Isn't 2^(0.5) rational?  Method for proving: Contradiction. So show not P:2^(0.5) is rational.

Can the expression $\sqrt{n} + \sqrt{m}$ be rational if neither $n,m \in \mathbb{N}$ are perfect squares? It doesn't seem likely, the only way that could happen is if for example $\sqrt{m} = a-\sqrt{n}, \ \ a \in \mathbb{Q}$, which I don't think is possible, but how to show it?


I have modified some changes in both lightning components and a community site which is built on Napili template in the sandbox. How can I move the changes from sandbox to production, Is it possible to do with change sets?

Okay so, I know that I can use the Migration Tool to pull down Lightning Components from my sandbox, and then use the same tool to upload them to production, but so far I have had no luck in moving a single PAGE from my community site in my sandbox over to our community site in production. I've searched online but am having trouble finding any documentation or instructions specific enough for this scenario.  We are using the Lightning Community Builder, so the page itself is created within the Community Builder, and the content of the page is a series of lightning components, text boxes, HTML, styling, and images.  I'd like to move that entire page (and only that page) to our production environment, to avoid the need to re-create it manually and put all of the lightning components back on the page, copy/paste all of the text areas, images, etc into Production.   These pages don't appear under the "Visualforce Pages" or "Visualforce Components" sections - the only place I seem to find them is IN the Community Builder itself. As of now, I am able to get the Lightning Components into production, but I still end up re-creating the page in production and manually dragging all of the components back into the right place.      Question: This is tedious of course, is there a better way to get a   single Lightning Community Builder page pushed into production?


Windows 10 has an option to do a PC reset that keeps your personal files, but uninstalls any apps and drivers you have installed.  What are considered personal files and what are considered apps for this? For example, I got 600 GB of games installed, are these considered apps or personal files? Is my dropbox desktop client considered an app or a personal file? Are apps just the ones you install through the Windows 10 store, or also any other apps you may have installed?

I want to use the "reset my PC" feature of Windows 10 to wipe the data on my Windows partition. But I have also a Linux system installed, which I want to keep.  Will Windows 10's full reset wipe all my disk, or just Windows's partitions ?


I am starting a brand new install and every time I go through the boot up process I get the message "running in low-graphics mode" I click OK, which then gives you the 4 options:  run in low-graphics mode for just one session;  reconfigure graphics;  trouble shoot this error;  exit to console login;   select run in low-graphics mode give you a message that graphics is going to restarts, but just hangs there after clicking ok (must ctrl-alt-del to restart - you see the normal unmounting [OK] etc. messages)  selecting reconfigure graphics gives you two options: use default (generic) configuration;  use your backed-up configuration;  I chose use default and it just gets caught in a loop you can click ok 100 times and still just gives you the same options.  You hit cancel and it sends you back to the main menu  Troubleshoot this error allows you to look at the xlog where it says:  Warning couldn't open module nvidia; then loaded module nouveua.  It does this 3 times once for each card.  Then it proceeds to load all the DVI interfaces DVI-1 - DVI-10 giving them the correct model for each monitor  detected and setting initial mode sizes for each.  Each monitor detected with proper model and serial number.  The Xlog then goes on to load the rest of the hardware mouse, keyboard, etc. Last 3 lines of the log file read;  AIGLX: Suspending AIGLX clients for VT switch;  NOUVEAU(0):NVLeaveVT is called;  Server terminated with error (1). Closing log file;   It gives an option to review start-up errors, but that is empty.  Also gives you an option to edit the configuration file which just throws in a loop again.  you just keep clicking OK.  Selecting the Last option: Exit to console login just blacks the screen and you must ctrl-alt-del (flashes to show unmounting) to restart the PC  The system has 3 NVIDIA cards NVS285 (dual dvi) and two (2) NVS 440 (quad dvi).  I have tried both the 12.04.3 as well as 13.10 and both hang on the same section.  Does anyone have an idea what is going on?  Being there was no errors in the X-Log I can not seem to find out why this is stuck here.

Note: This is an attempt to create a canonical question that covers all instances of "low-graphics mode" error that occurs to a user, including but not limited to installation of wrong drivers, incorrect or invalid lightdm greeters, low disk space, incorrect installation of graphics card like ATI and Nvidia, incorrect configuration of xorg.conf file while setting up multiple monitors among others. If you are experiencing the "low-graphics mode" error when trying to login but none of the following answers work for you, please do ask a new question and then update the answers of this canonical question as and when your new question gets answered.   When I try to boot into my computer, I am getting this error:  The system is running in low-graphics mode Your screen, graphics cards, and input device settings could not be detected correctly. You will need to configure these yourself.   How do I fix the failsafe X mode and login into my computer?  Answer index:


I have been wondering like most of the desktop application which has to deal with the simulation and design stuff has been designed in WPF, So, I wanted to know is there anything similar to WPF in java and which has each & every capability of WPF  " This question may be having similar variants and all question ends up with the answer JavaFX and combination of couple of frameworks". as better explained at this question   So, does java have a single piece of framework which has got each and every capability of WPF Including hardware based rendering(GPGPU programming) and even call pixel shader, vertex shader and geometry shader.

I'm mostly a .Net person at the moment, but I've been playing with Java some lately-- exploring what's out there.  Now I'm looking for the Java equivalent for WPF.  I know I could find an OpenGL library or two out there, but that's not really as rich or simple as the WPF system.


I want to get user input and validate if it is correct or not in the backend... There is something missing but I am not able to figure it out:  run.py code:  @app.route('/game', methods = ["GET","POST"]) def game():     global answer_number      global user_correct      global user_wrong       with open ("data/riddles.json", "r") as jason_data:         data = json.load(jason_data)     if request.method == "POST":         user_answer.append(request.form["answer"])         if user_answer [-1] == data[answer_number]["answer"]:             answer_number += 1             user_correct += 1         else:             user_wrong += 1         print (answer_number, user_correct, user_wrong)     return render_template("game_page.html",                             user_list = user_list,                             riddles_data = data,                            user_answer=user_answer,                            answer_number=answer_number)   game_page.html code:  <form class="form" autocomplete="off" spellcheck="false">                 <label for="name">Write down your answer</label>                 <input type="text" class="form-control" autofocus="autofocus" id="answer" name="answer">             </form>

What's the difference when using GET or POST method? Which one is more secure? What are (dis)advantages of each of them?  ()


When I have Visual Studio 2017 generate properties for me, it will always use the new expression-bodied properties, for example:  private static string username; internal static string Username { get => username; set => username = value; }   Is there any advantage of using this style over the following or is it just a matter of preference and readability?  internal static string Username { get; set; }

Note: This was posted when I was starting out C#. With 2014 knowledge, I can truly say that auto-properties are among the best things that ever happened to the C# language.  I am used to create my properties in C# using a private and a public field:  private string title; public string Title {     get { return title;  }     set { title = value;  } }   Now, with  3.0, we got auto-properties:  public string Title { get; set; }   I know this is more a philosophical/subjective questions, but is there any reason to use these auto-properties except from saving five lines of code for each field? My personal gripe is that those properties are hiding stuff from me, and I am not a big fan of black magic.  In fact, the hidden private field does not even show up in the debugger, which is OK given the fact that the get/set functions do nothing. But when I want to actually implement some getter/setter logic, I have to use the private/public pair anyway.  I see the benefit that I save a lot of code (one vs six lines) without losing the ability to change the getter/setter logic later, but then again I can already do that by simply declaring a public field "Public string Title" without the need of the { get; set; } block, thus even saving more code.  So, what am I missing here? Why would anyone actually want to use auto-properties?


I have the following code:  private static final Logger logger = LoggerFactory.getLogger(Some.class); ... String[] splits=someString.split(".."); logger.info("The string was split into <{}>",splits); // prints first element   What is the right way to print the full content of an array with slf4j?

In Java, arrays don't override toString(), so if you try to print one directly, you get the className + '@' + the hex of the  of the array, as defined by Object.toString():  int[] intArray = new int[] {1, 2, 3, 4, 5}; System.out.println(intArray);     // prints something like '[I@3343c8b3'   But usually, we'd actually want something more like [1, 2, 3, 4, 5]. What's the simplest way of doing that? Here are some example inputs and outputs:  // Array of primitives: int[] intArray = new int[] {1, 2, 3, 4, 5}; //output: [1, 2, 3, 4, 5]  // Array of object references: String[] strArray = new String[] {"John", "Mary", "Bob"}; //output: [John, Mary, Bob]


In School, students were taught that "if $m$ and $n$ are two non-negative integer, then their product $m \times n$ is equal to the sum of $n$, $m$-times or sum of $m$, $n$-times". If one of them is negative, then the principle still work. After this they were taught that "$ - \times - = +$", so the product of two negative integers is well defined. Does this follow from the above principle? Some people told me that it follows from the above principle, but i don't know how it follow. If someone ask you that how "$ - \times - = +$", what will be your answer?  Thanks in advance

Someone recently asked me why a negative $\times$ a negative is positive, and why a negative $\times$ a positive is negative, etc.  I went ahead and gave them a proof by contradiction like so:  Assume $(-x) \cdot (-y) = -xy$  Then divide both sides by $(-x)$ and you get $(-y) = y$  Since we have a contradiction, then our first assumption must be incorrect.  I'm guessing I did something wrong here. Since the conclusion of $(-x) \cdot (-y) = (xy)$ is hard to derive from what I wrote.  Is there a better way to explain this?  Is my proof incorrect?  Also, what would be an intuitive way to explain the negation concept, if there is one?


This question is from a test:     The {people | peoples} of Europe are white-skinned.   Which is correct? Can we use either?

Would anyone like to comprehensively explain? I am not sure peoples word exist or not. Kindly request to you all please explain about this.  Thanks.


The old passport with a still valid US visa on it has Given Names: XXX YYY and Surname: YYY  Due to this my visa has the same combination i.e. full name reading XXX YYY YYY (surname twice at the end).   On my new passport this was corrected to Given Name: XXX Surname: YYY  Will this cause an issue during travel? The new passport has the old passport number officially recorded in the alterations page.   I would like to clarify that the name change in the new passport was correcting the old mistake (a clerical error). It is not an official name change with legal documents to back it.

I'm a Malawian national and I got US Visa years back.  Recently, due to some reasons, I had to get my first name partially changed on my passport. I have got an affidavit certificate stating the reason and proof.  Since the visa on my old passport has still not expired, but there is a difference in first name, will I face any problem?


Quick question, can I use  and choose to sacrifice  but in response sacrifice Strip Mine to use it's effect too?

My opponent has a  with scads of loyalty. I've got a  and a  on the battlefield.  He activates Sorin's "ultimate" ability, targeting Gideon.     -6: Destroy up to three target creatures and/or other planeswalkers. Return each card put into a graveyard this way to the battlefield under your control.   Is there any way I can use the Spellbomb to prevent my opponent from stealing Gideon after he is sent to my graveyard?


