\\ .&\\ 0&0&...&0&0\\ 1&0&...&0&0\\ \end{bmatrix}$$  If $L \in \mathbb{R}$ is lower triangular, what is the structure of $QLQ$? Use this to show that one can factorize $A=UL$ where $U$ is unit upper triangular and $L$ is lower triangular.  I can see that $QLQ = L^T$  And $Q^2=I$  So here's what I am doing  $A=LU$  $QAQ=QLUQ = QLQ^2UQ =QLQQUQ = UL$  But now I am left with $QAQ = UL$ rather than $A=UL$  But does that matter?  It seems like it does as the factorization I get would be for solving $A^Tx=b$ rather than $Ax=b$  So have I missed something, is there a way to get the factorization $A=UL$ or have I actually got it but it's the case that I am misinterpreting my answer?


For example, "Lucy and I are going to a movie" vs. "Myself and Lucy are going to a movie" vs. "Lucy and myself are going to a movie"

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


A list is a sequence of one or more pipelines separated by one of the   operators ‘;’, ‘&’, ‘&&’, or ‘||’, and optionally terminated by one of   ‘;’, ‘&’, or a newline.   I can't find an explanation, what does semicolon (;) do after the last command. For instance, what's the difference between the following two commands:  a;b;c  a;b;c;  ?

I often see tutorials online that connect various commands with different symbols. For example:  command1 |  command2 command1 &  command2 command1 || command2     command1 && command2   Others seem to be connecting commands to files:  command1  > file1 command1  >> file1   What are these things? What are they called? What do they do? Are there more of them?    .


I have a code that already searches for the latitude and longitude and pastes to my worksheet, which works perfectly. I'm looking for a way to take that latitude and longitude, load google maps, and either take a screenshot of the google maps page or embed the map into Excel.   In my code below I have a code that already loads google maps for any input address, but I do not know how to either take the screenshot of the map (preferably without the input information on the side of the page) or embed the map into Excel. The extra code at the bottom is for a request/response from a USGS website that pulls official seismic information for a location, but should not effect the top part of the code.  Please note that I want this to just be a static screenshot of the map if possible. I do not want to install Google Earth on multiple desktops to be able to embed an interactive map into the worksheet if at all possible.  Option Explicit  Public Sub Seismicgrab()  Dim browser As New ChromeDriver Dim URL As String Dim ws As Object Dim xmlhttp As New MSXML2.XMLHTTP60  browser.Get "http://www.google.com/maps?q=" & Range("H13").Value  browser.Wait 5000  Cells(19, 13).Value = browser.URL  browser.Close  URL = Range("M24").Value xmlhttp.Open "GET", URL, False xmlhttp.Send Worksheets("Title").Range("M25").Value = xmlhttp.responseText End Sub

Is there any way, using the scripting available to Excel 2007 to display a Google Earth map inside a sheet?  I've used Excel to house the data that I've then gone and generated a KML file to load into Google Earth, but now they want to see a pretty little cell with a client address mapped out in Excel directly to pretty up the presentation.


Just as the title says. I'm pretty new to Ubuntu, but I've used it before about a year ago. I had help then, but now this seems pretty confusing. I've already read the  article, I'm currently trying to install Steam and when I do:  cd ~/downloads/ sudo dpkg steam_latest.deb   I get a error saying that I need python-apt and I tried doing  sudo apt-get python-apt   but it says invalid operation can you guys list the ways to install an application, and describe it like I'm five? Thanks.  Edit: I'm not talking about using wine in this case, just using the actual package from Valve themselves.


Croatia is going into the World Cup finals having won their 3 knockout matches so far in extra time/penalties. If they bring their match against France to extra time and win, they'll have done it in every single knockout stage match.  Has any team ever won a World Cup by winning all of their knockout matches on extra time/penalties?

