I am facing problems with library dependencies when trying to install sphirewall-core. Is there any way to solve this or to install that dependencies?  These are the steps I followed:   $ sudo apt-get install sphirewall-core Reading package lists... Done Building dependency tree        Reading state information... Done Some packages could not be installed. This may mean that you have requested an impossible situation or if you are using the unstable distribution that some required packages have not yet been created or been moved out of Incoming. The following information may help to resolve the situation:  The following packages have unmet dependencies:  sphirewall-core : Depends: libboost-random1.49.0 (>= 1.49.0-1) but it is not installable                    Depends: libboost-regex1.49.0 (>= 1.49.0-1) but it is not installable                    Depends: libboost-serialization1.49.0 (>= 1.49.0-1) but it is not installable                    Depends: libboost-system1.49.0 (>= 1.49.0-1) but it is not installable                    Depends: libboost-thread1.49.0 (>= 1.49.0-1) but it is not installable                    Depends: libprocps0 (>= 1:3.3.2-1) but it is not installable                    Depends: libboost-random1.49-dev but it is not installable E: Unable to correct problems, you have held broken packages.

After upgrading from 10.04 to 12.04 I am trying to install different packages.  For instance ia32-libs and skype (4.0).  When trying to install these, I am getting the 'Unable to correct problems, you have held broken packages' error message.   Output of commands:  sudo apt-get install -f Reading package lists... Done Building dependency tree        Reading state information... Done 0 upgraded, 0 newly installed, 0 to remove and 0 not upgraded.   After running this:  sudo dpkg --configure -a foo@foo:~$ sudo apt-get install -f Reading package lists... Done Building dependency tree        Reading state information... Done 0 upgraded, 0 newly installed, 0 to remove and 0 not upgraded.


Whenever I render something in Blender Cycles the renderlayer node seems to have a Z-Depth output, however whenever I try to use it it is completely white. What is it useful for?

How can one make a render pass with black and white data to display depth of field based on the Settings > Camera dof settings? I want to blur or defocus in the compositor, similar to the way it is done with the Z pass but with a more accurate dof information that is based on a target, as opposed to distance away from the camera.  I tried to fiddle with the settings in a new Render layer, overwriting the material, but I have been unable to achieve a render pass effect that outputs something useful.


The main objective in modern physics research is to find a way to unify quantum mechanics and general relativity thorugh a series of theoretical approaches called "quantum gravity theories"  But what if quantum mechanics and general relativity are not connected/related? What if we never find evidence of such connection?

What I am interested to see are specific examples/reasons why gravity should be quantized. Something more than "well, everything else is, so why not gravity too". For example, isn't it possible that a quantum field theory on curved space-time would be the way treat QFT and gravity in questions where the effects of neither can be ignored?


A gambler enters casino with $k$ dollars and he starts betting $1$ dollar each time, with probability $1/2$ he wins $1$ dollar, and with probability $1/2$ he loses his bet (1 dollar), and to win he needs to reach $n$ dollars before getting ruined.  So if he reaches $n>k$ amount, then he wins and leaves, or he loses all his money and leaves.     Find a formula to calculate the probability of the gambler’s winning using $n$ and $k=1$, and $p= 1/2$.

I read upon  Gambler’s Ruin problem and encountered this interesting question. Consider a simple random walk on $\{0, 1, \ldots, N\}$ with absorbing barriers at $0$ and $N$. What is the probability $u_k$ that the walk is absorbed at $N$ if it begins at a point $k$, $0 \leq k \leq N$?  If the question doesn't indicate anything, does it mean this is symmetric? If so, would it be $u_k=\left(\frac{1}{2}\right)^{(N-k)}$?


In the following example, the symbol \omega does not show up after compiling the file. This is the first Greek later for which I have this kind of the problem. Is there a way to solve this problem. This question is related to my previous question in   \documentclass{article} \usepackage[utf8]{inputenc} \usepackage[LFE,LAE,OT1]{fontenc} \usepackage[farsi,english,arabic]{babel}  \begin{document} \selectlanguage{farsi}  $\omega$  \end{document}

Is it impossible to insert the mathematical symbol \times when using the arabi package?  After compiling  A\times B   it becomes AB and the sign \times disappears   See the example below.  \documentclass{article} \usepackage[utf8]{inputenc} \usepackage[LFE,LAE,OT1]{fontenc} \usepackage[farsi,english,arabic]{babel}  \begin{document} \selectlanguage{farsi}  سلام    $A\times B$ \end{document}


Well, I don't know if this is even fixable. At the start of the game, I ended up joining the Imperials like I do any other time, but I accidentally joined the Stormcloaks by giving the Jagged Crown to Assface over in Windhelm.   My controller has always had issues with lag for odd reasons and often selects things I don't want it too. So, my question is: Am I stuck with this guy for the rest of the game? Is there a way to go back to the Imperials? I am playing on the Xbox 360.

This is my first time through playing Elder Scrolls and initially I grabbed every quest that has come available...  At first I thought I wanted to be part of the Imperial Legion but I feel like I picked the wrong side and am now regretting my choice.  So...is there any way to un-join the Legion and join up with the Stormcloaks, or will I have to wait and join them next time?


I'm a beginner in android developer and I want to create an action for an item in menu. This is the mainActivity.java:  public class MainActivity extends AppCompatActivity {  private TextView m; @Override protected void onCreate(Bundle savedInstanceState) {     super.onCreate(savedInstanceState);     setContentView(R.layout.activity_main);     m = (TextView)findViewById(R.id.principal); }  @Override public boolean onCreateOptionsMenu(Menu menu) {     getMenuInflater().inflate(R.menu.menu_main,menu);     return true; }  @Override public boolean onOptionsItemSelected(MenuItem item) {     if (item.getItemId()==R.id.info){         m.setText(R.string.about_text);         return true;     }     return super.onOptionsItemSelected(item); } }   And this is activity_main.xml:  <RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android" xmlns:tools="http://schemas.android.com/tools" android:id="@+id/principal" android:layout_width="match_parent" android:layout_height="match_parent" android:paddingBottom="@dimen/activity_vertical_margin" android:paddingLeft="@dimen/activity_horizontal_margin" android:paddingRight="@dimen/activity_horizontal_margin" android:paddingTop="@dimen/activity_vertical_margin" tools:context="bd2c.bd2c_appdemo.MainActivity">  <TextView     android:layout_width="wrap_content"     android:layout_height="wrap_content"     android:text="@string/app_text" /> </RelativeLayout>   and menu_main.xml:  <menu xmlns:android="http://schemas.android.com/apk/res/android"> <item android:id="@+id/info"     android:title="@string/get_info"/>     When I start my app, It display: unfortunately app has stopped

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 it possible to assign multiple keyboard shortcuts for same default command. I want to switch between workspaces using CTRL+NUMPAD_1 and using CTRL+1 too.  Or how to add custom command for switching?

I've been wondering how can I assign to multiple keyboard shortcuts to do the same action? More specifically, I want to be able to change my volume with both my headset buttons and my keyboard.  I'm able to change the volume with just one at the time: with the one I define in the 'Keyboard shortcuts' application. Is there any way?


I'm trying to proof that the Thomae's function doesn't have a limit as  $\lim_{x\rightarrow x_0}$, $x_0\in \mathbb{Q}$.  I'm pretty sure, that I can solve this by using the $\epsilon-\delta$-critereon, but I cant figure out how. If a limit would exist, that would mean:  $\forall\epsilon>0 \exists\delta : |f(x)-L|<\epsilon, \forall x\in D, 0<|x_i -x|<\delta$  I'm pretty sure that you simply can't find a matching $\delta$ as in the environment of each rational number there are some irrational numbers where the Thomae's function is equal to $1/q$ and not $0$.   Could you help me to complete this proof by helping me arguing&writing this mathematicly correct?  Edit:  This isn't a duplicate because I'm looking for the limit and not discontinuity. I have to proof this with the $\epsilon-\delta$-critereon for the limit and not for the discontinuity (even though they are kind of similar, they're different!)

I know there are many answers for this question. I had read almost every answer And try get arguments But something that goes missing in each time. I had been stuck on this problem since half day but not understating. Please help me in this regard. Let $f$ be defined on $[0,1]$;  $$ \begin{align} f(x) = \begin{cases} 0 & \text{if $x$ is irrational}\\ \frac{1}{q} & \text{if $x = \frac{p}{q}$ where $(p,q) = 1$ and $q$ > 0}. \end{cases} \end{align} $$ For the rational numbers, I consider a sequence of irrational points $x_n$ converging to some rational number say $m/n$.  If this function is continuous for any rational say $m/n$ then this must hold: $\forall \epsilon >0$ ,$\exists \delta>0$ such that $|1/n|<\epsilon $ whenever $|x_n-m/n|<\delta$.But for any particular $m/n,1/n$ need not be small. Therefore function is discontinuous at the rational points.  For the irrational points, consider rational sequence $y_n$ converging to $a$, irrational number. Consider $y_n \to a$ therefore $\forall \epsilon >0 $, $\exists N$ such that $|y_n-a|<\epsilon $ $\forall n>N$ In case the function is continuous at $a$ then it must satisfy following $\forall \epsilon >0 $ ,$\exists \delta>0$ such that|$f(y_n)$|<$\epsilon $ whenever $|y_n-a|<\delta$. I wanted to make that $f(y_n)$ small for that $y_n$ in neighborhood  of $a$.From this I am not able convince myself from last answers.   This is not a duplicate, since I specified my particular problem with this proof. Please help me.


I need some help understand why a relationship is created between arrays when I replicate an array by reference. Take the following example:  let a = [1,2,3]; let b = a; b.push(4); console.log(b); // [1,2,3,4] console.log(a); // [1,2,3,4] a === b; // true   For some reason, {a} changes when I modify {b}, when I expected them to be independant arrays.  This kind of relationship is not true for variables, it appears. Take the following example:  let a = 'test'; let b = a; b = 'test1'; console.log(b); // "test1" console.log(a); // "test" a === b; // false   Does anyone know the reasoning behind the behavior for arrays?

The primitive types (number, string, etc.) are passed by value, but objects are unknown, because they can be both passed-by-value (in case we consider that a variable holding an object is in fact a reference to the object) and passed-by-reference (when we consider that the variable to the object holds the object itself).  Although it doesn't really matter at the end, I want to know what is the correct way to present the arguments passing conventions. Is there an excerpt from JavaScript specification, which defines what should be the semantics regarding this?


if ((vnd = (struct diam_vnd_t *)g_hash_table_lookup(vendors,vend))) {...}   Can you tell me why it is an assignment but not a boolean expression in the brackets ? And in what situation this assignment can be considered "true" or "false" ?