I need to find the length of thread that is winded in a bobbin. I tried to find out with the rotation of the shaft. but as the diameter of the bobbin (with thread) increases the length winded is also increasing.  Say,  on the initial stage the thread winded for 10 rotation of shaft is 13 inches  after some stage for same 10 rotation of shaft thread winded is 21 inches  and in the final stage for 10 rotation of shaft thread winded is 30 inches.  Is there any formula I can use here?

Fun with Math time.   My mom gave me a roll of toilet paper to put it in the bathroom, and looking at it I immediately wondered about this: is it possible, through very simple math, to calculate (with small error) the total paper length of a toilet roll?   Writing down some math, I came to this study, which I share with you because there are some questions I have in mind, and because as someone rightly said: for every problem there always are at least 3 solutions.  I started by outlining the problem in a geometrical way, namely looking only at the essential: the roll from above, identifying the salient parameters:    Parameters  $r = $ radius of internal circle, namely the paper tube circle;  $R = $ radius of the whole paper roll;  $b = R - r = $ "partial" radius, namely the difference of two radii as stated.  First Point  I treated the whole problem in the discrete way. [See the end of this question for more details about what does it mean]  Calculation  In a discrete way, the problem asks for the total length of the rolled paper, so the easiest way is to treat the problem by thinking about the length as the sum of the whole circumferences starting by radius $r$ and ending with radius $R$. But how many circumferences are there?   Here is one of the main points, and then I thought about introducing a new essential parameter, namely the thickness of a single sheet. Notice that it's important to have to do with measurable quantities.  Calling $h$ the thickness of a single sheet, and knowing $b$ we can give an estimate of how many sheets $N$ are rolled:  $$N = \frac{R - r}{h} = \frac{b}{h}$$  Having to compute a sum, the total length $L$ is then:  $$L = 2\pi r + 2\pi (r + h) + 2\pi (r + 2h) + \cdots + 2\pi R$$  or better:  $$L = 2\pi (r + 0h) + 2\pi (r + h) + 2\pi (r + 2h) + \cdots + 2\pi (r + Nh)$$  In which obviously $2\pi (r + 0h) = 2\pi r$ and $2\pi(r + Nh) = 2\pi R$. Writing it as a sum (and calculating it) we get:  $$ \begin{align} L = \sum_{k = 0}^N\ 2\pi(r + kh) & = 2\pi r + 2\pi R + \sum_{k = 1}^{N-1}\ 2\pi(r + kh) \\\\ & = 2\pi r + 2\pi R + 2\pi \sum_{k = 1}^{N-1} r + 2\pi h \sum_{k = 1}^{N-1} k \\\\ & = 2\pi r + 2\pi R + 2\pi r(N-1) + 2\pi h\left(\frac{1}{2}N(N-1)\right) \\\\ & = 2\pi r N + 2\pi R + \pi hN^2 - \pi h N \end{align} $$  Using now: $N = \frac{b}{h}$; $R = b - a$ and $a = R - b$ (because $R$ is easily measurable), we arrive after little algebra to  $$\boxed{L = 4\pi b + 2\pi R\left(\frac{b}{h} - 1\right) - \pi b\left(1 + \frac{b}{h}\right)}$$  Small Example:  $h = 0.1$ mm; $R = 75$ mm; $b = 50$ mm thence $L = 157$ meters  which might fit.  Final Questions:  1) Could it be a good approximation?  2) What about the $\gamma$ factor? Namely the paper compression factor?  3) Could exist a similar calculation via integration over a spiral path? Because actually it's what it is: a spiral.  Thank you so much for the time spent for this maybe tedious maybe boring maybe funny question!


You can say "The cats of Mary" or "Mary's cats". But the alternative to "Supreme Court of the United States", that is, "United States Supreme Court" is written without an apostrophe. Why?

May I ask if the following sentence is grammatical?      Our remit is to conduct research on customer's requirements.   In my understanding, as 'customer' is a countable noun, so the plural form 'customers''' should be used instead for this general reference (without specification of certain customers).   However, I know that we can say 'traveller's cheques' - e.g.,      Traveller's cheques are available at the bank.    In this sense, actually can we say 'customer's requirements' in the first case?


I just started playing Dungeons and Dragons again. The group I'm playing with has characters that were already at 3rd level. I came in early to the session, so the DM and I could get my character (halfling rogue) finished, and level him up to 3rd level.  We played about 30 minutes, until the party go to a point where they met my character. Basically, him and a group of people (NPCs) come running out of the jungle, being chased by a group of "bad guys" (also NPCs, of course).  Both the existing party, and the party my character is in, join together, and after a fairly long fight, kill all of the bad guys. Unfortunately, during the encounter, all but one of the NPCs in my party die. Since my rogue sees no reason to stay with just one person, he asks to join the party of the other players.  One of them asks what I do/what I am... I had no idea how to answer, but one of the other characters suggested I say "I'm in resource acquisition."  Though, I guess, technically true... The barbarian in the group, who's character is not very bright, pushed it a bit farther, wanting to know if I did spells, or was a fighter, or what.  I didn't really want to say it, but I said I killed things, by sneaking up on them from behind... so he calls me a "backstabber" now, haha.  I think the DM would probably let me retcon it just a bit, if I could come up with a better way of saying what I do, without giving away the fact that I'm a rogue.  Any ideas on how to do so?

I just thought that they wouldn't announce themselves as such. So what would they say if they are trying to get the message across but not be open about it. Anyway I wanted an opinion so why not here?


My HP laptop , shows that it is plugged in but not charging , When ever I take out my adapter it simply shuts down . It Always stays at 0% , its has been this way for years and im considering to buy a new battery . Please help if you know the answer .

My laptop battery won't charge anymore, sits at 0%, and the laptop only operates if plugged to the AC adapter (it detects the power cord, but charge remains at 0%) The battery is already 2.5 years old, saw extensive use (at least daily recharge). so I wouldn't be surprised if it is damaged/beyond repair, but could it just be a software issue? I'm running Arch Linux.


I created a dataset which has no error for the purposes of learning. I then ran the following code. Note that Wafer and Temp are fixed with Quarter as a random effect. library(lme4) data<-read.csv('WaferData.csv', header=TRUE, sep=",", strip.white=TRUE) colnames(data) = c("Wafer","Quarter","Temp","data")  ##required due to strange byte encoding error mixedModel = lmer (data ~ Wafer + Temp + (1|Quarter), data=data)  summary(mixedModel) ranef(mixedModel)$Quarter   I get these results for the mixed model. Note the standard deviation for the random effect (Quarter) is .3249.  Random effects:  Groups   Name        Variance  Std.Dev.   Quarter  (Intercept) 1.055e-01 3.249e-01  Residual             2.861e-14 1.691e-07 Number of obs: 32, groups:  Quarter, 4  Fixed effects:              Estimate Std. Error   t value (Intercept) 2.000e+01  1.641e-01 1.219e+02 WaferW2     1.000e+01  8.457e-08 1.182e+08 WaferW3     2.000e+01  8.457e-08 2.365e+08 WaferW4     3.000e+01  8.457e-08 3.547e+08 Temp        1.000e-01  2.990e-08 3.345e+06  With the following random effects intercepts.  (Intercept) Q1  -1.1536939 Q2  -0.3219838 Q3   0.3152949 Q4   1.1470049  The standard deviation of those four intercepts is .975 which is not even close to the standard deviation of the random effect. The mixed level model is data = bintercept + bWafer + bTemp + effectQuarter + epsilon. Where effectQuarter = N(0,γ). I would have expected the standard deviation estimate (.3249) and the standard deviation of the effects (.975) to both be estimates for the square root of γ. But clearly it does not. If anyone can shed light on this I would be most appreciative.

I'm having trouble understanding the output of my lmer() model. It is a simple model of an outcome variable (Support) with varying State intercepts / State random effects:  mlm1 <- lmer(Support ~ (1 | State))   The results of summary(mlm1) are:  Linear mixed model fit by REML  Formula: Support ~ (1 | State)     AIC   BIC logLik deviance REMLdev  12088 12107  -6041    12076   12082 Random effects:  Groups   Name        Variance  Std.Dev.  State    (Intercept) 0.0063695 0.079809  Residual             1.1114756 1.054265 Number of obs: 4097, groups: State, 48  Fixed effects:             Estimate Std. Error t value (Intercept)  0.13218    0.02159   6.123   I take it that the variance of the varying state intercepts / random effects is 0.0063695. But when I extract the vector of these state random effects and calculate the variance  var(ranef(mlm1)$State)   The result is: 0.001800869, considerably smaller than the variance reported by summary().  As far as I understand it, the model I have specified can be written:  $y_i = \alpha_0 + \alpha_s + \epsilon_i, \text{ for } i = \{1, 2, ..., 4097\}$  $\alpha_s \sim N(0, \sigma^2_\alpha), \text{ for } s = \{1, 2, ..., 48\}$  If this is correct, then the variance of the random effects ($\alpha_s$) should be $\sigma^2_\alpha$. Yet these are not actually equivalent in my lmer() fit.


In a Stack Exchange Q&A kind of system, what is the rationale for letting the user up/downvote questions and answers, but only upvote comments?   made me think about the Stack Exchange system. What is the reason behind giving users the option to up/downvote questions and answers, but only upvote comments?  I am looking for the rationale behind the way this kind of system works.

Answers and questions allow both upvoting and downvoting - comments, however, only allow upvoting.  I think it would be useful to allow downvoting of comments for two reasons:   First, if you accidentally upvoted a comment you didn't intend to Second, if you strongly believe that a comment is , misleading, incorrect or off topic


I shined a laser pointer on a mirror to see how it reflects, quite interestingly, I saw the image of the laser point on the floor inside the mirror and an image on the floor right beneath me OUTSIDE the mirror without any distortions or loss of resolution. So a plane mirror technically should only produce a virtual image  in all cases, but there seems to be a contradiction here as both a real and virtual image are seen at the same time.

Theoretically, if I shined a laser at a mirror at an angle of 0 degrees so that the light was perfectly reflected back to the light source, then I should not be able to see the light because it is not reflected to my eyes.  | |  me | |============ laser | | |   However this is evidently not the case, as I am able to see the laser point on the mirror. Why is this the case? My initial assumption is that it is due to diffuse reflection on the imperfect mirror's surface, but I am not sure.


My app crashes when I do any networking activities (specifically, reading text through an InputStream), but only on Android Pie. I've tried it using emulators running various API versions, but this only happens on API 28. I have also tried this on an actual phone running Pie, and it crashes there as well. The app runs fine on all other Android versions afaik.  The logcat shows this:  2018-12-09 14:59:16.917 6864-6925/<package> E/AndroidRuntime: FATAL EXCEPTION: Thread-4     Process: <package>, PID: 6864     java.lang.NullPointerException         at java.io.Reader.<init>(Reader.java:78)         at java.io.InputStreamReader.<init>(InputStreamReader.java:72)         at <package>.<Activity class>.<method>(<Activity class>.java:304)   The statement that the stack trace leads to in my code is:  BufferedReader br = new BufferedReader(new InputStreamReader(text));  where text = con.getInputStream(); up above, which when I debugged, was returning null. con is a URLConnection that opens a connection to a particular URL. The value of con seems alright and is identical to con values on different API versions.   So, the culprit seems to be text = con.getInputStream(); which is returning normally on API 27 and below, but is returning null on Pie.  Any idea what could be causing this? Let me know if there's any more information I could provide.

