Proof of derivative of $x^TBx$ using the product rule

I'm trying to prove that when $f(x) =x^TBx$, then $f'(x) = (B + B^T)x$. I haven't found this formula online but going through the calculations using index notation this is what I came up with. This would simplify to $2Bx$ when $B$ is symmetric. The accepted response to  says that the solution is actually $f'(x) = x^T(B + B^T)$, going through the proof there, I see how he got there but I can't see where the mistake is in mine then.  The setup   $x \in \mathbb{R^n}$, it is always a column vector $B \in \mathbb{R^{n \times n}}$, $B$ may not be symmetric   My approach  Let $g(x)=x^TB$ and $h(x)=x$, then I can write $f(x)=g(x)h(x)$. Then   $f(x) \in \mathbb{R}$ $g(x) \in \mathbb{R^{1 \times n}}$ $h(x) \in \mathbb{R^n}$ $f'(x) \in \mathbb{R^n}$ $g'(x) \in \mathbb{R^{n \times n}}$ $h'(x) \in \mathbb{R^{n \times n}}$   I've gone through myself why $g'(x) = B$ and $h'(x) = I_n$, so I won't go through those here.  Then, using the product rule I get:  $$f'(x) = g'(x)h(x) + g(x)h'(x)$$  The problem is that the dimensions don't add up. I get $g'(x)h(x) = Bx \in \mathbb{R^{n}}$, which is good. However, I also have $g(x)h'(x) = x^TBI_n = x^TB \in \mathbb{R^{1 \times n}}$ and as far as I know I can't add up two vectors of different sizes.  I know that the solution is going to be the transpose of second term, I just can't seem to find where that transpose would come from.   Why do I need to take the transpose of the second term?  [Edit]: Please don't reply with a different proof. What I'm looking for is to understand where I made the mistake in my calculation because obviously I made a step which was incorrect and without understanding where that is I'm likely to make that mistake again.


Animating scale of edge loop to cover texture, not stretch

I have a circle with a inner loopcut, and would like to be able to scale the ring without affecting the UV texture on the circle. Currently it warps it, as Blender tries to fit the UV to the (now thinner) ring.  I also need the ability to animate the scale of the inner loop.     When scaling the inner ring, I'd like it to simply "crop" the outer UV texture, instead of "squashing" it.


How to prevent the passenger in front of you from reclining without notice?

I can totally understand . On a short hop, I don’t have any sympathy for anyone using his “right” to recline his seat. The seat pitch on short flights these days make you an anti-social person by default if you choose to recline. I had my share of not being able to even drink a cup of coffee because somebody just wanted to “rest”.  I usually try to reposition my legs as much as possible, not only because I have to, but also to try to make the journey as unpleasant for the rester as it is for me. I’m aware that is just childish behaviour, so I am wondering whether there are more effective and more civilized countermeasures to make the flight pleasant for both of us.


Finding trace and determinant of linear operator

I've got the following question     Consider the linear operator of left multiplication by an $m \times m$ matrix $A$ on the vector space of all $m \times m$ matrices. Determine the trace and determinant of this operator.   I'm a bit stuck as to how to even begin, I know this is going to involve eigenvalues/vectors and that if $\lambda_1, \lambda_2, ... ,\lambda_m$ are the $m$ roots of the characteristic polynomial of an $m \times m$ matrix $A$, then:  $\det(A) = \lambda_1 ... \lambda_m$  and  $\text{trace}(A) = \lambda_1 + ... + \lambda_m$  But obviously not all $m \times m$ matrices have $m$ eigenvalues so I'm really stuck on this question.  Thanks!


I started downloading about 1gb from a colleague, and received 750mb in about 8 hours. The command I used was $ scp dev@dev_server:/home/dev/trainingVM/Centos7VMa_app_zxTmw457.ova  What command could I use next, so that the remainder would download in under 3 hours, not 10?


Copy single feature into another feature class

I do a lot of editing, in this case areas. Sometimes I add an area to one shapefile, only to realise a bit later that it should have been in another.   Is there an easy way of copying only that polygon into the proper shapefile? Something along the lines of rightclick the row in attribute table, copy and then paste in the next attribute table.   I do know that I can select the polygon and use , but this seem unnecessary complicated?


Mismatching colors from multiple textures (2.90)

I feel like I'm missing something simple (newbie here), but in Blender 2.90, when assigning multiple image textures with MixRGB nodes, the colors that are shown on the 3D Viewport don't match the colors from each source image. I believe I need to be in Material Preview to show multiple textures.  There're four .png images:  Base color Highlights (white color on transparent background) Shadows (grey color on transparent background) Final image (combined in Krita as reference)   I hope I was clear and thank you for reading it.


I want to do some timing tests on a Java application. This is what I am currently doing:  long startTime = System.currentTimeMillis(); doSomething(); long finishTime = System.currentTimeMillis(); System.out.println("That took: " + (finishTime - startTime) + " ms");   Is there anything "wrong" with performance testing like this?  What is a better way?  Duplicate:


How long is Mass Effect 3 on normal difficulty?

How many hours does it typically take to play through the single-player campaign of Mass Effect 3 from start to finish on the default/normal difficulty level? How many hours does completing all the side quests tack on to that?


I know that $$\int^\infty_0\frac x{e^x-1}dx=\frac{\pi^2}{6}$$ For substituting $u=2$ into $$\zeta(u)\Gamma(u)=\int^\infty_0\frac{x^{u-1}}{e^x-1}dx$$  However, I suspect that there is an easier proof, maybe by the use of complex analysis. I haven't learnt the  yet. All I know is the above formula and $\zeta(2)=\frac{\pi^2}{6}$. Can we can use the above integral to find out some of the $\zeta$'s value?


Intuitive explanation of the shape of the Maxwell-Boltzmann distribution

At higher temperatures (for an ideal gas), the Maxwell-Boltzmann distribution is spread more widely and has a lower maximum. At lower temperatures, the spread is much more narrow and the peak is much higher. Why is this so? I was thinking that this is to maintain constant area under the curves, but the integration of the curve gives total energy—and total energy should not be constant since temperature is increasing.  So why does the distribution curve change thus? I’m looking for an explanation that’s intuitive or that involves math not surpassing first-year university level calculus. I would appreciate it if it could be explained without the Maxwell-Boltzmann distribution equation, since at this level I’m really treating this qualitatively.


I am user QGIS and I use composer and atlas to create my maps exports print. in the atlas settings I use for scale 20% margin but now I need to print in specific scale numbers.for example if my atlas feature scale where i use scale 20% margin is the scale is between 100 and 200 then I need to take scale 200. if the scale is between 1500-2000 then I need to take 2000 scale.  any idea how to do this ?with some condition ?  summary I want to avoid to print features with scales like this 10006 or 12221 I need to print in scales with specific numbers like 10000 or 15000 or 100 or 200.


Why is the speed of sound in air constant (relative to temperature) when the wave speed formula is Vwave = fλ?

By the logic of the wave speed equation, shouldn't a 1000 Hz sound travel twice as fast as a 500 Hz sound? I know it doesn't, but why not?


Let $U_1$, $U_2$ and $U_3$ be i.i.d. $\mathsf {Uniform}[0,1]$ random variables. Find $P(U_1+U_2 > U_3)$  Here the answer states that the probability is $\frac{5}{6}$. However I am quite confused as to how we obtain such an awnser. A hint is to use conditional expectation.  Any advice or explanation is apreciated.  I saw the following link :   And the key argument was the symetry of the system.


What if the answers of a historical locked question become obsolete?

My understanding is that a question is historically locked because the information in it is too valuable for the question to be deleted.   But if the "valuable information" becomes obsolete, what happens then?  We cannot modify the question content, or the answers for a historically locked question, right?


Does C# support nested strongly typed tree structure?

I would like to know if C# has a way of defining strongly-typed nested jagged arrays without using object[].   Something like:   var nested = new {1, 2, {3, {4, 5}, 6}, 7};   I would like to have a nested array of int.  Consider this array below: [[1, 2, [3]], 4, [5], [[[6]]]]  This is how I've done it:  var myNestedJagged = new object[] {     new object[]     {         1, 2, new object[] {3}     },     4,     new object[] {5},     new object[] {new object[] {new object[] {6}}} };


Let G be an abelian group. Suppose $a, b$ are elements of orders $m$ and $n.$ Let $d =\operatorname{lcm}(m, n).$ Show that $(ab)^d = 1$

Here are my thoughts so far: G is abelian so $ab = ba.$ For $d = mn, (ab)^{mn} = abab..ab = aaaa..bbb$  as abelian $= a^{mn}b^{mn} = e$ as $a^m = e$  and $b^n = e.$ For $d< mn,$ let $d = qm$ and $d = pn.$ Then $$\begin{align}(ab)^{qm} &= a^{qm}b^{qm} \\& = eb^{qm} \\&= b^{qm}\\   (ab)^{pn} &= a^{pn}b^{pn} \\& = a^{pn}e \\&= a^{pn}\end{align}$$ so $b^{qm} = a^{pn}$ so $a^d = b^d.$ I'm not really sure how to continue from here/ if this is even the logically path I should be following


We currently have a website set to redirect to a new address (our client changed domain names, but wants the old domain to send people to the new site) in IIS 8.5 using permanant redirects found in the 'HTTP Redirect' feature for the site.  The SSL cert has come up for renewal for the old domain, and there is an open question in our tech department as to whether or not it needs to be renewed.  With the HTTP Redirect set up in IIS, does the site need an SSL cert?  Or will a visitor be redirected before such things are checked?


How to cut off an old swing to get rid of it

I need to dispose of an old swing in my yard. Problem is some screws are so rusty they can't be unscrewed and the whole swing wont's pass the door.   Is there any simple way to cut this thing into a few pieces ? I guess the rods are hollow so perhaps it's not too hard. Any suggestion would be welcome.


java.util.ConcurrentModificationException due to unintended modification

I'm implementing the A* algorithm to allocate a given number of taxis to a given number of customers:  public SearchNode AStarSearch(List<Car> allCars, List<Customer> allCustomers) {      // creates first node     SearchNode firstNode = createFirstNode(allCars, allCustomers);     open.add(firstNode);      SearchNode currentNode;      while(true) {         currentNode = open.poll();   //error thrown here         if (currentNode.allCustomers.isEmpty()) break;          closed.add(currentNode);          SearchNode temp;          Iterator<Customer> itrCus = currentNode.allCustomers.iterator();         Iterator<Car> itrCar = currentNode.allCars.iterator();          while (itrCus.hasNext()) {             Customer currentCustomer = itrCus.next();             while (itrCar.hasNext()) {                 Car currentCar = itrCar.next();                 temp = new SearchNode(currentNode, currentCar, currentCustomer);                 openUpdate(currentNode, temp);             }         }     }     return currentNode; }   Now for the children SearchNode I want to delete the customer, that it has served. But this should only happen inside the search node.  This is what's happening in the SearchNode class:  public class SearchNode implements Comparable<SearchNode> {  List<Car> allCars; List<Customer> allCustomers; SearchNode parent;  public SearchNode(SearchNode parent, Car currentCar, Customer currentCustomer) {     // inheriting values from parent search node     this.allCars = parent.allCars;      this.allCustomers = parent.allCustomers;     this.parent = parent;      // now updating this node's values     this.allCustomers.remove(currentCustomer); }   I checked with some prints and in the second iteration of the while(itrCar.hasNext()), the parent's allCustomer list is missing the currentCustomer.  Edit: I should rather ask: can someone please tell my why I changed my parent node's value? It's probably because I haven't understood the whole java being actually pass-by-reference.