In many languages assignments are legal in conditions. I never understood the reason behind this. Why would you write:  if (var1 = var2) {   ... }   instead of:  var1 = var2; if (var1) {   ... }


I'm trying to compare two same dates in the browser console and getting the result as false. I don't understand how is it comparing as both the dates are the same?    $(function() {   var d1 = new Date("01-12-2001");   var d2 = new Date("01-12-2001");      console.log(d1 == d2); }); <script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script>     but here if try to compare with GT and LT then its working.

Can someone suggest a way to compare the values of two dates greater than, less than, and not in the past using JavaScript? The values will be coming from text boxes.


In an exercise I have to prove that $f_n(z)=nz^n$ converges uniformly for $|z|<\frac{1}{2}$.  So I have to prove that:  $$\forall \varepsilon>0, \exists N \in \mathbb{N}:|nz^n-f(z)|<\varepsilon\ \ \ \text{if } n\geq N$$  I calculated $\lim_n nz^n=0$, so we basically need to prove that:  $$\forall \varepsilon>0, \exists N \in \mathbb{N}:|nz^n|<\varepsilon\ \ \ \text{if } n\geq N$$  My approach:  we can write $z=re^{i\varphi}$  then we have that $|nz^n|<\varepsilon$ is equivalent to $nr^n<\varepsilon$ and we have that $r<\frac{1}{2}$ but I got stuck here. How can I procede?

In an exercise I have to prove that $f_n(z)=nz^n$ converges uniformly for $|z|<\frac{1}{2}$.  So I have to prove that:  $$\forall \varepsilon>0, \exists N \in \mathbb{N}:|nz^n-f(z)|<\varepsilon\ \ \ \text{if } n\geq N$$  My question is, how can I find that $f(z)$?  I've tried calculating the $\lim_n nz^n$ but I got stuck. How can I evaluate this limit?


Let $\mathcal{A}$ be a Lie algebra, and $$  \operatorname{Aut}(\mathcal{A})=\{a \in \operatorname{End}(\mathcal{A}) \mid[a(x), a(y)]=a([x, y]), \forall x, y \in \mathcal{A}\}, $$ where $\operatorname{End}(\mathcal{A})$ denotes the set of linear maps $\mathcal{A}\to\mathcal{A}$. I have to show that $\operatorname{Aut}(\mathcal{A})$ is a closed Lie subgroup of $GL(\mathcal{A})$, and I've been provided the hint that I should first show that $\mathrm{Aut}(\mathcal{A})$ is the isotropy group (a.k.a. the little group or the stabilizer) of some point in some representation of $GL(\mathcal{A})$. Could someone give me a sketch or clue of how to prove the latter?

Let $G$ be a lie group with lie algebra $\frak{g}$. Let $Aut(\frak g)$ be the automorphism group of $\frak{g}$.   Its clear to me that $Aut(\frak{g})$ $\subset GL(\frak{g})$ since any automorphism of $\frak{g}$ is also a linear transformation. Now i have several questions:   How do i prove that $Aut(\frak{g})$ is actually a lie subgroup of $GL(\frak{g})$? I've tried playing with actions to realize $Aut(\frak g)$ as an orbit or an isotropy subgroup but nothing worked out... Say $H \subset G$ is an abstract subgroup (not necessarily lie). Are the following statements equivalent?   $$\{T_e H \text{  is closed under the lie bracket of } \frak{g} \}$$  $$ \{H \text{is a lie subgroup of } G\}$$   How does the lie algebra of $Aut(\frak g)$ look like? When does $Aut(\frak g)$ $= G$? what does $Aut(\frak g)$ tell me about $G$?


I need to sort a file based on names in the first column. Some of the names end in a question mark. sort persistently ignores this question mark during sorting:  sort -k 1 -t , <<TEST a?,1 a,2 b?,2 b,1 TEST     a?,1 a,2 b,1 b?,2   I don’t really care about how sort orders the question mark, if it only did it consistently. But it doesn’t, it seems to consider the second column instead, even if I tell sort explicitly only to use the first column as key.  Version info:  $ sort --version sort (GNU coreutils) 8.22 Packaged by Gentoo (8.22 (p1.0))   Incidentally, on OS X 10.9 (where sort identifies itself as “sort (GNU coreutils) 5.93”), the above works as expected for me.

Consider the following input to sort:  cat > foo <<EOM D,,5014978 DD,,25 D,I,1972765530 D,Y,4223624 -,Y,71285059 YA,I,2 EOM   Now try running sort foo  The output is not sorted when trying this on any of my linux boxes (gnu coreutils versions 6.9-7.4).  The output is sorted when run under cygwin (gnu coretuils 8.5).  Comments?


I've seen responses using , where the code is broken up into html, css, javascript and the output.  Q: If I have a post that includes a lot of code, is is better to post it to an outside source, or simply paste it into my question in a code block?

. (See comments to the question: the OP tried to include a couple of long XML files, but that wasn't possible.)  What's the recommended approach to including code/data, when there's just too much of it to embed in the question?  I could think of a few approaches myself:   Paste the data to a pastebin and link (and wait for the links to die) Encode the (compressed) data in an image and include that (kludgy!) Implement an attachment feature in Stack Overflow (which will probably be abused)


This is my CSS code  footer {     position: relative;     height: 50px;     width: 100%;     background-color: white; } p.copyright {       position:absolute;     width:100%;     line-height:40px;     color:red;     vertical-align:bottom;     text-align:center;     bottom:0; }   This is my aspx HTML code
   Copyright 2017 Anime Toys
        I'm trying to keep footers at the bottom of all web pages. The problem that I'm facing is that some web pages contains small amount of content, the footer can sometimes sit halfway up the page leaving a blank space underneath.  How do I solve this issue? Can someone fix my code?

I have a simple 2-column layout with a footer that clears both the right and left div in my markup.  My problem is that I can't get the footer to stay at the bottom of the page in all browsers.  It works if the content pushes the footer down, but that's not always the case.


I had wubi installed on my pc with Windows 7 and recently I removed wubi and the partition I had my wubi installed (I removed wubi because I had installed Ubuntu on a separate partition as a dual boot). This lead me to grub rescue problem. But I was able to resolve this my issuing the commands mentioned in the first answer .  This got me my windows and ubuntu on the grub back but had to re-issue the commands every time I restarted my machine. To get rid of this I used the  tool to fix it as was suggested on the web.   Now this had lead me to a situation where I have ubuntu but can't see the windows 7 on the grub list. Can someone please let me know how do I get it back?

i am newbie to this i installed Ubuntu using separate drive and i choose windows 7 loader as a boot device loader and after the installation i can only choose Ubuntu no windows 7 os so please help me to solve this .


This is a problem from a previous math competition. $a, b$ can be anywhere in the range $[1,10^9]$ ($a \le b$). Edit: We can choose any subset of numbers from $a$ to $b$ to form a single sum. Each number cannot be used twice for the same sum. For example, if $a = 2, b = 5$, then one possible sum is $2 + 4 + 5 = 11$. The possible sums we can get range from $a$ up to $\frac{b(b+1)}{2} - \frac{a(a-1)}{2}$.  I got this second number by using the formula $\sum_{i = a}^{b}{i} = \sum_{i = 1}^{b}{i} - \sum_{i = 1}^{a-1}{i} $. But still, this is a really large range to be brute-forced. For example, if $a = 1, b = 10^9$, then the range to be brute-forced would contain around $10^{18}$ numbers. How do I solve this? Any help would be much appreciated :)

For example, given four distinct numbers $5, 6, 7, 9$ We have $2^4-1$ sums, $5, 6, 7, 9, 11, 12, 14, 13, 15, 16, 18, 22, 20, 21, 27$ which are the sums from the numbers.  But if given five distinct numbers $5, 6, 7, 8, 9$, then we see $5 + 9 = 6 + 8$, hence the possible distinct sums of them cannot be easily counted by $2^5-1$.  Is it possible to easily count all the possible distinct sums from distinct numbers? Thanks!


Suppose we have the a random variable $X$, which is normally distributed $N(\theta,1)$ and we estimate $\theta$ using the squared error loss function, $L = (\theta, d) = (\theta - d)^2$. To find the Bayes estimator, we find $d$ which minimizes the expected loss and we obtain that the Bayes estimator is the posterior mean. Isn't this the same procedure to also find the maximum likelihood estimator of $\theta$? Wouldn't we also aim to minimize the expected loss in that case? I struggle to see what the difference is between the two concepts, at least in this context.

Please explain to me the difference in Bayesian estimate and Maximum likelihood estimate?


I am using HP 15 BS576tx laptop, but while I am installing Ubuntu 16.04 the Wi-Fi is not working.

I have not much experience with ndiswrapper but some vague memory of using it with some broadcom module long back. Now, here is the problem. Realtek RTL8723DE wireless module is used in my new HP 15-BS576TX laptop. I haven't installed Linux yet. But, would like to check if Ndiswrapper can help use the Windows driver to work in Linux. Here is the Windows 10/8/7 driver for this RTL8723DE wlan module:   I extracted the exe and can see a folder /RTWLANE_Driver/Wind7X86/ which has rtwlane.sys and few other files which I presume is related to the wireless driver. Is there any chances of luck with ndiswrapper considering the driver executable actually contains win8/win7 drivers.  Thank you.


I've been working on a website almost social-media-like that, amongst other things, allow users to upload/share files as attachments. I intend to permit every file type and a limit of maybe 200mb per attachment. I have zero experience with website hosting. I earlier thought that I would deal with it later when the time comes, but now I want to at least have an idea of the challenges I will encounter and be prepared and to keep them in mind as I continue development. I know of the existence of free web hosting services but I doubt those will allow me to keep GBs of data. So if anyone will be kind as to suggest good hosting services, their pricing, storage capacities, or point me to where I can learn about them. The website I am working on is built with Reactjs for frontend and ASP.NET Core for backend.