Croatia has played in the extra time of each of their first 3 knockout stage games in the 2018 World Cup. They played Denmark, Russia, and England in the round of 16, quarterfinals and the semifinals respectively.  What is the most number of games a team has played extra time in a single World Cup? Similarly what's the most number of consecutive extra time games played in a single World Cup?


I am using a keyword to display a website page on google search. After entering the keyword, on the first page of google, I am redirected to a page, whose domain is exactly similar to the website whose page I want to display, but it is showing a page which doesn't even exist on the domain. Also, as similar domain with spam characteristics is also getting displayed.   To practically demonstrate this issue, do follow the below steps.   Go to  Type dolce streichquartett and click on search. The 4th/5th URL has this link http://www.dolce-streichquartett.de/?high_ry=/casinos/de/spielautomaten-casino-bregenz.php, which is no where on the website and looks like spam The 7th/8th link you see is http://deonlinecasino.org/doc/kostenlos-roulette-spielen-spielgeld-ausdrucken.php, which is exactly similar to the above with the title as the keyword but a different domain.   What is this issue and why is this happening?


I was investigating some weird noise when riding the bike and I realized the sound is made by some small elastic spikes on the tires hitting the chainstays. Do these spike have a role or they are just leftovers from the manufacturing process? Is it OK to cut them?

Up close you can see at least three 'hairs' of rubber from this picture from the side of my tyre:    Why do they exist? I've heard they are just a bi-product of the manufacturing process.


this question has been asked for several times but I need an elementary solution without advanced  techniques  there are some links that can help you  1-  2-  3-  4-

If $k$ is a positive natural number then $\phi(k)$ denotes the number of natural numbers less than $k$ which are prime to $k$. I have seen proofs that $n = \sum_{k|n} \phi(k)$ which basically partitions $\mathbb{Z}/n\mathbb{Z}$ into subsets of elements of order $k$ (of which there are $\phi(k)$-many) as $k$ ranges over divisors of $n$.  But everything we know about $\mathbb{Z}/n\mathbb{Z}$ comes from elementary number theory (division with remainder, bezout relations, divisibility), so the above relation should be provable without invoking the structure of the group $\mathbb{Z}/n\mathbb{Z}$. Does anyone have a nice, clear, proof which avoids $\mathbb{Z}/n\mathbb{Z}$?


Show that $\mathbb{Z}/n\mathbb{Z}$ is a semisimple ring if n is square-free..   Some articles suggests that we can use Chinese remainder theorem. But I can't exactly figure out how to do that.  Thanks in advance!!!

$\mathbb Z_n$ is J-semisimple iff $n$ is square free.     A ring  $R$ is said to be $J$ semisimple if intersection of all maximal ideals of $R$ is $\{0\}$.   If $n$ is square free then $n=p_1p_2...p_k$ then $\mathbb Z_n\cong \mathbb Z_{p_1}\times\mathbb Z_{p_2}\times...\mathbb Z_{p_k}$ Since $\mathbb Z_{n}$  is a PID every prime ideal ideal is a maximal ideal and hence the maximal ideals will be $\mathbb Z_{p_i}$ for each $i$; but intersection of all $\mathbb Z_{p_i}$' s is $\{0\}$ since $p_i$ 's are distinct.  How to do the converse?


I have a asus u32u and just install the ubuntu 13.10. I'm new working with linux and need a little help.  My pc has a Qualcomm Atheros AR9285 and I can connect to my Wi-Fi, my problem is in my college, where i can connect via cable but not via Wi-Fi.  My college Wi-Fi:   security: WPA2 Enterprise authentication: Protected EAP (PEAP) inner authentication: MSCHAPv2   Any question, just ask. If you need me to put some information about my pc, please leave the respective code.

