A black hole has:   a mass electrical charge angular momentum?   In the inner, there is a singularity, all the mass, collapsed to one point. The event horizon is surrounding that singularity.  How can a point rotate? What is meant when speaking about a one-dimensional thing rotating?

I guess nobody really knows the true nature of black holes, however, based on everything I know about black holes, there is a "singularity" at their center, which has finite mass but is infinitely small and thus infinitely dense.  So a black hole is really just a point mass that dramatically warps the space-time around it so that an event horizon is achieved.  What doesn't make sense to me is how a true mathematical "point" can rotate, or at least how it is even possible to determine if a point is rotating (or if it should even make a difference about whether or not it is rotating, for the same reason it would be impossible to tell if a perfect, featureless sphere were rotating (I know it would have higher rotational energy but lets assume you can't measure that because a true "point" can't attain rotational energy since it has no radius)).  The only conceptual solution I have to describe a rotating black hole would be to compare it to a rotating whirlpool, where the surface of the water is the fabric of space-time... but this is different because there is no "singularity" in a whirlpool that causes the water around it to rotate, whirlpools form from flow of water around a point (put into motion perhaps by some kid swirling water in a 2-liter bottle... it's due to an external cause), but the only thing that could cause rotation around a black hole would be the singularity itself, which doesn't make sense because, once again, how can we know if a true point is actually rotating?  Aside from everything I've said, here is what I am actually asking:  Why/how do some black holes rotate... what is the mechanism of their rotation (is analogous to a spinning point or a 3-d whirlpool, or something different)?


I'm a freshman in college this semester without any previous experience in rigorous proofs or such, however I am interested in the learning more about mathematics and for that reason I picked up the book Concrete Mathematics.  I'm doing the warmup exercises on the first chapter right now, its taken me hours to do up to question 4. The problem is:  Are there any starting or ending configurations of n disks on three pegs that are more than $2^n -1$ moves apart in the Tower of Hanoi problem  My thought process so far has been:   For any $k$ disks in a stack of $n$ disks it takes $T(k-1)$ moves to clear the top. Then it takes one move for the $k$-th disk and then $T(k-1)$ moves again at most to move any number of the remaining disks back to the moved pile of $k$ disks. Therefore, all the possible legal configurations can be achieved with at most $2(T(k-1)) + 1$ moves. Which in closed form is $2^{k}+1$.   While this argument may make sense to me, I know that it isn't rigorous, it might even be false. I would like to know of a way to make a more rigorous argument here.

This is an exercise from Chapter 1 of "Concrete Mathematics". It concerns the Towers of Hanoi.     Are there any starting and ending configurations of $n$ disks on three pegs that are more than $2^n - 1$ moves apart, under Lucas's original rules?   My initial guess is no, there are no starting and ending configurations of $n$ disks on three pegs that are more than $2^n - 1$ moves apart.  I will post an answer to this question with my attempt at a solution. I would like to confirm if my solution is correct and complete, or if there is a better approach.  Edit: I added to the answer a second method of solving this problem, based on the comments to the answer.


Can sentences end with 'only'? If yes, then in what cases you can or cannot? For example   P2: I have had some problems but overall XYZ has been great.  P1: No, XYZ is a great product  P2: You misunderstood me. I was saying that only. / I was saying only that.

I only teach you.   I teach only you.   I teach you only.      I think that all the sentences have same meaning, but my teacher says that they are different from each other.  I think that the expressions are different but their meaning are same.  Can you help me understand the meaning of each sentence?


I'm having trouble doing this in a clean and simple way in python. What I'd like to do is having a piece of code that calculates the number of days passed between 2 dates. For example today being the 22nd of december and i want to know how many days i have before the 15th of febuary. There are 55 days difference (i took this example because it englobes 2 different years an multiple months) What i made was very messy and dosen't work half the time so i'm kind of embarrassed to show it. Any help is appreciated. Thanks in advance

If I have two dates (ex. '8/18/2008' and '9/26/2008'), what is the best way to get the number of days between these two dates?


I am trying to follow the answers to  about an intersection of affine open sets being covered by affine open sets.  However, I can't seem to figure out why given $\operatorname{Spec} A \cap \operatorname{Spec} B$, it is possible to find a distinguished open set $D_{A}(f) \subseteq \operatorname{Spec} A \cap \operatorname{Spec} B$.  How would one show this?

I am reading the proof of proposition 5.3.1 of , and I have a problem with the last sentence : "If $g' = g''/f^n$ ($g''\in A$) then $\textrm{Spec}((A_f)_{g'}) = \textrm{Spec} (A_{fg''})$, and we're done."  Noting $V = \textrm{Spec} (B)$ and $V' = \textrm{Spec} (B_g)$, and noting $D_Z (h)$ the distinguished affine open subset of an affine scheme $Z$ associated to a section $h\in\Gamma(Z,\mathcal{O}_Z)$, I understand perfectly that if we note $U' = \textrm{Spec} (A_f)$ then the inclusion $U'\subset V$ induces a morphism $f : \Gamma(V',\mathcal{O}_X)\to \Gamma(U',\mathcal{O}_X)$ and that if we note $\varphi$ the associated morphism of affine schemes then $\varphi^{-1}(V') = D_{U'}(g')$ where $g'$ is the image of $g$ by $f$, but as $\varphi$ is the the inclusion $V'\subset U'$, we have $\varphi^{-1}(V') = V'$ because $V'\subset U'$ so finally $V' = D_{U'}(g')$ and $V'$ is distinguished in $U'$. I guess that the last sentence of the proof is supposed to show that this $V'$ is also distinguished in $U$, but I don't understand why.


I'm trying to figure out how to free up some space on my MacBook. I downloaded Disk Inventory X, and in looking at the storage breakdown it provides, I see that my Library folder is 119.4 GB. Library > Caches inside there has 96.7 GB. Caches > Adobe has 93.1 GB. Looks like After Effects is taking up the most space in there with 92 GB. That seems like an insane amount of space for one program cache.   Also, Library > Application Support has 21.8 GB. And Application Support > Adobe has 20.2 GB.  What can I delete without messing up my computer? I use the Adobe Suite pretty much every day, so I don't want to screw it up.

Is it safe to delete the file Caches, in the Library of the Mac OS X Hard Drive?  It's a pretty big file, 3.56 GB, Caches reminds me of logs i don't need or browser cookies.   Is it safe to delete the folder "Caches"?


Can you prove that magnetic monopoles don't exist? Can you disprove their existence or will they remain a hypothesis until/if discovered? Qiestions similar to this one don't focus on an actual proof and this question is asking about a proof.

Electric monopoles do exist, but why cannot magnetic monopoles exist?    The question is closed because I need to clarify it, but I don't know how I could ask it another way. However, I've recieved many answers that were appropiate and added something to my knowledge, so I consider it answered.


I'm starting to work on a AI / Azure machine learning project. And there I have to play the QA engineer role. I'm not sure about how to start and what to test. Can someone please give me advice or help on where to start?

I have been asked to test a new project, which is a web application for performing job searches. I've tested these kinds of products before, but this new project implements machine learning to enhance a couple features. These features include suggesting suitable jobs to a profile, and sending out targeted jobs via emails.   I've not tried to test a system which relies on machine learning. How would I go about doing so?  Specifically, how would I test this system to test that profiles are being sent 'correct' jobs via emails and through the website?


The fact is that I am not getting the question clear if $a_m=5$ and $a_n=17$ and if I take $m=3$ and $n=7$ .This doesn't hold true.Can someone help me to understand what the question is asking me ?

I am a beginner in number theory and I would like some hints to solve the following  problem : Assume we have natural numbers $a_1,a_2,...$ such that $i$ is not equal to $j$ and $\gcd(a_i , a_j) = \gcd(i,j)$. Prove that $a_i = i$. I know that I have to show $i$ counts $a_i$ and $a_i$ counts $i$ but I don’t know how to show this. Since $\gcd(i,j) = \gcd(j,i)$ is it also true that $a_i = j$?


I installed a program using make and sudo make install. Is there a command I can use to remove these files now?

I used source code to build one package such as below:  ./configure --prefix=/usr --sysconfdir=/etc --localstatedir=/var --libexecdir=/usr/lib --with-package-name="Myplugin" --with-package-origin="http://www.ubuntu.org/" --enable-gtk-doc --disable-static make make install   But unfortunately, i discovered that its the latest version, and has lot of bugs, so i need to remove it/uninstall it. But how can i do so? I tried make clean; make uninstall but still i see it exist:  # pkg-config --list-all | grep Myplugin myplugin-.... $ ls /usr/lib/myplugin/libXYZ.so exist....   How do you remove this now?


How to count the nodes which are in the left side of a root node? This is not similar to counting all the left nodes in the tree.

First of all, I swear this is not homework, it's a question I was asked in an interview. I think I made a mess of it (though I did realise the solution requires recursion). Here is the question:  Implement the count() method which returns the number of nodes in a tree. If a node doesn't have either a left or right child, the relevant getXXChild() method will return null  class Tree {    Tree getRightChild() {     // Assume this is already implemented   }    Tree getLeftChild() {     // Assume this is already implemented   }    int count() {     // Implement me   } }   My reason for asking the question is simply curious to see the correct solution, and thereby measure how bad mine was.  Cheers, Tony


I know this question has been asked many times, but I could not find a good answer for my question, yet...  I wanted to develop my own thesis style i.e. \usepackage{harthesis}, which I did, but when I compile it, I got an error saying harthesis.sty is not found...  What is the easiest and best way to create your own thesis style? I am sure this question would be very helpful for many people.  These are part of my developed, but not limited to thesis styles:   \permanentaddress \examiners \convocation   and so on..  These were intended to be my title page and other university requirements before I even start writing my Intro..  Any suggestions?  Thanks.

What are some good tutorials on writing custom styles (classes) that clearly explain commands used and some of the features that TeX has to offer in the way of styles?


Per , a multiple is the product of any quantity and an integer. The requirement for an integer strikes me as subjective. Why do we define a multiple in a manner that require an integer be present in the multiplication step.

Definition of multiple is :     In mathematics, a multiple is the product of any quantity and an integer. In other words, for the quantities a and b, we say that b is a multiple of a if b = na for some integer n, which is called the multiplier or coefficient .   But in the definition of  it is written that $Av$ is a scalar multiple of eigenvector $v$ .  But $A $ is a matrix .   How can i relate $A$ with the definition of multiple that $A$ is an integer ?


I have rejected  today which was approved with only one approval vote.  The edit received only three votes with two rejects and one approval.  The editor already  the same edit before which got rejected with three reject votes.  One more thing is, the approved reviewer(Jack Ramzi) name's label has a blue background unlike others.