This is a "catch-all" question designed to serve as an answer for all questions about choosing web hosting.  Pro Webmasters no longer accepts new questions about how to choose hosting.  All future questions pertaining to finding web hosting should be closed as a duplicate of this question. For more information about this policy please see .    How to find web hosting that meets my requirements?  What we're looking for in answers to this question are the basics about web hosting:   What is web hosting? What is the difference between shared, VPS, and dedicated hosting? How does a content delivery network relate to web hosting? Anything else you feel is helpful in finding a web host.   What we do not want is:   Endorsements or recommendations for specific web hosts We do not want your experience or other subjective information (just the facts please)


Everything found at the word |Agristats and beyond to the end of the line should be deleted.    I have tried a couple things which do not appear to working-- |Agristats.*$ and |Agristats*$.  References I have consulted are--  and .  Need help solving this, please!   INPUT  0011  |86|19|SALVAGE EVIS WINGS            | 0000029| 0001423.11|Agristats new trial_200 (edited).xlsx|'2-17$' 0012  |86|19|EVIS SALVAGE - BONELESS BREAST|-0000019|-0001080.38|Agristats new trial_200 (edited).xlsx|'2-17$' 0013  |86|19|SALVAGE EVIS DARK MEAT        | 0000024| 0000859.95|Agristats new trial_200 (edited).xlsx|'2-17$' 0011  |86|19|SALVAGE EVIS WINGS            |-0000022|-0001687.17|Agristats new trial_200 (edited).xlsx|'2-24$' 0012  |86|19|EVIS SALVAGE - BONELESS BREAST| 0000000| 0000063.71|Agristats new trial_200 (edited).xlsx|'2-24$' 0013  |86|19|SALVAGE EVIS DARK MEAT        | 0000016| 0000956.60|Agristats new trial_200 (edited).xlsx|'2-24$' 0018  |88|19|SMALL FRONT HALF SALVAGE      | 0000045| 0003087.42|Agristats new trial_200 (edited).xlsx|'2-24$' 0227  |78|19|DISJOINTED WING W/O TIP (6377,|-0000019|-0035659.00|Agristats new trial_200 (edited).xlsx|'12-2$' 0438  |78|19|WIP BLSL FILET 3.5OZ - 8.75OZ |-0000019|-0035218.00|Agristats new trial_200 (edited).xlsx|'12-2$' 0611  |78|19|SLIT BL SL BREAST FILET      (|-0000019|-0036078.05|Agristats new trial_200 (edited).xlsx|'12-2$' 1525  |78|19|WOG 2.50-DN  14HD CW  BF      |-0000790|-0024238.08|Agristats new trial_200 (edited).xlsx|'12-2$'   OUTPUT (desired)  0011  |86|19|SALVAGE EVIS WINGS            | 0000029| 0001423.11 0012  |86|19|EVIS SALVAGE - BONELESS BREAST|-0000019|-0001080.38 0013  |86|19|SALVAGE EVIS DARK MEAT        | 0000024| 0000859.95 0011  |86|19|SALVAGE EVIS WINGS            |-0000022|-0001687.17 0012  |86|19|EVIS SALVAGE - BONELESS BREAST| 0000000| 0000063.71 0013  |86|19|SALVAGE EVIS DARK MEAT        | 0000016| 0000956.60 0018  |88|19|SMALL FRONT HALF SALVAGE      | 0000045| 0003087.42 0227  |78|19|DISJOINTED WING W/O TIP (6377,|-0000019|-0035659.00 0438  |78|19|WIP BLSL FILET 3.5OZ - 8.75OZ |-0000019|-0035218.00 0611  |78|19|SLIT BL SL BREAST FILET      (|-0000019|-0036078.05 1525  |78|19|WOG 2.50-DN  14HD CW  BF      |-0000790|-0024238.08   Replace Dialogue  I do not understand why the replace prompt says Replaced All: 1,223 occurrences were replaced, and yet the file looks exactly the same with not changes made.

I am tired of always trying to guess, if I should escape special characters like '()[]{}|' etc. when using many implementations of regexps.  It is different with, for example, Python, sed, grep, awk, Perl, rename, Apache, find and so on. Is there any rule set which tells when I should, and when I should not, escape special characters? Does it depend on the regexp type, like PCRE, POSIX or extended regexps?


I have a multidimensional array in PHP and I want to un-nest all elements to bring them to the top level. Here is the array:   Array (     [0] => Array         (             [id] => 1             [color] => red          )      [1] => Array         (             [0] => Array                 (                     [id] => 2                     [color] => blue                 )              [1] => Array                 (                     [0] => Array                         (                             [id] => 3                             [color] => green                         )                  )              [2] => Array                 (                     [id] => 4                     [color] => blue                 )          )      [2] => Array         (             [id] => 5             [color] => purple         )  )   What I want end the end is this... so basically it loops over the array and any group it just unnests it. Sorry, I don't know the proper terminology. Is there PHP function for this? I've tried several solutions on stack but it moves all key values pairs up to the top and not just the array groups --- it just creates a mess.   (     [0] => Array         (             [id] => 1             [id] => red                         )     [1] => Array         (             [id] => 2             [color] => blue         )      [2] => Array         (             [id] => 3             [color] => green         )      [3] => Array         (             [id] => 4             [color] => blue         )       [4] => Array         (             [id] => 5             [color] => purple         )  )   Thanks!

It's probably beginner question but I'm going through documentation for longer time already and I can't find any solution. I thought I could use implode for each dimension and then put those strings back together with str_split to make new simple array. However I never know if the join pattern isn't also in values and so after doing str_split my original values could break.  Is there something like combine($array1, $array2) for arrays inside of multi-dimensional array?


9999 coins is super tricky and maximum number getting this many coins allows you to buy outfits that cost 9999 skeleton and 3D 8 bit blocky version also this can help you participate endlessly in challenges. If you want to buy many outfits this is your number also do you want toad hints each is 50 get this many coins for endless ones.

I'm saving up for a 9999 coin item in the shop (post-game content) so I need a lot of coins. Outside of the few vault chambers associated with a few power moons, are there any dense locations for farming coins?


I'm cruising round trip out of London in July 2019, my ship stops at several EU ports. Do those port days count towards the 90 day limit for the EU zone? I will be in EU before and after cruise so I need this info to calculate my total days.

I am planning on spending 90 days in Schengen zone countries.  I will be taking a cruise between Lisbon and Barcelona.  Do the days at sea count against the 90 days allowed for staying in the Schengen zone?


I know that SSDs have a shorter write lifespan, even tho many say it will last more that the average user would use, I think that using it as virtual memory would burn it out way faster than the usual read/writes of a common user that do not work with audio/visual for example. Is there any definite answer for this? Would it burn that section faster? Is there anything one could do to align the sections so that an minimum amount of cells are damaged at once?

I'm considering getting an SSD drive to run as the primary OS partition.  As I understand, this should provide a substantial improvement in performance.     My question is this: Should I leave the swap file on that drive?     The swap partition will be largely random seeks and so should benefit from the speed.  On the other hand, it will be constantly written to which will wear out the drive faster.


I was looking on some examples and I don't know what this means:  if(FileExistsA("File.ext"), false) {      .... }   Can someone explain me this please?


How to produce diacritical (accented) characters under Ubuntu 14.04? I used to be able to do it under 12.04 by installing the relevant language support, however under Ubuntu 14.04 the only available language seems to be English. The language support seems to relate to the language of the interface rather than the keyboard input. When I upgraded from ubuntu 12.04 to 14.04 on my previous computer, the language support seemed to be unaffected. How come I cannot have it on my current one which had the 14.04 installed from scratch? If there's no way of getting this feature, could you please let me know how do downgrade to the 12.04 version? Maybe upon upgrading it, I could keep my language settings?

I use Ubuntu-Gnome 13.04 and I can't change system language. I set it to Polish with "language & regions". It was though because there is no option for adding so i installed:  language-pack-pl  language-pack-gnome-pl  then i could pick it in "language & regions" and then reboot. However this didn't solve my problem  I also change it with gnome-language-selector and still got english.  Please help, because if the language is other than polish i will have to switch back to windows. I like the gnome3.


How should I go about compiling programs that depend on libraries whose development packages (headers and such) aren't pre-installed on the system when I don't have sudo access?  In this particular case I have Ubuntu 12.04, but I'm hoping for a more general solution, because it seems bizarre to me that I would need administrator privileges just to install the dev packages so I can compile.

Assume I have ssh access to some Ubuntu server as user and I need some not system tools to be installed for convenience (mc, rtorrent, mcedit). I do not want to bother admins for these small programs.   Is there a way to install them (make them run) without using something like sudo apt-get install?


I’m trying to find a feature selection package in R that can be used for regression. Most of the packages implement their methods for classification using a factor or class for the response variable. In particular I’m interested if there’s something using random forest for that purpose. Also if someone knows some good paper in this field would be welcome.

I am very new to R. I am learning machine learning right now. Very sorry, if this question appears to be very basic.  I am trying to find a good feature selection package in R.  I went through Boruta package. It is a good package but I read that it is only useful for classification.  I want to do implement feature selection in R for regression tasks. I went through the caret package documentation but for my level, it is very difficult to understand.  Can any one please point me to a good tutorial or list any good packages or most frequently used packages in R for feature selection.  Any help would be appreciated. Thanks in advance.


I am trying to create a button on a button click and if this created button is also clicked there should be another action.  Here is my code:  //EDIT FUNCTION             $('.edit').on('click', function(e){                 e.preventDefault();                 content = $(this).prop('name');                 id = $(this).prop('id');                 if(!document.getElementById('editnews')) {                     jQuery('#edit').append('
<textarea id="editnews" value="'+id+'"></textarea>
');//is not shown, needed to stop, damn online lib                     jQuery('#edit').append('<button name="'+id+'" class="saveedit btn btn-success btn-mini"> Save</button>');                 }                 $('#editnews').val(content);             });          // EDIT (SEND) FUNCTION         $('.saveedit').on('click', function(e){             console.log("oke");             e.preventDefault();             $.ajax({                 type: 'POST',                 url: 'index.php?page=news',                 data: {editid:$(this).prop('name'), editcontent:$('#editnews').val()}             }).done(function(response) {                 location.reload();             });         });   So the first edit function works fine, but the second not as the button could not be tracked. Hope you can help meh

I have a bit of code where I am looping through all the select boxes on a page and binding a .hover event to them to do a bit of twiddling with their width on mouse on/off.  This happens on page ready and works just fine.  The problem I have is that any select boxes I add via Ajax or DOM after the initial loop won't have the event bound.  I have found this plugin (), but before I add another 5k to my pages with a plugin, I want to see if anyone knows a way to do this, either with jQuery directly or by another option.


May be this is a stupid question? Sorry it sounds so. I have following codes.  Condition 1  public class Test {      int a;      void display() {         System.out.println(a);     } }   Condition 2  public class Test {      void display() {         int a;         System.out.println(a);     } }   I am very clear about the second condition. The a is not initialized. So, this will produce an error. But in first condition, I've not initialized property a. While running the following code, it will not produce an error. Instead it will display 0. It may be due to integer is initialized to 0.  Test t; t = new Test(); t.display();   What is the logic behind not to initialize local variable and to initialize property(integer) to 0?

Was there any reason why the designers of Java felt that local variables should not be given a default value? Seriously, if instance variables can be given a default value, then why can't we do the same for local variables?  And it also leads to problems as explained in :     Well this rule is most frustrating when trying to close a resource in a finally block. If I instantiate the resource inside a try, but try to close it within the finally, I get this error. If I move the instantiation outside the try, I get another error stating that a it must be within a try.      Very frustrating.