I'm getting the error: ! Paragraph ended before \@@label was complete

I've scoured this forum and it looks to me like I'm setting up the tree correctly, but I'm still getting this error, I have   \usepackage{tikz} \usepackage{tikz-qtree}   in the header.  Here is the code that is causing the problem:  \begin{tikzpicture}  \Tree  [.{Boolean Groups}     [.{Abelian Groups}         [.Groups]     ]     [.{Class 3}          [.{Class 5}]         [.{Class 1}]         [.{Class 2}]         [.{Class 4}]     ] ]  \end{tikzpicture}


Why is the result a recurring number when it should be an integer?

Hi so i'm writing some code for class and this for Linear Regression. The values calculated by hand is a=1.7 and b=1.6 for the data you can see in the code.  I've tried separating different parts of the formula into different variables but the answer remains the same (1.6999999999999993).  import numpy as np   x=np.array([2,3,5,6])   y=np.array([4.5,7.2,9.2,11.5])   b=(np.sum((y-np.mean(y))*x))/(np.sum((x-np.mean(x))*x))   a=np.mean(y)-(b*(np.mean(x)))   print(a)    print(b)     The expected result is a=1.7 and b=1.6, but the output is a=1.6999999999999993.


Can Mac Messages connect to more than one apple id?

Say I have two iCloud accounts, personal@example.com and work@example.com. My iPhone is logged into personal@example.com, while the Messages app on my work computer is logged into work@example.com.  Is there a way to get text messages on the Messages app? I've tried going to "Messages > Preferences > Accounts > +" to add an account, but the only option seems to be Jabber.


Question regarding exponentiation of cardinal numbers

Let $2\leq \kappa\leq \gamma$ where $\gamma$ is an infinite cardinal number and $\kappa$ is any cardinal. Prove that $2^\gamma = \kappa^\gamma$.  One direction is obvious but I'm stuck with the other. i.e. showing $\kappa^\gamma\leq 2^\gamma$.  Any hints or solutions will be appreciated.


I have this for a success function:   success: function(data){         $('#pleaseWaitDialog').modal('hide');           data = $.trim(data);           if(data == 'true'){             $('#myTab a[href="#intro"]').tab('show');           }           else{             $("#alert").attr('class', 'alert alert-warning');             $("#alert").html('Your Pass Phrase was incorrect! Please try again.');           }       }   How do I delay the $('#pleaseWaitDialog').modal('hide'); from happening for 1200 milliseconds.  I've tried:   $('#pleaseWaitDialog').modal('hide').delay(1200);   But it did nothing.


When listing refereed papers in a CV, should I highlight my name in authors lists?

I am experimental physics grad student updating my CV / publications/talks list in preparation for applying to postdoctoral positions.  In my refereed publications list, while a few of the most recent papers have me as the first author, the majority do not. So my question is as follows: Should I highlight my name in the lists somehow? If so, italics, boldface, or something else?


prevent a command from sending both stdout & stderr to any terminal or file

I would like to prevent my program from sending stdout and stderr to any terminals, files or devices. For this, I have three command crossing my mind, but I cannot distinguish their differences. Could you please explain the meaning of each of them to me please.  # ./run > /dev/null # ./run > /dev/null 1>&2 # ./run > /dev/null 2>&1


Does writing a file to a solid state drive change the mass?

Some stupid meme my sister showed me went along the lines of "will my laptop get heavier if I put more files in it?", but it was sufficient to get me thinking--is there an energy change & associated mass change when a file is written to a solid state drive? I don't know enough about how a solid state drive works to know for sure... but my intuition says that for highly compressed files, the informational entropy is probably the same as an unwritten (sector? Again, I don't know that much about SSDs). However, I wonder if highly organized/low entropy files, such as uncompressed text files or bitmaps, would affect a change in the mass of the drive, one way or another.


Is there something wrong with that sentence? It feels... redundant? "Clunky", for want of a better word?  I want to say something along the lines of "I am at a loss for words, in every definition of the phrase", though perhaps in not as many words. Is that the correct use for "literally"?


Stop DataContractSerializer putting in namespace?

I want to serialize datacontract classes into XMl, but without the Namespaces.  I've added:  [DataContract(Namespace="")]   but I still get:  <Person xmlns:i="http://www.w3.org/2001/XMLSchema-instance"> <Title>Mr</Title> ... </Person>   Is there any way to stop this happening as I just want the clean xml to pass into a legacy component.


BibLaTeX: Some entries show author field as a dash (-)

I am observing a strange effect in BibLaTeX. When I have two papers printed in succession that do have the same author (see example below) I get only a dash (-) in the second reference where the author is supposed to be printed.  What is that and where in the manual can I read more about this (I can personally not imagine why anybody wants such a behaviour)?  I would like that authors are always printed regardless if they where mentioned or listed before before or depending on the environment of the citation...  Here a self-contained example:  \documentclass{article}  % BibLaTeX \usepackage[   backend=bibtex,   style=authoryear,   firstinits=true,   maxbibnames=99]{biblatex} \addbibresource{mybib.bib}   \begin{document}  \nocite{Meyer1,Meyer2}  \setlength\bibitemsep{5pt} \printbibheading[title={Bibliography}] \printbibliography[type=article, heading=subbibliography, title={Journals}]  \end{document}   And the bib file:  @article{Meyer1,   author = {Meyer, Bob},   title = {{Some Great Paper}},   journal = {Some Great Journal},   volume = {9},   year = {2015},   pages = {99--109},   issue = {9},   doi = {99.9999/99999-999-9999-9}, }  @article{Meyer2,   author = {Meyer, Bob},   title = {{EAnother Great Paper}},   journal = {Another Great Journal},   year = {2015},   volume = {9},   pages = {99-109},   number = {9},   doi = {88.8888/8888888.8888888} }


How can I block incoming SMS from certain senders?

What is a good app for blocking incoming SMS? I want it to be easy and able to add numbers from contacts and not require to many privileges (probably only some storage and intercepting SMS).


2 side by side divs of different height aligned

I have 2 different height divs side by side:   .box {       color: white;       display: inline-block;       }        #box-a {         background-color: black;         height: 90px;         width: 100px;        }         #box-b {         background-color: blue;         height: 50px;         width: 100px;        }

 div a

 div b

    Now I want something like this  and no matter how hard I have tried and researched I can't get it to work.


In Python, how do I remove this white space?

class Direction:     def __init__(self,position=0):         self.position=position         self.dir=1     def display(self):         print("Positon:",self.position,",Direction: Up")   Here is what's printing now:   >>> a=Direction(3)   >>> a.display()   Positon: 3 ,Direction: Up   I want to remove the space after 3.


Installing Ubuntu Server 12.04.3 using Raid 1, Need a step by step guide

Lately, I am trying to build a server that uses Ubuntu Server 12.04.3(64bit) . I am facing problem while wanting to install under a software RAID(RAID 1). My Server spec are as below:  Proccesor: Intel i5-4670 Motherboard： Asus H87M-E V1 RAM: 2X 4GB 1600mhz Hardisk: 2x 2TB WD Red Cavier  I already tried either Software RAID and Hardware RAID. Software RAID can't install bootloader and Hardware RAID won't let me partition. This is my first time directly doing RAID 1 on the OS HDD. Kind of Newbie here. Anyone who had this experience please share. Thank You


Mysterious disappearance of disk space on Catalina (and not any other OSX)

I am on 10.15.2.  I did not upgrade/update (I seldom do, and when I do it is after much deliberation).  My new Air came with Catalina on it and, in view of a Sierra install (or any OSX install any more compared to the good old days) being far from straightforward, I just went with Catalina. I am following up from my earlier question:  What I did was to move some subdirs/folders I don't really need on my SSD to an external drive that usually stays connected via USB.  Doing so increased free space to about 25 GB, so that should have done it.  Except it didn't. It is worth mentioning that I do not log out or shut down or even reboot much.  Since the days of PowerBook G4s and Puma all I do is shut the lid. Now, since I cleared up about 25 GB on the SSD about two months back, the max space I have used is about 2 GB; impossible that I would have used up more than 4 GB.  But the free disk space I have now is only about 11 GB.  No such thing ever happened on various OSX versions up to and including Sierra (from which I made this big, sudden, and awful jump to Catalina). So where did the 14 GB disappear?  The only think I can think of is memory leaks through VM taking up blocks and blocks of disk space and never releasing them.  If this is correct, is there a way to trace the rogue application(s)?  And what is this problem with Catalina making disk space mysteriously disappear? Thanks for any help.


Calculate the Integral for all n=1,...n  $\int _{ 0 }^{ \pi/2 }{ \frac { \sin^n(x) }{ \sin^n(x)+ \cos^n(x) }  } dx$  hint: substituion with $x= (\pi/2)-t$  I tried it many times, but always ended up with the Integralsinus $Si(x)$ which i cant use. Thanks for help


Lambda variable capture in loop - what happens here?

I am trying to get  my head around, what happens here ? What sort of code does the compiler produce?  public static void vc() {     var listActions = new List<Action>();      foreach (int i in Enumerable.Range(1, 10))     {         listActions.Add(() => Console.WriteLine(i));     }      foreach (Action action in listActions)     {         action();     } }  static void Main(string[] args) {    vc(); }   output:  10 10 ..  10  According to , a new instance of ActionHelper would be created for every iteration. So in that case, I would assume it should print 1..10. Can someone give me some pseudo code of what the compiler is doing here ?  Thanks.


If $K$ is a finite field, then $|K|=p^d$ where $p$ is prime and $d\geq 1$.

Let $K$ a finite field. I want to show that $|K|=p^d$. I consider an homomorphism $\Phi:\mathbb Z\to K$ which is clearly not injective, therefore $\ker\Phi\neq\{0\}$.   What I want is to prove that $\ker \Phi= p\mathbb Z$ for a certain prime, and thus $\mathbb Z/p\mathbb Z\cong \text{Im}(\Phi)$. In particular, I would like to have $\text{Im}(\Phi)=K$ and thus, since $\Phi(\mathbb Z/p\mathbb Z)=k$, we need to have $p\mid |K|$ and thus $|K|=p^d$.  Well, every thing is confuse in my mind, so any help si welcome.  PS: My hint is : consider $\Phi: \mathbb Z\to K$.


How to download Ubuntu Server backups automatically?

I'm thinking of an investment in a new root server running ubuntu. Due to the fact, that the provider won't have extra backup-space, I need an other solution.  Is it possible to download the server backups automatically when my desktop machine is connected to the internet and in idle state?