When clicking "edit" I see:  Your edit will be placed in a queue until it is peer reviewed. We welcome edits that make the post easier to understand and more valuable for readers. Because community members review edits, please try to make the post substantially better than how you found it, for example, by fixing grammar or adding additional resources and hyperlinks.  Like:     Likewise, when I am not logged in, clicking "improve this question" or "improve this answer" shows:  You are not . Your edit will be placed in a queue until it is .  And when I click 'Save', I get:  Thanks for submitting an edit. It is only visible to you until it's been approved by trusted community members  Like:     Who can suggest an edit? Where do suggested edits go? Who can vote on a suggested edit? How do suggested edits get reviewed? Can I earn reputation? What about abuse or bad edits? Sometimes the Community user approves or rejects my edit. Why is that? When can I not suggest an edit? Is there a minimum change requirement for a suggested edit? How do I check my suggested edit history? I disagree with the reasons why my suggested edit was rejected. What can I do? How do I know whether there are edits waiting for review? Someone suggested an edit to my own post, and the reviewers took the wrong action. What can I do? Are tag wikis included in this scheme? What do the "Improve Edit" and "Reject and Edit" buttons do? Why are apparently valid links to rejected edits resulting in 404 errors?   For more information about editing, see "" in the .


Hi I have tried both the methods of upgrading.   Via terminal, I have typed:  sudo apt-get update. sudo apt-get distr-upgrade. sudo do-release-upgrade   But failed to upgrade distribution. It's showing error as:  The required dependency 'apt (>= 1.0.1ubuntu2.13)'is not installed.  When I opened update manager, it shows certain security updates but when I clicked install, it is unable to download, showing an internet connection error. Actually my internet is working at good 3G speed.    Please help me with upgrading.

When trying to upgrade using the terminal, my upgrade stops. This is the line showing in the terminal:  The required dependency 'apt(>=1.0.10.2 ubuntu2)' is not installed.   my problem is that I don't know the command to install this dependency. Using other commands, it says apt is up to date. Solutions?


Would this even assist math in the way that $i$ did? Or is this just outright pointless and/or too exclusive to call for a definition?

Before, the concept of imaginary numbers, the number $i = \sqrt{-1}$ was shown to have no solution among the numbers that we had. So we declared $i$ to be a new type of number. How come we don't do the same for other "impossible" equations, such as $x = x + 1$, or $x = 1/0$?  Edit: OK, a lot of people have said that a number $x$ such that $x = x + 1$ would break the rule that $0 \neq 1$. However, let's look at the extension from whole numbers to include negative numbers (yes, I said that I wasn't going to include this) by defining $-1$ to be the number such that $-1 + 1 = 0$. Note that this breaks the "rule" that "if $x \leq y$, then $ax \leq ay$", which was true for all $a, x, y$ before the introduction of negative numbers. So I'm not convinced that "That would break some obvious truth about all numbers" is necessarily an argument against this sort of thing.


I am looking for good proofreading methods for latex. I am just writing a thesis and my supervisor is not familiar with latex. So at the moment I am giving her either a PDF or printed document to use adobe commenting function etc.  Are there any better ways comparable to the MS word "review/track changes" functions?  Would maybe Lyx be an option?

I am writing a scientific paper with my collaborator. We have submitted a version to a journal and now we got a review from them, so we need to fix a few things. In Microsoft Word there is the option to "track changes", which displays the deleted text as crossed out and the new text bolded (if I remember the details correctly). Is there a way to achieve a similar result in LaTeX?  I was thinking to create a new file for the revised version and then write a script which would basically compare the two files and make the differences either bold or crossed out before sending it to latex. Is there a tool that already does it?


If $X$ is finite dimensional, $A$ is a convex dense subset, prove  that $\mathrm{Aff}(A)=X$. Here $\mathrm{Aff}(A)$ is the affine hull of $A$, we have the expression $\mathrm{Aff}(A) = \{x\in X: x = \sum_{i=1}^n \lambda_i x_i, \forall x_i\in A,\forall \lambda_i\in\mathbb{R},\sum_{i=1}^n \lambda_i = 1 \}$.

I am trying to prove that the affine hull of a set $X \subseteq \mathbb{R}^d$ is equal to the affine hull of the clojure of that set: $$ \text{aff}(X) = \text{aff}(\text{cl}(X)). $$  Proving $\text{aff}(X) \subseteq \text{aff}(\text{cl}(X))$ is easy, but containment in the other direction is harder.  I am assuming there is a sequence $\{ x_k \}_{k=1}^\infty \subseteq X$ such that $\lim_{k\to \infty} x_k = x^*$. The point $x^*$ is obviously contained in $\text{aff}(\text{cl}(X))$. But I am not sure how to show it is also in $\text{aff}(X)$, specifically because I am not sure how to show that $x^*$ lies on a line connecting two points in $X$.  Any suggestions on how to surmount this hurdle are welcome.


I'd like to build a query string with a variable length in where clause.  In PHP I might do this like  <?php $vars=array('john','mike','matt'); $placeHolders=array_fill(0,sizeof($vars),'%s'); $whereClause=" name in (".join(',',$placeHolders).")";   Is there a concise Python translation of this in python

I have a python list, say l  l = [1,5,8]   I want to write a sql query to get the data for all the elements of the list, say  select name from students where id = |IN THE LIST l|   How do I accomplish this?


I am trying to add the navigation layout to my activity but I keep getting an error of type       Caused by java.lang.NullPointerException: Attempt to invoke virtual   method 'void   androidx.drawerlayout.widget.DrawerLayout.addDrawerListener(androidx.drawerlayout.widget.DrawerLayout$DrawerListener)'   on a null object reference   What might be the problem of the code  package com.agile.Login;  import androidx.appcompat.app.ActionBarDrawerToggle; import androidx.appcompat.app.AppCompatActivity; import androidx.appcompat.widget.Toolbar; import androidx.core.view.GravityCompat; import androidx.drawerlayout.widget.DrawerLayout;  import android.os.Bundle;  public class Homedashboard extends AppCompatActivity {     private DrawerLayout drawer;     @Override     protected void onCreate(Bundle savedInstanceState) {         super.onCreate(savedInstanceState);         setContentView(R.layout.activity_homedashboard);         Toolbar toolbar = findViewById(R.id.too_bar1);        setSupportActionBar(toolbar);          setTitle("Hazina Sacco");         drawer =  findViewById(R.id.navigation_drawer);         ActionBarDrawerToggle toggle = new ActionBarDrawerToggle(this, drawer, toolbar,                 R.string.navigation_drawer_open, R.string.navigation_drawer_close);        drawer.addDrawerListener(toggle);         toggle.syncState();      }     @Override     public void onBackPressed() {         if (drawer.isDrawerOpen(GravityCompat.START)) {             drawer.closeDrawer(GravityCompat.START);         } else {             super.onBackPressed();         }     } }   <?xml version="1.0" encoding="utf-8"?> <androidx.drawerlayout.widget.DrawerLayout xmlns:android="http://schemas.android.com/apk/res/android"     android:layout_width="match_parent"     android:layout_height="match_parent"     xmlns:app="http://schemas.android.com/apk/res-auto"     xmlns:tools="http://schemas.android.com/tools"     android:fitsSystemWindows="true"     tools:context=".Homedashboard"     android:id="@+id/navigation_drawer"     tools:openDrawer="start">     <LinearLayout         android:layout_width="match_parent"         android:layout_height="match_parent"         android:orientation="vertical">         <androidx.appcompat.widget.Toolbar             android:layout_width="match_parent"             android:layout_height="176dp"             android:background="@color/colorPrimary"             android:elevation="4dp"             android:theme="@style/ThemeOverlay.AppCompat.Dark.ActionBar"             app:popupTheme="@style/ThemeOverlay.AppCompat.Light"             />         <FrameLayout             android:id="@+id/fragment_container"             android:layout_width="match_parent"             android:layout_height="match_parent"/>     </LinearLayout>     <com.google.android.material.navigation.NavigationView         android:layout_width="wrap_content"         android:layout_height="match_parent"         app:headerLayout="@layout/nav_header"         app:menu="@menu/nav_menu"/>     </androidx.drawerlayout.widget.DrawerLayout>

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?


Assume $I+AB$ is invertible, prove then that $I+BA$ is invertible and $(I+BA)^{-1} = I-B(I+AB)^{-1}A$.    My work:  $(I+AB)(I+AB)^{-1} =  I$  $B(I+AB)(I+AB)^{-1} = B $  $(I+BA)B(I+AB)^{-1} = B$  $(I+BA)B(I+AB)^{-1}B^{-1} = I$  Thus $(I+BA)$ is invertible and $B(I+AB)^{-1}B^{-1}$ is its inverse. But I have no clue how to arrive to the given inverse formula. I feel like I'm missing something. Can anyone help?

The problem is from  Algebra by Artin, Chapter 1, Miscellaneous Problems, Exercise 8. I have been trying for a long time now to solve it but I am unsuccessful.      Let $A,B$ be $m \times n$ and $n \times m$ matrices. Prove that $I_m - AB$ is invertible if and only if $I_n - BA$ is invertible.    Please provide with only a hint.


I am having difficulty understanding which is correct as each seems to be singular and them seems to be plural.

A source says that the word "each" should always be followed by a singular noun, but however I look at it in this sentence it just doesn't seem to fit:     foo [comprises] multiple binary programs that each performs a single task.   Should it be "performs" or "perform"?


Say if i have a keyword "gold jewellery" this ranks my site on the first page of google. However typing: gold jewellery in google does not rank the site. What is the best way to overcome this issue?

What are the best ways to improve a site's position in the Google search results?


What will be the remainder when $2^{100}$ is divided by $153$?

How do I efficiently compute $a^b\bmod c$:  When $b$ is huge, for instance $5^{844325}\bmod 21$? When $b$ is less than $c$ but it would still be a lot of work to multiply $a$ by itself $b$ times, for instance $5^{69}\bmod 101$? When $(a,c)\ne1$, for instance $6^{103}\bmod 14$?  Are there any other tricks for evaluating exponents in modular arithmetic?  This is being asked in an effort to cut down on duplicates, see  and .


I just downloaded Blender to my Surface Pro 4 tablet, but I cannot read the menu bars, the fonts are too small. How can I make the menu fonts bigger?

The Blender UI elements are incredibly small by default on high resolution screens on Windows (15" UHD screen).  I found the Preferences -> System -> DPI setting which can be set up to 144.  This makes Blender usable, but still uncomfortable and difficult on the eyes.  Is there a way to make the UI elements even larger?