I would like to ask a question about a licence (GNU GPL) but, I am not sure which is the right community. I have already read many sources, including the official one and also the most frequent asked questions section. However, since this is a delicate matter and I would not want to ruin things, I want to make sure that I understood correctly. Also, not being a native english speaker causes me trouble when it comes to specific topics - like licences for example. Someone suggested me Superuser, but It did not seem like the right place.

Is it appropriate to ask questions about software licenses/licensing on ? Or is the appropriate place  ? Or is there no appropriate site currently and we should suggest such a site on ?


I am confused as to why eigenvalues are the principal components. What is the intuition behind finding the eigenvectors of the covariance matrix for PCA?

In today's pattern recognition class my professor talked about PCA, eigenvectors and eigenvalues.   I understood the mathematics of it. If I'm asked to find eigenvalues etc. I'll do it correctly like a machine. But I didn't understand it. I didn't get the purpose of it. I didn't get the feel of it.        I strongly believe in the following quote:     You do not really understand something unless you can explain it to your grandmother. -- Albert Einstein   Well, I can't explain these concepts to a layman or grandma.   Why PCA, eigenvectors & eigenvalues? What was the need for these concepts? How would you explain these to a layman?


My account was blocked from asking questions. Help center says to make some positive contributions to the site?  What are some of the ways that Stack Overflow expects from me?

If you are reading this, you may have been affected by one of our post quality bans. If so, it is important that you  to understand what has happened and how to regain the permissions that you lost. While trying to ask a question, one could see:  We are no longer accepting questions from this account. See  to learn more.  Likewise, for answers:  We are no longer accepting answers from this account. See  to learn more.   Why am I getting this message? Are deleted posts taken into account too? Is a question/answer ban the same as a suspension? How do I avoid getting a question ban? How long do I have to wait before I can post again? What can I do to release the ban? How can I reactivate my account? Can I simply create a new account? I'll just ask somewhere else on the SE network, and they'll migrate my question to the correct site! Will a ban on one Stack Exchange site affect my standing on other sites in the network? Does this apply to meta sites too? My account is in good standing. Why am I still blocked?


Let's say we have the equation: $$x^y=y^x$$ what are the solutions when $x,y \in \Bbb Z$ for ${x}\ne{y}$..   The only one I have found is 2 and 4. There are infinite non-integer solutions but I am interested in the integer ones. Also you can find a new definition for $e$ from this equation $e=x^{\frac{y}{xln(y)}}$ and also $log_x(y)=\frac{y}{x}$

We know that $2^4 = 4^2$ and $(-2)^{-4} = (-4)^{-2}$. Is there another pair of integers $x, y$ ($x\neq y$) which satisfies the equality $x^y = y^x$?


We are going the create our Sql-Servers new on new hardware / VM's and think about which Sql-Server Version to go with. We are actually using Sql Server 2008 R2. We have already done a project for testing everything for any compatibility issues between 2008 and 2014 - and have fixed all issues in application code as well as in the db schemas to be ready for 2014.   Now the question for simply dismissing 2014 and directly go to 2016 came up. We are not sure.  I have ran SQL 2016 Upgrade Advisor - it said "ready for upgrade (2016)" and raised around 500 warnings for deprecated ntext, text and image columns.   Are there any special additional downsides of going to 2016 instead of 2014? Are there new compatibility issues? AFAIKS there have been no new deprecations in 2016 that are not yet in place of 2014... What do we have to consider?

A dilemma probably faced by quite a few DBAs. Does one upgrade to the latest version, in this case SQL SERVER 2016, or play it safe and upgrade to 2014, which hopefully has most bug fixes in place by now?  I will only be upgrading in Standard Edition and from what I've read there isn't much between 14 & 16 in terms of functionality, enterprise is a different story.  The only things of interest to me at the moment in 2016 are probably the query store features and possibly the tabular BI stuff.  I have read 2016 does use fewer resources and depending on the tasks it executes faster, which is obviously a big bonus.  At the moment I am leaning towards 2016 as opportunities to upgrade are few and far between, just worried about potential bugs and applying them in 24/7 up time environment with no maintenance window.  Would be great to hear if anyone else has faced the same/similar upgrade path, and ultimately what decision they took.  I will probably get a down vote as there is no right answer...but its a question that must be asked a lot..


I changed the password but I don't know how to do the username

Some time ago, when I installed Ubuntu, I chose a rather stupid username for my account that I do not want to use anymore. How do I change this (including the name of my home directory, and the name in the terminal) without losing settings for applications? How do I keep permissions and my keys for various authentification (e.g. email, SSH, GPG and more)? What settings could possibly get lost if I changed my username?


How can I install PHP5.3 on my ubuntu 14.04 server?    apt-cache showpkg php5   shows no 5.3 versions.  I tried to install them using the example from this post (using 3.13 for my ubuntu version) but apt-get says the version doesn't exist.    Also tried downloading 5.3 from php.net and compiling but received compile errors.  Any other ideas?

I've just installed Ubuntu 14.04 and am trying to install php 5.3. But when I run   apt-get install php5    it's installing php 5.5.9-1ubuntu4. I need to use php 5.3 in the system because the application I'm working on is built with php 5.3.   How can I achieve this?


I am a Ph.D student, and I've been considering for some time starting my own blog as a hobby, to write mostly on philosophical/political topics that interest me; these are definitely not related to my field of research (at least, not most of them). As it happens, some of the topics I want to address are controversial, and much of what I would write could be interpreted as being offensive to one group or another.  Let's assume I want to look for a tenure-track position, and later on get tenure. Ideally, I hope everyone would agree that such a personal blog should not alter in any way my case for obtaining the position. In practice, I am concerned that the existence of such a blog could be used to attack my case for the position (and later on, my case for tenure) on the grounds that the opinions therein found are "offensive" or even "hate speech" (as might be interpreted by some very sensitive people in these modern times). More subtly, one imagines it could cause some decision-making persons to develop an effective bias against me, which would probably have a negative effect.  Thus my question in the title. I am looking both for personal experiences that people have had, and for some statistical data that may answer the question or a closely-related one (such as, does non-trivial political participation affect academic career? etc.)

I am an undergraduate student in the hard sciences, and am thinking of pursuing a research career after graduation. I am also quite politically involved on the left, and have political articles published online. I am critical of many governments (including my own) and corporations, and of many of the applications of technology in fields I am interested in.  My politics are very important to me, and I could not give them up. That said, I often worry about how they could be detrimental to my career, especially before I'm already established. I worry, for instance, that grad school admissions would Google my name and find my views and affiliations, and that this would negatively impact my chances to get in. How realistic is this fear?


Is there a Truffle glitch where you can't get them when after you beat Plantera? I got him in my old world, and can't get him in my new world. In which I beat Plantera, I even saw someone say you can't get him after defeating Plantera.

I currently find myself in a pickle because even after I've built the mushroom biome and met all other requirements, the Truffle NPC won't move in.   I've defeated not only the Wall of Flesh but Ocram already. Created a surface mushroom biome. Built a house made out of mushrooms with mushroom furniture.   I have no idea how long it takes for the NPC to move in or if I'm wrong in any of the steps.


i have laptop Lenovo ideapad z50-75 AMD version and i want to install Ubuntu on my external HDD. I setup bios to legacy mode and boot from liveCD. After boot ubuntu from liveCD i should see a window, where i choose language and if i wanna try or install. But i only see black screen, only dark purple frame of this window and nothing else.  Computer spec:    processor: AMD FX-7500 radeon R7 graphic card: AMD R7 M260DX   RAM: 8GB   I download Ubuntu 14.04 64-bit version. Is any solution how to repair graphic to see choices?  This is, what i see, when i do UEFI boot from liveCD and start files browser. if i boot in legacy mode, same thing happend but with the window, where u can choose language and  try Ubuntu or Install.

I am trying to boot Ubuntu on my computer.  When I boot Ubuntu, it boots to a black screen.  How can I fix this? Table of Contents:


The limit $$\lim_{n\to\infty} e^{-n}\sum_{i=1}^{n}\frac{n^i}{i!}$$ can be seen to be $\frac{1}{2}$, yet isn't the sum in this expression just going to be $\lim\limits_{n\to\infty}e^{n}$, making the limit 1?  I'm having trouble wrapping my head around why this isn't the case. Any help would be much appreciated.

I'm supposed to calculate: $$\lim_{n\to\infty} e^{-n} \sum_{k=0}^{n} \frac{n^k}{k!}$$ By using WolframAlpha, I might guess that the limit is $\frac{1}{2}$, which is a pretty interesting and nice result. I wonder in which ways we may approach it.


Please consider the following code:  public class A<T> {       public void main(String[] args) {         A<String>[] array = new A<String>[10];         System.out.println(array.length);     } }   I am trying to define (and allocate space for it) an array of 10 elements where each element of the array is of type A. I thought the above code would do it, but it fails to compile.  Thanks, Bob

Due to the implementation of Java generics, you can't have code like this:   public class GenSet<E> {     private E a[];      public GenSet() {         a = new E[INITIAL_ARRAY_LENGTH]; // error: generic array creation     } }   How can I implement this while maintaining type safety?  I saw a solution on the Java forums that goes like this:  import java.lang.reflect.Array;  class Stack<T> {     public Stack(Class<T> clazz, int capacity) {         array = (T[])Array.newInstance(clazz, capacity);     }      private final T[] array; }   But I really don't get what's going on.


Let $X, Y, Z$ be i.i.d. random variables distributed as $N(0, 1)$. How to show that $\dfrac{X + ZY}{\sqrt{1 + Z^2}} \sim N(0, 1)$? The only solution I see is to progressively find the distributions of  First, $ZY$ Then $U := X + ZY$ Then $V := \sqrt{1 + Z^2}$ Then $\dfrac{U}{V}$  But finding these distributions appears to be a nightmare in terms of the number of calculations to be done. And this solution doesn't really explain the intuition behind this problem: how could this expression randomly end up being $N(0, 1)$-distributed? That makes me wonder if there is a more nice solution. I also think, this is probably a well-known problem, but I couldn't find a solution anywhere. Any help would be greatly appreciated!

I am trying to find distribution of random variable:  $$\frac{X_1+X_2 X_3}{\sqrt{1+X_3^2}}$$  where $X_i \sim \mathcal{N}(0,1)$ and independent.  My thinking so far is to use random variable algebra and to find distributions step by step. However, I don't know what to do with the variable: $\sqrt{1+X_3^2}$ (it seems like some variant of $\chi$-distribution).   Moreover, I'm worried that my thinking is to complicated and that the solution should be more elegant.