Error changing between Nvidia and Intel GPU using Nvidia-settings (no module named 'dbus')

I can't change between Nvidia GPU and Intel using sudo nvidia settings. I get the following error:  Traceback (most recent call last):  File "/usr/share/screen-resolution-extra/nvidia-prime.py", line 22, in <module>     import sys, dbus, logging ModuleNotFoundError: No module named 'dbus'   I already tried reinstalling dbus but it did not work.


Is it illegal to going to someone's bank account and do a transfer?

A person I've been talking to for a while asked me to go into his bank account  and make a transfer to a US beneficiary account. It's a continental account. It showed the  date that the account was opened in 2007 as well as a picture of him.   I trusted him and I did it. Now he is asking me to do it again and this time red flags are coming up. Can someone help me? Is it illegal to go into someone's account and make a transfer for them?


How to describe duration of, and duration since, a finished past event?

If I ate from 7:00 until 7:30am,   At 7:10, could I say      I am eating for 10 minutes?  At 7:40, could I say      I ate for 30 minutes, 10 minutes ago?


How to use the Mean Value Theorem to prove the following statement:

Suppose $f(x)$ is continuous on $[a,b)$ and differentiable on $(a,b)$ and that $f '(x)$ tends to a finite limit $L$ as $x \to a^+$. Then $f(x)$ is right-differentiable at $x=a$ and $f '(a)=L$.  (epsilon-delta proof not needed).  This is a practice exam question.  I am having trouble translating this into a 'mathematical' statement. The MVT states that there exists $c$, $a\leq c\leq b$, such that:  $f'(c) = (f(b)-f(a))/(b-a)$  I suppose to prove that $f(x)$ is right differentiable at $x=a$, using the MVT, I need to somehow show that as $x \to a^+$, $f'(c)=f'(a)=L$ ??? Am I on the right track here? Can someone help me get started?


Proof that every finite dimensional normed vector space is complete

Can you read my proof and tell me if it's correct? Thanks.  Let $V$ be a vector space over a complete topological field say $\mathbb R$ (or $\mathbb C$) with $\dim(V) = n$, base $e_i$ and norm $\|\cdot\|$. Let $v_k$ be a Cauchy sequence w.r.t. $\|\cdot\|$. Since any two norms on a finite dimensional space are equivalent, $\|\cdot\|$ is equivalent to the $l^1$-norm $\|\cdot\|_1$ which means that for some constant $C$, $\varepsilon > 0$, $k,j$ large enough, $$ \varepsilon > \|v_j - v_k\| \geq C \|v_j - v_k\|_1 e_i= C \sum_{i=1}^n |v_{ji} - v_{ki}| \geq |v_{ji} - v_{ki}|$$ for each $1 \leq i \leq n$. Hence $v_{ki}$ is a Cauchy sequence in $\mathbb R$ (or $\mathbb C$) for each $i$. $\mathbb R$ (or $\mathbb C$) is complete hence $v_i = \lim_{k \to \infty} v_{ki} $ is in $\mathbb R$ (or $\Bbb C$) for each $i$. Let $v = (v_1, \dots , v_n) = \sum_i v_i e_i$. Then $v$ is in $V$ and $\|v_k - v\| \to 0$:  Let $\varepsilon > 0$. Then $$ \|v_k - v\| \leq C \|v_k - v\|_1 = C \sum_{i=1}^n |v_{ki} - v_i| \leq C^{'}n \varepsilon$$  for $k$ large enough.


Batch file to delete files older than N days

I am looking for a way to delete all files older than 7 days in a batch file.  I've searched around the web, and found some examples with hundreds of lines of code, and others that required installing extra command line utilities to accomplish the task.  Similar things can be  in just a couple lines of code. It seems that something at least remotely easy could be done for batch files in Windows. I'm looking for a solution that works in a standard Windows command prompt, without any extra utilities. Please no PowerShell or Cygwin either.


I am trying to upgrade to Drupal 9, but I have two modules that aren't compatible. I patched both the modules to make them compatible. However, I can't upgrade to Drupal 9. When I do, it tells me those modules don't meet the requirements, which of course is true, since they need to be patched. How can I upgrade to Drupal 9 if those modules initially don't meet the requirements?


Want to set a guest session password for login. How do you do this after skipping it at OS install?


How can I disable creepers' block damage on my Minecraft server?

Please note that these are NOT acceptable solutions:   Completely disabling monsters (peaceful mode) Completely removing creepers Completely disabling explosions (TNT + Creepers) Disabling creeper explosions   More exactly, I want the creepers to be able to spawn and explode, but without doing their terrain damage (they should still be doing health damage to the players).  I'm fine with the use of mods but I'd prefer a built-in solution if possible.


Logging into Stack Overflow chat has no effect

I just tried logging into chat and it seems to have no effect. I am redirected to the login form which I fill out successfully, then I am redirected back to chat which still considers me as a guest and offers me to login again.  The Stack Exchange global chat seems to work fine though - I am redirected to a different-looking page (with an iframe to put in my SE OpenID credentials) and then I am redirected back to chat where I am considered logged in. No effect on Stack Overflow chat - still thinks I'm a guest.  The network login troubleshooting page says everything is fine, and I've tested in a brand new Internet Explorer 11 with no add-ons just to make sure it's not my main browser that's causing the issues (which does have uBlock and HTTPS Everywhere).  If that could be relevant, I've recently changed my e-mail and thus migrated all my accounts to a new SE OpenID.


Proof of $L_q(\Omega) \subset L_p(\Omega)$ when $1\leq p \leq q \leq \infty$

I need to prove that  $L_q(\Omega) \subset L_p(\Omega)$ when $1\leq p \leq q \leq \infty$ when $\Omega$ is bounded. The hint given is that I should use Hölders inequality. How do I start my proof using this inequality?


Think thee that I would desert thee? Think thee that I don't care?  or:  Think thou that I would desert thee? Think thou that I don't care?  Which one is right?


Proving convergence iff projection converges in product topology

question is regarding the same problem. I wish to present my proposed solution and get feedback on my argument, and as such, I claim that it is not a duplicate. (In particular, the other asker actually knew what he was doing, so this question will probably be sufficiently different. It also includes the discussion about the box topology, which the original question lacked.) We are given that $\{x_n\}$ is a sequence of points in the product space $\prod X_\alpha$. We are to show that this sequence converges to $x$ if and only if $\{\pi_\alpha(x_n)\}$ converges to $\pi_\alpha(x)$. Moreover, we are to determine if this holds if we equip $X = \prod X_\alpha$ with the box topology. We first show $\implies$. Suppose, for the sake of contradiction, that $\{\pi_\alpha(x_n)\}$ does not converge to $\pi_\alpha(x)$ for a fixed $\alpha$. Then there exists an open set $U_\alpha$ containing $\pi_\alpha(x)$ such that $X_\alpha - U_\alpha$ contains infinitely many $\pi_\alpha(x_n)$. Since every projection in the product topology is continuous, $\pi^{-1}(U_\alpha)$ is open in $X$. This contradicts the assumption that $\{x_n\} \to x$, since we now have an open set of $X$ where one of the $\{x_{n_i}\}$ clearly do not converge, where $\{x_n\} = (\{x_{n_1}\},\{x_{n_2}\},\cdots)$ We proceed to show $\impliedby$. We are given that $\{\pi_\alpha(x_n)\} \to \pi_\alpha(x)$ for every $\alpha.$ Let $\prod U_\alpha$ be an open set in $X$ containing $x$. By the definition of the product topology, we know that $U_{\alpha} \ne X_\alpha$ for only finitely many $\alpha_1, \alpha_2,\cdots,\alpha_k$. Now, since we know that $\{\pi_\alpha(x_n)\} \to \pi_\alpha(x)$, it follows by the definition of convergence that there exist numbers $N_{\alpha_1},N_{\alpha_2},\cdots,N_{\alpha_k}$ such that $\pi_{\alpha_i}(x_n) \in U_{\alpha_i}$ for $i \in \{1,\cdots,k\}$ and $n \ge N_{\alpha_i}$. Letting $N = \max\{N_{\alpha_1},\cdots,N_{\alpha_k}\}$, we see that $x_n \in \prod U_\alpha$ for $n \ge N$. (Recall that for $\alpha$ not in the finite collection, it equals the whole space $X_\alpha$, where inclusion is trivial.) We conclude that $\{x_n\} \to x$ Lastly, we consider $X$ with the box topology. In $\implies$ we did not use any particular properties of the product topology, aside from the continuity of projections, which also holds for the box topology. As such, I claim that $\implies$ still holds. However, I claim that $\impliedby$ does not hold. I ask for an example that shows this, since I am not able to find any argument I'm happy with. ("Well, our proof used properties of the product topology, so..." is only acceptable for my private notes.)


What is the difference between photoelectric effect and Compton scattering?

What is the difference between  and ? These two effects explains interaction of photon with electron. Why in photoelectric effect whole energy of photon is used up and in Compton photon gets reflected with some energy?


What is the remainder when dividing $((1997!+11)!+29)!$ by $7$?

This question appeared in one of the national exams in Saudi Arabia which was on Saturday, November $29, 1997$.  If today is Saturday, what day of the week will it be $((1997!+11)!+29)!$ days from now?  Actually I do not know how to start. I saw a similar problem asking $10^{{10}^{10}}$ days from now, it was a simple one.  Any help would be appreciated. THANKS!


. What about his first and last name? Where do Philip and Fry come from? Perhaps it is based on Philips the company, and Fry's Electronics? Or am I thinking too far into this?


break a python loop using not in operator

This loop does not work as expected. It prints all 4 elements (expected 3) guj = ["बळींचाी", "आठ़वले", "मोठय़ा", "धाांची"]  for y in guj:     for i in y:         x = i.encode("raw_unicode_escape")         if x[:5][-3:] not in [b"090", b"091", b"092", b"093", b"094"]:             break     print(y)  The third word should not be printed because it contains a character having 095 series that is invalid. # "य़".encode("raw_unicode_escape") # b'\\u095f'  output.txt बळींचाी आठ़वले मोठय़ा धाांची  expected.txt बळींचाी आठ़वले धाांची


Suppose we have a baseline exposure group and 2 other exposure groups for a case control study. Suppose the odds ratio for the first exposure is $1.5$ and the odds ratio for the second exposure is $1.8$. Does this mean that cases are $1.5$ times as likely to have exposure 1 than the controls? Also does this mean that cases are $1.8$ times as likely to have exposure 2 than the controls?


Prove by induction that if the first car stops, all of them stop

I have to prove this by induction:      $n$ cars are travelling down a narrow one-way street. We know that:          The distance d between each two cars is the same.   The safe breaking distance b is the minimum distance between two cars that is needed for the second car to stop on time if the car in front suddenly breaks.   d < b         Prove by induction or refute: if the first car suddenly stops moving, all cars will stop moving. Before you do the induction state the property P you are using in the induction axiom.   So this is what I have until now and please tell me if it is right or wrong.  The property P: if $n=1$ stops, then $n=2$ will stop. (Is this property correct?)  We consider 2 cases:   Base case:  n=1 -> Since there is one only car on the road, that car will stop. (Should the base case start at 0, 1 or 2? )  Step case: (Supposed that the base case should start at 1)  As mentioned, for n=1 if the only car stops, then we can say all the cars have stopped.   Assume that all cars stop for n cars and then we prove that all cars stop for $n+1$. We create the set C of Cars in which are included all the cars in road. The moment the first car $(n=1)$ stops, the following cars have 2 ways to stop:    $n+1$ car stops without touching the n car $n+1$ car stops by touching and having/or not an accident with n car   Any suggestion?