Thank you for giving me an idea to try to find a way to calculate this sum:  $$S= \sum_{i=0}^n \lfloor\sqrt{i} \rfloor$$

I need to find a clear formula (without summation) for the following sum:  $$\sum\limits_{k=1}^n \lfloor \sqrt{k} \rfloor$$  Well, the first few elements look like this:  $1,1,1,2,2,2,2,2,3,3,3,...$  In general, we have $(2^2-1^2)$ $1$'s, $(3^2-2^2)$ $2$'s etc.  Still I have absolutely no idea how to generalize it for $n$ first terms...


I just want my checkerOddEven() method to be an ArrayList type instead of void, and I want it to be able to return both Arraylist that was stored inside each variables, so that it will print out exactly like the current output with void method.  this is the output of the current code:   int[] numbers;  public Main(){     numbers = new int[] {1,2,3,4,5,6,7,8,9,10}; }  public boolean oddEven (int number){      if(number%2!=0){         return true;     }     return false;  } public void checkerOddEven (int[] numbers){      ArrayList<Integer> answerOdd = new ArrayList<Integer>();     ArrayList<Integer> answerEven = new ArrayList<Integer>();      for(int number : numbers){         if(oddEven(number)){             answerOdd.add(number);         }         else answerEven.add(number);     }      System.out.println("The Odd numbers are :"+answerOdd);     System.out.println("The Even numbers are :"+answerEven);  }  public static void main(String[] args) {     Main main = new Main();      main.checkerOddEven(main.numbers); }

I want to return two objects from a Java method and was wondering what could be a good way of doing so?  The possible ways I can think of are: return a HashMap (since the two Objects are related) or return an ArrayList of Object objects.  To be more precise, the two objects I want to return are (a) List of objects and (b) comma separated names of the same.  I want to return these two Objects from one method because I dont want to iterate through the list of objects to get the comma separated names (which I can do in the same loop in this method).  Somehow, returning a HashMap does not look a very elegant way of doing so.


Can the following assignment on objects be made into a functor from the category of topological spaces into the category of groups? Each topological space $X$ gets mapped to $\mathrm{Aut}(X)$, its automorphism group (group of all homeomorphisms from $X$ to $X$). I know that one necessary condition of functors $F\colon \mathcal C\to\mathcal D$ is that whenever $X, Y\in\mathcal C$ are isomorphic, then $F(X)$ and $F(Y)$ are isomorphic. This should be true for $F = \mathrm{Aut}$.  I read that in algebraic topology one is interested in so-called algebraic "invariants". Is $\mathrm{Aut}$ such an invariant (after all, it assigns to each topological space a group)?

Once upon a time I proved that there is no functorial 'association' $$F:\ \mathbf{Grp}\ \longrightarrow\ \mathbf{Grp}:\ G\ \longmapsto\ \operatorname{Aut}(G).$$ A few days ago I casually mentioned this to someone, and was asked for a proof. Unfortunately I could not and still can not recall how I proved it. Here is how much of my proof I do recall:  Suppose such a functor does exist. Choose some group $G$ wisely, and let $f\in\operatorname{Hom}(V_4,G)$ and $g\in\operatorname{Hom}(G,V_4)$ be such that $g\circ f=\operatorname{id}_{V_4}$. Then, because $F$ is a co- or contravariant functor we have $$F(g)\circ F(f)=F(g\circ f)=F(\operatorname{id}_{V_4})=\operatorname{id}_{\operatorname{Aut}(V_4)},$$ or $$F(f)\circ F(g)=F(g\circ f)=F(\operatorname{id}_{V_4})=\operatorname{id}_{\operatorname{Aut}(V_4)},$$ where $\operatorname{Aut}(V_4)\cong S_3$. In particular $\operatorname{Aut}(G)$ contains a subgroup isomorphic to $S_3$. Then something about the order of $\operatorname{Aut}(G)$ leads to a contradiction.  I cannot for the life of me find which goup $G$ would do the trick. Any ideas?


I need to automate the task of search and install Windows 7 and 8 updates through the command line(it could be over cmd, vbs or powershell), there is some way?  Thanks in advance.

It often happens that I have to watch this screen for minutes:    I have no clue what's happening in the back. And I'm also not interested in watching the  for changes.  I would love to know if there's a way that gives more feedback. Preferably something I can invoke from the command line (like apt-get).


I have a table candidate. It contains two columns name and roll. The values in all three rows of data are AA and 10. Now I want to delete only the second row. How can I do it?  Say we have an invoice number which automatically updates, but for some reason it has not updated and continued to register the same number again. In such case if I wish to delete the second row, what should I do?  I used this query:  delete from candidate where (SELECT * FROM candidate limit 1,1);   ...but it throws an error saying     operand should contain one column

I've inherited a DB that was lacking a unique constraint so data was/is duplicated. I'm now trying to remove the duplicate records, then add a constraint to block this going forward.  I have this query:  SELECT count(*) as dacount, substr(group_concat(id), (locate(',', group_concat(id))+ 1)) FROM `game` group by matchid, ordinal having dacount > 1 order by dacount desc   which correctly gives me the ids of the rows I need to delete. The problem with this though is that I can't use this as a subquery on the DELETE because of the dacount with the having parameter. Is there another way to do this?  Here was my plan:  DELETE FROM game WHERE id IN (SELECT count(*) as dacount, substr(group_concat(id), (locate(',', group_concat(id))+ 1)) FROM `game` GROUP BY matchid, ordinal HAVING dacount > 1)


Suppose we have a group $G$ and $H,N \leq G$ such that $HN \leq G$. Then how do I justify the formula:  $$ |HN| = \frac{|H||N|}{|H\cap N|} $$  Also, are there any other assumptions neccesary for the formula to hold? Thanks

Let $H$, $K$ be subgroups of $G$. Prove that $o(HK) = \frac{o(H)o(K)}{o(H \cap K)}$.  I need this theorem to prove something.


$A \setminus B \cup C$ or $A \setminus (B \cup C)$?  Sorry as this is a very soft question, but I couldn't find the answer anywhere. Are these two things generally considered the same?

I don't know how to evaluate this expression:  $A-B\cap C$  Is it true that:  $A-(B\cap C)=(A-B)\cap C$  or, in other words, that the associative property applies to these operations?


Some date is stored in a json file, how can I comment out some lines like below?  [     {         "id":"aaaa",     //  "path": "xxxx",         "path": "yyyy"     },    {        "id":"bbbb",        "path": "cccc"     } ]   My IDE is Visual Studio.

Can I use comments inside a JSON file? If so, how?


I’m after a book about an amphibian race, a guy found a creature, there was a scientist involved, the thing learnt English and lives in an advanced civilisation under the Earth that can be accessed through a cave under the sea. Something about peanut butter and jelly sandwiches and down there you press a button on a machine that makes a pill that tastes like the food you wish for or something like that my memory is fuzzy I read this cover less book when I was 9 (it was like .50c from a thrift store) and I think it was 60’s or 70’s maybe earlier again not sure.

When I was a kid, I read a book (likely from the '60s) about a pair of kids who find an ancient lizard/fish man inside a cave. The cave has been recently exposed by an earthquake and the creature is inside a super technologically advanced stasis chamber. I think this creature's name is something like "Sslaa". He takes the kids on a quest to find his lost underwater city.  They end up finding the city, which is still populated by creatures like himself and protected from the ocean above by an immense diamond dome. Eventually, Sslaa has to drive an advanced mining vehicle deep into the crust of the earth, presumably to prevent his city's destruction by an impeding magma flow or other seismic event.  For extra obscurity bonus points, I could swear I managed to find this book on Google several years ago, and was shocked to learn that it had originally been written in German, and then translated to English.  Does anyone out there recognize this one?


I am trying to find an efficient way of evaluating the gamma function gamma(t) where t is a complex number.  The Wolfram Mathworld page  gives a number of formulas involving infinite series and infinite products, but it does not appear to have any information on rates of convergence.

The question is simple. I would like to implement the Gamma function in my calculator written in C; however, I have not been able to find an easy way to programmatically compute an approximation to arbitrary precision.  Is there a good algorithm to compute approximations of the Gamma function?  Thanks!


I have a setup where I have accounts and teams. One account can belong to multiple teams and one team can belong to multiple accounts. How should I go about designing this in Postgres?

I want to build a composite primary key made up of foreign keys from two different tables. I'm still pretty green to this...  A great answer was given to building a composite key from multiple foreign keys on  but I want to do this from multiple tables. I am using Oracle 11g.  foreign key (Name, BoughtFrom, TimeBought)    references the_other_table_name (Name, BoughtFrom, TimeBought)   Imagine that the "references" line actually includes multiple tables. I'm not even sure that the above syntax will work with Oracle.  I have one table "Student" and one table "Parent". It is a many-to-many relationship. My association table is named "Relation" and I would like to make a composite primary key from "PAR_ID" and "STU_ID". Both are foreign keys.


I am trying to find the name and author of a children's fantasy/sf book. The plot involves people who are simply disappearing from the world. Usually they come to some decision and mysteriously tell their family they are leaving, and soon after they simply cannot be found.  The protagonist (I think a boy) discovers that the family cat can see strange black blobby creatures that are invisible to everyone else. (This is why cats stare at things we cannot see.) I think the cat decides to "leave" as well. Finally, the boy discovers that the blob creatures are the connection to another world where everything is rural. He and his family step into the other world. The story ends with a description of how they farm the blob things.  I think the author is female.

I'm trying to trace what was probably a short story rather than a full novel from my childhood.  I think it starts in the present day (so the 80s or thereabouts) and there was some kind of alternate reality bleed which meant there were (i think) ghost boars or pigs, they were becoming more physical with time, and so problematic. The family escaped when the family dog led them to and through a portal which they couldn't perceive to a safer place.  In the end, they ended up in some kind of rural community who had a religion / custom that required them to say "Bless the beasts that bless us" but some folk shortened it to BTBTBU which irritated the girl who was the principle character.  I used to read a lot of kids short story sci-fi and fantasy including Nicolas Fisk but I don't know whether this was from a compilation of several authors or a single author's collection.


Why, in some instances, is the text Here is some text presented before the picture.jpg in the final document, please?  \begin{figure}[h] \centering \includegraphics[width=...]{picture.jpg} \caption{The best caption in the world.} \end{figure}  Here is some text.   I have had similar problems when doing \protect\footnotemark inside the \caption{...}, when the \footnotetext{...} which is supposed to come afterwards, is presented before the image.