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


Is there any standard symbol for the set $\{x\in\mathbb{R} : x > 0\}$?  I think $\mathbb{R}^{+}$ usually includes zero. Some sources say I should use $\mathbb{R}^{*}_{+}$ but it looks slightly bizarre to me.  Suggestions?

What is the "standard" way to denote all positive (or non-negative) real numbers? I'd think  $$ \mathbb R^+ $$  but I believe that that is usually used to denote "all real numbers including infinity".  So is there a standard way to denote the set  $$ \{x \in \mathbb R : x \geq 0\} \; ?$$


I'm looking to extract only what appears after '/g' and before the '+' or '?'  urls = ["https://www.google.com/es/g/Dmitry+Kharchenko?searchterm=isometrico",        "https://www.google.com/es/g/Irina+Strelnikova?searchterm=isom%C3%A9trico",        "https://www.google.com/es/g/ParabolStudio?searchterm=auto"]  for i in urls:     print(re.findall(r'g/(.*)[\+|\??]', i))   ['Dmitry+Kharchenko'] ['Irina+Strelnikova'] ['ParabolStudio']  Desired result:  'Dmitry' 'Irina' 'ParabolStudio'

I have this gigantic ugly string: J0000000: Transaction A0001401 started on 8/22/2008 9:49:29 AM J0000010: Project name: E:\foo.pf J0000011: Job name: MBiek Direct Mail Test J0000020: Document 1 - Completed successfully  I'm trying to extract pieces from it using regex. In this case, I want to grab everything after Project Name up to the part where it says J0000011: (the 11 is going to be a different number every time). Here's the regex I've been playing with: Project name:\s+(.*)\s+J[0-9]{7}:  The problem is that it doesn't stop until it hits the J0000020: at the end. How do I make the regex stop at the first occurrence of J[0-9]{7}?


How to implement it in C?  openssl req -new -key cert.key -out cert.csr  openssl x509 -req -in cert.csr -CA rootCA.crt -CAkey rootCA.key -CAcreateserial -out cert.crt -days 5000

I have a C/C++ application and I need to create a X509 pem certificate containing both a public and private key.  The certificate can be self signed, or unsigned, doesn't matter.  I want to do this inside an app, not from command line.  What OpenSSL functions will do this for me?  Any sample code is a bonus!


I don't want to see any Windows 10 security stuff anywhere. I already disabled UAC, and made my account Admin.  However, I still get security prompts with networking my three PCs together as well as pop-ups that say I don't have access to this or that until I select "continue".  How do I rid my PC of this stuff? No one uses my PC, there is nothing of value on my PC, and it is hard for me to read stuff about how to do this and that with the security features of Windows 10.  I miss the ease on Windows 3.1 and how i could simply right click a drive on other PC and select map.   Thank you, DReeves  Tried to look at the "exact duplicate this was marked as, but then i remember, i have never been on this site before and therefore, it cannot be an "exact duplicate". Someone may have asked a similar question of which i was unable to locate, and would gladly look at it and try and get the answers i need. Thank you.

I am using Windows 8 Enterprise on my development machine. Most of the time, I need full administrator for debugging, changing system files, etc.  In Windows 7, setting UAC to "never notify" would disable any administrator prompts. In Windows 8 this is no longer the case. Even with UAC disabled I get prompted to grant programs elevated privileges.  Is there a way disable this behaviour?  Note: I am fully aware of the repercussions. I have antivirus, firewall, etc and am generally quite careful about what I download or install on my machine.


I have seen advice in several places to use the following shebang line  #!/usr/bin/env bash   instead of  #!/usr/bin/bash   My knee-jerk reaction is, "what if somebody substitutes this executable for their own in say ~/.local/bin ?" That directory is often set up in the user's path before the system-wide paths. I see this raised as a security issue often as a side note rather than anything to take seriously, but I wanted to test the theory.  To try this out I did something like this:  echo -e "#!/usr/bin/python\nprint 'Hacked!'" > $HOME/.local/bin/bash chmod 755 $HOME/.local/bin/bash PATH=$HOME/.local/bin env bash   This yields  /usr/bin/env: ‘bash’: No such file or directory   To check whether it was picking up anything at all I also did  echo -e "#!/usr/bin/python\nprint 'Hacked!'" > $HOME/.local/bin/perl chmod 755 $HOME/.local/bin/perl PATH=$HOME/.local/bin env perl   which prints, as I expected,  Hacked!   Can someone explain to me why the substitute bash is not found, but the substitute perl is? Is this some sort of "security" measure that (from my point of view) misses the point?  EDIT: Because I have been prompted: I am not asking how /usr/bin/env bash is different from using /bin/bash. I am asking the question as stated above.  EDIT2: It must have been something I was doing wrong. Tried again today (using explicit path to env instead of implicit), and no such "not found" behaviour.

In shell scripts one specifies language interpreter on shebang(#!) line. As far as I know, it is recommended to use #!/usr/bin/env bash because env is always located in /usr/bin directory while location of bash may vary from system to system. However, are there any technical differences if bash is started directly with /bin/bash or through env utility? In addition, am I correct that if I do not specify any variables for env, the bash is started in unmodified environment?


I am trying to prove that If $z\in \mathbb{C}-\mathbb{R}$ such that $\frac{z^2+z+1}{z^2-z+1}\in \mathbb{R}$. Show that $|z|=1$.  1 method , through which I approached this problem is to assume $z=a+ib$ and to see that $$\frac{z^2+z+1}{z^2-z+1}=1+\frac{2z}{z^2-z+1}$$.  So problem reduces to show that $|z|=1$ whenever $\frac{2z}{z^2-z+1}\in \mathbb{R}$  I put $z=a+ib$ and then rationalise to get the imaginary part of $\frac{2z}{z^2-z+1}$ be $\frac{b-b^3-a^2b}{something}$. I equated this to zero and got my answer.  Is there any better method?

If z is a complex number and $ \frac {z^2 + z+ 1} {z^2 -z +1}$   is purely  real then find the value of $|z|$ .  I tried to put $ \frac {z^2 + z+ 1} {z^2 -z +1} =k $ then solve for $z$ and tried to find |z|, but it gets messy and I am stuck. The answer given is |z|=1


I can't mount my other partition with Windows 8, I have Ubuntu 12.10 amd64:  Error mounting /dev/sda1 at /media/ricardo/003E8A7D3E8A6C0A: Command-line `mount -t "ntfs" -o "uhelper=udisks2,nodev,nosuid,uid=1000,gid=1000,dmask=0077,fmask=0177" "/dev/sda1" "/media/ricardo/003E8A7D3E8A6C0A"' exited with non-zero exit status 14: Windows is hibernated, refused to mount. Failed to mount '/dev/sda1': Operation not permitted The NTFS partition is hibernated. Please resume and shutdown Windows properly, or mount the volume read-only with the 'ro' mount option, or mount the volume read-write with the 'remove_hiberfile' mount option.  For example type on the command line:   mount -t ntfs-3g -o remove_hiberfile /dev/sda1 /media/ricardo/003E8A7D3E8A6C0A

Whenever I boot Ubuntu, I get a message that it cannot mount my windows partition, and I can choose to either wait, skip or manually mount.  When I try to enter my Windows partition through Nautilus I get a message saying that this partition is hibernated and that I need to enter the file system and properly close it, something I have done with no problem so I don't know why this happens.    Here's my partition table, if any more data is needed please let me know.     Device Boot      Start         End      Blocks   Id  System /dev/sda1            2048    20000767     9999360   83  Linux /dev/sda2        20002814   478001151   228999169    5  Extended /dev/sda3   *   478001152   622532607    72265728    7  HPFS/NTFS/exFAT /dev/sda4       622532608   625141759     1304576   82  Linux swap / Solaris /dev/sda5        20002816   478001151   228999168   83  Linux


I have a question Blender "eats" my constructions with gray spaces. I would like to know how to move away those gray spaces so that I can work with more space. Thank you so much to anyone who answers me!

Ok so In blender, I'm making a city, but in the 3d view, it disappears when going to a certain distance:  I'm not using a camera or anything, this is user perspective Help?


Should I repeat on the pronoun "I" in the following sentence:     "I hope and (I) wish that the rest of the staff will be like you."   Or is it enough to mention the pronoun in this case one time in the beginning?

Is it always necessary to repeat the pronoun before each verb?  For example, do I need always to say:     She called me and she said X   or can I use a shorter one     She called me and said X   ?


when i wanta set the environment variable for java: someone said "~/.bashrc" and someone else said "/etc/profile" or "~/.profile"  i wanta know what different from these files?   And why the commod is  "export PATH=$JAVA_HOME/bin:$PATH" but "export PATH=$JAVA_HOME/bin"

I've used a number of different *nix-based systems of the years, and it seems like every flavor of Bash I use has a different algorithm for deciding which startup scripts to run.  For the purposes of tasks like setting up environment variables and aliases and printing startup messages (e.g. MOTDs), which startup script is the appropriate place to do these?  What's the difference between putting things in .bashrc, .bash_profile, and .environment?  I've also seen other files such as .login, .bash_login, and .profile; are these ever relevant?  What are the differences in which ones get run when logging in physically, logging in remotely via ssh, and opening a new terminal window?  Are there any significant differences across platforms (including Mac OS X (and its Terminal.app) and Cygwin Bash)?


In the sentences Jack wants food and Jack wants to eat, it seems like food and to eat both serve as direct objects of the verb wants. Can a verb in the infinitive serve as a direct object in a sentence like this, or does it play some other role?

The professor wants to retire. Here 'to retire' is used as object or complement? Also, in "The man gave Amy some good advice" Is 'some good advice' an object or complement?


My desktop storage capacity reaches its limit.  How can I visualize my storage partition between files and apps (Android-like) to efficiently dig into the heaviest files?

I have only one disk in my computer, a 80 GB SSD. It is formatted as a single ext4 partition (no swap), and all the usual folders are installed on it (I keep lots of data on external media, but /home and all the rest is on the SSD).   Today I booted it and I got a message that the drive is full. I opened Disk Usage Analyzer to look at what takes up space. It insists that 67.8 GB of the disk are used, and that / is taking up 36.4 GB. Which leads to the question, where are the missing 30 GB, if not on the file system?!    Just to have a comparison, I added up all the sizes of all readable folders listed in Nautilus as subfolders of / (including the hidden ones). I got 20.9 GB. Trash was unreadable, but I know it has 16.2 GB, so the sum is 36.1 GB, around the same as what Disk Usage Analyzer is reporting. There were some system folders which were unreadable, like proc, but I doubt that they add up to 30 GB - else it wouldn't be possible to install Ubuntu on small disks, and I've seen it run on 2.5 GB. I think they must be the 0.3 GB difference between my calculation and the Disk Usage Analyzer's report.   So I'd like to know, what is eating up these 30 GB and how do I get it to free them?     Edit with answers to CYREX's questions   Booted from Ubuntu 10.10 64-bit live CD (same as my system).  fsck result:   root@ubuntu:~# fsck /dev/sda1 fsck from util-linux-ng 2.17.2 e2fsck 1.41.12 (17-May-2010) /dev/sda1: clean, 265956/4890624 files, 18073343/19537408 blocks  Booted from the SSD. Emptied the trash, and the 16 GB from there are now free. The 30 GB are still missing.    I'm not experienced enough to know what counts as weird in a log. Here are my messages log and my syslog since last boot. Maybe you can find something in them:       Here it got really strange. I plugged in an external 500 GB HDD. Disk Usage Analyzer overreported the available space, then showed space missing (76 GB used, but only 24 in folders).      Booted again from the LiveCD, started the Disk Usage Analyzer from it and got the same results as from the installed Ubuntu, within 1-2 GB.   Edit with answer to CodeMonk:  That would have been a nice solution, but the partition is really 80 GB - I mean 74 GB + marketing "error", anyway the whole disk is formatted. It also shows that over 50 GB are used, so where are the 30 GB if not in files and folders?    GParted also reports the correct size of the external HDD.