How can the Test Coverage can be fulfilled for the Apex classes which queried for External Objects.I have written Test class just like assuming External Object behaves like a custom Object but getting error repetitively "CANNOT_INSERT_UPDATE_ACTIVATE_ENTITY: You can't create records for the object".  I used the DML statements like Database.insertAsync but no use. Gone through some articles saying that we need to mock the external object for the Apex Test coverage on External Object. If so is there document which explains about this concept.


Is the quantum analogue of electrostatic field photon? What will be its wavelength then?

When two charges are separated there is an electrostatic field between two. Quantum mechanically, is it actually the discrete energy packet or photons that's travelling from one charge to another? If yes, what is its wavelength? How can I better understand the interaction between two charges with the perspective of quantum theory?


My problem is that I can't ring or loop-cut a set of polygons that are co-planar.    This is the sort of thing that's happening, as you can see I can only affect 2 faces at a time. I've cleaned up the mesh, welded all vert's and made sure there aren't any holes in the mesh in the area that I was to cut a ring/loop.


Why does the imported JPEG from my Canon Powershot G9X Mark II on PC screen differ quite significantly from the camera display?

Consider the attached sample images. I took them circa 4:50 AM and 3:50 AM, respectively. On the Live View display of the Powershot G9X Mark II, they were full of light.     The pictures were taken as JPEG (yes, I should've shot that in RAW and figured out the shadows later, but the screen told me the shadows were fine, so I didn't bother). IrfanView claims that the colorpace is sRGB, and there is no explicit setting for color space in the camera. The laptop screen is IPS 8-bit 1920x1080 14" (Lenovo Thinkpad L440). I do not "import" the pictures in any application, just copy the files using Explorer on 64-bit Windows 7 64-bit, which was preinstalled by Lenovo.   Consider the first picture. The shadows below the hull of the utility vessel did not blend with the color of the hull, which in turn was gray and the detail was easily visible. On the PC display, it's really dark in that area, all nearly black. Next, the trees in the background lose detail in the shadows as well on the PC. Now consider the second picture. It's not as dramatic a change as with the first one, but still, the whole photo is just lighter on the camera screen, with seemingly better visibility in dark areas as well as slightly better contrast, and the water is more vivid, more blue than gray. I like the water more as displayed by the camera.   Hence the following questions.   Does any hidden conversion take place inside the camera before the image is displayed on the Live View screen? Take into consideration that there is no RAW file to process and display. The problem manifests itself with JPEG-only shooting. Is the camera screen built with a 10-bit panel or using some other colorspace? Is adjusting photo settings for the next shot based on how the Live View screen displays the result of the previous shot the correct way of finding the right settings for a given shot? Can I see the same picture on the PC display and if yes, how?   P.S. The utility vessel is static in that location so I can go and re-take the picture as the discussion unfolds with corrections applied.  Edit: The answers to the linked question #1 don't mention correct shooting technique using the histogram, so it doesn't quite solve my problem.  The question #2 is about viewing RAW files, hence it does not apply.


19th century English texts occasionally use Germanic-style number words, such as "four-and-twenty". When did this fall out of use?

19th century English texts occasionally use Germanic-style number words, such as "four-and-twenty", but the same text would also have the modern "twenty-four" in places (see e.g. Conan-Doyle for several examples).   How did the usage of germanic-style numbers change historically? When did the Germanic forms fall out of use?   (I have asked this question previously on  (German) and got a short , but would appreciate any additional input.)


Question about Maximum Modulus Principle applied to $|f|+|g|$

Let the functions $f$ and $g$ be holomorphic in $U$ and continuous in $\overline{U}$. Show that $|f(z)| + |g(z)|$ attains its maximum on $\{|z| = 1\}$. Hint: consider the function   $h = e^{iα}f + e ^{iβ}g$ with suitably chosen constants $α$ and $β$.   Even with the hint I am lost. Of course $|h(z)|$ must attain its maximum when $|z|=1$, and $|h| \le |f|+|g|$, but that doesn't mean that $|f|+|g|$ couldn't attain its maximum inside the unit circle.  ny help?


Restart returned to session indicator menu after upgrading to 13.10

This is the first time I'm having problems during Ubuntu upgrade. I had previously enabled the new Unity logout/shutdown dialogs and the restart option had gone. But now it's back again, though utterly useless, because each one leads to the same new Unity dialog: restart or shutdown. I wonder how I can get rid of this duplicate menu option?


== vs hashcode comparision of string in java

String obj1 = new String("abc");     String obj2 = new String("abc");      if(obj1.hashCode() == obj2.hashCode())         System.out.println("hashcode()");       if(obj1==obj2))         System.out.println("==");     it prints hashcode() ,but why it does not print == as hashcode of both objects are same ?  having  same hashcode doesn't mean references are pointing to same object?


What is Change Detection and performing such analysis with open source tools?

From  page:  Change detection for GIS (geographical information systems) is a process that measures how the attributes of a particular area have changed between two or more time periods. Change detection often involves comparing aerial photographs or satellite imagery of the area taken at different times. The process is most frequently associated with environmental monitoring, natural resource management, or measuring urban development  How is the comparison done? With what tools? I feel that the description is not complete. Or something is missing. Where or in which books can I find more information about Change Detection? What tools should I use to perform such an analysis using the data in a shapefile? (only open-source please)  Some papers on change detection (theory and techniques)  Trend change detection in NDVI time series: Effects of inter-annual variability and methodology Forkel, M. , Carvalhais, N. , Verbesselt, J. , Mahecha, M.D. , Neigh, C. , Reichstein, M. (2013) Remote Sensing 5 (2013)5. - ISSN 2072-4292 - p. 2113 - 2144. Shifts in global vegetation activity trends Jong, R. de , Verbesselt, J. , Zeileis, A. , Schaepman, M.E. (2013) Remote Sensing 5 (2013)3. - ISSN 2072-4292 - p. 1117 - 1133. Relationships between declining summer sea ice, increasing temperatures and changing vegetation in the Siberian Arctic tundra from MODIS time series (2000–11) Dutrieux, L.P. , Bartholomeus, H.M. , Herold, M. , Verbesselt, J. (2012) Environmental Research Letters 7 (2012)4. - ISSN 1748-9326 - p. 12. Near real-time disturbance detection using satellite image time series Verbesselt, J.P. , Zeileis, A. , Herold, M. (2012) Remote Sensing of Environment 123 (2012). - ISSN 0034-4257 - p. 98 - 108. Trend changes in global greening and browning: Contribution of short-term trends to longer-term change Jong, R. de , Verbesselt, J. , Schaepman, M.E. , Bruin, S. de (2012) Global Change Biology 18 (2012)2. - ISSN 1354-1013 - p. 642 - 655. Phenological change detection while accounting for abrupt and gradual trends in satellite image time series Verbesselt, J. , Hyndman, R. , Zeileis, A. , Culvenor, D. (2010) Remote Sensing of Environment 114 (2010)12. - ISSN 0034-4257 - p. 2970 - 2980. Detecting trend and seasonal changes in satellite image time series Verbesselt, J. , Hyndman, R. , Newnham, G. , Culvenor, D. (2010) Remote Sensing of Environment 114 (2010)1. - ISSN 0034-4257 - p. 106 - 115. (I'll add more in the future as If I discover more notable  papers)


When is the Hamiltonian of a system not equal to its total energy?

I thought the Hamiltonian was always equal to the total energy of a system but have read that this isn't always true. Is there an example of this and does the Hamiltonian have a physical interpretation in such a case?


Cluster into communities a graph with negative edge weights representing repulsion

Consider an undirected graph $g$ with some edges having negative weight - all weights in $[-1,1]$. We are seeking . Negative edge weight means repulsion and positive means attraction. Most of the methods I've seen work with positive edges or somehow ignore the negative sign, for example, by rescaling $[-1,1]$ to $[0,2]$ or simply considering absolute value $\|[-1,1]\|$, - etc.   But I cannot ignore the sign. Consider for example a graph with only negative edge weights. If we ignore the negative sign (rescaling, or $\|x\|$, etc.) and use regular methods, then clustering communities will still appear. But by the meaning of repulsion, each node should form its own community in a graph with only negative edge weights, because it cannot cluster with a node that linked to it by an edge with negative weight.  Does anyone know of any method or algorithm that does this?  P.S. This stems from some applied problems, for example, finding communities in groups of people where hate-love relationships are allowed. Note  was asked IMHO in a less precise formulation and got vague responses. I am still not sure if this is the same as mine, but in any case there are no useful (for me) answers there, and my repulsion seems absent their at all.


How can I find which operating system my Ruby program is running on?

I want my Ruby program to do different things on a Mac than on Windows. How can I find out on which system my program is running?


Finding the intersection of 2 lines defined by 2 points

I need to be able to find the intersection between two lines defined by 2 points each. I have 2 functions; one to calculate if there is an intersection between two lines, and on to determine the point of intersection of those lines. Please respond with some possible code for each function.  Code structure so far:  struct Pos {     float x;     float y; };  struct Line {     Pos Pos1;     Pos Pos2; };  bool Collide(Line Line1, Line Line2) {     return true;// Return if there is an intersection  }  Pos CollidePoint(Line Line1, Line Line2) {     return {0, 0};// return the point of intersection }  int main() {     Line Line1 = { { 10, 20 }, { 20, 20 } };// Define one line      Line Line2 = { { 5, 30 }, { 15, 15 } };// Define another line      if (Collide(Line1, Line2))//check if a collision exists     {         //Display the point of intersection         cout << "X:" << CollidePoint(Line1, Line2).x << " Y:" << CollidePoint(Line1, Line2).y << endl;     }     else     {         //If there is no collision         cout << "No Collision" << endl;     }     return 0; }   NOTE: The function has to be able to work if one or all the lines are vertical and if the lines are on top of each other. Because of this, the code probably won't work with the form y=m*x+b due to the divide by 0 error with vertical lines.  If there is a better way to do this than using the 2 functions please tell me. I'm open to any solution.  EDIT: The two lines are bounded by the points; they are not infinite.


Can't install gsfonts-x11 or flashplugin-installer on Ubuntu 12.10?

So I downloaded Ubuntu 12.10 on a Dell mini Inspiron 910. Had problems with wifi, but I bought a wireless adapter and so I fixed that. But when I try installing flash, with sudo apt-get install flashplugin-installer gsfonts-x11 it gives me:  Reading package lists... Done Building dependency tree        Reading state information... Done Package gsfonts-x11 is not available, but is referred to by another package. This may mean that the package is missing, has been obsoleted, or is only available from another source  E: Unable to locate package flashplugin-installer E: Package 'gsfonts-x11' has no installation candidate   which I don't really understand.