I am doing linear regression with SPSS. There are two potential Predictors $X_1$ and $X_2$ for Dependent Variable $Y$. I found that $X_1$ and $X_2$ are strongly correlated $(r=0.63, p<0.001)$. So I induce the interaction term $X_1*X_2$. However, I found the Model 1,   $Y=a_1X_1+a_2X_2+b(X_1\times X_2)+c$, $(\text{sig.}=0.098)$   is less significant than Model 2,   $Y=aX_1+b(X_1\times X_2)+c$,  $(\text{sig.}=0.040)$,   and the standardized coefficients of $X_2$ in Model 1 are near $0$ $(\text{sig.}=1.000)$. Since $X_1$ is the main predictor I am interested, could I use Model 2 instead of Model 1?

Is it ever valid to include a two-way interaction in a model without including the main effects?  What if your hypothesis is only about the interaction, do you still need to include the main effects?


The question is similar to this one:   Except that I would like to know whether it is possible to do it through command line, instead of GUI.  The task is to set the shortcut of /home/usr to super+E on a newly installed Ubuntu.   The reason to to this is that it is a pain to configure many machines through GUI. As a last resort, it is always possible to simulate mouse and key board to automate. However, for the sack of question, assuming that is not an option.

How to set custom keyboard shortcuts from terminal for different Linux versions?  Basically I want to know where Linux stores the keyboard shortcut files and how it can be edited.  On my research I found a file ~/.config/compiz-1/compizconfig but it was more or like encrypted when I tried to open it with nano.


In QGIS, I can add WKT data stored in a CSV by clicking the 'Add Delimited Text Layer' tool and setting it to 'WKT'. This works fine:    But how can I do it as a python script?  Ideally I'd like a script which- 1. Imports the CSV into QGIS as a polygon (drawn from the WKT field) 2. Exports the new (temporary?) polygon layer to a shapefile on my disk  I have minimal experience writing scripts in QGIS. Using help guides, I've written a script to import a CSV to a point layer, with X and Y fields defined. ()  But obviously a WKT is different as you only need to define the WKT field.  Here's what my source CSV looks like:

I'm trying to use QgsVectorLayer() function to add delimited text layer in QGIS. So I have a txt file (T_1999_1_2.txt) in path: "D:\PATRICIA\DOCUMENTOS\ESTACOES METEOROLOGICAS\DADOS METEOROLOGICOS\T" and I want to create a shapefile named: T_1999_1_2.shp. The txt file structure is:     par;num;ano;mes;dia;D;btq   3;705;1999;1;2;-999,9;S;40,43885833;-8,43994167   3;619;1999;1;2;25,0;A;41,70972;-8,02699   3;718;1999;1;2;104,0;A;39,78055278;-8,82096667   3;766;1999;1;2;28,0;A;38,76620278;-9,12749444   3;560;1999;1;2;333,0;A;40,71492778;-7,89591667   3;669;1999;1;2;-999,9;S;39,83950000;-7,47866944   3;848;1999;1;2;-999,9;S;38,48486667;-7,47291667   3;555;1999;1;2;8,0;A;41,70655556;-8,80210833   I have tried to run the script but appears the same window error ("Error in file. File cannot be opened or delimiter parameters are not valid") My sript is the following one:  uri = "D:\PATRICIA\DOCUMENTOS\ESTACOES METEOROLOGICAS\DADOS METEOROLOGICOS\T\T_1999_1_2.txt?delimiter=%s&xField=%s&yField=%s" % (";", "x", "y")  vlayer = QgsVectorLayer(uri, "D:\PATRICIA\IG\QGIS\FWI\T\T_1999_1_2.shp", "delimitedtext")   I don't understand, why it doesn't work.


Is there a way in math / programming to tell if a fraction (reciprocal in particular) does not end?  For example, 1/3 is 0.33 repeated, but 1/2 is just 0.5  Is there a way to find if 1/n for any natural number n is never ending?  Context: Writing a program and want to find out if I need to round 1/n (round in my way rather than whatever the machine does) before adding it to another digit.  E.g Since 1/3 is never ending, the machine will probably cut off some of the 3's at the end, and 1 + 1/3 = 1.33333. I want to be able to catch that 1/3 is never ending (or if 1/n is Not never ending) so that when I add a "never ending" number to 1, I can round it in my own way (i.e. I can round 0.3 up to 0.5, rather than the computers way of rounding never ending reciprocals / fractions).

I am trying to figure out how to prove that all rational numbers are either terminating decimal or repeating decimal numerals, but I am having a great difficulty in doing so. Any help will be greatly appreciated.


Given $x,y \in \Bbb{R}$, show that:$$x^2+y^2+1\ge xy+y+x $$ I tried using the fact that $x^2+y^2 \ge 2xy$ But then I'm not sure how to go on, Also tried factoring but didn't help much, also tried substituting $\frac{x^2+y^2}{2}$ instead of $xy$ but that gave me the same result of the first substitution, i.e. $xy+1\ge x+y$  This inequality seems very easy, I'm feeling dumb for not having solved it yet

How can the following inequation be proven?  $$a^2 + b^2 + c^2 \ge ab + bc + ca$$


I'd like to ask a question, whether it's possible to create patches using git format-patch against a remote git repository (i.e. not from a local clone/checkout).  As this is not necessarily about programming itself and does not require knowledge of a programming language, it doesn't fit that well at , but might still be interesting and valuable for programmers. But then, should it be asked better at  or on  and is there some way to distinguish between those three sites in general for new questions?   Took a look at the respective tour pages, and for some more generic question I have to admit there is some slight overlap, especially between superuser and unix stackexchange.  Took a look at    on this topic but didn't quite help on this matter.

There seems to be more than a few computer science/programming Stack Exchange networks (is that the correct term?). Stack Overflow, being the first, has by far the most users, questions, and answers.  What is the reasoning for creating the others, and are there clear guidelines for which kinds of questions should be posted? I can see a large amount of potential overflow, many cases of people not getting a good answer to their question, because the person who has the answer isn't browsing that particular network at the moment.  I understand that they were probably created for organizational purposes, but wouldn't it almost make more sense to just have them as categories under Stack Overflow, keep them separated but still connected, instead of making people have to create multiple 'account's, one for each network?  I am sure there was a very good reason to break them up, but as someone that is new to SE, it can be somewhat intimidating to decide which one to post in to ensure you get a good answer. For example, if I am a computer science student, my first instinct might to be to post in the computer science network, until I see that it literally has 1% of the users as the Stack Overflow network, which still seems to be for programming/computer science related questions.  So my second instinct would then to be to post it into the Stack Overflow site on the basis that I have a significantly higher chance of my question being seen and getting a good answer. Then I notice that there is also a 'programmers' network, and I don't even begin to know where that fits in. I, and I am assuming most people, will probably just post on Stack Overflow to be safe.  My question is, other than the short little description blurb of each one, is there a clear cut set of guidelines which what each network is intended for, what kinds of questions should go to each one, and is anything being done to encourage people to post in these newer, smaller (more specialized?) networks as opposed to just posting in big daddy Stack Overflow?  Now again, this is for computer science/programming/"why isn't this code doing what I want?" related questions, I am not saying that if I had a question about Linux or WordPress or something I would have the same confusion.


How can I create an Ubuntu bootable USB to boot on a Windows 10, using a MAC running El Capitan? I tried using Unetbootin running on Mac (El Capitan), however my USB is not recognized! Also tried Disk Utility with no success. How to do it?

How do I make an Bootable Ubuntu USB containing the the latest version of Ubuntu?  For completeness, how would I be able to do this on Ubuntu, Windows, OS X or another Linux distro?


I need to show that there are only 2 groups of order 6 up to isomorphism.  I did prove it, but the proof is quite cumbersome. I wonder if there is a very concise proof.  My proof outline: Suppose $G$ is of order 6 and is not $\mathbb{Z}_6$. Then any element that is not identity must have order 2 or 3.  I went on to show that there must be a element of order 2 and another one of order 3, and the intersection of the cyclic subgroups generated by the two is the identity. Then I'm able to show it is isomorphic to $S_3$.

Prove that every non-abelian group of order $6$ has a non-normal subgroup of order $2$. Use this to classify groups of order $6$.   I proved that every non-abelian group of order 6 has a nonnormal subgroup of order 2, but then how can I use this to classify groups of order 6?


I want to understand the Higgs Boson. Not in terms of analogies and metaphors, but in terms of hard math.  Assume I have a solid background in pre-university maths and physics. (I have many bits and pieces of higher-level stuff, but let's ignore that knowledge because it is not comprehensive or cohesive.)  What sequence of things do I need to learn in order to properly understand the Higgs Boson?

There's a fairly standard two or three-semester curriculum for introductory quantum field theory, which covers topics such as:   classical field theory background canonical quantization, path integrals the Dirac field quantum electrodynamics computing $S$-matrix elements in perturbation theory, decay rates, cross sections renormalization at one loop Yang-Mills theory spontaneous symmetry breaking the Standard Model   What is a good, complete and comprehensive book that covers topics such as these?


Let R be the ring of continuous functions  f:[0,1]→R   with pointwise addition and multiplication, and suppose M is a maximal ideal. Prove that there is  a∈[0,1]  such that  M={f $\in $ R:f(a)=0}. I know how to prove its converse. I am trying to use the fact that since M is a maximal ideal then R/M is a field ; but can't really make any progress with it. Is there any alternative way of doing this?

I am learning abstract algebra by myself using Dummit & Foote, and sometimes by working very hard I find very complicated non-proofs of things and I have no idea if they are the best or the worst ideas for those kind of things out there (obviously if they're not working they're probably wrong, but maybe not!). So I feel like talking about it and see what the audience thinks about it. Hence I am asking for a full solution only if you don't feel like giving a hint. If a hint has been given please don't try to come up with the answer and wait for me to accept.  So here's the exercise (page 259, Dummit & Foote's Abstract Algebra) :  Let $R = C[0,1]$ with addition and multiplication as the ring operations. For each $c \in [0,1]$ define $M_c = \{ f \in R \, | \, f(c) = 0 \}$.   It can be easily seen that $M_c$ is a maximal ideal of $R$ because $f(x) = (x-c) \in M_c$ and if $g \notin M_c$ then $g(c) \neq 0$, thus $f^2 > 0$ everywhere except at $c$ and $g^2(c)> 0$, hence $f^2 + g^2$ is a strictly positive continuous function, and since any ideal $I$ such that $M_c \subsetneq I \triangleleft R$ is such that $(M_c,g) \subseteq I$, $f^2 + g^2 \in (M_c,g)$, thus $f^2 + g^2$ is a unit in $(M_c,g)$ and that means that for every $g \notin M_c$, $R = (M_c, g) = I$.   Using this trick with $f^2 + g^2$ I wanted to show the following :  Prove that if $M$ is any maximal ideal of $R$ then there is a real number $c \in [0,1]$ such that $M = M_c$.  I tried considering $K(g) = \{ c \in [0,1] \, | \, g(c) = 0 \}$ and then defining decreasing sequences $K(g) \supsetneq K(g_1) \supsetneq K(g_2) \supseteq \dots$ (using the $f^2 + g^2$ trick) and then looking at the intersection of all those $K$'s but that got me to the weird need of using Zorn's Lemma and got me depressed after multiple tries. Also tried to use the fact that $R/M_c$ is a field but even if I had shown that it was isomorphic to $\mathbb R$ it wasn't clear what I could do in that direction so I gave up pretty fast on that one.   Any hints are welcome!