Just wondering, is this valid:  $$ \left(\frac{df}{dx}\right)^2=\frac{d^{2}f}{dx^{2}} $$

I have a simple question for you guys, if I have this:  $$\left(\frac{d^2}{{dx}^2}\right)^2$$  Is it equal to this:  $$\frac{d^4}{{dx}^4}$$  Such that if I have an arbitrary function $f(x)$ I can get:  $$\left(\frac{d^2 f(x)}{{dx}^2}\right)^2 = \frac{d^4 f(x)}{{dx}^4}$$  Sorry if it's a pretty simple question, but I was trying to simplify something like this:  $$\left(a \cdot \frac{d^2}{{dx}^2} - f(x)\right)^2 g(x)$$ that's where it came up.


I have heard that there about a dozen companions. I would like to know who is available and where I have to look for them in order to recruit them.

I have quite the number of companions and I've just scratched the surface of Boston. I'm wondering if there is a definitive list of companions and information on how to get them all to join me on my crusade!


This is the question I am really eager to know. If I already have an EU residence permit from Poland, when I enter into the EU zone, can I line up in the same channel as EU citizens? Or is there any special channel for residence holders?

When I was transferring this morning at Schipol, the staff directed non-EU citizens with Schengen area residence permits to the "EU" line at passport control.  Is this always allowed for people with residence permits, or was it just because the lines had become particularly unbalanced?


I use Ubuntu Studio 18.04.2 LTS (64 bit Linux).  I experimented some kind of crash, due to some app which left some too big temporary file, so the home partition was full and the system couldn't start at all.  I erased some personal files, from the documents folder (unfortunately, Ubuntu put that user data folders in that partition and I don't know some way to avoid it when we install Ubuntu) and, then, I recovered some space and the system started normally, again.  But... The question is: Where is/are and What is/are that/those useless temporary files and how to full erase it?  Is there some full automatic command line to do this?  Is there some specific GUI app to do this?

I used Ubuntu 14.04 (Trusty Tahr) for about a year (actually upgraded it from Ubuntu 12.04 (Precise Pangolin)), and during the time I installed some packages, and removed some other packages.  Now I think it's probably time to clean up the system as it's likely several unused stuff is lying out there (both from the old 12.04 and the new 14.04), and I hope to have a cleaner system that works faster.  I found these two links:       Both links seem good, but when I came across to what they said about Bleachbit then one says yes, and one says no - a bit contradicting.  What should be done for this common task?


I have a table that I want to insert on a page, but at least one (perhaps both) of the following conditions are met:   The table is too wide to fit within the text block or page. That is, I'm exceeding some horizontal restriction. The table is too tall to fit within the text block or page. That is, I'm exceeding some vertical restriction.   What are my options to make this table fit? If it doesn't fit, regardless of my attempts, what other options exist?


This might be a n00b question, but recently I started to use Vagrant with Ubuntu 12.04 and I discovered, every line in the command line looks like this:    I have a Raspberry Pi, but Debian on it has the same look as Ubuntu:    How could I change the look of this "title" before every command, to show the actual time for example? It would be nice sometimes to see, when I entered a command.

The default PS1 variable on my machine (Kubuntu 13.10) is this:  \[\e]0;\u@\h: \w\a\]${debian_chroot:+($debian_chroot)}\u@\h:\w\$   I'm looking for a reference for how the $PS1 variable works that, at a minimum, allows me to understand the above PS1 variable.


Show that there is a dense subset $S$ of $A=[0,1]\times [0,1]$ such that $S$ contains at most one point on each vertical line and at most one point on each horizontal line.   When I think about dense subsets and which contain "not so many" points, the rational numbers come to mind. So if we take $P=\mathbb{Q}\cap[0,1]$, and $S=P\times P$, then we do have the closure of $S$ equal $A$. However, $S$ contains more than one point on each vertical/horizontal line (in fact, infinitely many). How might we adjust so that each horizontal/vertical line contains at most one point in $S$?

Given a subset $A$ of $\mathbb{R}^{n}$, a point $x \in \mathbb{R}^{n}$ is said to be in the boundary of A if and only if for every open rectangle $B\subseteq\mathbb{R}^{n}$ with $x\in B$, $B$ contains both a point of $A$ and a point of $\mathbb{R}^{n}\setminus A$.  My question is from Spivak's Calculus on Manifolds: Construct a set $A \subseteq [0,1]\times [0,1]$ such that $A$ contains at most one point on each horizontal and vertical line but has boundary equal to $[0,1]\times[0,1]$.


I am new to Python (30 minutes). I want to know how to identify whether the number is an integer or a string, and proceed with the result using if else.  My code is:  number = input("enter the number \n")  integer = int(number)  if integer.is_integer():      if integer > 0:         print("positive ", integer)     elif integer < 0:         print("Negative ", integer)     else:         print("Number is", integer) else:     print("Enter integer value")

I have a Python function that takes a numeric argument that must be an integer in order for it behave correctly. What is the preferred way of verifying this in Python?  My first reaction is to do something like this:  def isInteger(n):     return int(n) == n   But I can't help thinking that this is 1) expensive 2) ugly and 3) subject to the tender mercies of machine epsilon.   Does Python provide any native means of type checking variables? Or is this considered to be a violation of the language's dynamically typed design?  EDIT: since a number of people have asked - the application in question works with IPv4 prefixes, sourcing data from flat text files. If any input is parsed into a float, that record should be viewed as malformed and ignored.


The first page of stackexchange.com is the hot questions list. How is it generated? How often does it refresh?

Right now  is fairly broken -- it's a simple descending sort by views. As Joel said , it is "a self-fulfilling prophecy." But this is not intentional, it's only because we haven't had time to improve it yet! As I sit down to write a better algorithm, I thought you guys might have some insight into what would make a good formula to determine the "hot" questions -- over the last 24 hours, the last week, the last month, and all time. Here are the variables we have to work with:  Votes [aka Score] Views Answers Answer Votes [aka Score] Whether the question has an accepted answer or not Time question was originally asked Time of last activity on question Reputation of asker Reputation(s) of answerers  Joel cited the reddit formula as an example, but I think our site is a little different than just a basic link submission site. Plus, we have more variables and data to work with. I found a  describing a few formulas: Y Combinator Hacker News  (p - 1) / (t + 2)^1.5 p = votes (points) from users t = time since submission in hours  Reddit  t = (time of entry post) - (Dec 8, 2005) x = upvotes - downvotes y = {1 if x > 0, 0 if x = 0, -1 if x < 0) z = {1 if x < 0, otherwise x} log(z) + (y * t)/45000  Thoughts? Ideas? I don't want to overthink this; I just want the "hot" questions to be relevant and useful to us. So the simpler the algorithm the better! Based on my analysis of the above and the comments so far, here's the second version of what I have implemented so far. This might suck. I don't know:  (log(Qviews)*4) + ((Qanswers * Qscore)/5) + sum(Ascores) -------------------------------------------------------- ((QageInHours+1) - ((QageInHours - Qupdated)/2)) ^ 1.5  Note that accepted answers weight not at all in hotness. This is intentional, as I feel accepted answers are a fine social contract, but not a good data point for question or answer quality. This algorithm will heavily favor questions with LOTS of answers, as the sum(Ascores) are now included -- one assumes if there are lots of answers, there will be a lot more voting on the answers, too. Update: Note that this formula is what is used on the  linked from the homepage of each site. It is not the formula used to determine the  list. See .


I have tried various recommendations from the web to no success. The apt-get update gives errors . Here are my error messages after sudo apt-get udpate:  W: Failed to fetch http://ppa.launchpad.net/upubuntu-com/java/ubuntu/dists/trusty/main/binary-amd64/Packages  404  Not Found W: Failed to fetch http://ppa.launchpad.net/upubuntu-com/java/ubuntu/dists/trusty/main/binary-i386/Packages  404  Not Found E: Some index files failed to download. They have been ignored, or old ones used instead.   I have reviewed and tried the existing stackexchange answers that are not working for me. Trying to cleanup the ppa as per advice in sourcse gives me the following errors :  For example, the following command to remove the ppa shows other scary messages :  winsella@winsella:~$ sudo rm /etc/apt/sources.list.d/ppaname-ppa-$(lsb_release -sc).list* [sudo] password for winsella: no talloc stackframe at ../source3/param/loadparm.c:4864, leaking memory Failed to open /var/lib/samba/private/secrets.tdb tdbsam_open: Failed to open/create TDB passwd [/var/lib/samba/private/passdb.tdb] tdbsam_getsampwnam: failed to open /var/lib/samba/private/passdb.tdb! tdbsam_open: Failed to open/create TDB passwd [/var/lib/samba/private/passdb.tdb] tdbsam_getsampwnam: failed to open /var/lib/samba/private/passdb.tdb! tdbsam_open: Failed to open/create TDB passwd [/var/lib/samba/private/passdb.tdb] tdbsam_new_rid: failed to open /var/lib/samba/private/passdb.tdb! rm: cannot remove ‘/etc/apt/sources.list.d/ppaname-ppa-trusty.list*’: No such file or directory

PPA seems to be constantly offline. Whenever I use sudo apt-get update, this error is shown:  W: Failed to fetch http://ppa.launchpad.net/ 404  Not Found   How do I fix these errors?


I want to compute the value of the complex line integral $$\int_{\{|z|=4\}}\frac{z^2+2}{(z-3)^2}dz$$ I don't think I can apply Cauchy's integral theorem nor Cauchy's integral formula here. So far, I have tried parametrizing $\{|z|=4\}$ as $\gamma(\theta)=4e^{i\theta}$ and expanding the function I am integrating, however I don't think this is a good way to proceed. Can someone help me?