Classifying slope (flat, slope, steep, very steep) in QGIS?

I want to classify the slope of the DEM data, by dividing the slope by 4 classes: flat, ramps, steep, very steep.  How to do this with QGIS?


Do the benefits of clipless pedals out weigh any danger they may pose the rider?

As a newbie rider, I was asked by many experienced riders and bike shop experts if I was using clipless pedals yet?  The implication was you are not really a serious rider until you are clipless, sort of a rite of passage. No one ever told me you can break bones, but told 'everyone' falls a few times, count on it, and move on.   Are there precautions or conditions where one could or should not use clipless pedal products?  The previous year, I had ridden 1700 street and paved bike trail miles on a comfort bike and a Mountain tandem with Pedal Cages and never had an issue.  I incorrectly assumed I was ready to advance.  I purchased a new touring bike with Shimano M540's.    Here is an  riding clipless.  It was an unexpected stop due to a flood closing a tame paved trail. Someone had painted a bright blue line from the trail up to where I fell ().  It was my error in trying to ride around the obstacle and ended in the railroad ballast (2"-3").  I had un-cliped going up but the M540's re-clipped  I stopped at the edge of the ballast but was clipped.  My ankle twisted > 150 degrees. It was my third ride and fall clipless. It all happened in 10-15 seconds.  I know through good friends of two very much younger but very experienced  riders who were hurt much more severely than I due to clipless.  Should I try again with the beginner clips and different pedals, or as my son and wife tell me, are you crazy?  Revisited  Having just rolled over 2,000 miles this year with flat pedals on the road I can report I have found a solid solution for me.  I now ride with "Pin" Pedals available from several manufacturers I use (Xpedo MX Force 3).  These pedals have a grid work of short pins sticking up on both sides of the flat pedals. These pins rather lock my foot on the pedal preventing foot creep or shifting out of position while allowing for quick mount and dismounting as necessary.


How to remove Ubuntu from dual boot system with Windows?

I wish to remove Ubuntu and I'm not quite sure how. I know it has something to do with partitions. I have 3 partitions. 1. OS [683 GB]  2. Recovery [14 GB] 3. Ubuntu 12.04 LTS (E:)  I know it says Ubuntu but when I installed Ubuntu I think I put 14 gigabytes for it so I think its the recovery one but I'm not sure. I could have sworn I put more than 700 megabytes for it.  I have googled this and I can't seem to find an answer. Any help would be nice.


How to solve the functional equation $f\left(x^2+f(y)\right)=y+f(x)^2$

How to solve the following functional equation:  Find all $f:\mathbb{R}\to\mathbb{R} $ such that: $$ f\left(x^2+f(y)\right)=y+f(x)^2 $$ Holds for every $x,y\in\mathbb{R}$.  A friend gave it to me, probably its an olympiad question.  I started with the equation $f(f(y))=y+f(0)^2$ which seems to be quite helpful, but I couldn't do it effectively. How to solve it properly?


Let $a$, $b$, and $c$ be real numbers such that $a − 7b + 8c = 4$ and $8a + 4b − c = 7$. What is the value of $a^2-b^2+c^2$ ?


I'm using the acronym package. Is it possible to automatically add an index entry each time an acronym is used?


How can I go about drawing a colored box around a column in a matrix with an arrow and text like this:    Here is the code that I have thus far:  \documentclass[11pt]{book}  \usepackage{amsmath,amsfonts,amssymb,amsthm}  \makeatletter \renewcommand*\env@matrix[1][*\c@MaxMatrixCols c]{%   \hskip -\arraycolsep   \let\@ifnextchar\new@ifnextchar   \array{#1}} \makeatother  \usepackage{tikz}   \begin{document}  \begin{equation} \begin{bmatrix}[cccc|c]   1 & 0 & -1 & 0 & 0 \\   0 & 1 & 2 & 0 & 0 \\   0 & 0 & 0 & 1 & 0 \end{bmatrix}\\ \end{equation}  \end{document}


how do I create a feature class from a table?

I have a database table that has the column and types defined. But it's a database table. I need a feature class so I can add spatial functionality, like add a SHAPE field. How do I create a feature class from a database table?  Update - I'm starting from a database table. The destination is an existing feature class in my enterprise SDE. I need to take some fields from the table and build a value for a SHAPE field. I also need to be able to use my fieldmappings to map fields from the source to the destination; hence the need to get this data into a feature class instead of a table.


Execute on the basename of a find command

Suppose I have a directory structure as follows  test test/a test/b   Now I want to execute a command, such that in the . folder I can execute a command on the basename of the files a and b.  So basically, I want something like this, which I naively tried  find test -type f -exec touch `basename {}` \;   Only, this does not result in empty files a and b in the parent directory. Suppose that my touch command can only take a single argument.  This will result in a directory structure like this  a b test test/a test/b   I know how to do this in a bash script, but I am interested in single command solution.


I was trying to clone a deep object in Angular and started by using this: const newObj = { ...oldObj }  But I noticed that when I changed a property of newObj, oldObj was also updated, so I assume the clone was not done but in fact I was just passing a reference. I than changed to this: const newObj = JSON.parse(JSON.stringify(oldObj))  And it worked as I wanted. When a property of newObj was changed, nothing changed in oldObj. I thought the deconstruct method of cloning returned a new object, is it really a reference? Thanks.


I'm using windows 7 right now. I want to install Ubuntu with dual boot. Is is safe? And does the process go safely?


Penalized methods for categorical data: combining levels in a factor

Penalized models can be used to estimate models where the number of parameters is equal to or even greater than the sample size. This situation can arise in log-linear models of large sparse tables of categorical or count data. In these settings, it is often also desirable or helpful to collapse tables by combining levels of a factor where those levels are not distinguishable in terms of how they interact with other factors. Two questions:   Is there a way to use penalized models such as LASSO or elastic net to test for the collapsibility of levels within each factor? If the answer to the first question is yes, can, and should, this be set up in such a way that the collapse of levels and the estimation of model coefficients occurs in a single step?


A man who sometimes works for the UN accidentally sells the Earth to an alien

Sci fi story from the 1950s:  In New York, a man in a trenchcoat approaches and offers to buy planets.  The man selling eventually "sells the earth".  The buyer says write me a bill of sale and put "in my official capacity" on it.  After signing, the seller remembers that he sometimes sells surplus property for the UN.  He tries to buy the earth back.  The buyer admits he is an alien and needs to buy parts for his crashed spacecraft.  The seller takes all the money and buys the parts for the alien, who tears up the bill of sale.


I am trying to use the CRPS formula in Latex and I am very new to it. I am getting a Missing $ inserted error from the equation below. I know it's a common problem, but I haven't been able to solve it. Please help!  CRPS = \int_{-\infty }^{\infty }        \left [ F_{y\right}\left (y \right )-1\left ( y \geq x\big\ \right ) \right]]^{2}dy   Hi, this is a part of the thesis template of my university. I am not supposed to edit the preamble.


Is representativeness a necessary condition for generalisability?

If a large sample of volunteers were not representative of a specific population, would it necessarily mean that any conclusion of a study performed with sound methodology on this sample could not be generalized to that population?


CPU Fan always on high speed after upgrade to 14.04

cpu fan always on high speed after update from 13.10 to 14.04  MB Asus P5G41T-M LX V2  It was working nice on 13.10  Output of sensors:  atk0110-acpi-0 Adapter: ACPI interface Vcore Voltage:      +1.17 V  (min =  +0.85 V, max =  +1.60 V)  +3.3 Voltage:      +3.39 V  (min =  +2.97 V, max =  +3.63 V)  +5 Voltage:        +5.17 V  (min =  +4.50 V, max =  +5.50 V)  +12 Voltage:      +12.20 V  (min = +10.20 V, max = +13.80 V) CPU FAN Speed:      922 RPM  (min =  600 RPM, max = 7200 RPM) CHASSIS FAN Speed:    0 RPM  (min =  600 RPM, max = 7200 RPM) CPU Temperature:    +42.0°C  (high = +60.0°C, crit = +95.0°C) MB Temperature:     +35.0°C  (high = +45.0°C, crit = +95.0°C)  coretemp-isa-0000 Adapter: ISA adapter Core 0:       +54.0°C  (high = +78.0°C, crit = +100.0°C) Core 1:       +54.0°C  (high = +78.0°C, crit = +100.0°C)  nouveau-pci-0100 Adapter: PCI adapter temp1:        +79.0°C  (high = +95.0°C, hyst =  +3.0°C)                        (crit = +130.0°C, hyst =  +2.0°C)                        (emerg = +135.0°C, hyst =  +5.0°C)


What is the significance of Latus Rectum?

So I just completed the chapter Conic Sections and the one thing I could not understand is what is the use of Latus Rectum? It is defined as " Line segment passing through the focus and parallel to directrix." I've done questions like what is the length of latus rectum when some values are given. Is it just a line with no significance? I mean there can be a line in parabola parallel to directrix with say 8 times the focus? Is it any less significant than Latus rectum?


Rutherford's model of atom was ruled out because it failed in explaining stability of an atom. Since any particle that is accelerating continuously emit radiation. And in case of an atom eventually electrons fall into the nucleus. Bohr said that they revolve in stable orbits around the nucleus. Still they're in uniform circular motion right? Why don't they radiate energy and fall into the nucleus?


Taking 40" TV to northern Cyprus as baggage?

I'm going to northern Cyprus with Turkish airlines and want to take a 40 inch smart TV that I bought here in the UK with me. Can't find out if this is possible or how much it would cost as it weighs 14kg and as it is fragile how it should be packed if going in the hold. This would be in addition to my 23 kg luggage. Reason is TVs in northern Cyprus are very expensive compared to UK


Can non-EU with Family Member Schengen visa travel alone?

My son is an EU citizen but I am not.   A few months ago, I applied for a Schengen visa from the Danish Embassy as an EU Family Member and got my visa. We then traveled to Denmark together as planned. Now I am going to holiday in Oslo with my sister, but my son is poorly and he will stay here in the UK (where we live).  I have the multiple entry Schengen on my passport, but I am wondering will it be a problem to travel without my son. On the visa itself no restrictions are listed. His name is on the plane ticket though as I booked him for the flight, as well.


Ubuntu has been installed but computer still boots into windows

Sorry if this is a stupid query, but I spent ages getting the Samsung NP905S3G to boot from usb and eventually got it to work. Wanted to try a dual-boot alongside windows 8 first and the install seemed to work but I now can't figure out how to boot the laptop in ubuntu without the usb. It keeps starting in windows no matter how I configure the BIOS. Any help welcome. Thanks Edited to explain further : I think Ubuntu has installed successfully. My problem now is getting it to boot.


\( \chi \) produces a letter that is slightly below the row, but I've seen in many papers a chi that is in the same line as the rest of the row)


I have the following question: Prove that a finite $p-$group $G$ with a unique subgroup $H$ of index $p$ is cyclic.  Since the subgroup is characteristic it is normal. I showed that either the center of the group $Z(G)$ is a subgroup of $H$ or $G=Z(G)H$ and the index $Z(G)/(Z(G)\cap H)$ is $p$. But I couldn't continue from this. Any help would be great.