I'm new to blender and I am trying to create basic shapes/models of few basic objects like - water pot, bottle, tea-cup etc. Now I'm trying to create an iPhone model.  So, when I started modelling, I came to know about precise sizing & other specific dimensions of iPhone. But I see options in XYZ as 0 & 1. My Question is - How can I create an object with specifications like - 4 inch wide, 1 inch tall etc?

How can I work with parameters in Blender? I tried searching on Google, but I didn't find results.   When I change the parameter on the X and Y axis, it works well, but when I go into Edit mode, I can't see the parameters. And when I extrude, I can't adjust them on the extrusion. How can I work with dimensions and how to make the parameters in real world scale?


Running OSX Catalina on a 2012 Macbook Pro, I recently edited the etc/hosts file and after I did I started having this problem in during my next startup, I somehow lost all use of sudo, anytime I try and use sudo I get the same error message:  sudo: /etc/sudoers is owned by uid 601, should be 0 sudo: no valid sudoers sources found, quitting sudo: unable to initialize policy plugin  Even when I change the etc/hosts file back it doesn't help so I'm not sure what or why this  triggered the issue. Any advice on how to fix this? Is this bound to happen anytime I edit the /etc/hosts file?

To run programs as sudo without password, I edited /etc/sudoers with wrong content.   Then I re-edited it with Mac's default text editor(course sudo cannot be used when /etc/sudoers is wrong).  I tried to run sudo agin, and get this error:   sudo: /etc/sudoers is owned by uid 501, should be 0 sudo: no valid sudoers sources found, quitting   What should I do? I cannot remember the root password (maybe I haven't ever set root password before).


I have read the proofs about why $0.9999.... = 1$, which are satisfying. But I can't get the following argument out of my head.  Defining $0.9999....$ : Lets construct a non-terminating but recurring real number n such that all digits before decimal point are zero and all digits after decimal point are 9.  Comparing $1.0000$ with $0.99999...$  Digit at ones place in $1.0$ (i.e. 1) $\ne$ Digit at ones place in $0.99999$ (i.e. 0)  Digit at tenths place in $1.0$ (i.e. 0) $\ne$ Digit at tenths place in $0.99999$ (i.e. 9). And so on....  Hence, $1.0 =0.9999...$ does not fit with our original definition of $0.9999...$ Can you find the mistake in the argument (other than saying that in-fact $1.0 = 0.9999...$)? Am I using a incorrect way to define (or perhaps compare) a number (with another)? Please help me. I am new to analysis. Thanks.

I'm told by smart people that $$0.999999999\ldots=1$$ and I believe them, but is there a proof that explains why this is?


model technique is very similar to , because both omitting each training case and perform retraining of the network on the left-out subset.  On wiki page we can read that jackknifing computes a statistic from the kept samples only, while LOOCV computes a statistic on the left-out sample(s). However it is still not clear for me.  Can anybody elaborate on it, ideally with same practical examples?

Is there really any difference between the jackknife and leave one out cross validation? The procedure seems identical am I missing something?


A friend of mine wants to play a variant human monk with the Tavern Brawler feat. He asked me if he could use improvised Weapons as monk weapons.  I personally haven't played a monk, or a character with the Tavern Brawler feat. As such, I'm having trouble judging whether this is unbalanced or totally fine.  Will allowing a character with the Tavern Brawler feat to use improvised weapons as monk weapons cause an unfixable balancing problem? If it does cause balancing issues, how can I address them?

Would a monk with the Tavern Brawler feat have improvised weapons count as monk weapons?  It states in the monk's Martial Arts feature (PHB, p. 78) that:     At 1st level, your practice of martial arts gives you mastery of combat styles that use unarmed strikes and monk weapons, which are short swords and any simple melee weapons that don’t have the two-handed or heavy property.   The Tavern Brawler feat (PHB, p. 170) states that:     You are proficient with improvised weapons and unarmed strikes.   And the rules for improvised weapons (PHB, p. 147-148) state:     In many cases, an improvised weapon is similar to an actual weapon and can be treated as such. For example, a table leg is akin to a club. At the DM’s option, a character proficient with a weapon can use a similar object as if it were that weapon and use his or her proficiency bonus. An object that bears no resemblance to a weapon deals 1d4 damage.    If the improvised weapon does not resemble a weapon, is simple, and is not heavy or two-handed, could a monk replace the d4 dice? For example if the monk is level 6 and has a unarmed attack of a d6, with a d6 dice instead?


On my farm I have a high pressure spring coming from the ground.it exits the ground from a 1 & 3/4" pipe.the water flows at a constant rate of 1 gallon per second (60 GPM.) Is it possible to approximately calculate the head or psi from these figures. I would like to use this spring to power a small water turbine but am unable to calculate head as the water comes upwards under pressure and if psi is calculated, how can that be converted to a 'metres head' number which most turbines are rated in. Many thanks

Is there any equation that states the relation between pressure and water flow.  I.e. Let's say that in 1 hour with 8mca (water collum meters) pressure I obtain 50m3. What if (giving the same contditions) I execute the same test but now with 15mca?  Is that just proportional?


This question should be a very common one between beginners because the introductory books in statistics don't seem to answer it clearly. We know when we do a sampling distribution, we have the parameter (in the case of the picture, the mean $\mu$) in the center of the distribution See the picture:  Let's call a population proportion as $p$ and $\hat p$ a sample proportion. Then, we have the 95% confidence interval: $$\hat p=p\pm1.96\times SE$$  However the 95% confidence interval is known as $$p=\hat p\pm1.96\times SE$$ I don't understand why $\hat p=p\pm1.96\times SE$ implies $p=\hat p\pm1.96\times SE$ with a 95% level of confidence.  So why we have $p=\hat p\pm1.96\times SE$ instead of $\hat p=p\pm1.96\times SE$? for it's not clear at all.

It seems that through various related questions here, there is consensus that the "95%" part of what we call a "95% confidence interval" refers to the fact that if we were to exactly replicate our sampling and CI-computation procedures  many times, 95% of thusly computed CIs would contain the population mean. It also seems to be the consensus that this definition does not permit one to conclude from a single 95%CI that there is a 95% chance that the mean falls somewhere within the CI. However, I don't understand how the former doesn't imply the latter insofar as, having imagined many CIs 95% of which contain the population mean, shouldn't our uncertainty (with regards to whether our actually-computed CI contains the population mean or not) force us to use the base-rate of the imagined cases (95%) as our estimate of the probability that our actual case contains the CI?   I've seen posts argue along the lines of "the actually-computed CI either contains the population mean or it doesn't, so its probability is either 1 or 0", but this seems to imply a strange definition of probability that is dependent on unknown states (i.e. a friend flips fair coin, hides the result, and I am disallowed from saying there is a 50% chance that it's heads).  Surely I'm wrong, but I don't see where my logic has gone awry...


I want to print some source code with minted, and the characters ^^I^^I^^I appears on the beginning of each line. It is independent on the chosen language syntax.  It looks like so:     What can I do to get rid of it?

I am producing LaTeX output with org mode.  My code snippets wind up being indented with tabs, because of my c-mode settings.  Changing these would be inconvenient.  Although the snippet I am posting could be compiled with latex, I need to be able to compile Unicode documents, so I am using xelatex -shell-escape to compile the automatically generated latex source. The generated source looks like this: Which produces LaTeX like the following (some irrelevant stuff removed, this reproduces the problem):  \documentclass[11pt]{article}  \tolerance=1000  \usepackage{fontspec}  \usepackage{minted}  \author{Glen Stark}  \date{\today}  \title{sample}  \begin{document}   \section{Foo}   \begin{minted}[]{c++}  void foo()  {      void bar = fb();      std::cout << "fbar" << "\n"  }  \end{minted}  \end{document}  Compiling this with xelatex -shell-escape results in output like:  void foo() ^^Ivoid bar = fb(); ^^Istd::cout //etc.  The whitespace in the minted block is a tab.  Obviously xelatex is inserting something funny in place of the tabs.  I have a workaround where I force generation of spaces instead of tabs, but this is inconvenient. Anyone know what the fix/problem is?


Looking at  I notice two different amd64 images. What's the technical difference between ubuntu-12.10-desktop-amd64+mac and ubuntu-12.10-desktop-amd64? Of course the first one is optimized to install on Apple machines, while the latter is more general.   But what is the difference that makes it more suitable for Macs?

At that location there is an ISO image which is described as "This image is adjusted to work properly on Mac systems."  What specific problems on the Mac does this image address that the standard images don't? I ask because I need to know which ISO to recommend to Apple Mac users.


I completely understand the use of out and ref in C# however why would I ever use out instead of ref as out is simply the same as ref just with restricted abilities. I see when it can be used but I don't see any point in ever using it really.  Thanks so much!

I'm creating a function where I need to pass an object so that it can be modified by the function. What is the difference between:  public void myFunction(ref MyClass someClass)   and  public void myFunction(out MyClass someClass)   Which should I use and why?


I have a code like this:  string str = ""; for(int i=0; i<100000; i++){     ...........     str += ...; } return str;   but, this code is very slow, and when execute, it takes 7 minutes.  Do you think a solution would be?

What's the most efficient way to concatenate strings?


I was reading about HMAC and why it is crucial to avoid security issues with normal prepending / appending the secret k to a message (issues due to merkel damagard construction). I am not familiar with the math and the detailed proof presented in the paper, but i was wondering why both ipad and opad are required. what if we use only one ? how will an attacker exploit that ?