I saw many examples how to calculate integrals with the residue theorem. But now I'm stuck with this integral: $$\int_{|z|=3}\frac{1}{(z-2)^n(z-4)^m}dz,$$where $m,n\in\mathbb{N}$ and $z=2$ and $z=4$ are the poles. Here we are only interested in $z=2$, because $4$ is not in $B_3(0)$.   For n=1 it is $2\pi if(z_0)=\int_{|z|=3}\frac{\frac{1}{(z-4)^m}}{(z-2)^1}dz$ with $f(z)=\frac{1}{(z-4)^m}$ and $z_0=2$ I would say, i.e. the integral is $2\pi i\frac{1}{(-2)^m}$ for $n=1$. But in genereal case I don't know what to do here, how to prove it ith the residue theorem.  I appreciate your help.


How to create CentOS 7 x64 USB disk on Windows 8? this is my question.

How would I go about creating a CentOS 7 bootable USB drive with Windows? I've read  and it says that Unetbootin and Universal USB installer won't work for CentOS 7. In addition, I've already tried dd for Windows, and that didn't work properly either - booting from the USB drive resulted in a "Machine Check Error".


So I haven been learning Java for a while but decided to switch to C#. It's been a while so I may forget some things. What I know is that in Java, when inheriting from a super class you can or can not call the super class and pass in the parameter if it accepts it. For example:  public class Super {     public Super(int x)     {     } }  public class Sub extends Super {     public Sub()     {         super(5);     } }   and then this other example:  public class Super {     public Super(int x)     {     } }  public class Sub extends Super {     public Sub()     {      } }   is also totally fine since it does not have to pass in parameter to the superclass, correct me if I am wrong. But then in C#, I am not sure if you are required to pass in the parameter for the superclass or not(like if it is still legal and won't cause any problem)

In C#, if I have an inherited class with a default constructor, do I have to explicitly call the base class' constructor or will it be implicitly called?  class BaseClass {     public BaseClass()     {         // ... some code     } } class MyClass : BaseClass {     public MyClass() // Do I need to put ": base()" here or is it implied?     {         // ... some code     } }


As far as I am aware, in Harry Potter, a wand is simply a means of channelling magic.  In Harry Potter and the Deathly Hallows, at Malfoy Manor, Harry grabs three wands from Draco and performs a triple-spell on his enemy. The force of the triple spell wasn't divided by three. Instead, the books mentions that it was multiplied by three.  Thinking about it, he increased his magical power by channelling it through not one but three wands simultaneously. If this can be done by wands, why didn't wizards think of congregating wands into one single powerful tool? Or maybe using some special Wand-like tools to increase channeling of magic through a Wand?  I'm not sure if what Harry did was a pure accident but had I seen this effect produced by three wands then I think I'd have bound multiple wands together with rubber tape.

In the Harry Potter and the Deathy Hallows, Harry used three wands to perform the Stupefy Charm to Fenrir Greyback, who was lifted off his feet by the triple spell, flew up to the ceiling and smashed the ground.  Having said this... using more than wand is ABSOLUTELY a quite huge advantage for wizards and witches to win a battle or a duel. If someone tries to cast a spell on someone, particularly the stunning spell, the one that receives the attack will surely fly high up into the air.  The question is, if every wizard in the books wants to win every single battle blocking their way, why don't they use more wands? That will surely help them a lot!


I have problem with sending mail in Crontab #!/bin/sh log_direc="/var/log/snort/alert" email="vodeni1953@heroulo.com" echo "TESST" | sendmail $email < output.txt`  It can run  normal on command and possible to send mail.  But when i put this script to Cron like this MAILTO=vodeni1953@heroulo.com * * * * * /bin/sh /home/weed/Desktop/test.sh  It looks like this  How can I fix it? Thanks

This is a  about using cron & crontab.   You have been directed here because the community is fairly sure that the answer to your question can be found below. If your question is not answered below then the answers will help you gather information that will help the community help you. This information should be edited into your original question.  The answer for 'Why is my crontab not working, and how can I troubleshoot it?' can be seen below.  This addresses the cron system with the crontab highlighted.


Based upon the first question I have implemented operator overloading to one of my List by inheriting from it.  Today I stumbled upon the second link. So my question is "Is it possible to do operator overloading with List without inheriting from it?"  //Copying the content of first question     I'm trying to overload an operator in C# (don't ask why!) that applies   to Lists. For example, I'd like to be able to write:  List<string> x = // some list of things  List<string> y = // some list of things  List<string> z = x + y        so that 'z' contains all the contents of 'x' followed by the contents   of 'y'. I'm aware that there are already ways to combine two lists,   I'm just trying to understand how operator overloading works with   generic structures.      (This is the List class from Systems.Collections.Generic, by the way.)

I'm attempting to use extension methods to add an operater overload to the C# StringBuilder class.  Specifically, given StringBuilder sb, I'd like sb += "text" to become equivalent to sb.Append("text").  Here's the syntax for creating an extension method for StringBuilder:  public static class sbExtensions {     public static StringBuilder blah(this StringBuilder sb)     {         return sb;     } }    It successfully adds the blah extension method to the StringBuilder.  Unfortunately, operator overloading does not seem to work:  public static class sbExtensions {     public static StringBuilder operator +(this StringBuilder sb, string s)     {         return sb.Append(s);     } }    Among other issues, the keyword this is not allowed in this context.  Are adding operator overloads via extension methods possible?  If so, what's the proper way to go about it?


When I try to load google.com in my browser (Firefox), Google redirects me to its local version of Google Search for my country:    Notice how, even though the URL is google.com, the page is effectively the one from google.hr (Google's Croatian search page). I don't mind the localized UI, the problem is the search results page which doesn't provide the functionality that I'm used to in the English version of Google Search. For example, define: searches:    In the screen shot above, the English version of Google Search is on the left, and my local version on the right. Notice the definition box which is displayed only in the English version. I was able to get the English version by adding ?hl=en to the URL. This is similar to the ncr suffix which FYI appears to have stopped working.  So, while I can get the English version by using the URL google.com/?hl=en, I would like to get it by default for all my searches (including Firefox's search field, for instance).   I've also checked my Google account settings. My language is set to English and no other language is defined:    Special thanks to Google for wasting my time.

How do I keep the Google search results in English regardless of where I am searching from? Google is a genius at knowing what ads to show me and what particular language to show me the ads.    If I travel to Germany, I start getting Google results in German, which is OK because I can somewhat manage. However, when I go to Brazil I don't speak Portuguese and would like the results in English. Or is Google only allowing me to read the ads in a language I know?  I'm constantly having to click and reclick the bottom link "Google in English". I have tried every setting I can think of set to English in my Google preferences/settings, is there one I'm overlooking?


I am using windows 8.I wanted to install ubuntu alongside with windows. I can install with windows 7 but not windows 8..Please Guide me

I'm absolutely new to Linux. I would like to know how to install Ubuntu alongside the pre-installed Windows 8+ OS.  Should I do it with Wubi, or through the Live USB/DVD?  What steps do I need to take to correctly install Ubuntu?


Bill thought of the problem carefully.   Bill thought about the problem carefully.  Any difference could be? Only difference is 'of' and 'about'. This means the answer is the difference between 'of' and 'about'.  of : a friend of mine, the leg of the table, sth consist of sth, remind A of B give hint, i.e., 'of' needs precedent before of and object after of, which means 'of' provides connection between specific two things and narrows sth down to specific information: A of B. So "think of sth" means think of specific B, the existance of B   about : about 10 mins gives hint, hid money about myself gives hint. about means scattered, i.e., not a fixed point. so 'think about X' means 'X' has some attrubutes around X and you think some of the attributes or the attributes.

Could someone help me to understand when I should use think of and when think about in sentences?  What is the difference between using one or the other?


If $\gcd (a,b)=1$, and $\gcd(a,c)=1$, then $\gcd (a,bc)=1$ Help proving this? I'm really confused how to go about it..

How do I go about proving this?  If $\gcd(a,b)=1$ and $\gcd(a,c)=1$, then $\gcd(a,bc)=1$. I'm very confused with gcd proofs.


I have to prove this $$\lim_{n \to \infty} \frac{1}{\sqrt[n]{n!}}=0$$ My proof is the following: By using $$n!>n^{\frac{n}{2}}$$ $$\frac{1}{n!}<\frac{1}{n^{\frac{n}{2}}}$$ $$\left(\frac{1}{n!}\right)^{\frac{1}{n}}<\left( \frac{1}{n}\right)^{\frac{n}{2}\cdot\frac{1}{n}}=\frac{1}{\sqrt{n}}\underset{n\to \infty}{\to}0$$ Using the Squeeze theorem $$0<\frac{1}{\sqrt[n]{n!}}<\frac{1}{\sqrt{n}} \implies \frac{1}{\sqrt[n]{n}}\underset{n\to \infty}{\to} 0$$ I think I have done something wrong. Can I even use the first inequality here? and if yes-do I have to prove that too? and is it Ok that I write too little words in my proofs?. Could you please help me?

How do I prove that $ \displaystyle\lim_{n \to{+}\infty}{\sqrt[n]{n!}}$ is infinite?


On the Android app, how do I view my favorited posts? Do I have to open a web browser for this and if so then what is the easiest way to open such a web browser from the app? Thanks.

I haven't been able to find my favorite questions in the official Stack Exchange Android app.  Looking at my accounts page gives nothing on them.


I have a content type I added with the machine name news.  Per  and  I have set up node--news.html.twig pushed to Acquia successfully and cleared all caches.  The answer on  says my file name should work.   says same thing: "Content specific node templates is simple - node--[content-type-machine-name].html.twig, e.g. node--article.html.twig, clear the cache."  I have twig debugging enabled and if I add page--node--336.html.twig it works as expected.  Debugging output using node--news.html.twig:  <!-- FILE NAME SUGGESTIONS:    * page--node--336.html.twig    * page--node--%.html.twig    * page--node.html.twig    x page.html.twig --> <!-- BEGIN OUTPUT from 'themes/fimc/templates/page.html.twig' -->  I have also tried page--node--news.html.twig with no success.  What am I doing wrong?

Is there any way to make a custom page.html.twig template in Drupal 8?  By default, Drupal generates some suggestions, but I'm looking for something like page--node--content-type.html.twig.


On slow connections (or if the server is randomly slow for some reason) it makes sense to have loading indicators. But when the connection is good, the req is too fast and the loading looks horrible. What is the usual way of handling this? Here are my 2 cases:  Loading on slow/md netowrk:   Loading on fast network:

In an app I'm building the user can click a button to load more content, which might take 1 second or up to X seconds (when X seconds passed I show a timeout error message). There is a "Loading" text (at the moment, it might end up being a spinner) that appears once the button is clicked and disappears when the content is loaded.  My idea is to show the loading state as soon as the user clicks. If the content arrives "too fast" the loading will appear for a very short time, so the user will know something was shown but won't be able to realize what it was (and look strange).  On one hand the content should arrive as soon as possible, but on the other hand, it might be strange to show some information without a minimum time (2 seconds maybe?) to assimilate it.  Any ideas of what is the correct way to go?  I am not looking for specific solutions on how to implement a loading state, @Majo0od provided a  in the comments. I am looking for rationale and/or any relevant case or information if there is.