Windows using full internet bandwidth continuously

I am using windows 10 pro for couple of months. I had no problem like this in past. My internet speed is 1.5 mbps. A windows built in program called svchost.exe (netsvcs) is taking all of my bandwidth and I can't even visit any website. Here are some screen shots:    Disclaimer: I am 100% sure this not happening for windows update and my system is up to date. I dont use any antivirus like avast or avg .I use windows defender and it is also up to date.  What can I do to prevent this?  Edit:  No one couldn't give me any correct method(answer). I think I have to uninstall windows and install linux or buy a mac. It's a super buggy os and the start menu crashes 100 times a day! I have to lose my favourite programs which is not available in mac or linux! Some one marked this question as duplicate. This is a different question.


How to invert/flip screen on windows xp?

How can I invert the screen on Windows XP? Not rotate, but flip/invert horizontally? I want the text, and everything else on the screen, to go from right to left.


Why isn't reflexivity redundant in the definition of equivalence relation?

An equivalence relation is defined by three properties: reflexivity, symmetry and transitivity.  Doesn't symmetry and transitivity implies reflexivity? Consider the following argument.  For any $a$ and $b$, $a R b$ implies $b R a$ by symmetry. Using transitivity, we have $a R a$.  Source: Exercise 8.46, P195 of Mathematical Proofs, 2nd (not 3rd) ed. by Chartrand et al


Does my age depend on the current timezone?

If I turn, say, 18 at home, and immediately travel westwards into a different time zone where it's still the previous day, will I be legally 17 or 18 there?  And if 17, how would that affect e.g. any rules that would require me to be of age for that specific journey (can't think of any specifics, and yes this is getting rather academical now).  This question is about the legal aspects, not the practical side of how to actually do it.


How can I make a bash counter script work when executing it from another script?

I have a script that uses wget and saves the output to a file with a name of an incrementing variable.  Counter.sh:  number=1 for i in $(cat file) do wget $i -S -O $number.html 2>&1 ((number++))  sleep 1    echo 'done'  done   I can run the script from the command line and it operates perfectly. However when I execute it from within another script:  Script 2:  ./counter.sh   I receive the following output:  scripts/counter.sh: 5: scripts/counter.sh: number++: not found done scripts/counter.sh: 5: scripts/counter.sh: number++: not found done scripts/counter.sh: 5: scripts/counter.sh: number++: not found done scripts/counter.sh: 5: scripts/counter.sh: number++: not found done   For some reason the counter ++ is not working when executed from within another script. How can I fix this?


label vector line with multiple attributes in QGIS

I have a line with two 2 attributes. I would like to display both information along with the line in frequent interval, one info above the line and the other is below the line. I am working in QGIS 1.8.0-Lisboa software.


questions about the nested loop on array

s = [[0]*3]*3  i = 0  while i < 3:     j = 0     while j < 3:         print(s[i][j])         s[i][j] += 1         j += 1     i += 1   The printed result of the above code really confused me, Why the second and third column of the array become [1,1,1] and [2,2,2] but not [0,0,0]?


So, I've been spending considerable more time on SO recently than I normally have, and one thing that I've noticed is quite a few people saying stuff like "There's a Null Pointer Error in this block of code, please help me fix it", with a huge amount of code posted, and no real clue as to where the NPE is. So my question is, what can we do to accomplish 2 goals?   Help the person asking the question become a better programmer. Help them to solve their problems.


How to get the two numbers after the decimal point as an integer

I have the number "159.82" and I need to get it to print just "82"  What I have been trying is something along the lines of   double total = 159.82; System.out.println(total - (int) total);    But that leaves me with 0.8199999999999 so clearly I am doing something wrong.


I would like to learn this type of fonts in latex. I have tried all the math fonts but it does not seem to be ana appropriate one. So my question is:what  the name of this font in latex?   Answer of Heiko Oberdiek  The question is already closed, thus I have to use the question for the answer; images cannot be put in comments.  Comparison of the image in the question        and the typewriter font of Computer Modern (or EC or Latin Modern):  \documentclass{article} \begin{document} \texttt{age=25 AND name=`Bob'.} \end{document}         Together with the original in black and the \texttt variant in red:  \documentclass{article} \usepackage{graphicx} \usepackage{color}  \begin{document}  \leavevmode \raise.8pt\rlap{\includegraphics[width=50mm,trim=0 0 -.7pt 0]{age25.png}}% \textcolor{red}{\includegraphics[width=50mm]{age25-cm.pdf}}%  \end{document}         The thickness is quite correct.  However the space between the ' and . is smaller. Next idea: the . is not set in a fixed-width font:  \documentclass{article} \begin{document} \texttt{age=25 AND name=`Bob'}. \end{document}         Comparison with this variant yields:  \documentclass{article} \usepackage{graphicx} \usepackage{color}  \begin{document}   \leavevmode   \raise1pt\rlap{\includegraphics[width=50mm,trim=-.25pt 0 -1.25pt 0]{age25.png}}%   \textcolor{red}{\includegraphics[width=50mm]{t-crop.pdf}}% \end{document}         Result: \texttt{age=25 AND name=`Bob'}. (cmtt or lmtt)


I'd like a way to add things to $PATH, system-wide or for an individual user, without potentially adding the same path multiple times.  One reason to want to do this is so that additions can be made in .bashrc, which does not require a login, and is also more useful on systems which use (e.g.) lightdm, which never calls .profile.  I am aware of questions dealing with  from $PATH, but I do not want to remove duplicates.  I would like a way to add paths only if they are not already present.


How can I reduce the salt taste in a dish

Can a dish prepared with too much salt be overcome without changing the water or ingredient content? Or least in a drastic way.


What's a better way to define individual link colours for a url in a macro?

I've got a document where I'd like two colours of links - cyan for links in headers that since it's brighter, and navy blue for links in the main body which is more subtle/less distracting. I already tried using the xcolor package and changing the text colour with textcolor, like \textcolor{cyan}{\href{url.com}{link name}}, but it doesn't override whatever link or url colour I have defined in hypersetup.   So this is what I've done:   I've defined the colour navy:   \definecolor{navy}{HTML}{2F729C}    And also imported the hyperref package and defined commands to set the global link/url colours to cyan / navy.   \usepackage{hyperref}                         \hypersetup{colorlinks=true,linkcolor=navy,urlcolor=navy}                        \newcommand{\navylinks}{\hypersetup{linkcolor=navy,urlcolor=navy}}               \newcommand{\bluelinks}{\hypersetup{linkcolor=cyan,urlcolor=cyan}}     Then I've defined another command specifically for the header links, where I turn on cyan links globally, include the header text and link, and then turn on navy links again:   \newcommand{\headerlink}[1]{\bluelinks\href{#2}{#1}\navylinks}   My issue with this is that I feel like there could be a better way to do it than to set the global link colour every time I use a link macro; is there a way to define the link colour just for one link, like one would do with \textcolor{...}, that would be able to override hypersetup?


How do I sync (upload to/download from) my contacts, with my Ubuntu Touch OS?


The roots of $x^2-2x+3=0$ are $\alpha$ and $\beta$. Find the equation whose roots are: $\alpha+2$, $\beta+2$. Not sure of answer in book.  My working:  $\alpha+\beta=2, \alpha\beta=3$  $(\alpha+2)+(\beta+2)=\alpha+\beta+4=6$  $(\alpha+2)(\beta+2)=\alpha\beta+2(\alpha+\beta)=7$  Therefore, equation whose roots are $\alpha+2, \beta+2$ is $x^2-6x+7=0$  Answer in book is $x^2-6x+11=0$


Here is my LaTex code:   \documentclass{article} \usepackage{amsmath} \usepackage{color} \pagestyle{empty} \begin{document} \definecolor{blu}{RGB}{31,111,130} \definecolor{gren}{RGB}{39,110,13} \definecolor{gra}{RGB}{92,102,88}  \scriptsize{\textbf{{\color{blu} \noindent{\color{gren}Fyysinen} malli k\"{a}ytt\"{a}\"{a}\\ fysiikan lakeja jonkin\\ suureen ennustamisessa. }}}  \end{document}   Here is my result:    I don't want the first line to be indented...Why is this happening?  Thnx for any help! =)   P.S. This LaTex is generated by using IguanaTex Add-In for Microsoft Powerpoint 2010 =)


Changing link in SharePoint 2010 Event Calendar

On the Event Calendar, if you click on one of the links, it takes you to the DispForm.aspx page. I would like to change that link to go to a custom page but am unable to locate where that change takes place.


Geometrically Reduced implies Reduced (resp geom. Integral, Irreducible)

I have a question about a remark from Liu's "Algebraic Geometry"  at page 90:    Our Lemma 2.6 states following:    My QUESTION is how the author concretely deduces remark 3.1.12?  My ideas: Wlog $X_K =X$ (so $k=K$). Assume that $X_{\overline{k}}$ is reduced (or connected or irreducible) and $X$ not. The statement says that then there ixist an intermediate field extension $k=K \subset K'$ and a unique reduced (resp connected or irreducible) component $Z \subset X_{K'}$ with $Z_{\overline{k}}=X_{\overline{k}}$. Why is this a contradiction to assumption that $X_{\overline{k}}$ is reduced (or connected or irreducible)?


Cancelling a Schengen Visa via the Italian Consulate

My wife has a Schengen visa issued by the Italian consulate in the UK.  It expires at the beginning of December, and as we want to travel to Europe for the Christmas holiday, we were hoping to cancel the current Schengen visa early in order to apply for another one in time.  I have contacted the Italian consulate in London by email, and they have told me that they are unable to do this.   After a quick search online, it seems other people have had more luck cancelling their visas.   So my question is: has anyone cancelled a Schengen visa issued by Italy, and if so - how?


Checking the health of my iPhone's battery

It seems that my iPhone's (4s - purchased Nov. 2011) battery loses its charge fast.   I have read all the relevant OPs. Is there any app which provides information about the battery's health? Or should I simply change it?


Currently, I'm using the acronym package to keep my thesis clear and understandable, because it is quite heavy on the use of acronyms in some parts. Because of this, some pages have so many acronyms, that they more or less look like someone went haywire with a blue text coloring tool.  So my question is: is it possible for either the acronym package, or the hyperref package, to only use one hyperref per acronym per page? So if one encounters an acronym for the first time on a page, he will be able to click on it and taken to the acronym definition list. The rest of the same acronyms on the same page will be printed without link.  I do not know if it is even possible for LaTeX to have this kind of 'reflection' on pages and links while compiling the document. Searching on this provided no results, which is why I'm resorting to the gurus over here.


Equivalence relations on S given no relation?

On my assignment, one of the questions ask to list all equivalence relations on S and count how many are of partial orders.   Let S = {u, v, w}. List all equivalence relations on S. How many of these are also partial orders?   Am I to assume the equivalence relations are the possible combinations of each pair S x S ({}, {{u, u}}, {{u, u}, {u, v}} ...) or should their always be a given relation?