Wikipedia lists the following pseudocode for HMAC:  function hmac (key, message)     if (length(key) > blocksize) then         key = hash(key) // keys longer than blocksize are shortened     end if     if (length(key) < blocksize) then         // keys shorter than blocksize are zero-padded ('∥' is concatenation)          key = key ∥ [0x00 * (blocksize - length(key))]      end if      // Where blocksize is that of the underlying hash function        o_key_pad = [0x5c * blocksize] ⊕ key      // Where ⊕ is exclusive or (XOR)     i_key_pad = [0x36 * blocksize] ⊕ key       // Where '∥' is concatenation        return hash(o_key_pad ∥ hash(i_key_pad ∥ message))  end function   Why are they there?  How were they chosen?  It seems to me that  $hash(key + hash(message))$ (where + is concatenation) would suffice.    Obviously I'm missing something.  What is it?


I'm a French citizen, I'm already in Philippines for 36 months. Normally I have to leave on September 17, 2018, means today. For personal reasons I'll be probably late, then I have to do my ECC.  How much total fees and fines will I be expected to pay when I depart after my overstay? Are there any other penalties that I can expect?

I'm a U.S. Citizen and I have been overstaying in the Philippines for 5 years. I want to go back to U.S what's the penalty?   I don't have enough money to pay a big fine, is there a way to avoid that?


I have a swift project that depends on an objective-c++ static lib. When I compile the static lib alone, there is no error. But when I add the lib as a sub project to a swift project and compile it, I got the following error:  Undefined symbols for architecture x86_64:   "___gxx_personality_v0", referenced from:       +[obj_photo open] in libphoto.a(photo.o)       Dwarf Exception Unwind Info (__eh_frame) in libphoto.a(photo.o) ld: symbol(s) not found for architecture x86_64 clang: error: linker command failed with exit code 1 (use -v to see invocation)  The objective-c++ file looks like this  // -- Obj-C++, photo.mm #include "photo.hpp" #import "photo.h" #import <UIKit/UIKit.h> #import <Photos/Photos.h> #import <Photos/PHAsset.h> #import <Photos/PHFetchOptions.h>  @implementation obj_photo + ( bool )open {     PHFetchOptions *options = [[PHFetchOptions alloc] init];     PHFetchResult *fetchResult = [PHAsset fetchAssetsWithOptions:options];     return true; } @end  bool photo::open_photo() {     return [obj_photo open ]; }   And in the swift file, I called the open_photo()  The weird thing is if I remove the following line:  PHFetchResult *fetchResult = [PHAsset fetchAssetsWithOptions:options];   I don't get the link error.  Any clues?

I've been getting this undefined symbol building with this command line:  $ gcc test.cpp Undefined symbols:   "___gxx_personality_v0", referenced from:   etc...   test.cpp is simple and should build fine.  What is the deal?


I understand the equation explaining angles of refraction related to wavelengths. But I'm looking for a more intuitive approach/visual explanation? Perhaps related to QM?

It is well known that a  can "split light" by separating different frequencies of light:    Many sources state that the reason this happens is that the  is different for different frequencies.  This is known as .  My question is about why dispersion exists.  Is frequency dependence for refraction a property fundamental to all waves?  Is the effect the result of some sort of non-linearity in response by the refracting material to electromagnetic fields?  Are there (theoretically) any materials that have an essentially constant, non-unity index of refraction (at least for the visible spectrum)?


I installed android lollipop from the factory images on googles website. I dont know if its supposed to be like this but i think not.   I cant click on the options in the notifications be it to answer a call or reply to an SMS.  I have to first swipe it right or left then go to the call or sms to continue.  Any idea ?

I have a Nexus 7 (2013) and a Moto X (2014) running Lollipop. On both of these, if I get a heads-up notification (i.e., those that show up on top of the screen when the device is unlocked) and swipe down on it with 2 fingers, it 'breaks' further heads-up notifications:   I can't tap on them to open the responsible app For, e.g., an incoming phone call with 'answer' and 'dismiss' buttons, tapping the buttons does nothing. I can't answer phone calls anymore!   I can still swipe to the side to dismiss the notifications, and they still disappear on their own after a few seconds. I haven't been able to find a way to get the correct behavior back aside from a restart.  Yeah, the obvious workaround is to not two-finger swipe on them, but it's second nature as that same gesture expands notifications in other contexts.  I'm guessing the problem is generic, but I've triggered it on Hangouts and Phone notifications.  Do others experience the same thing? Any known 'fixes' aside from restarting?


The story is set in a domed city, where all dangers and strife have been removed... almost. The most important character is called the Jester or maybe the Joker. His job is to create chaos and he is immune from all prosecution. His role prevents the city stagnating, presumably based on the notion that deviance and threat are what binds society together, without which, the need for societal bonds collapses.  What is the name of this story/book?

I read a novel written in English when I was a teenager in the 1970s  about a society that lives in an enclosed city which controls the population. I can't remember the name of the story or the city.   People are reproduced by machines in the city that have the DNA of everybody who can be born. No natural babies are born.  One in a while, a person is born who rebels against their society and tries to leave the city. There are only a few ways to exit through the outside wall of the city. In the story the city reveals that each time it produces a rebel they are produced from same DNA.   This story is about one of these rebels and how he escapes.   I can't remember what happens when he escapes, but I think it is through a window high up in a wall. I can't remember what the world is like outside of the city.


I am trying to get the local ip of the system using hostname -I. However, it is showing three IP addresses, instead of one. So, I would like to know what does more than one IP address signify?  Also, I would like to understand how did my system could end up with multiple IP addresses.

Sometimes I run   hostname -I   on my machine and got only one local IP returned like 192.168.0.10, but lately, there is occasions where I type it and got in return both 192.168.0.10 192.168.122.1.   If I go to my router page and to traffic settings, I don't see this second IP connected to it. How can I go further to investigate what is exactly this other IP, if its related to some other program or even to a security problem?


I've been looking for slimes for some time now and I don't seem to find any in the large room I built. I need to know how to easily find them without "cheating" whether they are in swamps or just underground

In early alpha I remember Minecraft videos showing slimes deep underground. I think you would attack them then they split into several smaller slimes. But I've never found a slime for myself. In what conditions can you find slimes? Are they definitely still in Minecraft?


I want to SSH into a remote machine but instead of typing the password, I want to redirect it from another file.  So I have a file password.txt that stores the password. File.sh is my bash file.   In File.sh  #!/bin/bash ssh -T user@10.2.5.1   While executing the file, I did:  ./File.sh < password.txt   But I was asked to enter password anyway.   How do I get the password to be input from the file?

I tried writing a shell script which can do automatic login into a ssh server using password which is mentioned in the script. I have written the following code:  set timeout 30 /usr/bin/ssh -p 8484 root@172.31.72.103 expect  {    "root@172.31.72.103's password"     {       send "password\r"     } }   This code is not running properly, still it is asking for the password. Can somebody please help me in solving this


In  it reads that:       normalization can be intractable when applying Bayes’ Theorem     And in  it says that:       it does not depend on the parameters since these have been integrated out.    ...  is nothing but a normalising constant   And in  the normalising constant is dropped.    But it seems very necessary to work out the denominator Pr(data) of the right hand side of the Bayes' Theorem in Variational Bayes:     $\Pr(\textrm{params} \mid \textrm{data}) = \frac{\Pr(\textrm{data} \mid \textrm{params}) \Pr(\textrm{params})}{\Pr(\textrm{data})}$       To be specific, in  it provides two answers but I don't get the question. That's I don't understand the problem setup section. How can I relate the left hand side P(Z|X) to what is being approximated P(X)? To be more straightforward, in what problems should I consider the normalization and then need to calculate the lower bound of the Pr(data) and when it is not necessary? And why? Could anyone please exemplify it simply.

Bayes theorem goes $$ P(\textrm{model}|\textrm{data}) = \frac{P(\textrm{model}) \times  P(\textrm{data}|\textrm{model})}{P(\textrm{data})} $$  This is all fine. But, I've read somewhere:     Basically, P(data) is nothing but a normalising constant, i.e., a constant that makes the posterior density integrate to one.   We know that $0 \leq P(\textrm{model}) \leq 1$ and $ 0 \leq P(\textrm{data}|\textrm{model}) \leq 1$.    Therefore, $P(\textrm{model}) \times P(\textrm{data}|\textrm{model})$ must be between 0 and 1 as well.  In such a case, why do we need a normalizing constant to make the posterior integrate to one?


I have a desk drawer that I need to get into but it only opens and inch. I had a lot of stuff packed inside, I'm not sure if something is jammed.

Does anyone have any bright ideas for how to open a drawer that has become jammed shut because it has been filled up too much? I've had a look at the underside and can get at the bottom of the drawers but unscrewing the rails etc. is not an option because I can't get at them. Currently my best plan is to try and remove or cut out the hard board base of the drawer which would then need to be replaced. Any better ideas much appreciated.


I just began  with     Ha, I just ran into this myself!   but it would come out as     I just ran into this myself!   and an edit would not help.  Now I see how that beginning of an answer is not strictly adding to its content value, but it seems like it does not hurt and – especially with regard to the recent push for more friendliness on SE – make the user experience a bit more … natural. Maybe the software is a bit too eager with manual editing of posts?

I edit a lot of posts every day. I often run across posts with 'Hi' and 'Thanks' on the top and the bottom of the post respectively. I also run across things like:     --User   Should these items be removed during the editing of the post by an editor?


I have got an object of defaults, then some values which will over-ride the defaults. However when i use Object.assign to create a new object, and update this, the defaults also get changed. let defaults = { test: 'hello world' }; let values = { test: 'beep' }; let merged = Object.assign(defaults, values);  merged.test = 'updated'  // defaults: { test: 'updated' }  Defaults should remain the same and only merged should get updated. I was under the impression that Object.assign copies the object, not references it.

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


As order of group is even then $G$ can contain an element of order 2 as 2|even but how it is must?

I am working on the following problem from group theory:     If $G$ is a group of order $2n$, show that the number of elements of $G$ of order $2$ is odd.   That is, for some integer $k$, there are $2k+1$ elements $a$ such that $a \in G,\;\; a*a = e$, where $e$ is the identity element of $G$.


I am currently trying to solve problem which is formulated in the following way:  "An ectopic pregnancy is twice as likely to develop when the pregnant woman is a smoker as it is when she is a nonsmoker. If 32 percent of women of childbearing age are smokers, what percentage of women having ectopic pregnancies are smokers?"  which is conditional probability problem. Currently, I am stuck, as it appears I don't have enough information to solve the problem. The way I see it, problem requires me to find how is $P(E)$ divided between $P(E \cap S)$ and $P(E \cap \bar S)$, where $E$ is "woman have ectopic pregnancy" event, and $S$ is "woman smokes" event (I denote "woman do not smoke as $\bar S$). I can derive $$P(E) = P(E \cap S) + P(E \cap \bar S) = P(E|S)\cdot P(S) + P(E|\bar S)\cdot P(\bar S) = 2\cdot P(E|\bar S)\cdot P(S) + P(E|\bar S)\cdot P(\bar S) = 0.64 \cdot P(E|\bar S) + 0.68 \cdot P(E|\bar S)$$ but I have no idea how to go from there. There is not enough information to use Bayes formula, as I don't have any idea what $P(E)$ is. What am I missing in my thoughts?