I'll be traveling to India via London from Helsinki in April 2019( post brexit) , I currently hold a residence premit issued by Finland, Do I need to apply to for a transit Visa (Direct Air Transit ) or I'm still exempt from it

On 23rd of June, 2016, the UK . This leads to the following questions:   Are UK citizens traveling to the EU affected? Are EU citizens traveling to the UK affected? Are UK/EU family members traveling both way affected? Are Commonwealth citizens traveling to the UK affected? Are other visa-free nationals (such as US/Canada citizens) affected? What other consequences might 'Brexit' have on travelers?   Also, see the  on Expats.SE.


Installed ubuntu 18.04 along side with windows 10. Ubuntu 18.04 grub menu does not appear, and always boots to windows 10.  How can cause the grub menu to appear to select my OS of choice?

I have both windows 10 and ubuntu 16 installed on my system.   Lately the system is automatically booting to windows. To boot to ubuntu, I first have to pause startup by pressing escape and then boot into ubuntu.  I know that I have to change the boot order to Ubuntu  but am not able to do so and the grub customiser helps to change only the boot order in grub menu to the best of my knowledge.  What should I do? I am unable to find any way to change the boot order in bios


I know this may be an incredibly easy answer but I couldn't find the answer to this so is there an easy way to convert between hex and decimal and binary and hex in python like the way you can convert from decimal to binary with int()?  Thanks in advance for your answers. - Ed

How do I convert a hex string to an int in Python?   I may have it as "0xffff" or just "ffff".


I have followed some posts in order to redirect all incoming traffic public IP to an internal IP address using iptables. I set sudo sysctl net.ipv4.ip_forward=1 and used the following rules: iptables -t nat -A PREROUTING -p tcp --dport 9080 -j DNAT --to-destination 192.168.178.1:80 iptables -t nat -A POSTROUTING -j MASQUERADE  The idea is that I have a remote server (Ubuntu 20.04.1 LTS) which I can always reach using a reverse SSH tunnel. In that network I would like to access some devices like gateway and other devices. With the iptables I would like to be able to access, for example, the GUI of the gateway. On the local network the rules work! The problem is that on the server I cannot set up the tunnel to redirect 9080 to 192.168.178.1:80. When I try other things on the server, for example ping I get the following: $ ping google.com ping: google.com: Temporary failure in name resolution  And when I set the tunnel: $ ssh user@remoteserverfortunnel.com ssh: Could not resolve hostname remoteserverfortunnel.com: Temporary failure in name resolution  When I set up the tunnel before the rules (removing then with -D), and adding the rules again a get this when requesting the remoteserverfortunnel.com:9080 ssh -N -R 9080:localhost:9080 user@remoteserverfortunnel.com user@remoteserverfortunnel.com's password:  connect_to localhost port 9080: failed.  I can still login the server using the normal port 22 SSH. My question is, why are the rules blocking the tunnel? Is there an extra rule I have to add? EDIT: I added the interface option: iptables -t nat -A PREROUTING -i enp2s0 -p tcp --dport 9080 -j DNAT --to 192.168.1.103:80 iptables -t nat -A POSTROUTING -o enp2s0 -j MASQUERADE  The failure in name resolution is solved. Unfortunately the idea using the tunnel still does not work, I get connect_to localhost port 9080: failed. I did found out that I could also tunnel direct to the device, for example using ssh -N -R 9080:192.168.178.1:80 user@remoteserverfortunnel.com. Using this avoids using the iptables, I would still want to the IP tables option to learn. Some devices also do not work as expect through the tunnel.

I'm trying to redirect a single port to a local server via IPtables.  Currently I have the following rules:  iptables -t nat -A PREROUTING -p tcp -m tcp --dport 55555 -j DNAT --to-destination 10.188.44.125:3306 iptables -t nat -A POSTROUTING -j MASQUERADE   When I have these rules in place, my rsync process of ssh fails.  I'm assuming something here is conflicting, but I'm not sure what.  Any suggestions?  Thanks!  Update: Here are the rules I have in place to allow the rsync over ssh connection.  My input policy is set to drop.  Other policys are set to accept.  iptables -A INPUT -p tcp -m tcp --dport 22 -j ACCEPT iptables -A INPUT -p tcp -m tcp --dport 80 -j ACCEPT iptables -A INPUT -p tcp -m tcp --dport 443 -j ACCEPT iptables -A INPUT -m state --state RELATED,ESTABLISHED -j ACCEPT iptables -A INPUT -p icmp -j ACCEPT iptables -A INPUT -s 127.0.0.1/32 -d 127.0.0.1/32 -i lo -j ACCEPT   Update 2  Here are the results of iptables-save for the nat:  *nat :PREROUTING ACCEPT [8:468] :INPUT ACCEPT [7:408] :OUTPUT ACCEPT [2:134] :POSTROUTING ACCEPT [0:0] [0:0] -A PREROUTING -p tcp -m tcp --dport 53306 -j   DNAT --to-destination 10.183.42.125:3306 [2:134] -A POSTROUTING -j MASQUERADE COMMIT


If reference in C++ is just an alias to an existing variable, why does it have same size as pointer? If they are implemented like pointers only then why creating a separate topic?  struct a{            int x;            int &y=x; };   In this scenario sizeof(a) turns out to be 8 which tries to say that y is taking extra memory for itself.  Which of them is actually fast or both of them consume same time? Which of these concepts is then moved to Java and is closely related to references in Java?

I know references are syntactic sugar, so code is easier to read and write. But what is the difference between a pointer variable and a reference variable?


I'm getting strange IP address while do ping command to localhost by name:  C:\Users\user>ping gold  Pinging GOLD [fe80::c5f8:b871:61d:8182%5] with 32 bytes of data: Reply from fe80::c5f8:b871:61d:8182%5: time<1ms Reply from fe80::c5f8:b871:61d:8182%5: time<1ms Reply from fe80::c5f8:b871:61d:8182%5: time<1ms Reply from fe80::c5f8:b871:61d:8182%5: time<1ms   My PC has only wifi network adapter and it's IP according settings->wifi is simple :  SSID:   SS Protocol:   802.11ac Security type:  WPA2-Personal Network band:   5 GHz Network channel:    104 IPv4 address:   192.168.1.189 IPv4 DNS servers:   192.168.1.254 Manufacturer:   Qualcomm Atheros Communications Inc. Description:    Qualcomm Atheros QCA61x4A Wireless Network Adapter Driver version: 12.0.0.312 Physical address (MAC): 58-00-E3-42-1F-2A   UPD :  I have disabled IPV6:

Something's screwy on our network at work, and I'm no longer able to reach a server where I'm developing a database application. I'm not the network admin, and he's out sick.  When, from my workstation, I ping the server on which SQL Server instance lives:    ping server6   this is the reply:  Pinging SERVER6 [fe80::6579:d35e:3471:f21c%11]  Why is there no IP address as there normally is? Is this an IPv6 address, and if so, why am I seeing it?


Hi I'm an iOS developer and I'm wondering how you design professionals create all those iOS icon sizes that are needed for an app.  For the most part I have seen this as a two-step process:   Create the icon image in one editor Export it into the different sizes   Is there a tool that can easily do both?  That isn't overly complicated?  One button press and all your icons are created and appropriately named?

I am designing an app for Android and as you may know that Android uses 6 different density buckets from LDPI to XXXHDPI.   Is there a way to save multiple outputs of different sizes from one design using either Photoshop, Illustrator, or another software?  If not will I have to resize it 6 times or is there an easy way?


$n>1$. Prove that $n$ is an abelianness-forcing number iff. $n=p_1^{a_1}p_2^{a_2}\dots p_r^{a_r}$, where $p_1,p_2,\dots,p_r$ are distinct primes, is  -cubefree -$p_i\nmid p_j^{a_j}-1,\forall i,j$  (Abstract Algebra: Dummit & Foote, Semidirect products)  The 'only if' part requires me to construct  non-abelian groups of order $n$ if $n$ fails to be cubefree or $p_i\mid p_j^{a_j}-1$, for some $i,j$. If $n$ is divisible by $p^3$ for some prime $p$, we can have either $\Bbb Z_{p^2}\rtimes\Bbb Z_p$ or $(\Bbb Z_p\times\Bbb Z_p)\rtimes\Bbb Z_p$ as a direct product factor for a group of order $n$. Surely it can't be abelian. If $n$ has two distinct prime factors $p$ and $q$. If for instance, $n=pq\dots$ and $p\mid q-1$, we can have $\Bbb Z_q\rtimes\Bbb Z_p$ as a factor for a group of order $n$. Again it can't be abelian. If $n=pq^2\dots$ and $p\mid q^2-1$, which in this case doesn't imply $p\mid q-1$, we have $(\Bbb Z_q\times\Bbb Z_q)\rtimes\Bbb Z_p$ as a direct product factor. The homomorphism associated with this semidirect product can be nontrivial: $$\varphi:\Bbb Z_p\rightarrow\operatorname{Aut}(\Bbb Z_q\times\Bbb Z_q)\cong GL_2(\Bbb F_q)$$ $GL_2(\Bbb F_q)$ has order $(q^2-1)(q^2-q)$, divisible by $p$, so it has a subgroup of order $p$. Again we're done. I have no idea how to deal with the 'if' part, however. The authors do not much hint. They only refer us back to the exercise showing that 'if $G$ is a finite group, with every proper subgroup being abelian, then $G$ is solvable'$-(*)$. I decide to use induction. Let $G$ be a group with an order that is cubefree and satisfies the divisibility condition for all prime factors. Assume the result is true for all groups with order $<|G|$. If $H$ is any proper subgroup of $G$, then its order is cubefree and satisfies the divisibility condition. By induction, $H$ is abelian. By $(*)$, $G$ is solvable. Derived series is either: $1\lhd G$, or $1\lhd [G,G]\lhd G$. I don't know how to show that the latter case is impossible. I think I'm also far from finishing the proof... Can somebody please help?

My question is:     For Which  natural numbers $n$, a finite group $G$ of order $n$ is an abelian group?   Obviouslyو for $n≤4$ and when $n$ is a prime number, we have $G$ is abelian. Can we consider any other restrictions or conditions for $n$ to have the above statement or the group itself should have certain structure as well? Thanks.


If $X$ is a continuous random variable taking non-negative values only, how do I show that $$\mathbb{E}(X)=\int_0^{\infty}[1-F_X(x)]dx$$   It's easy to give a proof if we assume the density function $f_X$ exists (use Fubini's Theorem to interchange the integrations). However, I got stuck in the general case. What if $X$ does not have a density function?

Show that for a non-negative random variable $X$,   $$\mathbb E(X)=\int_0^\infty \mathbb P(X\ge x) \, dx.$$   I started with  $$\mathbb E(X)=\int_0^\infty x \, dF(x)=\int_0^\infty \int_0^x dt\,dF(x).$$ This is my try.


