Why String.Concat returns 'True' instead of 'true' (the same with false)? I'm studying boxing and unboxing topic from C# 5.0 in a Nutshell by Joseph Albahari and Ben Albahari. Copyright 2012 Joseph Albahari and Ben Albahari, 978-1-449-32010-2, but I need to extend the deep of knowledge and I found the MSDN article: , on it I found this example code (evidently not intrinsically related to the main topic):  Console.WriteLine (String.Concat("Answer", 42, true));   Once executed it returns:  Answer42True   Why this is happening with the literal 'true' (the same occurs with 'false')?  .  Thanks in advance.
Why does Boolean.ToString output "True" and not "true" true.ToString()  false.toString();  Output: True False   Is there a valid reason for it being "True" and not "true"? It breaks when writing XML as XML's boolean type is lower case, and also isn't compatible with C#'s true/false (not sure about CLS though).  Update  Here is my very hacky way of getting around it in C# (for use with XML)  internal static string ToXmlString(this bool b) {     return b.ToString().ToLower(); }   Of course that adds 1 more method to the stack, but removes ToLowers() everywhere.
PostgreSQL crash when connection failed Error log is:  016-02-21 21:22:34 GET DETAIL:  Connection matched pg_hba.conf line 83: "host    all             all             ::1/128                 md5" .... .... 2016-02-21 21:22:37 GET DETAIL:  Connection matched pg_hba.conf line 83: "host    all             all             ::1/128                 md5" 2016-02-21 21:22:37 GET FATAL:  password authentication failed for user "postgres" 2016-02-21 21:22:37 GET DETAIL:  Connection matched pg_hba.conf line 83: "host    all             all             ::1/128                 md5" 2016-02-21 21:22:37 GET LOG:  CreateProcess call failed: A blocking operation was interrupted by a call to WSACancelBlockingCall.       (error code 299) 2016-02-21 21:22:37 GET LOG:  could not fork new process for connection: No error 2016-02-21 21:22:37 GET LOG:  incomplete startup packet 2016-02-21 21:22:38 GET FATAL:  password authentication failed for user "postgres" 2016-02-21 21:22:38 GET DETAIL:  Connection matched pg_hba.conf line 83: "host    all             all             ::1/128                 md5" 2016-02-21 21:22:42 GET FATAL:  password authentication failed for user "postgres" 2016-02-21 21:22:42 GET DETAIL:  Connection matched pg_hba.conf line 83: "host    all             all             ::1/128                 md5" 2016-02-21 21:24:26 GET LOG:  could not receive data from client: An operation on a socket could not be performed because the system lacked sufficient buffer space or because a queue was full. 2016-02-21 21:24:26 GET LOG:  incomplete startup packet 2016-02-21 21:24:29 GET FATAL:  password authentication failed for user "postgres" 2016-02-21 21:24:45 GET PANIC:  could not write to log file 000000010000000100000041 at offset 4259840, length 8192: Invalid argument 2016-02-21 21:24:45 GET STATEMENT:  COMMIT 2016-02-21 21:24:53 GET LOG:  server process (PID 470944) was terminated by exception 0xC0000409 2016-02-21 21:24:53 GET DETAIL:  Failed process was running: COMMIT 2016-02-21 21:24:53 GET HINT:  See C include file "ntstatus.h" for a description of the hexadecimal value. 2016-02-21 21:24:53 GET LOG:  terminating any other active server processes   Can anyone help to solve the problem? I spent many hours but didn't find a solution.   Postgres version 9.4 Operating System: Windows  postgresql.conf is:  listen_addresses = '*' port = 5432  max_connections = 100 shared_buffers = 128MB   dynamic_shared_memory_type = windows   pg_hba.conf is:  # IPv4 local connections: host    all             all             127.0.0.1/32            md5 host    all             all             0.0.0.0/0               md5 Is it possible to set start-up applications to initialize in certain workspaces? I'd like to not have to manually distribute my start-up applications across my numerous workspaces every time I boot up my machine. I'm running Ubuntu 12.04 .  Any Help ? I have an external hard drive and I did something which I shouldn't have done, and I am annoyed that many files are prompting me about Administrator permissions to move a folder.  They are regular files.  How do I reset all the permission on the external hard drive? How to stop event propagation with inline onclick attribute? Consider the following:  &lt;div onclick="alert('you clicked the header')" class="header"&gt;   &lt;span onclick="alert('you clicked inside the header');"&gt;something inside the header&lt;/span&gt; &lt;/div&gt;   How can I make it so that when the user clicks the span, it does not fire the div's click event? Does "corresponding author" carry an implied meaning? Show f is continuous on (0, ∞) iff f is continuous at 1 for a defined function. exercise: Suppose that $f:(0,∞) → R$  satisfies $f(x) - f(y) = f(x/y)$  for all $x,y$ in $(0, ∞)$ and $f(1) = 0$.   Prove f is continuous on $(0, ∞)$ if and only if f is continuous at $1$.    (proof→:) Suppose that $f:(0,∞) → R$ satisfies $f(x) - f(y) = f(x/y)$ for all $x,y$ in $(0, ∞)$ and $f(1) = 0$. Suppose f is continuous on (0,∞), then by definition f is said to be continuous at a point $a$ if for every $ε &gt; 0$  there is a $δ &gt; 0$ such that $|x-a| &lt; δ$ implies $|f(x) - f(a)| &lt; ε$.   Then suppose f is continuous at $1$, then by our defined function  f(x) - f(y) = f(x/y) , we get $|x-1| &lt; δ$ implies $|f(x) - f(1)| = |f(x) - 0| = |f(x)| =  &lt; ε$.   (proof ←) :Suppose that $f$ is continuous at $1$, then we need to show $f$ is continuous on every point $a$ on $(0, ∞)$. Thus, by definition, f is said to be continuous at a point $a$ if for every $ε &gt; 0$ there is a $δ &gt; 0$ such that $|x-a| &lt; δ$ implies $|f(x) - f(a)| &lt; ε$. Thus, $|x-a| &lt; δ → |f(x) - f(a)| = |f(x/a)| &lt; ε$. Then $f$ is continuous on on $(0, ∞)$.  Please can anyone please help me verify this makes sense. If not, can someone please give any feedback/hints. Thank you in advance. When is it correct to use upper case letters for nouns that may only be unique in a given context? Proof of $\lim_{n\to \infty} \sqrt[n]{n}=1$ Thomson et al. provide a proof that $\lim_{n\rightarrow \infty} \sqrt[n]{n}=1$ in . It has to do with using an inequality that relies on the binomial theorem:  I have an alternative proof that I know (from elsewhere) as follows.  Proof. \begin{align} \lim_{n\rightarrow \infty} \frac{ \log n}{n} = 0 \end{align} Then using this, I can instead prove: \begin{align} \lim_{n\rightarrow \infty} \sqrt[n]{n} &amp;= \lim_{n\rightarrow \infty} \exp{\frac{ \log n}{n}} \newline &amp; = \exp{0} \newline &amp; = 1 \end{align}  On the one hand, it seems like a valid proof to me. On the other hand, I know I should be careful with infinite sequences. The step I'm most unsure of is: \begin{align} \lim_{n\rightarrow \infty} \sqrt[n]{n} = \lim_{n\rightarrow \infty} \exp{\frac{ \log n}{n}} \end{align} I know such an identity would hold for bounded $n$ but I'm not sure I can use this identity when $n\rightarrow \infty$. Question: If I am correct, then would there be any cases where I would be wrong? Specifically, given any sequence $x_n$, can I always assume: \begin{align} \lim_{n\rightarrow \infty} x_n = \lim_{n\rightarrow \infty} \exp(\log x_n) \end{align} Or are there sequences that invalidate that identity?  (Edited to expand the last question) given any sequence $x_n$, can I always assume: \begin{align} \lim_{n\rightarrow \infty} x_n &amp;=  \exp(\log \lim_{n\rightarrow \infty} x_n) \newline &amp;=  \exp(\lim_{n\rightarrow \infty} \log x_n) \newline &amp;=  \lim_{n\rightarrow \infty} \exp( \log x_n) \end{align} Or are there sequences that invalidate any of the above identities? (Edited to repurpose this question). Please also feel free to add different proofs of $\lim_{n\rightarrow \infty} \sqrt[n]{n}=1$. Point Release upgrade from 14.04.1 to 14.04.2? I wanted to upgrade to 14.04.2 point release from 14.04.  What I did was:  sudo apt-get update &amp;&amp; sudo apt-get upgrade &amp;&amp;  sudo apt-get dist-upgrade -y   Then I wanted to upgrade to 3.16 kernel, since it wasn't done with the the above command, so what I did was:  sudo apt-get install linux-generic-lts-utopic xserver-xorg-lts-utopic libegl1-mesa-drivers-lts-utopic xserver-xorg-video-all-lts-utopic xserver-xorg-input-all-lts-utopic sudo apt-get install linux-signed-generic-lts-utopic   Now when I do:   uname -a I get   Linux Y500 3.16.0-33-generic #44~14.04.1-Ubuntu SMP Fri Mar 13 10:33:29 UTC 2015 x86_64 x86_64 x86_64 GNU/Linux  cat /etc/os-release | grep VERSION= I get  VERSION="14.04.2 LTS, Trusty Tahr"   And when I do lsb_release -a I get  Distributor ID: Ubuntu Description:    Ubuntu 14.04.2 LTS Release:    14.04 Codename:   trusty   I know that uname -a and lsb_release -a both refer to different info, but why does  cat /etc/os-release | grep VERSION= show different version? Can I publish an article or thesis about my research without supervisor? Will reformatting my hard drive fix bad sectors on it? I would like to try a different video display driver, but I'm not sure which one I'm currently using.    What's the simple way to see what driver my system is using currently? Which piece of equipment is holding me back? I am primarily an amateur photographer but I do take small jobs from time to time.  I'm looking to upgrade my equipment but I'm not sure if I should be spending money on my body, glass, or both.  I have two common issues that I'd like to improve.   I shoot a lot at ice rinks and find that even in servo mode I get a lot of shots that are slightly out of focus.  I try to keep the AF target on face masks but many shots will come out focused an inch or two off (ears, hands, etc).  I'm shooting F/1.8-F/2.8 to get action stopping shutter speeds so you can really tell when the focus is even a hair off.  I don't know if this is a limitation of my camera, lens, or the human operator. Most of my paid work is indoors shooting candids where a flash is inappropriate.  I feel like I need to use a higher F-number to get more subject in focus but I usually can't do it without upping to ISO 3200 unless I'm using a flash.  