Elementary Derivation of the Quadratic Formula

I want a very elementary derivation of the quadratic formula. Something accessible to a middle-schooler.        Thanks for the help.


Prove sum of unindependent Gaussian random variable is still Gaussian

I know how to prove the statement when two r.v. are independent. But how to prove it when the r.v. are correlated?  Edit:or counter example?


Remove blue navigation bar in Sharepoint Online

I have a Sharepoint online page on which I would like to remove the blue navigation bar at the very top of the screen (the one with the seach bar in the middle and the button on the left with 9 dots to switch to different Microsoft apps). I have checked all of the header settings and also went into the site settings and modified the search settings. I was able to exclude the site from search results, however the blue bar still remains. Is this possible to remove in a default SharePoint online site without using custom CSS or anything like that?


I hope you get better vs. I hope you will get better

I'm an English speaker, and someone asked me why we say:     I hope you get better soon.   rather than      I hope you will get better soon.   Technically, you can say both. But why is the first ("I hope you get better soon") grammatically correct? I want to say it's because we use the word "hope" which, in this case, implies the future anyway (so adding "will" is a bit redundant).   Is that right, or is there another/better explanation?


NOTE: If client devices (computer B in this example) want to obtain   internet through the gateway computer, maybe they still need to configure   nameserver resolution. This is not explained here (a gateway does not necessarily serve internet).   I am trying to understand the fundamentals of networks routing. So I am experimenting with my LAN (I don't need internet for now, just LAN communications).    I know the network configuration matters are a rather complex thing, but I am just trying to make a computer (say A) to act as a gateway for another (say B) (both running Ubuntu Linux). I only need B to be capable to reach the router, that is only reachable for A.    This is the case:  Router for computer A  -->  192.168.0.1 Computer A - eth0      -->  192.168.0.2 Computer A - eth1      -->  192.168.1.1  Computer B - eth0      -->  192.168.1.2   Computer A connects fine to router. Computer A and B connect fine (ping, SSH... etc) between them. Computer B can not reach the router for computer A.    I was thinking that just adding on B Computer A as default gateway and activating IP Forwarding on A would make B to be able to reach the router for A:  luis@ComputerB:~$ sudo route add default gw 192.168.1.1 luis@ComputerB:~$ sudo routel  target            gateway      source        proto    scope  dev   tbl 127.0.0.0         broadcast    127.0.0.1     kernel   link   lo    local 127.0.0.0 8       local        127.0.0.1     kernel   host   lo    local 127.0.0.1         local        127.0.0.1     kernel   host   lo    local 127.255.255.255   broadcast    127.0.0.1     kernel   link   lo    local 192.168.1.0       broadcast    192.168.1.2   kernel   link   eth0  local 192.168.1.2       local        192.168.1.2   kernel   host   eth0  local 192.168.1.255     broadcast    192.168.1.2   kernel   link   eth0  local default           192.168.1.1                                eth0 169.254.0.0 16                                        link   eth0 192.168.1.0 24                 192.168.1.2   kernel   link   eth0   And on Computer A (the intermediate gateway):  root@ComputerA:~$ echo 1 > /proc/sys/net/ipv4/ip_forward   Computer B can still ping computer A, but router for A does not answer:  luis@ComputerB:~$ ping 192.168.0.1 PING 192.168.0.1 (192.168.0.1) 56(84) bytes of data. ^C   (No ping response)  Is this the correct procedure to make a computer running Linux to act as a gateway for another computer in a simple manner?


Creating a user without its account being disabled

Is there a way to create a new standard user, who can log in immediately? When I create users through a shell script, the users do get created, but they are disabled. Is there are way to create them so that they can log in without additional actions?  I use Ubuntu 16.04


What is the best way to store simple syrup, made from equal parts of sugar and water? Do I store it on the counter, or in the refrigerator?


U.S. college courses naming system -- how does it work?

:     ECO 305: Money and Banking   What do those three letters and the number exactly mean? Could you please give me a brief, general-terms type of introduction to the college courses naming system in the U.S. so that I at least have a basic idea of how this thing works?


Normally its easy to solving mean and covariance of Bernoulli Distribution but how we do when its Bernoulli Distribution vector in below Questions?

Maybe it's so easy to solve but I confused, Could anyone explain to me how can I solve these 2 questions?


Trying to boot and install ubuntu from USB

I'm trying to install ubuntu from a USB stick. I did it on my old computer, using the same stick, but this time I've replaced 14.05 with 16.04. I've tried choosing both the try ubuntu without installing and install ubuntu options. I get the loading screen, but then I get into initramfs:  BusyBox v.1.22.1 (Ubuntu 1:1.22.0-15ubuntu1) built-in shell (ash)  Enter 'help' for a list of build-in commands.  (initramfs) unable to find a live medium containing a live file system  I've tried formating the USB again and checking that I have the 64-bit desktop version. Any ideas?


Why bitlocker options are gone from one of my drive?

There is no such thing.  In managed bitlocker, everything is correct  Drive D has no difference with other drives. It is bitlocked. And unlocked, like usual.    Somehow the unlocked padlock icon doesn't show up on drive D but shows up on other drives.


Search traffic significant drop since HTTPS migration

My website has seen a dramatic drop in search engine traffic (over 50%) since swapping to https 2 months ago.   I have .htaccess rules for 301 redirects and since it is a Wordpress site, I also have a SSL plugin to change URLs on the website.   What could be causing this slump?


re.match in python to match pattern with string

I am trying to match string with mypattern, somehow I do not get correct result. Can you please point where am I wrong?   import re mypattern = '_U_[R|S]_data.csv' string =  'X003_U_R_data.csv' re.match(mypattern, string)


Meta analysis using the effect size based on mean and multiple outcomes

I have few questions on the meta analysis.  First, the data is longitudinal and according to the CMA (comprehensive meta analysis) guidebook "Working with more than two outcomes per study The formulas presented for a difference based on two outcomes can be extended to accommodate any number of outcomes using contrasts." My concern is how to choose proper contrast. The data shape is in a way that intervention shows better results for earlier time but both intervention and control have bouncing back effect and eventually get to similar results over time. So my first trial for the contrast was using same weight. For example, contrast 1 = T0-0.5T1-0.5T2 conrast 2 = T0-1/3T1-1/3T2-1/3T3 and so on. (Different studies have different time points). In this way I noticed that the equal weight contrast results in not significant differences. Would it be valid if I put more weight into earlier time points (T1,T2) and less weights to later time points (T3 and on)?


Star Trek: Routing of communicator calls

When we see an outgoing communicator call being made in Star Trek, the caller taps his commbadge and sais, e.g. "Picard to Riker." The answer is usually instantaneous.  When we see an incoming communicator call, the commbadge beeps and we hear the hailing message, i.e. "Picard to Riker." The called (Riker in this example) then answers.  My question:  Up until the last word of the hail is spoken, the commbadge does not know whom to call. Even if it temporarily stores the hailing message, relaying it as soon as the recipient is identified, shouldn't there be a pause on the caller's side of at least the length of the hailing message before the recipient even could answer?  (I fully understand why you wouldn't want to bore the audience with this, but is there any in-universe explanation I missed?)


I am confused between the two.     I demand that he leave!or I demand that he leaves!      I demand that this man leave!or I demand that this man leaves!   Which is correct with s or without and why?


How can I create a realistic stack of pages?

I'm really new to blender and one thing that I'm finding difficult is how to create pages on a notepad so when it is viewed from the side you can clearly see pages and image bleed (see picture in link).   I tried duplicating the plane 50 times but it didn't look good so I chose to extrude the plane to the final height of the notepad but now I can't figure out a way to split the sides so they look like they are pages.   This is what I want it to look like (more images ):    Any help would be greatly appreciated as I'm struggling to find a way to do this.  Thank you


Currently I need to highlight certain sections in PDFs, or add annotations (comments/notes). These modifications would need to be saved.   What tools are out there to do this on Ubuntu?


Taking ownership of an r-value reference

My goal is to take ownership of the temporary object created with Derived() in main() with BaseHolder. I'm getting an error at m_bases.push_back(base) because it invokes Base::Base() which is illegal because it's a purely virtual class, but I don't understand why it's invoked in the first place because my thinking is that the already constructed object would just be moved into m_bases. Is there a way to do what I'm trying to do here? #include <vector>  using namespace std;  class Base { public:     virtual void foo() = 0; };  class BaseHolder {     vector<Base> m_bases; public:     void add(Base&& base) {         m_bases.push_back(base);     } };  class Derived : public Base { public:     void foo() override {} };  int main() {     BaseHolder base_holder;     base_holder.add(Derived());     return 0; }


Expression to describe self-inflicted fall from a position of strength

Twelve months ago, Mr David Cameron — the British Prime Minister in government alliance with a smaller party — won a surprise outright victory in a general election. This put him in a position of considerable power. However he subsequently called a referendum on British Membership of the EU, campaigned for remaining in the EU, lost, and resigned. Is there an expression to describe squandering a position of such strength. “Shooting oneself in the foot” conveys the self-inflicted nature of his fall but does not convey the idea of squandering a strong position.  N.B. This is not a political question nor intended to invoke political discussion. There must be similar historical examples of this. I have stated what happened. I am looking for an expression to describe it.


I'm currently writing up some professional documentation and I know ending sentences with a preposition is frowned upon. Are there any English rules for converting these types of sentences that are more Grammarly correct?  An example is: "Session dates to search within."


how do you play world of tanks on ubuntu

how do you play wot on unbuntu.I`m new to linux os and know how to do about nothing on how to use it.


How is it, that $\sqrt{x^2}$ is not $ x$, but $|x|$?

As far as I see, $\sqrt{x^2}$ is not $x$, but $|x|$, meaning the "absolute". I totally get this, because $x^2$ is positive, if $x$ is negative, so $\sqrt{y}$, whether $y = 10^2$ or $y = -10^2$: $y$ is positive.  But then I remember that $\sqrt(x)$ is the same as $x^{1/2}$ and thus, $\sqrt{x^2}$ is the same as $x^{1}$.   So, as far as I get it, $\sqrt{x^2} = x^{2/2}$.  But then, I can cancel $\frac{2}{2}$ to $1$. So: $\sqrt{x^2} = x^1 = x$.  Where does the absolute value in this derivation of the calculation come from?  I get it why its there: Because $(-x)^2 = x^2$, so the radicand is always positive. But from $\sqrt{x^n} = x^{n/2}$ I dont understand how it gets there.


Parent and children relationships accessible via trigger?

I'm sure this has been addressed before but I can't seem to find the answer. In a trigger on a record, aside from the actual fields on the record, what do I have access to? The parent info? that record's children? Do you just add the fields by re querying in your handler?