How to influence the position of float environments like figure and table in LaTeX?   This is a general question and should collect useful answers for all users. I hope we can use this as a reference


Question:   The Fibonacci numbers are $1,1,2,3,5,8,13,21,34,\dotsc$ In general, the Fibonacci numbers are defined by $f_1=1$, $f_2=1$, and $f_n = f_{n-1} + f_{n-2}$ for $n \geq 3$. Prove that the $n$-th Fibonacci number $f_n$ satisfies $f_n < 2^n$.   I know that I am supposed to use induction to prove this. I'm just not sure where to start. I set $n=1$, which made $f_n = f_1 < 2^1$. Therefore, I believe $n=1$ satisfies $f_n < 2^n$. I think I now need to set $n= k + 1$ where $k$ is some integer. I do not know where I should plug this in.  Looking for some guidance please!

I'm trying to find the proof by induction of the following claim: For all $n\in\mathbb N$, $\operatorname{fibonacci}(n) \le  2^n$ My Proof: Base case: $n = 1$ $\operatorname{fibonacci}(1) \le 2^ 1$ is $1 \le 2$, true. Base case holds Inductive Hypothesis: Assume true for $n = k$: $\operatorname{fibonacci}(k) \le 2^k$ Show True for $\operatorname{fibonacci}(k+1) \le 2^{k+1} $ $$\operatorname{fibonacci}(k) * k  \le 2^k   k$$ $$\operatorname{fibonacci}(k) \le  2^{k+1} $$ I get stuck here Any help?


I am trying to rewrite every file after cdn.minora.me/forum/ to another directory:  server {     listen   443 ssl;     listen   [::]:443 ssl;     ssl on;     ssl_certificate /etc/nginx/ssl/minora.me.crt;     ssl_certificate_key /etc/nginx/ssl/minora.me.key;         root /srv/minora.me/webservices/cdn.minora.me;     index index.html index.htm index.php;     server_name cdn.minora.me;     location ~* \.(eot|ttf|woff|js|css|svg)$ {     add_header Access-Control-Allow-Origin *;     }     location /forum/(images|language|sounds|templates|uploads|vendor|src\/modules|nodebb\.min\.js(\.map)?|stylesheet\.css|admin\.css) {         alias /srv/minora.me/webservices/forum.minora.me/public/;     }     location / {         try_files $uri $uri/ /index.php;     }     location ~ \.php$ {         fastcgi_split_path_info ^(.+\.php)(/.+)$;         fastcgi_pass unix:/var/run/php5-fpm-cdn.minora.me.sock;         fastcgi_index index.php;         include fastcgi_params;     }     location ~ /\.ht {         deny all;     } }   The files I am trying to access, e.g.:  cdn.minora.me/forum/stylesheet.css   definitely exist, for example the stylesheet above can be found under the following path on my server  /srv/minora.me/webservices/forum.minora.me/public/stylesheet.css.   But nginx is trowing an 404 not found error when I am trying to access e.g.  cdn.minora.me/forum/stylesheet.css  It seems like it doesnt use the rule at all, here a part of the nginx error log:  2014/12/23 15:30:51 [error] 30277#0: *8 open() "/srv/minora.me/webservices/cdn.minora.me/forum/stylesheet.css" failed (2: No such file or directory), client: 141.101.105.127, server: cdn.minora.me, request: "GET /forum/stylesheet.css HTTP/1.1", host: "cdn.minora.me" 2014/12/23 15:30:53 [error] 30277#0: *9 open() "/srv/minora.me/webservices/cdn.minora.me/forum/stylesheet.css" failed (2: No such file or directory), client: 141.101.105.127, server: cdn.minora.me, request: "GET /forum/stylesheet.css HTTP/1.1", host: "cdn.minora.me" 2014/12/23 15:30:57 [error] 30277#0: *9 open() "/srv/minora.me/webservices/cdn.minora.me/forum/stylesheet.css" failed (2: No such file or directory), client: 141.101.105.127, server: cdn.minora.me, request: "GET /forum/stylesheet.css HTTP/1.1", host: "cdn.minora.me" 2014/12/23 15:31:14 [error] 30277#0: *23 FastCGI sent in stderr: "Primary script unknown" while reading response header from upstream, client: 141.101.93.222, server: img.minora.me, request: "HEAD /assets/loader/main@2x.gif HTTP/1.1", upstream: "fastcgi://unix:/var/run/php5-fpm-img.minora.me.sock:", host: "img.minora.me", referrer: "https://minora.me/" 2014/12/23 15:35:24 [error] 30281#0: *31 open() "/srv/minora.me/webservices/cdn.minora.me/forum/stylesheet.css" failed (2: No such file or directory), client: 141.101.105.127, server: cdn.minora.me, request: "GET /forum/stylesheet.css HTTP/1.1", host: "cdn.minora.me" 2014/12/23 15:35:26 [error] 30278#0: *43 FastCGI sent in stderr: "Primary script unknown" while reading response header from upstream, client: 141.101.105.168, server: cdn.minora.me, request: "GET /favicon.ico HTTP/1.1", upstream: "fastcgi://unix:/var/run/php5-fpm-cdn.minora.me.sock:", host: "cdn.minora.me"   Also replacing root with alias doesnt work. Can anyone help?

I've got a pretty much default sites-enabled set up in my nginx on debian squeeze and i'm now trying to get it to serve up my munin graphs on myhost/munin/  Heres the location i've added to the config         location /munin             {                     root /var/cache/munin/www/;                     index index.htm index.html;             }   And here is the error I recieve:              2012/07/09 23:52:03 [error] 3598#0: *13 "/var/cache/munin/www/munin/index.htm" is not found (2: No such file or directory), client: 93.*.*.*, server: , request: "GET /munin/ HTTP/1.1", host: ""   This set up used to 'just work' in apache. I'm new to nginx so a bit lost as to why its adding the extra /munin when looking for the path. Any advice?


My timeline will only go upto 350 frames then the simulation will end. I have tried to increase the end time for it but it will not work is there another way i can do this?

I've set up the physics of a swinging wrecking ball and set the animation to run for 240 frames.  This was not long enough for the entire "swing" of the ball-and-chain.   I'm unable to reset the timeline, but I can set the end frame to (say) 1000 frames, but when I try to play the animation, the animation progress halts at frame 240 and I cannot get it to go any further.   There are no markers or keyframes in the timeline.  What should I do to "force reset" the animation-timeline, to allow changes to the length?


Where I can learn to use OpenLayers and GeoServer?

I need to create a web map showing many raster layers. I am using mapserver and want to use Openlayers, however I can't find any good tutorial about it. I see a couple of old questions ( and ) saying that there were no good documentation. Have the things changed recently?  I would like to find a tutorial teaching from basics to rather complicated things with good explanations of the code and pictures/examples of the results. For now I managed to do only the simplest web map with my .map file, but I need to customize it (add legends, group layers, add more controls, embedding, etc).


I am looking to fill in small gaps of no data/null values in my raster image within ArcMap.   Are there any good techniques to approach this, while also not degrading the image in the process?

I have a raster with gaps in it. I want to fill these in with averages of surrounding cells using ArcGIS 10.2 for Desktop.   I have tried "Focal Statistics" but it averages EVERY cell and not just the gaps.   I have tried [Mosaic].IsNull.Con([Average], [Mosaic]) found here   but don't know how to implement it/it won't work for me  I have tried  but I think they were using versions before 10.2.   What I want. Make a fake raster with gaps filled in. Use the fake raster to fill in the gaps of the real raster without replacing the points with actual data.


I am having problem understanding what the following sentence means exactly:     Bill's and my car had to be towed last night.   I can't quite figure out why the possessive is used in Bill's and what it means.

I want to talk to someone about the house that my wife and I own.  Saying, for example, "My wife's and my house is awesome," sounds a bit funny to me.  What's the best way to express this?  Clarification  I'm asking specifically about the grammar of multiple nouns in possessive form.  I'm particularly curious if it's possible to do this with a first-person pronoun (me).  I am capable of rephrasing this in other ways - my question is not how to express the idea, but about this particular grammatical construction, if it is even legal.


I would like to know whom a street was named after. That's how I am asking it:       Whom was this street named after?   Is the question correct?

Many times, I've been asked the difference between "who" and "whom". I myself know the difference, but it is hard to explain to others. What is the easiest way to explain it to those with a basic understanding of English? A mnemonic (if possible) would help.


Is it possible/necessary to configure a "Battery is full, remove charger notification" similar to the Low Battery Alert?  I run macOS Sierra on my computer and wonder what software or scripts or configuration is needed to perform this.  [Based on an answer, the question has been modified to include if this is necessary since that was the main intention behind the query]

My friend told me that I need to disconnect the power cord when the battery is fully charged. Otherwise, I will shorten the life of the battery.  Other people say you should drain it once a month or point out that for long term storage, you should charge it to 50% and then periodically (3 to 6 months) bring it back to 50% and store it again.  I am going to use my laptop at home 90% of the time. So, I plan to have the power cord connected all the time.  I'd prefer to just plugging in my MacBook Pro and letting it be on charge long term and occasionally taking it away from the charger when I'm not at home or my desk.  Are these specific recommendations worth the inconvenience?


I refer to Allen Hatcher's famous book on Algebraic Topology:   What software or LaTeX package can be used to draw those figures? Or are those best hand drawn?  Thanks for any help!

What packages do you use and recommend for creating graphics in your LaTeX documents?     As this is a community wiki post, please add your package to the accepted answer (or add a comment, and someone with >100 rep will add it to the CW answer), and include a brief description of what differentiates it from others and how it can be used (GUI drawing tool which generates code, type in raw text, or generates image for inclusion in document).   We'll eventually sort these answers under headings.


I understand that a circuit with just one bulb will be brighter than a circuit with two, because Ohm's law states that current is inversely proportional to distance, and therefore the greater resistance presented by two bulbs will cause a lower current to pass through the circuit.  The thing that I am unsure about is why all of the bulbs in a series circuit will have the current shared equally and therefore be equally bright, as my intuition would say the first bulb would receive more energy than the second, and that more than the third etc. At the risk of asking a silly question, how do the electrons 'know' how much energy to give the first bulb without having any obvious way of 'knowing' the number of bulbs / total resistance of the system?  My teacher said he thought it might have something to do with the idea that the electrons pass round the circuit repeatedly, so the charge averages in some sense, but if this is true would the first light seem brighter if the circuit was only activated for long enough for the electrons to complete a single circuit?

When I connect two identical lightbulbs in series, how come they have equal brightness?  Why can't one lightbulb have a larger voltage drop than the other?  (i.e. the first lightbulb "uses up all the energy" and the second lightbulb is barely lit because "there isn't much energy left"?


Let $\Gamma$ denote the positively oriented circle of radius $2$ with center at the origin. Let $f$ be an analytic function on $\{z \in\mathbb C : |z| > 1\}$, and let $$\lim_{z\to\infty} f(z) = 0$$ Prove that $$f(z) =\frac{1}{2\pi i}\int_{\Gamma}\frac{f(\zeta)}{z-\zeta}$$ for all $z \in\mathbb C$ with $|z| > 2.$ I tried to define a function $g(z)=f(1/z)$ and apply Cauchy Integral Formula on $g$, but could not come up with anything.