An ectopic pregnancy is twice as likely to occur when the pregnant woman is a smoker than when she is a nonsmoker. If 32% of women of childbearing age are smokers, what percentage of women having ectopic pregnancies are smokers?  Attempt: Given the women has had an ectopic pregnancy, we can condition on her being a smoker. So I believe the prob we want in this question is P(woman smoke| she had ectopic preg).  Denote ectopic preg by EP  This is equal to P(EP and woman smoke)/P(EP), which can be rewritten as P(EP|woman smoke)/(P(woman smoke)P(EP)) by Bayes.  Then taking into consideration data in the question, I said the above can further be written as 2P(EP|woman not smoke)/(P(woman smoke)P(EP)).           (1)  Using the total Prob law on P(EP) gives P(EP) = P(EP|woman smoke)P(woman smoke) + P(EP|woman did not smoke)P(woman did not smoke), which is equal to P(EP|woman did not smoke)[2P(woman smoke) + P(woman did not smoke)]  Subbing this into (1)  and cancelling gives 2/(.32)(0.64 + .68) which is > 1. There is probably a simpler method to mine, but I also want to know where I went wrong. Many thanks.


I have a Nikon D750 with a Nikkor 28-300mm VR lens. I am an absolute newbie and I've been trying to capture a reasonably good picture of the moon. But no matter what I try, the pictures are never sharp.  I've tried mounting the camera (by the camera, not the lens) on a tripod, set the shutter release to remote or timer (2s) and tried taking several shots at varying shutter speeds (10s to 30s) and ISOs (1600 to 6400) with the maximum aperture (f/5.6 I believe) at 300mm. But no matter how I take the photo, the moon always looks a bit blurred.  I tried with VR turned on and off, on my lens. What am I doing wrong?   Any help is appreciated.

I took this photo of the blood moon this morning and I am finding many of my photos, especially landscape photos, have a significant lack of clarity. I'm not looking for a photo critique because I know this particular photo is crap. I'm looking to identify my source of failure to nail a significantly clear photo.     Setup  Canon EOS 70D with a 100-300 telephoto lens (I'm sorry I don't know the exact model. It's from Canon but not one of their professional quality lenses.)   Aperture: f/5.6 Shutter: 1 sec. ISO: 1000 Focal Length: 300mm Metering mode: Spot White Balance: I manually set the WB to 5500 kelvin, it looked fine in live view. Focus Mode: Manual Drive: 2 sec timer delay   Mounted on a decently stable tripod  Process  I turn on live view, and square up the target in the display. I then set my focal length, focus in using live view, adjust the focus as sharp as possible and take the pic. I've noticed that in this case, the picture was incredibly grainy, which doesn't translate to the final photo, but wonder if it has anything to do with it.  This particular shoot I found it difficult to balance out the variables with a dark sky and a moving moon that starts blurring after 1-2 seconds of exposure, which is why I had the aperture wide open and the ISO cranked up.  I can't tell where I'm failing:  Equipment:  The 70d takes great photos but the telephoto is not great when it's totally zoomed in. My wallet doesn't hold enough cash for a motorized mount to track objects in the sky.  Circumstance: I've seen great photos of the moon with the use of a camera and a tripod, so I know this is possible. Although, I keep seeing pictures of this big gorgeous moon over the landscape, and when I use my wide-angle, the moon shows up as a dot. What the hell are people doing to get the moon so big?  Beginner skill level: I know this is the biggest culprit, but being the beginner, I'm unable to know where to adjust.


I am working on a Java project that runs on Linux/WebLogic that needs to integrate with an existing SQL Server instance that only allows authentication through a windows domain account. I've seen .Net applications use impersonation to connect and run the query as the domain account with the permissions.  Is there an equivalent way to do this with Java?

I am currently investigating how to make a connection to a SQL Server database from my Java EE web application using Windows Authentication instead of SQL Server authentication. I am running this app off of Tomcat 6.0, and am utilizing the Microsoft JDBC driver. My connection properties file looks as follows:  dbDriver              = com.microsoft.sqlserver.jdbc.SQLServerDriver dbUser                = user dbPass                = password dbServer              = localhost:1433;databaseName=testDb dbUrl                 = jdbc:sqlserver://localhost:1433   I have zero problems with connecting to a SQL Server database in this fashion when using SQL Server authentication.  Is there any way I can retrieve the credentials of the user's Windows Authentication and use that authentication for SQL Server?  UPDATE: I know in ASP.net there is a way to set up Windows Authentication for access to the webapp, which is exactly what I am looking for, except I want to pass that token off to SQL Server for access to the database.


I'm a non-physicist so pls pardon this dumb question. (Maybe one of you high school physics teachers could use this to puzzle your students?) Say we're at big hard pan desert. A referee fires a gun and two cars on either side of him take off in opposite directions, each reaching a speed of 80mph. Relative to the man, they are both going 80mph away from him. But when the two cars look back toward each other, they can easily see (or measure by sonar) the other car receding at 160mph. Now say we're at some point in outer space and, when the referee gives the signal, two star ships start off in opposite directions, each reaching a speed of 80% of the speed of light (.8c). Now, the referee can see (using the red shift I guess) both ships receding at this speed. But what happens when the ships look back toward each other? Presumably they can't be receding from each other at 1.6c (.8c+.8c). If they shine a light beam back toward each other, could the crew on each ship ever even see the light beam from the other ship? It is really hard for me to conceive this situation. I know that the ships can not be exceeding light speed even relative to each other, and I guess this fact must somehow be reconciled by time, although I can't conceive exactly how. On another point, I've never been able to comprehend cosmologists when they say the Big Bang never originated in a certain point in space. Maybe it is the word "bang," which implies an explosion, and indeed they say the entire universe was condensed into a space smaller than an atom, right? I don't understand how you can have an explosion which does not originate in a specific point in space.

Let's say we have $2$ particles facing each other and each traveling (almost) at speed of light.    Let's say I'm sitting on #$1$ particle so in my point of view #$2$ particle's speed is (almost) $c+c=2c$, double light speed? Please say why I am incorrect :)    EDIT: About sitting me is just example, so in point of view of #1 particle, the second one moves at (almost) $c+c=2c$ speed?


What is the best way to copy text to the clipboard (multi-browser)? The below code  which I have tried.  function copy(data){        let info = data;        document.execCommand("copy");        alert("Copied the text: " + info);    }  I am trying to copy data which I have passed.

What is the best way to copy text to the clipboard (multi-browser)? I have tried: function copyToClipboard(text) {     if (window.clipboardData) { // Internet Explorer         window.clipboardData.setData("Text", text);     } else {         unsafeWindow.netscape.security.PrivilegeManager.enablePrivilege("UniversalXPConnect");         const clipboardHelper = Components.classes["@mozilla.org/widget/clipboardhelper;1"].getService(Components.interfaces.nsIClipboardHelper);         clipboardHelper.copyString(text);     } }  But in Internet Explorer it gives a syntax error. In Firefox, it says unsafeWindow is not defined. A nice trick without using :


For any matrix $A$, let $A^T$ denote its transpose matrix. What is the minimum value of $\mathrm{trace}(AA^T)$ for an $n \times n$ non-singular matrix $A$ with integer entries?

For invertible $A_{n\times n}$ find $\min(\operatorname{trace}(AA^T))$  (a) $0$ (b) $1$ (c) $n$ (d) $n^2$  Clearly for $A=I$, it is $n$, and I am unable to get any lower values, but how do I prove it.


I have following data structure in MySQL database:  { date: text name: text }   and a data set:  "2016-01-01" "a1" "2016-01-02" "a2" "2016-01-02" "a3" "2016-01-03" "a4"   I would like to combine "name" field, if the "date" is a same in different rows. So at the end to have something like:  "2016-01-01" "a1" "2016-01-02" "a2, a3" "2016-01-03" "a4"   Of course I could iterate over results-array and build a new structure, like this one, programmatically.. but maybe its a faster way to do this directly in SQL Query?

Basically the question is how to get from this:   foo_id   foo_name 1        A 1        B 2        C   to this:   foo_id   foo_name 1        A B 2        C


I was reading that the best way to iterate over a HashMap to remove entries from it was to use an iterator. I did that. However, I am still getting a ConcurrentModificationException at "i.remove." Does anyone know why?      Iterator<Map.Entry<Integer, ArrayList<JLabel>>> i = tab.getReport().getRows().entrySet().iterator();     while (i.hasNext()) {         Entry e =  i.next();         int keyId = (int) e.getKey();         if (toChange.contains(keyId)) {             tab.getReport().getRows().put(keyId - 1, tab.getReport().getRows().get(keyId));             tab.getReport().getRows().get(keyId - 1).get(0).setText(Integer.toString(keyId - 1));             i.remove();         }     }   Exception in thread "AWT-EventQueue-0" java.util.ConcurrentModificationException at java.util.HashMap$HashIterator.remove(HashMap.java:1443)

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


So I got on my mc windows 10 edition survival world and I found a skeleton horse that had spawned for whatever reason(No lightning/storm), and I tried to ride/tame it and it doesn't do anything. I don't even know why it spawned, I didn't use cheats or anything either. It did however spawn in my nether portal room so it could of possibly came out of the nether?

So the 15.0 update came out for minecraft pocket edition. Well along with horses there are also the zombie horse and skeleton horse. Is it possible to tame these? If so how?


When I logged in today on my laptop and tried to do something  it asked me for my password. So i typed in my password  and it keeps on saying that It's invalid.  I know for sure I didn't change it. Is there any way to change it or make it work without loosing any data from my laptop ? How do I reset a lost  password? doesn't work for me.  please any one suggest how to make it work without loosing any data because if any data are remove my research work are totally stop .

I'm working on a Ubuntu system, and my client has completely forgotten his administrative password. He doesn't even remember entering one; however it is there.  I've tried the suggestions on the website, and I have been unsuccessful in deleting the password so that I can download applets required for running some files. Is there a solution?


I want to generate symbol like this:    But I can't find a proper method in LyX. I tried frame decoration with \overset like this:    I also tried square braces with matrix inside, but is too large. It's surprising that LyX doesn't offer equal size room inside "frame decorations". How can I do here?

While using MathJax to typeset binomial coefficients, I came across this problem of different sized brackets if my lower index contains the '0' character. Is there anyway to make the brackets the same size?