By the time I clean up the high ISO noise in Camera Raw I end up with an image lacking detail.  So far this hasn't been a big problem because the photos are typically used in magazine prints only an inch or two wide but it's still driving me nuts.   Here is the equipment currently in my bag:   Canon Rebel T2i Canon EF-S 18-55mm f/3.5-5.6 II (no IS)   Collecting dust, came with my old Rebel XTi.  Canon EF-S 18-135mm f/3.5-5.6 IS   Purchased with my T2i.  This is my workhorse lens but I'm disappointed with the soft images it produces at higher focal lengths.  Stopping down makes the images acceptable but that's not always an option.  My eyes want more contrast and color but considering how inexpensive this lens is I can't really complain.  Canon EF 70-300mm f/4-5.6 IS USM   This was purchased with an older camera and doesn't get used much anymore.  The images are too soft beyond 200mm and the AF seems sluggish.  Canon EF 50mm f/1.4 USM   I am extremely happy with the images I get from this lens.  I use it indoors all the time and also paired with extension tubes for some macro work.  Some of my best ice hockey images have been from this lens even though I didn't have sports in mind for this lens.    My initial plan was to upgrade to a 60D or 7D body but after doing some reading it occurred to me that I might invest in better glass first.  I'm unsure of what will help improve focusing, image quality, high ISO shooting, etc.  Maybe it's a new camera, new glass, photography lessons, or a little of everything?  I'm looking to keep my next round of purchases under $3,000 and am willing to trade in some of my used equipment to offset costs.  Would anyone care to make a recommendation?  I'm looking at the EOS 60D and 7D bodies.  Not sure if the 7D is overkill for my needs.  I'm also looking at the EF 24-70mm f/2.8L USM lens to be my new workhorse but I'm concerned that it may not be wide enough on an APS-C body and the lack of IS might be an issue.  There's also the EF 70-200mm f/2.8L IS II USM but I'm thinking it wouldn't be wise to spend all my budget on that lens right now (or maybe not?). unzip error "End-of-central-directory signature not found" I try to unzip a zip file, but got an error:  $ unzip COCR2_100.zip  Archive:  COCR2_100.zip   End-of-central-directory signature not found.  Either this file is not   a zipfile, or it constitutes one disk of a multi-part archive.  In the   latter case the central directory and zipfile comment will be found on   the last disk(s) of this archive. note:  COCR2_100.zip may be a plain executable, not an archive unzip:  cannot find zipfile directory in one of COCR2_100.zip or         COCR2_100.zip.zip, and cannot find COCR2_100.zip.ZIP, period.   I googled but didn't find a solution. I was wondering why it is and how I should fix it? Thanks!  The zip file can be downloaded from . It is an application, and here is its website .  My OS is 10.10. In the middle of touching up a new texture, I pressed save and suddenly my textures all turned black on the model and UV texture - just vanished.  I tried reopening the file in another instance of Blender, I tried to CtrlZ too and it just did this weird patchy thing on my texture.   How do I recover it and what did I do wrong? Cycles Normal Bake does'nt bake indents that are not tapered I couldn't find anything about Ubuntu acting as a  receiver or sender.   Can it work at all? Are there hardware prerequisites? Is WiFi a requirement or can it work over LAN or another kind of network connection? WiFi direct seems to be a necessary requirement, is it a sufficient one? (i.e. if a system supports WiFi direct does that mean it supports Miracast?) Are there differences in support between receiving/sending? How is the latency? (compared to the competition, i.e. VNC, commercial Miracast devices, etc.) How do I actually use it, if it's difficult?   Specifically, I plan to use it together with an Android phone (4.x Jelly Bean). I've been struggling with this all day today. I imagine it's not very hard, but my algebra skills are terrible. So, how can I show that if $m&gt;n$ and $a$ is a positive integer, then $$a^{2^n}+1 \mid a^{2^m}-1.$$ I just can't get a coherent picture of what I'm supposed to do. If this too (see yesterday's question) boils down to the Unique Factorization Theorem, I would be very grateful for any intuition on how to think about this! How to disable command-Q for Quit? Is there any way to disable command+Q for quitting apps?  I tried adding this menuitem to the "Keyboard Shortcuts" preference pane (as ), and remapping it to command+option+Q (slightly harder to hit), and the menu item changed to show this, but command+Q still causes the app to quit.  I'm using OS X 10.7, but I'd happily upgrade to 10.8 if it fixed this.  The app I really want this for is Firefox, but if there was a solution that disabled command+Q for every app, that would be fine, too. $\lim_{x \to 0} f(x)=\frac{\tan 3x}{\tan 2x}$ without L'Hospital