Let $f$ be analytic in $|z|\ge1$ and  $\lim_{z\to\infty}f(z)=0$. Then is $f(z)=\frac1{2\pi i}\int_{\Gamma}\frac{f(\zeta)}{z-\zeta}d\zeta$,$\forall |z|\ge2$, where $\Gamma$ is the circle of radius $2$ with centre at the origin.   I think yes, by the Cauchy integral formula. But, how do we ensure that the non analyticity of $f$ in $|z|<1$ dosent affect the formula? Thanks beforehand.


Hello I have convert doc file to only string text. I use this function: :  function getRawWordText($filename) {     if(file_exists($filename)) {         if(($fh = fopen($filename, 'r')) !== false ) {             $headers = fread($fh, 0xA00);             $n1 = ( ord($headers[0x21C]) - 1 );// 1 = (ord(n)*1) ; Document has from 0 to 255 characters             $n2 = ( ( ord($headers[0x21D]) - 8 ) * 256 );// 1 = ((ord(n)-8)*256) ; Document has from 256 to 63743 characters             $n3 = ( ( ord($headers[0x21E]) * 256 ) * 256 );// 1 = ((ord(n)*256)*256) ; Document has from 63744 to 16775423 characters             $n4 = ( ( ( ord($headers[0x21F]) * 256 ) * 256 ) * 256 );// 1 = (((ord(n)*256)*256)*256) ; Document has from 16775424 to 4294965504 characters             $textLength = ($n1 + $n2 + $n3 + $n4);// Total length of text in the document             $extracted_plaintext = fread($fh, $textLength);             $extracted_plaintext = mb_convert_encoding($extracted_plaintext,'UTF-8');              // if you want to see your paragraphs in a new line, do this              // return nl2br($extracted_plaintext);              return ($extracted_plaintext);         } else {             return false;         }     } else {         return false;     }   }   This function return:     jednoznacznie implikuje poBo|enie   It should be:     jednoznacznie implikuje położenie   I try convert this string to polish letters:  return strtr ($mystring, array (             'B' => 'ł',             '|' => 'ż',             ));   But I have return:     jednoznacznie implikuje po�o�enie   I add (like here: )  header("Content-Type: text/html; charset=ISO-8859-1");   now I have this:     jednoznacznie implikuje po³o¿enie

I'm setting up a new server and want to support UTF-8 fully in my web application. I have tried this in the past on existing servers and always seem to end up having to fall back to ISO-8859-1.  Where exactly do I need to set the encoding/charsets? I'm aware that I need to configure Apache, MySQL, and PHP to do this — is there some standard checklist I can follow, or perhaps troubleshoot where the mismatches occur?  This is for a new Linux server, running MySQL 5, PHP, 5 and Apache 2.


I try to add additional space between two paragraphs but I'm getting the error:"There is no line here to end". I want to have exact two line breaks between each paragraph.  \documentclass[10pt, a4paper]{report} \usepackage{graphicx} \usepackage{ngerman} \usepackage[utf8]{inputenc} \usepackage{textcomp} \usepackage[T1]{fontenc} \usepackage{titling} \usepackage{times} \usepackage{setspace}  \vspace*{-2.54cm} \begin{document} \begin{center} \fontsize{16}{0}\selectfont \textbf{some text} \end{center}  \newline \newline  \begin{center} \fontsize{12}{0}\selectfont some other text \end{center}  \end{document}

When I want to have a space between lines I use \\~\\ or \newline  For example       Hello this is an example      \\~\\     Goodbye   I get the error there is no line to end here.  What am I doing wrong?


A  was recently migrated to  because it was about a Network-wide bug with the Stack Exchange iOS application.  Before it was migrated I upvoted the question on Meta Stack Overflow:    ..and the vote was carried across to Meta Stack Exchange, but it doesn't think I've voted yet:    ..meaning I can upvote the question again:    This bug could exist because the system may only migrate the number of votes, not including who actually voted.  If so, it can't really be called 'Migration, but rather be called copy and delete.  Is this bug intentional?

was created on Server Fault, answered on Server Fault, I upvoted some of those answers on Server Fault, and then moved by consensus to Super User.  Now that the question is on Super User, I can upvote the same answers I previously upvoted on Server Fault.


What exactly is gravitational attraction? In my textbook it was quoted " all objects both tiny and large objects are attracted to the earth. This is known as gravitational attraction, or the force due to gravity". But the force due to gravity is weight. I think that gravitational attraction is the action of attraction and is different from the force due to gravity (weight). Pls clarify.

Is there a difference between Weight and Force of Gravity or they just mean the same thing? My textbook does not clarifies this point.


Please read the requirement before thinking it is duplicate of any similar question. As far as I found more than 20 Email validation regular expressions But all of them allows  a@a.co.in.in.in.in.in.in.in  as valid email address!!! I want to restrict that only two dots(.) should be allowed. For Example: Valid Emails  somename@yahoo.in somename@yahoo.co.in somename@somesite.bizz somename@gmail.com somename@somesite.net  Invalid Emails  @.co @a.com a@a a@.com a@a.co.in.in //maximum two dots allowed otherwise invalid a@a.co.in.in.in.in.in.in //maximum two dots allowed otherwise invalid  For this I tried with  [a-zA-Z0-9._%+-]+@[a-zA-Z0-9]+\.[a-zA-Z]{2,5}[\.[a-zA-Z]{2,5}]{0,1}  It is working with 2 dots but throwing invalid message for  somename@somesite.com

Over the years I have slowly developed a  that validates MOST email addresses correctly, assuming they don't use an IP address as the server part.  I use it in several PHP programs, and it works most of the time.  However, from time to time I get contacted by someone that is having trouble with a site that uses it, and I end up having to make some adjustment (most recently I realized that I wasn't allowing 4-character TLDs).  What is the best regular expression you have or have seen for validating emails?  I've seen several solutions that use functions that use several shorter expressions, but I'd rather have one long complex expression in a simple function instead of several short expression in a more complex function.


I was looking at the event loop in Javascript and it keeps mentioning the word heap. The only source I could find explaining was a small one-line definition on the MDN website:     Objects are allocated in a heap which is just a name to denote a large   mostly unstructured region of memory.   Can someone provide a more detailed explanation of what a heap is in the sense of the JavaScript event loop, and its role in JavaScript?

Programming language books explain that value types are created on the stack, and reference types are created on the heap, without explaining what these two things are. I haven't read a clear explanation of this.  I understand what a stack is. But,    Where and what are they (physically in a real computer's memory)? To what extent are they controlled by the OS or language run-time? What is their scope? What determines the size of each of them? What makes one faster?


From :     Typically, if you don't have any significant P values for the   individual coefficients in your model, the overall F-test won't be   significant either. However, in a few cases, the tests could yield   different results. For example, a significant overall F-test could   determine that the coefficients are jointly not all equal to zero   while the tests for individual coefficients could determine that all   of them are individually equal to zero.   Could you please provide a graphical and/or real life example?

In a multiple linear regression, why is it possible to have a highly significant F statistic (p<.001) but have very high p-values on all the regressor's t tests?  In my model, there are 10 regressors. One has a p-value of 0.1 and the rest are above 0.9    For dealing with this problem see the .


$$\int \cos\left(x^2\right)dx$$ I tried to evaluate the formula $\int cos(x^2)dx$ using substitution integral and integration by parts... But I couldn't  Can someone help me evaluating this integration?

What is the result of this integration in a closed form?  $ \int{\cos{ x }^2}dx $  We can say $\int { cos\left( 2x \right) dx= } \frac { sin(x) }{ 2 } $  So why we can't say $\int { cos({ x }^{ 2 })dx=\frac { sin({ x }^{ 2 }) }{ 2x }  } $


I wanted to switch from Win7 to Ubuntu. I have two partitions, C where my system is, and D where I keep personal files and other stuff I need (It would be really a disaster if something happened to them). My question is how to install Ubuntu on my C partition and format it of course?

I would like to see a full how-to guide on how to install Ubuntu.


I am trying to figure out how to configure proper indentation when writing an algorithm in LaTex.  The algorithm code should look like:   Let a = 0 let b = 1 if (a > b)     do action 1 else if (a = b)     do action 2 else      do action 3 all done   I could have more than one level of indentation involved in the algorithms, so it needs to be a flexible solution.  Any suggestions are greatly appreciated.

I have defined my own language whose syntax is very close to the one of Pascal. I would like to type the following program for instance. Many people use the packages algorithmicx or algorithm2e to print programs, but it seems that we have to use their specific keywords of its syntax like procedure, end while.  I just want to indent spaces when needed, and bold some words when I want (sorry that I could not bold letters in the following figure). Do I have to use  texttt for each line? Also, with verbatim, I could not bold words...  Also, as the program is not large, I would need to put it on the left side of the page, and leave space for some explanasion text on its right hand side. So I  guss I need to get them all together, and use multicols.  Could anyone help?  program test                                      some text here var   i : integer;                                    ...    b : boolean; begin    i := 1;                                        ...    b := true;    while i < 15 do       i := i  + 1;       b := not b                                  some text here    od end   Edit1: Following @Werner's tabbing solution, I have made the code a minipage:  \begin{minipage}[t]{0.48\linewidth}% \begin{tabbing} Werner's solution \end{tabbing} \end{minipage}\hfill \begin{minipage}[t]{0.48\linewidth} a paragraph \end{minipage}   Actually as the code shows, I want the texts to be another separated minipage on the right hand side of the code. I have then 2 questions:   is it reasonable to make 0.48\linewidth instead of 0.5\linewidth? 0.48\linewidth is a conventional choice? is it possible to make a frame around the code, and use \caption and \label to make it a reference (I prefer figures)?


In the American university system, how relevant to the graduate admission committee is the institution from which a given candidate obtained his/her bachelor's degree?

Due to a combination of factors, I ended up going for my undergraduate studies to a relatively unknown university that was close to me geographically.  Let's say that I have a relatively standard background for someone trying to apply to top tier schools for graduate studies (some research experience, some low to medium quality publications, very strong grades, good recommendation letters). Then how much does the alma mater have an impact for someone like me? I obviously know that it is still possible to be accepted, but how much of a disadvantage am I looking at exactly?