I'm having severe issues w/ package-loss and a generally bad connection w/in a WiFi-network at my uni. I'm usually encountering a package loss of ~50% and aborting connections which makes working w/ SaaS impossible.  I'm using Ubuntu 13.04 and my network-adapter is an Atheros AR9462.  Applying the nohwcrypt=1-option doesn't change anything.  Also very noticable: The connection works as intended in other networks; the problematic network uses WPA2 w/ MSCHAPv2.  Anyone can help my out here?  $ sudo lshw -class network  *-network UNCLAIMED             description: Ethernet controller        product: NetLink BCM57780 Gigabit Ethernet PCIe        vendor: Broadcom Corporation        physical id: 0        bus info: pci@0000:04:00.0        version: 01        width: 64 bits        clock: 33MHz        capabilities: pm msi pciexpress bus_master cap_list        configuration: latency=0        resources: memory:d3500000-d350ffff   *-network        description: Wireless interface        product: AR9462 Wireless Network Adapter        vendor: Atheros Communications Inc.        physical id: 0        bus info: pci@0000:09:00.0        logical name: wlan0        version: 01        serial: e0:06:e6:76:ba:89        width: 64 bits        clock: 33MHz        capabilities: pm msi pciexpress bus_master cap_list rom ethernet physical wireless        configuration: broadcast=yes driver=ath9k driverversion=3.8.0-22-generic firmware=N/A ip=131.173.74.130 latency=0 link=no multicast=yes wireless=IEEE 802.11abgn        resources: irq:19 memory:d3400000-d347ffff memory:9fb00000-9fb0ffff


I would to have my current working file on main screen, and the file used to import data from on my side screen.

I have to do work between two spreadsheets and I need to view them side by side. I can't just open the workbooks in separate instances because I need to make use of features like paste formatting, and all of that goes away when the workbooks aren't in the same instance.  Is there anything I can do to get two windows open, each with a separate workbook, each maximized on a different monitor, and still have access to the advanced cut/paste features?


This question may sound weird but anyway here it goes. Is the following equation true? $$\emptyset = \{ \emptyset \}$$  The reason I think it is not true:    The empty set is an element by itself, therefore the R.H.S contains one element.  But due to L.H.S, the amount of elements of the R.H.S must be $0$.    The reason I think it is true:   The empty set is a subset of every set. Therefore, the emptyset on the R.H.S must be a subset of the L.H.S. In other words, we have the following relation: $\emptyset \supseteq \{ \emptyset \} \Rightarrow \emptyset = \{ \emptyset \}$.

Herbert in his book "Elements of set theory" on page no 3 says that      we can form the set $ \{ \emptyset \} $ whose only member is $\emptyset $. Note that $ \{ \emptyset \} \neq  \emptyset $, because $ \emptyset \in \{ \emptyset \} $ but $\underline{ \emptyset \notin \emptyset} $·   By the last argument $\emptyset \notin \emptyset$, is he saying that empty set is not a member of or does not belong to empty set  OR  it is a typo and he wanted it to be $ \{\emptyset \} \notin \emptyset $, that set containing empty set is not a member of empty set


I've deleted ~/.macromedia and ~/.adobe contents and after a restart chromium can't detect flash plugin. It works just fine in Firefox  I have only "Chromoting Viewer" on chrome://plugins/  chromium-browser 34.0.1847.116-0ubuntu2 adobe-flashplugin 11.2.202.350-0trusty1   I have profile-sync-daemon active (tried stopping it, of course) and broken PolicyKit as in   Does the detection depend on PolicyKit? What else can I do?

I want to play online games, and other online stuff that requires Flash Player on the internet. Flash Player works just fine under Firefox, but in Chromium I just get a blank page. I don't know what is the exact problem or know to fix it.


If $\mathbb{F}$ is a field, what is the difference between $\mathbb{F}[a]$ and $\mathbb{F}(a)$? To my understanding $\mathbb{F}(a)$ is the smallest field containing $\mathbb{F}$ and $a$ whereas $\mathbb{F}[a]$ would have to be the polynomials over $\mathbb{F}$? Am I missing something here?

Sorry to ask this, I know it's not really a maths question but a definition question, but Googling didn't help. When asked to show that elements in each are irreducible, is it the same?