I'm just starting an assignment for school and I'm getting the following error:    I don't know why this is happening. I've included the class header and I'm not using any fancy methods from other classes, just trying to make an object of the class to test the basics of the code. All of these files are in the same project on code blocks, the file sturcture is .  This is my code, can anyone point out what I'm doing wrong, I'm just trying to start the assignment.   Main Method  #include <iostream> #include "sorting.h" using namespace std;  int main() {     sorting<int> object; }   Header  #ifndef SORTING_H #define SORTING_H  template <class T> class sorting {     public:         sorting();         ~sorting();     private: }; #include "..\src\sorting.cpp" #endif // SORTING_H   Implementation  #include "sorting.h" #ifdef _SORTING_H_ template<class T> sorting<T>::sorting() {     //ctor } template<class T> sorting<T>::~sorting() {     //dtor } #endif

Quote from :     The only portable way of using templates at the moment is to implement them in header files by using inline functions.   Why is this?  (Clarification: header files are not the only portable solution. But they are the most convenient portable solution.)


The Wi-Fi icon in the menu bar is displaying as empty. When I open Network Preferences and press “Turn Wi-Fi On”, nothing happens.  I have tried making the Wi-Fi service inactive, deleting it, then restarting the MacBook and adding the service back.   This fix actually worked, but the problem returned after about thirty minutes.   Since then, I have simply been repeating the process every time the Wi-Fi turns itself off, but it is very inconvenient and I hope it is not the only fix.  I’m afraid that the fact that the Wi-Fi turning itself back off again indicates that it’s a hardware issue.  After seeing a response to another user who had a similar problem, I have also tried using Terminal to “cycle the power to my wireless card”. It had no effect.  After restarting the MacBook again, it now says “Wi-Fi: No hardware installed” and will not let me create a new Wi-Fi service.  After another reboot I was able to turn WiFi on again, but it turned off after about ten minutes. I imagine that I will sometimes get “No Hardware Installed” again in the future.

I have a MacBook Pro 2009 running MacOS El Capitan. Recently the Wi-Fi has stopped working.   When I click on the Wi-Fi icon it displays the message "No hardware installed", but Ethernet still works.   Is there any way of fixing this by using a Wi-Fi dongle or something of the sort, if so do I need a specific dongle and how do I install it?


I'm at a loss here.  I have an Android client trying to connect a server on my pc.  It is an actual device not emulated. On sending data I am getting SocketExceptions.  I am connected to the same network as the pc and the port is forwarded. I'm not sure where the issue is now. heres the stacktrace   07-05 11:20:06.876 21128-21587/com.apklegion.pcnotetest W/System.err:  java.net.SocketException: Socket is not connected 07-05 11:20:06.877 21128-21587/com.apklegion.pcnotetest W/System.err:     at  java.net.Socket.getOutputStream(Socket.java:921) 07-05 11:20:06.878 21128-21587/com.apklegion.pcnotetest W/System.err:     at  com.apklegion.pcnotetest.MainActivity$sendData.doInBackground(MainActivity. java:80)        at  com.apklegion.pcnotetest.MainActivity$sendData.doInBackground (MainActivity.java:61)     at android.os.AsyncTask$2.call(AsyncTask.java:304)     at java.util.concurrent.FutureTask.run(FutureTask.java:237)     at android.os.AsyncTask$SerialExecutor$1.run(AsyncTask.java:243)     at     java.util.concurrent.ThreadPoolExecutor.runWorker  (ThreadPoolExecutor.java:1133)     at java.util.concurrent.ThreadPoolExecutor$Worker.run (ThreadPoolExecutor.java:607) 07-05 11:20:06.879 21128-21587/com.apklegion.pcnotetest W/System.err:     at  java.lang.Thread.run(Thread.java:761)   here is the code for the app    private static String ip = "10.0.0.3"; private static int port = 5555;    @Override protected void onCreate(Bundle savedInstanceState) {     super.onCreate(savedInstanceState);     setContentView(R.layout.activity_main);          el = (EditText)findViewById(R.id.text);          button = (Button)findViewById(R.id.button);          button.setOnClickListener(new View.OnClickListener() {              @Override              public void onClick(View v) {                      message = el.getText().toString();               SendData sd = new sendData();              sd.execute(message);                   Toast.makeText(getApplicationContext(),"Data  Sent",Toast.LENGTH_LONG).show();  Toast.makeText(getApplicationContext(),message,Toast.LENGTH_LONG).show();              }          });  }  class SendData extends AsyncTask<String, Void, Void> {    @Override  protected Void doInBackground(String... voids) {       String message = voids[0];     try {         Log.i(TAG, "Attempting to send...");         s = new Socket();         s.connect(new InetSocketAddress(ip,port));         Log.i(TAG,"Socket connected...");     }     catch (IOException e) {   e.printStackTrace();      }        try {      pr = new PrintWriter(s.getOutputStream());          Log.i(TAG,"Get Outstream...");      error here-->     pr.write(message);          Log.i(TAG,"writing message...");          pr.flush();           Log.i(TAG,"flushing...");          pr.close();       } catch (IOException e) {           e.printStackTrace();      }              Log.i(TAG,"closing...");      try {          s.close();          Log.i(TAG,"socket closed...");      } catch (IOException e) {           e.printStackTrace();      }       return null;  }     }  }   and last but not least the server code on the pc side  public class Testtcp2 {     private static  ServerSocket ss; private static Socket s; private  static BufferedReader bufferedreader; private static InputStreamReader isr; private static String message;    public static void main(String[] args) {     try{         ss = new ServerSocket(5555);            while(true){               s = ss.accept();               isr = new InputStreamReader(s.getInputStream());               bufferedreader = new BufferedReader(isr);               message = bufferedreader.readLine();                System.out.println(message);          }            }  catch (IOException ex) {             Logger.getLogger(Testtcp2.class.getName()).log(Level.SEVERE, null,  ex);        }   } }

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


In Extended Universe aka Legends continuity, it is established that after being thrown to the pit, Boba Fett survived Sarlacc due to his extremely strong armor.  Is this true for the current Star Wars canon?

In the EU/Legends material Boba Fett fought his way out of the Sarlacc's guts- Has there been any announcements or anything to suggest he survived getting swallowed by it in the new films (from TFA and beyond)?


Let a < b. Investigate whether there exists a function $f : [a,b]\rightarrow R$ that is continuous and that takes exactly twice each of its values.

I want to prove the following nice statement I've found:  A function $f: [0,1] \rightarrow \mathbb{R}$ takes every function value twice - proof it is not continuous  I've already found an answer to my question but one thing is still not clear to my mind. The answer I found was :   Whole post:  "Assume that you have a function $f$ that does take every real value exactly twice. Let $f(a) = f(b) = 0$ with $a < b$. Let $c \in (a,b)$ be given, and assume without loss of generality $f(c) > 0$. Then for every $0 < \epsilon < f(c)$ there exist $d \in (a,c)$ and $e \in (c,b)$ such that $f(d) = f(e) = \epsilon$. So on the intervals $[0,a)$ and $(b,1]$ our function cannot go any higher than zero. That means that $f$ should take every positive real value on the interval $[a,b]$. However the restriction of $f$ to $[a,b]$ is continuous from a closed interval to $\mathbb{R}$ and thus bounded. Contradiction."  Now everything is clear here except for:  "However the restriction of $f$ to $[a,b]$ is continuous from a closed interval to $\mathbb{R}$ and thus bounded. Contradiction."  Well I think know what Arthur is telling there: Because of the boundary there is always at least one function value that can't be taken twice by the function, e.g. just like the peak of $-x^2$.  But that is exactly where I was stuck before I started researching that issue. Is it really possible to just say it the way Arthur did? I thought that I'd have to further somehow prove the statement that boundary leads to that contradiction.    I hope that it is clear what I was trying to express here...  Anyways as always - thank you for your help!  FunkyPeanut


I want to use an object as a clipping mask for another object. So that the sound waves take on that wedge shape and can be animated as moving through the wedge shape, but of course you don't see the wedge, only the red sound waves.    I need this to be a node setup, probably with ID Masks, Object passes, etc. and not with a boolean modifier as those are unpredictable.  I've done a lot of research and gotten very close but still can't quite figure it out!

I am animating objects that will be rendered with video footage in the compositor. My difficulty is how to apply a mask so that the objects disappear when they expand past a certain point.  Objects within circle mesh should be visible   Objects outside of circle mesh should be invisible   Current nodes set-up for object materials:   What masking options are at my disposal to achieve this effect, and how can I apply them?   Thanks for any insights.


There were at least two books for sure. I don't remember the author or the publishing year, but they were from the 20th century.  The setting was in the somewhat distant future and the story followed two timelines:  The first one was when the main character, who was wildly rich, was in the office of a robot psychiatric counselor that was named after Sigmund Freud. They were trying to find out where the main character's depression came from. I remember the lots of complaining about how annoying the robot was and mildly rude remarks from time to time.  The second timeline was when the main character was young (~25 years old, I think). He had worked most of his life in oil mines (they made butter or something out of it). After winning the lottery he bought a couple of rounds at the pub and took the first shuttle to an alien space station that orbited Earth. There all major nations had sent all kinds of scientists and military forces under one global corporation.   The station had something like 1% Earth's gravity and was filled with 1, 3 and 5 seat alien ships, that people couldn't control a lot. Every ship had a predetermined destination that was locked in the nav computer, which people didn't understand. Everyone had a chance to go to the station and become an explorer (provided they could afford the shuttle ticket).   The point to it all was to see where the ships went, land with a lander module that was attached to the ships, scavenge for any remains of the alien civilization and bring them back to the station, where it was sold to labs on Earth to be studied. The corporation took a huge cut of every artifact sold, and it was illegal to sell it yourself.  After he finished the 1-2 week training program, the main character fell in love (kind of) with a girl on the station, that had experience (bracelets on the hand for every flight). He got a job as a grounds keeper, because he was scared of his first flight being a fatal failure. She was also scared to fail and had a job as a babysitter.  After some time and arguing with the girl, they decided to board a 5 seat ship, which they had to share with 2 or 3 gays. They took turns using the lander module to have some privacy during the flight (the ships didn't have a lot of room).

I am looking for a novel that I'd love to re-read it with my wife (my 13-year old self must be proud of me I guess). Key Plot points The plot was about humanity finding an alien station on an orbit of Earth. (I'm not sure if it wasn't Moon itself). On this station there were thousands of ships ready to travel so there rose a company that paid people to get on those ships and explore the galaxy. The problem was humans didn't understand how to steer those ships so they had to rely on preset targets. Of course there was no telling where particular ship was to go and fair amount of them never returned. Chronology and other relevant information I read it as an early teenager back in early 2000s. It was Polish translation of a foreign (possibly English) story. I think (not sure) that the book wasn't new at the time. It was just one of those books you dig out in a library and take to see if it's good. I don't recall cover either and even if I did it'd be of the Polish version. Additional information could be that the narration was led along the psychoanalytics of the main protagonists where he relives his memories from inside the station and his journeys.


I want to upgrade my home rig with more memory, but I don't know which RAM chips I should buy. I currently have 6GB, I need more to be able to run VMs.   I am considering buying Kingston HyperX Red Fury 16GB RAM modules, a kit of 2x 8GB DDR3 1866Mhz CL10. These are "DDR3" but I am not sure if it's compatible with my rig. How can I tell?  This is my Motherboard:    and the CPU:    and the RAM:

If I want to add more RAM to my computer, how can I buy something compatible? What kinds are there? How do I determine which kind my computer will accept and how much I can add?