I have a 40 chars text String which is written in log files as follows:  0xee, 0x36, 0xe3, 0x57, 0x2b, 0x06, 0x1e, 0x3e, 0x5a, 0x3e, 0xc0, 0x07, 0xab, 0x81, 0xa7, 0x76, 0xa4, 0x27, 0x26, 0x37   I'm able to convert it statically with some functions:  static byte[] rawbytes = toBytes(0xee, 0x36, 0xe3, 0x57, 0x2b, 0x06, 0x1e, 0x3e, 0x5a, 0x3e, 0xc0, 0x07, 0xab, 0x81, 0xa7, 0x76, 0xa4, 0x27, 0x26, 0x37);  public static byte[] toBytes(int... ints) { // helper function     byte[] result = new byte[ints.length];     for (int i = 0; i < ints.length; i++) {         result[i] = (byte) ints[i];     }     return result; }   However the problem is that I cannot find a way to create the byte[] at runtime, starting from the String displayed in the logs. Any help? Thanks

I am looking for a way to convert a long string (from a dump), that represents hex values into a byte array.  I couldn't have phrased it better than the person that posted .  But to keep it original, I'll phrase it my own way: suppose I have a string "00A0BF" that I would like interpreted as the  byte[] {0x00,0xA0,0xBf}   what should I do?  I am a Java novice and ended up using BigInteger and watching out for leading hex zeros. But I think it is ugly and I am sure I am missing something simple.


Can I target a creature as soon as it is played, even with summoning sickness?  Example: If my card, , reads "Gain control of target creature," or 's "tap target creature opponent controls," can I gain control or tap a creature my opponent just played? I have a friend arguing I can't, because they're in summoning sickness, but I thought that just stopped their tap-ability and attacking for the first turn.

Note: this is intended to be a canonical question about summoning sickness.  "Summoning sickness", broadly, is the rule that stops you from attacking or paying {T} costs with a creature that you just played. But how exactly does it work? How does it interact with other rules and effects?  For example, if I'm trying to figure out how a creature is affected:   Does the status matter (tapped/untapped, face down/face up, etc.)? What if it came into play, but I didn't cast it? What if it's a token? What if it was on the battlefield when my turn started, but it wasn't a creature? What if it stops being a creature? What if it's a creature and also another card type? What if it's a double-faced card that just transformed? What if it changes control? What if it's a copy of another creature? Which of the creature's activated abilities can I use? Are any of its other abilities affected? Can I tap the creature to pay a cost that is not a {T} cost?   (These examples are primarily taken from questions about summoning sickness that have already been asked on the site)


On a long trip with a lot of wind my 400Wh battery went empty.When i tried to charge it at home it refuses to charge. The first of the five leds is flashing. Strange because in the manual is written 1,3,5 leds or 2,4 there is nothing about only the fisrt one. Any suggestions?

It is a  and the other day it stopped charging.    The charger seems to have some output since one of the LEDs on the battery lights up. It is only one LED though and I believe I remember the other LEDs (in the column of LEDs) light up in a fashion when charging. I only measure 5V of output from the charger which might, or might not mean something. The charger can be so cunning as to output only a low voltage until it has found out a proper Bosch battery is attached and is ready to be charged.  I have tried taking the battery out of the charger and depress the button for 10 seconds as I have been told it resets the battery but to no avail. I have unplugged the charger, waited for some time, and replugged. Nothing is running hot, not battery nor charger.    I am taking both battery and charger back to the shop but before that, is there another trick or check?    For future reference I add what has happened so far: The dealer has software with a license dongle s/he had to buy from Bosch. S/he connected a computer and saw some logs about the battery being too hot (I am certain it has not been) or cold (inprobable) and it being bricked due to hardware failure. S/he saved the log and then resetted the battery. I can now use the battery again. Bosch has commented the error log with "no danger". So Bosch bricked my (very expensive) battery without any reason and then forced me (the dealer) to pay for a solution. That is not serious business.


Does there exist a divergent series $\sum x_n$ such that $ \lim x_n=0$ and the partial sums of  $\sum x_n$ are bounded ?

So one of my professors proposed a problem to me and it has stumped me for some time now. Here's how it goes:  Suppose you have a sequence $a_n$ of real numbers such that $$\lim_{n\to\infty} a_{n} = 0$$ and suppose the sequence of partial sums $s_n$ is bounded. Prove that $s_n$ converges or give a counterexample.  I'm hoping to figure this out without anyone handing me the complete solution, so if someone could point me in the right direction with a hint, it would be much appreciated.


I recently signed up for a Graduate Quantum Mechanics class at my University for the Fall of 2021 and after doing some review of the notes that the professor made available to me, I'm afraid I will be a little overwhelmed in the class. This is my first class in Quantum Mechanics although I have taken Modern Physics (giving me some very non-formal introduction to Quantum Mechanics) and wanted to know what are the best resources for some self-study during the summer before I start the class. I'm interested in learning the notation, and motivation behind QM while hopefully gaining some fluency in the Linear Algebra that will be involved.

I'm really interested in quantum theory and would like to learn all that I can about it. I've followed a few tutorials and read a few books but none satisfied me completely. I'm looking for introductions for beginners which do not depend heavily on linear algebra or calculus, or which provide a soft introduction for the requisite mathematics as they go along.  What are good introductory guides to QM along these lines?


At first blush, the right to acquire a scarce resource for only two units of your "abundant" resource is an advantage over having to trade four units of the same resource. But because of "side" conditions, that is not always true in Catan. There are five resources. Call them A, B, C, D, and E. Let's say that E is the scarce resource. You can either build a road followed by a port settlement to access either a "2 to 1" harbor or else you can trade at a "4 to 1" ratio (these are references to the required payments for the scarce resource ) with no strings attached. The "catch" is, at the "4 to 1" rate, you can trade any of the four other resources at that ratio, whereas at a "2 to 1" harbor, you can trade only one specific resource, say, D, for E, at the favorable 2 to 1 ratio. On the other hand, you do not have to build a port settlement to trade at the 4 to 1 ratio, whereas you need to do so to trade at the 3 to 1 and 2 to 1 ratios. Maybe the question resolves into the following: You want to trade for E, and D is "only" your third most abundant resource (out of four), with A being very abundant, and B being more abundant than D. How do players determine whether they should aim for the 4 to 1 "straight up" ratio where they can trade A or B (or even D) at that ratio for E, versus needing to build a port settlement where they can only trade D at the ratio of 2 to 1? Note: Someone pointed out that the original question about the comparison of a 2 to 1 versus 3 to 1 trade ratios was a duplicate of another question. I had planned a follow up question about the comparison of the 2 to 1 trade terms versus the 4 to 1 trade terms, and reworded the original question into this "followup" form, which I believe is not a duplicate. One important difference with the other question is that you do not need to build a port settlement to trade at the 4 to 1 ratio, whereas you need to do so to trade at the 3 to 1 ratio.

Which type of ports do you find more useful in Settlers of Catan, General 3-to-1 ports or 2-to-1 ports for a specific resource?


I have data comprised into different variables (between females and males, measurements of body fat through 3 different methods) and after running a shapiro-wilk test, the output tells me parts of the data are normally distributed and other parts are not normally distributed. This is an uni assignment, so we're directed into assuming shapiro-wilk test is what we should use to assume normality.  Aim of the study is:  To investigate the validity of anthropometric measures for the estimation of body fat percentage using the BodPod as the gold standard.   Objectives:  - Identify how measurements differ according to sex. -Describe your sample population using the appropriate reference categories for each measure.  - Assess how classification of each measure compares with that of the BodPod                              I have non normal data for Bodpod Male and Ratio Female. I don't really know what to do next. I know which tests I should run if all the data were normally or not normally distributed, but since this is not the case, I don't know if  should split data and run different tests or not.

I'm pretty new to statistics and I need your help. I have a small sample, as follows:    H4U   0.269   0.357   0.2   0.221   0.275   0.277   0.253   0.127   0.246   I ran the Shapiro-Wilk test using R:    shapiro.test(precisionH4U$H4U)   and I got the following result:   W = 0.9502, p-value = 0.6921   Now, if I assume the significance level at 0.05 than the p-value is larger then alpha (0.6921 > 0.05) and I cannot reject the null hypothesis about the normal distribution, but does it allow me to say that the sample has a normal distribution?  Thanks!


I want to take a photo someone else captured of a celebrity, then use illustrator to manually illustrate a vector of that celebrity, adding my own artistic touch.  The main goal is to be artistic, not technically accurate.  Is it legally safe to use that illustration commercially?   Does it help if I distort the image so it doesn't look like the original photo, (while still keeping the celebrity's face identifiable)?  I've seen many businesses do this - some even take photos outright without altering them at all. I just find it hard to believe they all got permission, or that they are all just cheating.  Thank you.

I have some stock vector files from istock that I'd like to use as the starting point for a logo. I'd like to stress I wouldn't be using the original image in the logo - but using as a starting point to develop a new piece of work.  The license agreement states that you can't use the file as a logo - but what about work created using bits from the vector file?  Many thanks in advance for all replies.


Defining a new command as \newcommand{\boo}{\texttt{boo}} and then using it in the text as \boo removes the space after boo and the next word. This is fine if the next word happens to be a period, ., but not good otherwise. The workout is to write \boo \ in the main text. Question: Is there a way to avoid this "\" (to be able to type faster)? What I tried: I tried \newcommand{\boo}{\texttt{boo}\ } instead, but then the problem with the period is reversed - it is not fine if the next word happens to be  period, ., but is fine otherwise.

I have a definition:  \newcommand{\arnold}{Arnold Schwarzenegger}   When I refer to it by:  \arnold is a   it is rendered as:   Arnold Schwarzeneggeris a    In order to have a space in front of "is" I would need to write  \arnold\ is a   Is there some other shorter way?


I'm used to writing classes like this:  public class foo {   private string mBar = "bar";   public string Bar {     get { return mBar; }     set { mBar = value; }   }   //... other methods, no constructor ... }   Converting Bar to an auto-property seems convenient and concise, but how can I retain the initialization without adding a constructor and putting the initialization in there?  public class foo2theRevengeOfFoo {   //private string mBar = "bar";   public string Bar { get; set; }   //... other methods, no constructor ...   //behavior has changed. }   You could see that adding a constructor isn't inline with the effort savings I'm supposed to be getting from auto-properties.  Something like this would make more sense to me:  public string Bar { get; set; } = "bar";

How do you give a C# auto-property an initial value?  I either use the constructor, or revert to the old syntax.    Using the Constructor:  class Person  {     public Person()     {         Name = "Initial Name";     }     public string Name { get; set; } }   Using normal property syntax  (with an initial value)  private string name = "Initial Name"; public string Name  {     get      {         return name;     }     set     {         name = value;     } }   Is there a better way?


I know this question has been asked many times before but I don't seem to get my example right. How can I make the purple div fill the remaining height of the window?    <!DOCTYPE html>

I am working on a web application where I want the content to fill the height of the entire screen.  The page has a header, which contains a logo, and account information. This could be an arbitrary height. I want the content div to fill the rest of the page to the bottom.  I have a header div and a content div. At the moment I am using a table for the layout like so:  CSS and HTML    #page {     height: 100%; width: 100% }  #tdcontent {     height: 100%; }  #content {     overflow: auto; /* or overflow: hidden; */ }

...

...

     The entire height of the page is filled, and no scrolling is required.  For anything inside the content div, setting top: 0; will put it right underneath the header. Sometimes the content will be a real table, with its height set to 100%. Putting header inside content will not allow this to work.  Is there a way to achieve the same effect without using the table?  Update:  Elements inside the content div will have heights set to percentages as well. So something at 100% inside the div will fill it to the bottom. As will two elements at 50%.  Update 2:  For instance, if the header takes up 20% of the screen's height, a table specified at 50% inside #content would take up 40% of the screen space. So far, wrapping the entire thing in a table is the only thing that works.


I have a bootable USB pen drive which has bootable Ubuntu. Now I want to write to a DVD from the pen drive. How can I do this? Please explain it, so that I can save the software for future.

I have an iso file of operating system's set up.  Now, I don't have dvd burner right now.  But the alternate - 4gb pen drive is available.  If I copy entire iso file to pen drive,  Can my system boot through pend drive?


If a person stops masturbating, will it have negative effects on their health? Can a person live perfectly without masturbating at all?

Can males safely cease masturbation if they so desire, assuming the person isn't sexually active?


I grew up outside the US, and in our culture, tipping almost never ever happens.  I am aware that when eating at a restaurant in the US, you are expected to tip between 15-20%.  When I stay in a hotel in the US, am I expected to tip the housekeeping? Why or why not?

Following on from  about how it is appropriate to tip housekeeping where it is expected.  In what countries/regions is it expected to tip housekeeping?  Does this expectation vary depending on the type of accommodation (eg Hostel/Bed & Breakfast/Motel/Apartment/Aparthotel/Tourist Hotel/Business Hotel)?


Let $f,g \in L^2[0,1]$, multiplication operator $M_g:L^2[0,1] \rightarrow L^2[0,1]$ is defined by $M_g(f(x))=g(x)f(x)$. Would you help me to prove that no nonzero multiplication operator on $L^2[0,1]$ is compact. Thanks.

Suppose we have an bounded linear operator A that operates from $L^2([a,b]) \mapsto L^2([a,b])$.  Now suppose that $A(f)(t) = tf(t)$.    Is A compact?  Edit: I know $A = A^*$ but I'm not really sure how to start on this.  It's not homework, just summer fun :D


I'm pretty sure the answer to this is yes, but was hoping to get community confirmation of that since I can't find any post asking the question or any documentation specifically indicating one or the other.  Let's say I have the following map in my class, which gets its values by passing a list of contacts to the CommunityUsersManagerUtil - but sometimes that list being passed to the method (contactsThatChangedEmailList) may be empty:  Map<String, User> usernameChangeToUserMap = CommunityUsersManagerUtil.getCommunityUsersForContactsByUserName(contactsThatChangedEmailList);     Then, the getCommunityUsersForContactsByUserName method puts together a list of usernames from the contact list. In this scenario, that set of Strings would also be empty. That empty string is then used in a query which will return 0 results.  public static Map<String, User> getCommunityUsersForContactsByUserName(List<Contact> contacts){     Set<String> usernames = new Set<String>();     for(Contact con : contacts){             usernames.add(generateUsername(con));     }      List<User> users = [SELECT IsActive, ID, ContactID, Username FROM User WHERE username in: usernames AND ProfileID =:communityProfileIDStatic ];     Map<String, User> result =  new Map<String, User>();     for(User u: users){         result.put(u.username, u);     }     return result; }           Ultimate Question: The above scenario, even though it returns 0 results, still counts as 1 of 100 available SOQL queries in a   transaction, correct?      If so, I would like to begin working on wrapping all of these Util   classes in an if(!list.IsEmpty){} block to stop them from running   unnecessarily and bogging down my query limits

Let's say I have a following piece of code:  Set<Id> accountIds = new Set<Id>();  for(Contact c : [SELECT Name FROM Contact WHERE AccountId IN :accountIds]){     System.debug(c); }   The accountIds set is obviously empty in the example above, but will my Apex code consume 1 SOQL query?


I know if you put an electrolytic capacitor backwards they explode and it's quite fun to observe them exploding. I am wondering if you can use two of them (and some diodes) to turn it into a bipolar capacitor so it may be used with AC signals?

There was some discussion on this question        which I don't see as being conclusively resolved:   "turns out that what might LOOK like two ordinary electrolytics are not, in fact, two ordinary electrolytics." "No, do not do this. It will act as a capacitor also, but once you pass a few volts it will blow out the insulator." 'Kind of like "you can't make a BJT from two diodes"' "it is a process that a tinkerer cannot do"   So is a non-polar (NP) electrolytic cap electrically identical to two electrolytic caps in reverse series, or not?  Does it not survive the same voltages?  What happens to the reverse-biased cap when a large voltage is placed across the combination?  Are there practical limitations other than physical size?  Does it matter which polarity is on the outside?  I don't see what the difference is, but a lot of people seem to think there is one.  Summary:   As posted in one of the comments, there's a sort of electrochemical diode going on:     The film is permeable to free electrons but substantially impermeable to ions, provided the temperature of the cell is not high. When the metal underlying the film is at a negative potential, free electrons are available in this electrode and the current flows through the film of the cell. With the polarity reversed, the electrolyte is subjected to the negative potential, but as there are only ions and no free electrons in the electrolyte the current is blocked. —    Normally a capacitor cannot be reverse-biased for long, or large currents will flow and "destroy the center layer of dielectric material via electrochemical reduction":     An electrolytic can withstand a reverse bias for a short period, but will conduct significant current and not act as a very good capacitor. —    However, when you have two back-to-back, the forward-biased capacitor prevents a prolonged DC current from flowing.  :     For circuit positions when reverse voltage excursions are unavoidable,   two similar capacitors in series connected “back to back” ... will create a   non-polar capacitor function ... This works because almost all the circuit voltage   is dropped across the forward biased capacitor, so that the reverse   biased device sees only a negligible voltage.   :     The oxide dielectric construction that is used in tantalum capacitors   has a basic rectified property which blocks current flow in one   direction and at the same time offers a low resistance path in the   opposite direction.


I got this:     You last voted on this answer Feb 8 '11 at 16:40 Your vote is now   locked in unless this answer is edited (click on this box to dismiss)   So this was shown to me on stackoverflow. I tried to remove an upvote to an already downvoted answer, I did not see that that the answer was really flawed. Another commenter saw this and responded. I wanted to take of my +1 (the tally was -1) so it would be a -2 which would mean more to visitors in my opinion.  I guess what I'm trying to say here is that a comment from somebody else other than the author (who clearly didn't take the downvotes as a hint) might influence my opinion.  This question is slightly different because the assumption is that your comment is picked up by the editor of the question.

If I made a mistake downvoting or upvoting a post, there's no way for me to fix that unless asking the person to edit its answer.   Let's say I downvote something, then explain in a comment thinking that I'm right and the user's wrong. The user convince me that he was right in the first place and that I should not have downvoted him (everybody make mistakes or it could have been a misundertanding on words... whatever). Then I can't undo my downvote.   I get the point of forbidding removing up/down votes without edit, but in some cases it gets annoying.  Could it become so that one can undo his vote if a comment is left by someone else (to avoid dummy comments just to rollback a vote) ?  EDIT: Added a bounty to get more feedback


More specifically:  I don't want everyone spawning at the same place, I want it to not need to know who's playing (so "spawnpoint playername x y z" won't do it). I guess I'm thinking that when people log into the game it senses this person logged in first, they are player1, the second to log on is player2, etc.  Thus it would spawn people in respective spawn points:  spawnpoint player1   -100 10 -100 spawnpoint player2    100 10 100 spawnpoint player3    100 10 -100 spawnpoint player4   -100 10 100   The map i'm making should spawn each player in separate places, while part of the goal is to meet in the middle.  Also, if it matters, the game is for 4 people only, no more no less. Players can't leave spawn points until each has signaled he/she is ready. so somehow I need to set up a ready count of 4 to let the game begin.

I want to know if there's a way I can set it so that on first join, a player gets teleported to a random location on the map automatically. Then if the player dies without having a home set, they are once again teleported to a random location but not if they have their home set.   What would be the best way to accomplish this? May it be through command blocks or plugins.   Thank you for your time.


Below code represents the same operation but results getting differes ? can any one tell me how the java executs the == operation ?            String str = new String("Hello");           String str1 = new String("Hello");           System.out.println(str == str1);   o/p  False            String str = "Hello";           String str1 = "Hello";           System.out.println(str == str1);   o/p  True

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


I am uploading multiple records and want to use five digit zip code as the georeference.  I would like to display each of those records on a map. Some of the records have identical zip code fields, meaning that several records share a single zip code.  In the map view, only one of those records, among the handful that share a single zip code, appears. Is it possible to show on the map all of the records that share that single zip code?

I'm creating a map with specific information (name, DOB, etc) to be displayed for a street address, which is mapped to an exact lat and long. Problem I'm realizing is that for items such as apartment buildings, this isn't going to work within CartoDB using the Simple Visualization Wizard.   Any suggestions in CartoDB to display multiple fields of the same type in a click/hover window?


I have old 35mm lenses for my old Minolta camera. I'm going back to photography and getting an Olympus PEN E-PL1 (micro four thirds mount).  Can I use my old lenses on such a box or do they become completely useless? They were pretty expensive lenses, so why throw them away?

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


I cannot understand how quadratic formula to solve for $x$ was derived.  On this , it explains the steps  Following I understand    but I cannot understand how they got   $b/2a$  and why they are squaring it  $b^2/4a^2$  Really, I am baffled!

In algebra, all quadratic problems can be solved by using the quadratic formula. I read a couple of books, and they told me only HOW and WHEN to use this formula, but they don't tell me WHY I can use it. I have tried to figure it out by proving these two equations are equal, but I can't.  Why can I use $x = \dfrac{-b\pm \sqrt{b^{2} - 4 ac}}{2a}$ to solve all quadratic equations?


Does anyone know a good general measure book that has good examples and theories. I tried reading Royden real analysis but I need more books to help me understand the material. any help is greatly appreciated thank you.