If a Rogue gets into melee combat with another combatant wielding a bow, what actions are permitted to disable the bow?   Could the Rogue use Sleight of Hand to unhinge the bow string?   Could he make a melee attack to cut the string or destroy the bow or does he have to disarm the opponent and make him drop his weapon before he may destroy it?  I couldn't find any rules on how to handle such a situation as a DM.

I want to hit enemy's axe to break it. How this is properly played in D&D 5e? And what about shield or armor? Can I attack these items to break it?


When viewing a defensive building (and unit statistics), it will show how much damage per second the building/unit does. Considering the cannon only shoots every 2/3 seconds, does that mean cannon damage x 2/3?

The way that Clash of Clans chooses to convey information about how much damage defense buildings output is bad. The current method of telling the user that a mortar does X dmg a second is pretty worthless since they fire much slower than once a second.  Where can I find a break down / what is the damage break down for how much damage these buildings do per shot rather than per second?  Sure, information on each level of the buildings would be nice but if that is too much I think simply providing the data for level one of each building would also work.


On the German Wikipedia , we can read: "The higher the azimuthal quantum number $\ell$ for a fixed principal quantum number $n$, the more the average distance of the electron from the nucleus increases." Can someone explain to me why this is correct? I thought that the average distance should decrease for increasing $\ell$ and fixed $n$, as \begin{equation} \langle r\rangle _{n\ell} = \frac{a_\mathrm{B}}{2}(3n^2-\ell(\ell+1)). \end{equation}

I was looking at a plot of hydrogen radial wave functions $r^2|R_{nl}(r)|^2$, and I noticed that for fixed $n$, the states with smaller $l$ were "further out" from the nucleus.  This conflicted with my classical notion that the centrifugal force should push things with high angular momentum outwards.  And indeed, the expectation value of $r$ is  $$\tag{1} \langle r\rangle = \frac{a_0}{2}(3n^2-l(l+1)).$$  Is there a physically intuitive reason why lower $l$ states have higher $\langle r \rangle$, and higher $l$ states have lower $\langle r \rangle$?


When I go to The Computer, any key I press comes out as six copies of that key. When I type test it comes out as tttttteeeeeesssssstttttt. Someone else had a similar problem, with all letters coming out doubled.

For some reason when I try and use the developer's computer to make cheats it also gets triple the input. So hhh instead of just h. completely unusable. I'm using firefox and tried it in internet explorer but that still gets 2 inputs. Gah I'm going crazy.


I've installed Ubuntu 14, but I can't install Skype as the required version of Ubuntu is 12!? Is there a way to run Skype on Ubuntu 14?

I want to install Skype, but I can't locate it in Software Center or by using Synaptic Package Manager. Can anyone help me?


Lets say you're in an area of dim light (20% miss chance). You get in combat with some archers, and so cast  on your weapon/holy symbol. This lowers the light in a 20ft radius, in this case to darkness (50% miss chance). Ignore low-light vision and Darkvision.  Can you still see your enemies (assuming they are > 20ft away)? If so, they would have 50% miss chance against you, but you would only have 20% miss chance attacking them.  Ps. I've read some similar questions, but they were all for other systems or not answered.

So, the penalties that are applied when two characters are in darkness, attacking each other, are perfectly clear in the Pathfinder rules:  In an area of dim light, a character can see somewhat. Creatures within this area have concealment (20% miss chance in combat) from those without darkvision or the ability to see in darkness. In areas of darkness, creatures without darkvision are effectively blinded. In addition to the obvious effects, a blinded creature has a 50% miss chance in combat (all opponents have total concealment), loses any Dexterity bonus to AC, takes a –2 penalty to AC, and takes a –4 penalty on Perception checks that rely on sight and most Strength- and Dexterity-based skill checks.  Clearly, two enemies in the same light level are going to have a miss chance and possibly no dex bonus and a penalty to AC. Where the problem comes in is when there are two enemies in different light levels attacking eachother.  In the following situations, who gets what penalty? Xylitol, a wizard in bright light, is firing a scorching ray at Aspartame, a wizard in dim light.  Aspartame fires a scorching ray back at Xylitol.  By RAW, which wizard(s) get a 20% miss chance? Aspartame casts deeper darkness, placing himself in darkness.  Xylitol and Aspartame fire more scorching rays at each other.  By RAW, which wizard(s) have a 50% miss chance, and which one(s) lose their Dex bonus to AC, take -2 to AC, and -4 to Perception checks?


For $ x^2+1=0 $ , can we say that: $ x=+i $ and $ x=-i $

What's the thing with $\sqrt{-1} = i$? Do they really teach this in the US? It makes very little sense, because $-i$ is also a square root of $-1$, and the choice of which root to label as $i$ is arbitrary. So saying $\sqrt{-1} = i$ is plainly false!  So why do people say $\sqrt{-1} = i$? Is this how it's taught in the US?


I've inherited an old Nikon EM camera and Vivitar 35-105mm f/3.5 zoom lens. I have absolutely zero experience in photography but I wanted to get into it. Would the lens that I have fit on a modern day digital camera body? From what I have seen the lens is the most expensive part of the kit. If I could buy a digital body for cheap that would be awesome.  Thank you!

I've got some lenses of brand X, but I've just got a new camera of brand Y. How can I tell if it's possible to use my lenses on my camera? I accept that I may lose a lot of automatic functionality like autofocus, aperture control and metering when using an adapter to connect the two.


Why is the earth shaped like a sphere and not any other shape: cube, prism?

Why are stars, planets and larger moons (approximately) spherical in shape (like, the Sun, the Moon, the Earth, and other planets)?


Of the Ring-bearers since Isildur, we have:   Gollum, on whom the Ring's influence was strongest: it caused him to murder his best friend almost as soon as they found it, and turned him into a wretched creature that lived only to serve/possess the Ring; it also extended his lifespan to several hundred years Bilbo, who was extremely reluctant to give up the Ring to Frodo's care, and always desired to see it again; it also enabled him to become the longest-lived hobbit ever Frodo, who felt irrational dislike towards each of Bilbo and Sam when they tried to 'take' the Ring, and who ended up claiming it for his own rather than destroying it as promised; in later years, its burden never seemed to leave him   That leaves Sam, who bore the Ring for a relatively short time, but did so - and even wore it - on the boundary of Mordor itself.  deals with the issue of why Sam was less affected by it than the others. My question is to what extent was he affected at all: is there any evidence of the Ring either corrupting him by its addictive influence, or unnaturally extending his lifespan, or any other Ringly effect?

There are two characters who seem to be able to handle and wear the One Ring without being affected by its power. One is the mysterious Tom Bombadil. Later in the book, another character seems to have a similar ability:     Sam, believing Frodo to be dead, takes the ring and vows to finish the job. Upon learning that Frodo is still alive, Sam hurries to him and willingly gives the ring back to him. He was able to do this despite being inside Mordor, and despite Sauron's actively seeking the ring bearer.   How was Sam able to resist the temptations of the ring at such a critical stage in the journey?


The problem occurred on my PC with Ubuntu 20.04 and Nvidia GeForce RTX 2070. I tried to install the newest CUDA SDK and had problems with drivers so following various tutorials so following many tutorials I purged Nvidia drivers being willing to install newer ones, but after reboot choosing Ubuntu in GRUB, I get no signal (a blank screen). To fix it I had run Ubuntu Recovery Mode (with internet connection) with root terminal and tried to install drivers. The problem is that I am unable to install any Nvidia drivers now because the dkms package is missing and I cannot install it, constantly giving this message: E: Package 'dkms' has no installation candidate Does anyone have an idea how could I install dkms and so as the drivers and get my Ubuntu running properly again? Results of sudo apt update, sudo apt upgrade and sudo apt install dkms:

There are now errors when updating and I cannot install most software due to a corrupted  /etc/apt/sources.list   file. Is there a copy I can download to replace it?  The file would be for Ubuntu 12.04 (Final Beta) in the United States.


This is the objective function for Xgboost.  I have no idea where $g_{i}$ and $h_{i}$ came from  is some one explain how this two terms came form?  or direct me to the related tutorial page then I will search for it

As an example, take the objective function of the XGBoost model on the $t$'th iteration:  $$\mathcal{L}^{(t)}=\sum_{i=1}^n\ell(y_i,\hat{y}_i^{(t-1)}+f_t(\mathbf{x}_i))+\Omega(f_t)$$  where $\ell$ is the loss function, $f_t$ is the $t$'th tree output and $\Omega$ is the regularization. One of the (many) key steps for fast calculation is the approximation:  $$\mathcal{L}^{(t)}\approx \sum_{i=1}^n\ell(y_i,\hat{y}_i^{(t-1)})+g_tf_t(\mathbf{x}_i)+\frac{1}{2}h_if_t^2(\mathbf{x}_i)+\Omega(f_t),$$  where $g_i$ and $h_i$ are the first and second derivatives of the loss function.   What I'm asking for is convincing arguments to demystify why the above approximation works:  1) How does XGBoost with the above approximation compare to XGBoost with the full objective function? What potentially interesting, higher-order behavior is lost in the approximation?  2) It's a bit hard to visualize (and depends on the loss function) but, if the loss function has a large cubic component, then the approximation will likely fail. How is it that this doesn't cause problems for XGBoost?


Prove that if $a,b,c>0$ then ${1\over a}+{1\over b}+{1\over c}\ge{2\over a+b}+{2\over b+c}+{2\over c+a}$   Excuse me but I am new to inequalities and have been practicing some questions including the one above. The one above looks easy but for me is not. I tried to use AM-GM-HM but led to even greater problems. Here is my attempt: $${a+b+c\over3}\ge{3\over{1\over a}+{1\over b}+{1\over c}}$$ $${1\over 2}\biggl({(a+b)+(b+c)+(c+a)\over3}\biggr)\ge{3\over{1\over a}+{1\over b}+{1\over c}}$$ $$\iff {{1\over a}+{1\over b}+{1\over c}\over3}\ge\Biggl({1\over{6\over a+b}+{6\over b+c}+{6\over c+a}}\Biggr)$$ I could barely spot the wanted up there but cannot continue further. I also got that $${2\over a+b}+{2\over b+c}+{2\over c+a}\ge{1\over a+b+c}$$ Any help, if maybe a different method, would be appreciated. Thank you in advance.

If $a, b, c$ belong to positive real numbers then prove that  $$\frac{2}{b+c} +\frac{2}{c+a}+\frac{2}{a+b} \le \frac 1a +\frac 1b +\frac 1c.$$  I applied AM-GM inequalities on both sides but I cant even figure out what to do on left side.


Me and my friends play Terraria a lot and we only use one main world and I created it. I am not always on as much as they are and they want to use be able to play when i'm not on. Is there a way that I could send  one of my friends the World Save so they could host it instead??

Currently my map server is run on my laptop at home, and my brother and I play via LAN each on his desktop PC.  However, I'd like to transfer my character from the Desktop PC to my laptop in order to play on the go.  Can I do this? Where is the character information saved?