I would like to teach myself measure theory. Unfortunately most of the books that I've come across are very difficult and are quick to get into Lemmas and proofs. Can someone please recommend a layman's guide to measure theory? Something that reads a bit like this , starts out very gently and places much emphasis on the intuition behind the subject and the many lemmas.


pointed me in the right direction! (close this if you like)  Im trying to reinstall windows through a usb drive and remove ubuntu 14.04   My disks readout is  Size : 8.0 GB — 7.9 GB free (1.1% full)  Device : /dev/sdb1  Partition type : HPFS/NTFS (Bootable)  Contents : NTFS — Mounted at /media/f-17/bullshit  This is where I stand now, Ive tried unetbootin (After pushing OK imgur.com/6BQhtow) there is most definitely a USB drive in a working USB slot, and gparted returns in terminal  ====================== libparted : 2.3 ======================  (gpartedbin:10708): GLib-CRITICAL **: Source ID 7 was not found when attempting to remove it  (gpartedbin:10708): GLib-CRITICAL **: Source ID 6 was not found when attempting to remove it  (gpartedbin:10708): GLib-CRITICAL **: Source ID 26 was not found when attempting to remove it  (gpartedbin:10708): GLib-CRITICAL **: Source ID 25 was not found when attempting to remove it Input/output error during read on /dev/mmcblk0   and then when it opens gives the following error after thinking a while  Window title : Libparted bug found!  Error : Input/output error during read on /dev/mmcblk0  My mount options are set to this : imgur.com/RHyQaw8

I need to create a Windows installation USB drive from an ISO file. I used UNetbootin which seems to be the only tool that can write non-Linux images.  The USB disk boots (sort of), but it gets stuck at the very first stage. A UNetbootin splash screen appears that keeps counting down from 10 to 0, and then restarts.   The screen looks like this:    Is there a way to make Windows boot from a USB image created on Linux?


I'm a javascript noob trying to wrap my head around the closure exercise below.  Now, I know the result is 122. Can anyone walk me through this step by step (what gets passed to what), so I can understand how closures work?  var hidden = mystery(3); var jumble = mystery3(hidden); var result = jumble(2);  function mystery ( input ){   var secret = 4;   input+=2;   function mystery2 ( multiplier ) {      multiplier *= input;     return secret * multiplier;   }   return mystery2; } function mystery3 ( param ){   function mystery4 ( bonus ){     return param(6) + bonus;   }   return mystery4; }

How would you explain JavaScript closures to someone with a knowledge of the concepts they consist of (for example functions, variables and the like), but does not understand closures themselves?  I have seen  given on Wikipedia, but unfortunately it did not help.


I have asked before and am still trying to find a decent accounting program for Linux/Ubuntu.  Not a checkbook program but something for small business accounting.  I need to generate year end tax reports and things like a P&L  I have been struggling with Gnucash for years.  The program is generally OK but the transactions importer is a nightmare.  It adds hours of work to balancing accounts, due to things like mis-categorized transactions, transactions not being imported, and erasing already cleared transactions.  And support is difficult to get, the mailing list is only occasionally helpful.  I have searched multiple times and the list of software only reflects Checkbook programs.  I am looking for an alternative, not cloud based.  If someone has a suggestion of ANY kind, I would appreciate it.

I have performed numerous searches looking for accounting software for Linux (I am running Ubuntu) and haven't found any good solutions.  Maybe I am glossing over something?  I have been using GnuCash for years after dropping Moneydance.  I don't remember exactly why I stopped using it, probably for reasons similar to my wanting to get away from GnuCash. Plus, it isn't open-source and I didn't want to buy a product that I hadn't been satisfied with in the first place.  The problems I have with GnuCash are the constant errors I have in reconciliation.  Every statement is a wrestling match of importing data, matching data, transactions not being imported, account totals changing after a reconciliation, math errors and on and on.  Plus, I have tried to find support but there is little to be had; I have tried to get on the mailing list a couple of times with no success.  I am a sole proprietor of a business and own property so I have multiple accounts to handle.  I need accounting software mostly for year-end P&L statements for income tax preparation for my accountant.  If you have any suggestions, I'd love to hear about them.  GnuCash has pretty much worn me out, so I need to find something else.


I'm using PHP and Microsoft SQL 2003.    I have this table:    Page | Group ------------    1 |    1    2 |    2    3 |    1    4 |    2   I need to get an array grouped by "Group":    Array(    1 => Array(1, 3),    2 => Array(2, 4) );   I am using PDO, I'd like to get the array directly from SQL instead of parse the entire result with a PHP loop.    How can I do?

I'm trying to migrate a MySQL-based app over to Microsoft SQL Server 2005 (not by choice, but that's life).  In the original app, we used almost entirely ANSI-SQL compliant statements, with one significant exception -- we used MySQL's group_concat function fairly frequently.  group_concat, by the way, does this: given a table of, say, employee names and projects...  SELECT empName, projID FROM project_members;   returns:  ANDY   |  A100 ANDY   |  B391 ANDY   |  X010 TOM    |  A100 TOM    |  A510   ... and here's what you get with group_concat:  SELECT      empName, group_concat(projID SEPARATOR ' / ')  FROM      project_members  GROUP BY      empName;   returns:  ANDY   |  A100 / B391 / X010 TOM    |  A100 / A510   So what I'd like to know is: Is it possible to write, say, a user-defined function in SQL Server which emulates the functionality of group_concat?   I have almost no experience using UDFs, stored procedures, or anything like that, just straight-up SQL, so please err on the side of too much explanation :)


I have a theoretical question. I was reading about ridge regression, lasso and the elastic net, and is very impressed. One thing is not quite clear to me.  I would like to know when should I use each model: Linear regression, ridge, lasso and elastic net. What are the advantages and disadvantages of them all ?  I know that an advantage of the lasso is that it does not only shrinkage but also feature selection, it can force the coefficients to zero. Is there anything else ? Why using ridge then, ever ? And what about elastic net, can it shrink coefficients to zero? why would anyone want to combine lasso with ridge, I mean, lasso also shrinks the coefficients.  I am slightly confused.

I have a set of 150 features, and many of them are highly correlated with each other. My goal is to predict the value of a discrete variable, whose range is 1-8. My sample size is 550, and I am using 10-fold cross-validation.   AFAIK, among the regularization methods (Lasso, ElasticNet, and Ridge), Ridge is more rigorous to correlation among the features.  That is why I expected that with Ridge, I should obtain a more accurate prediction.  However, my results show that the mean absolute error of Lasso or Elastic is around 0.61 whereas this score is 0.97 for the ridge regression. I wonder what would be an explanation for this.  Is this because I have many features, and Lasso performs better because it makes a sort of feature selection, getting rid of the redundant features?


I have a custom button on my related list. I am doing url hacking on the web page to populate a lookup field.   This seems not to be working on Salesforce1 . Is there any way to autopopulate a lookup field in a standard layout in Salesforce1.

I have a URL button 'New Opportunity' which creates the new opportunity and takes the user to the edit page passing through some values through the button which is on Opp Related List in a custom object.  The problem is, now I need to adapt the majority of my custom buttons to Salesforce1 and this app doesn't accept custom buttons so I need to create a Publisher Action in order to replicate the same action.  I've created a Publisher Action redirecting to a Visualforce. Inside this visualforce I've tried passing the values through the sforce.one.navigateToURL(); function using the standard controller values  to redirect, but this doesn't seem to work. Do you know of a workaround for this?  URL Button Code: /006/e?&retURL=%2Fa0BS0000002pJhs&opp4={!Estudio_economico__c.Empresa__c}&opp3=No informar&RecordType=01220000000Iw8t&CF00N20000002GXnJ_lkid={!Estudio_economico__c.Id}&CF00N20000002GXnJ={!Estudio_economico__c.Name}


How would I recreate this effect using blending modes in Photoshop?

I have seen such an effect being used in many places however I haven't figured out how to replicate it via Photoshop.  I have tried desaturating the image, placing it under a layer of solid colour and then lowering the opacity of the colour. I have also tried a couple of blend modes, to no avail. The effect is nowhere near the same.  Can someone please tell me the effect used on these images?


I have set  from to minimize all windows settings to super + d button.   Some time later this Super + D button does not works.  When I check the setting i see that it is disabled.    What should I do not to disable itself after a time?

I recently installed Saucy Salamander on my computer. Previously in Ringtail, Super+D used to show the desktop. However for this release, the Super+D does not seem to work properly... Is it a bug?


Wouldn't Lanning's house be turned into a museum, considering his importance, rather than be demolished?

Shortly after the death of Dr. Lanning, Detective Spooner travels to the doctor's house to look for clues.  While he is searching the house a demolition bot (which had been programmed to demolish the house the next day) goes on a rampage and destroys the house with Detective Spooner in it.   The house is fully furnished and appears to be in good condition. Why would US Robotics want to destroy the house with everything in it? Why not sell the house and everything inside?


I can't join any minecraft servers because it keeps saying 'Can't connect to server' at every server i have. I can go on internet like post this question here. What's happening?

I just re-purchased Minecraft (because my old profile stopped working so I bought it) after not playing it for a couple of months. I've added a bunch of servers, but almost every one says "can not connect."  I know its not because the server is not 1.7.2, because I checked that they'd update. It will say "server can't connect" after a long time. I don't know if its me or the servers.  My server screen looks like this (notice the one at the bottom – it's still loading!):


As shown in the screenshot (showing a modified gnome favorite bar, but still with stock functionality), when I right click an application with multiple windows open on the gnome favorites bar, I get the menu entry "Quit # windows". Clicking this closes each of the windows belonging to the application gracefully, giving the opportunity to save. Does anyone know what method gnome shell uses to accomplish this or how I could hook into this function with the command line?  I'm trying to build a hotkey that will mimic the behavior of the Command+Q hotkey on MacOS, and since the gnome favorites bar provides exactly the same functionality, I would like to use the pre-existing functionality (if at all possible) as I have been able to find or modify wmctrl and xdotool scripts and methods offered in previous threads.

When I right click on an application's icon in the Unity launcher, I can press Quit to close all the windows corresponding to that application. Is it possible to do the same with a keyboard shortcut which operates on the active window (and all the other windows corresponding to the same application)?  I could do something similar with xkill, but in that case I do not have the message that remembers me of unsaved files.


When I run F12 Developer Tools in my Windows Server 2012 R2's install of IE 11.0.9600.17498 (Update 11.0.15), I get a blank white area with grayed out buttons:    (That white rectangle at the bottom of the image is F12 devtools)  I've discovered a number of other people with similar issues (e.g. ), but they're a bit different in that they have the "black stripe" above the tools and an error message.  I've tried running filesystem checks and updating all Windows Updates to no avail.  EDIT: I don't think this is a dupe, as I've installed the specified updates, and the issues persist.

the F12 Developer Tools windows is empty on my machine.    I've tried the following solutions, but nothing worked