Why there is no difference between / and ////// in bash path

ls -R /home/username/some/path   is the same as   ls - R /home///username/////////////some////path   Is there explanation for such interpretation of '/' character in bash?  I can't see implementation of ls program, but I can see my implementation of it:  #include <stdlib.h> #include <stdio.h> #include <sys/types.h> #include <sys/stat.h> #include <unistd.h> #include <fcntl.h> #include <assert.h> #include <unistd.h> #include <dirent.h> #include <string.h>   /* This program recursively prints files from given path. Should  be equivalent to ls -R /given/path call from shell, except we  don't concatenate '@' character at the end of symbolic link name,  '/' if directory entry is directory, we don't sort output etc.. */  static void error_fatal (char *message);  static void traverse (char *filename);  int main (int argc, char **argv) {  assert (argc == 2);  traverse (argv[1]);  exit (EXIT_SUCCESS); }  static void traverse (char *filename) { struct stat stats; DIR *dir; struct dirent *entry;     if (lstat (filename, &stats) < 0)     error_fatal ("lstat");    if (S_ISDIR (stats.st_mode)) {     printf ("\n%s:\n", filename);      if ((dir = opendir (filename)) == NULL)       error_fatal ("opendir");      if (chdir (filename) < 0)       error_fatal ("chdir");  // In the first pass, we print all directory entries.    while ((entry = readdir (dir)) != NULL)     {     if (!strcmp (entry->d_name, ".") || !strcmp (entry->d_name,       ".."))       continue;     printf ("%s\t", entry->d_name); }   putchar ('\n');    rewinddir (dir);    // In the second pass, we examine if entry is directory, and if so, recursively call traverse() function.    while ((entry = readdir (dir)) != NULL) {   if (!strcmp (entry->d_name, ".") || !strcmp (entry->d_name, ".."))     continue;    if (lstat (entry->d_name, &stats) < 0)     error_fatal ("lstat");    if (S_ISDIR (stats.st_mode))     {        char *a;       int size =     sizeof (char) * (2 + strlen (filename) +              strlen (entry->d_name));       a = (char *) malloc (size);       if (a == NULL)     error_fatal ("malloc");       if (getcwd (a, size) == NULL)     error_fatal ("getcwd");       strcat (a, "/");       strcat (a, entry->d_name);       traverse (a);       free (a);     }  }     if (chdir ("..") < 0) error_fatal ("chdir");    closedir (dir);  } }  static void error_fatal (char *message) {   perror (message);   exit (EXIT_FAILURE); }   uname -a gives me:  Linux mk-Inspiron-5570 4.15.0-43-generic #46-Ubuntu SMP Thu Dec 6 14:45:28 UTC 2018 x86_64 x86_64 x86_64 GNU/Linux   bash --version gives me:  GNU bash, version 4.4.19(1)-release (x86_64-pc-linux-gnu) Copyright (C) 2016 Free Software Foundation, Inc. License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html>  This is free software; you are free to change and redistribute it. There is NO WARRANTY, to the extent permitted by law.


How to increase the partition size of Ubuntu 14.04 installed under Windows 7?

I have windows 7 as primary OS. In past year I installed Ubuntu 14.04 from live USB. I don't use Wubi. Now I have to increase the partition /dev/sda6 size of Ubuntu.  user:~$ df -h Filesystem      Size  Used Avail Use% Mounted on /dev/sda6        16G   15G  275M  99% / none            4,0K     0  4,0K   0% /sys/fs/cgroup udev            3,9G  4,0K  3,9G   1% /dev tmpfs           785M  1,2M  784M   1% /run none            5,0M     0  5,0M   0% /run/lock none            3,9G  372K  3,9G   1% /run/shm none            100M   44K  100M   1% /run/user /dev/sdb1       279G  215G   64G  78% /media/user/035F3F68B14AD251   Update.  denis@denis:~$ sudo parted -l Model: ATA Samsung SSD 840 (scsi) Disk /dev/sda: 256GB Sector size (logical/physical): 512B/512B Partition Table: msdos  Number  Start   End    Size    Type      File system     Flags  1      1049kB  230GB  230GB   primary   ntfs            boot  2      230GB   256GB  25,6GB  extended  6      230GB   248GB  17,2GB  logical   ext4  5      248GB   256GB  8445MB  logical   linux-swap(v1)   Model: ATA Hitachi HTS54503 (scsi) Disk /dev/sdb: 320GB Sector size (logical/physical): 512B/512B Partition Table: msdos  Number  Start   End     Size    Type     File system  Flags  2      32,3kB  21,6GB  21,6GB  primary  ntfs  1      21,6GB  320GB   299GB   primary  ntfs         boot   And:  denis@denis:~$ lsblk NAME   MAJ:MIN RM   SIZE RO TYPE MOUNTPOINT sda      8:0    0 238,5G  0 disk  ├─sda1   8:1    0 214,6G  0 part  ├─sda2   8:2    0     1K  0 part  ├─sda5   8:5    0   7,9G  0 part [SWAP] └─sda6   8:6    0    16G  0 part / sdb      8:16   0 298,1G  0 disk  ├─sdb1   8:17   0   278G  0 part /media/denis/035F3F68B14AD251 └─sdb2   8:18   0  20,1G  0 part


The convergence of $ \lim\limits_{x\to\infty}\frac{f(x)}x=0$

Let $f$ be continuous such that $$\lim _{x\to \infty }\left(f\left(x+1\right)-f\left(x\right)\right)=0$$ show that $$\lim _{x\to \infty }\left(\frac{f\left(x\right)}{x}\right)=0$$  My idea was applying the sequential criterion for continuity: that if $f$ is continuous at $c$ if and only if for every sequence $x_n$ that converges to $c$, $f(x)$ converges to $f(c)$.  Also, I have the idea that since $$\lim_{x\to \infty }\left(f\left(x\right)\right)=\lim_{x\to\infty}\left(f\left(x+1\right)\right),$$ I can use it somehow in the demonstration, or am I wrong?


I have just started learning sums. I need to evaluate the following sum:  $$S_{n} = \sum_{k=1}^{n} \frac{1}{k(k+1)}$$  $$a_{1} = \frac{1}{2}, a_{2} = \frac{1}{6}, a_{3} = \frac{1}{12}, a_{4} = \frac{1}{20}, a_{5} = \frac{1}{30}, a_{6} = \frac{1}{42}, ...$$ I tried splitting it to partial fractions:  $$\frac{1}{k(k+1)} = \frac{A}{k} + \frac{B}{k+1}$$  $$1 = A(k+1) + Bk$$  $$1 = Ak + A + Bk$$  $$\begin{cases} A = 1 \\ 0 = A + B \quad \Rightarrow B = -1\end{cases}$$  $$\Longrightarrow S_{n} = \sum_{k=1}^{n} \Big( \frac{1}{k} - \frac{1}{k+1} \Big)$$  $$S_{n} = \sum_{k=1}^{n} \frac{1}{k} - \sum_{k=1}^{n} \frac{1}{k+1}$$  Wolframalpha gives answer $S_{n} = \frac{n}{n+1}$  Help's appreciated. P.S: Are the tags okay?


When I execute the following command:  #!/bin/bash while IFS= read -r -d '' file; do     files+=$file done < <(find -type f -name '*.c' -print0) echo "${files[@]}"   I do not get the same result as this one:  #!/bin/bash find_args="-type f '*.c' -print0" while IFS= read -r -d '' file; do     files+=$file done < <(find $find_args) echo "${files[@]}"   How can I fix the second scenario to be equivalent to the first one?  My understanding is that, because there are single quotes in the double quotes, the single quotes get escaped, which produces a bad expansion that looks something like that:  find -type f -name ''\''*.c'\'' -print0


How to programmatically download all contents of webpage, not only the source code in Java

I know how to download a webpage's source in java. But a webpage also contains image url, CSS and JS script url which need to be downloaded later like:  <LINK REL="STYLESHEET" HREF="htmlatex.css"> <img src=p10012.gif>   If I only download the source of a webpage, rendering it in offline mode will need to download this htmlatex.css and p10012.gif result in missing contents in offline mode. My objective is to download all contents of webpage programmatically and provide it as assets of an android app. HOw can I do that in java.  Note: please let me know if my question is not clear enough.


When kids reach a certain age they are shipped off to another planet

The kids are shipped to a different planet to survive for a certain period. I can remember there being a larger kid that had a gun and a dog for protection who ends up dead. In the end, the kids weren't actually shipped off to a different planet, but instead were on Earth the whole time.  I know it is not one of the Heinlein Juveniles books. Can anyone think of anything other than those books?


I understand that 2.675 rounds to 2.67 in python2. I understand WHY it rounds down instead of rounding up.  However, there is no case that I can think of where this is the desired outcome.   So, is there a better way to deal with this than defining my own round function?  def r2(n, d):   return round(n * 10**d) / 10**d   Is there a case where this will fail?  Also, how is this not considered a bug?


Lost partitions after accidently selecting "Erase entire disk" on Ubuntu install (but did not proceed with installation)?

I had an old Ubuntu installation (version 13), which had a partitioned drive, with /home mounted on a partition, and /data on another partition which I used to store my files. I wanted to install Ubuntu 14.04, but I accidently clicked on the "Erase entire disk" option, and now the old partitions are gone. I didn't proceed with the installation, so I except it to be recoverable. How can I recover what I had on /data?  Note that unlike a , I'm not sure what filesystem /data was. It could have been NTFS, but more probably it was ext4.  Thanks.


Let $w\in\mathbb{C}$ be a primitive 10th root of unity. What is $[\mathbb{Q}(w):\mathbb{Q}]$? Diagram the lattice of subfields of $\mathbb{Q}(w)$ giving generators for each.  So $w$ being a primitive 10th root of unity implies that $w^{10}=1$. We can rewrite the equation to be  $$ w^{10}-1=(x^5-1)(x^5+1)=(x-1)(x^4+x^3+x^2+x+1)(x+1)(x^4-x^3+x^2-x+1). $$ By Eisenstein's Criterion, we know that the factors of degree 4 are irreducible. So how do I use this to determine the index $[\mathbb{Q}(w):\mathbb{Q}]$?  I know for the lattice diagram I need to have the factors so is it enough to say, for example $\mathbb{Q}/(x^4+x^3+x^2+1)$, as a group of the diagram?


Who created the Borg concept?  Looking at  it is clear TNG had already started without the Borg as such, but with the idea that a new powerful adversary was needed.  This article suggests a collective effort in realising the Borg by the writers, but in reality it is usually one or two people who are initially responsible for a concept.  Is there a named person (or persons) responsible for the Borg, such as Gene Roddenberry and Leonard Nimoy were for the Vulcans initially or Branon Braga for Species 8472?


How can I enter the symbol in picture, which is like “O”,  in Latex? The symbol means "proportional to" in mathematics.  Thanks in advance.


Apex CALLOUT_REQUEST is failing with System.CalloutException: Read timed out

Our endpoint is an https request.       |CALLOUT_REQUEST|[217]|System.HttpRequest[Endpoint=https:[intentionally left off]   The logs show:     |EXCEPTION_THROWN|[217]|System.CalloutException: Read timed out   We have already tested the https request externally from Salesforce and determined that 21/24 requests will fail with a timeout of 10 seconds.  As the time taken varies from 10 seconds to 18 seconds.  We are thinking of increasing the timeout to 20 seconds by setting a custom timeout in Apex.   The default timeout is 10 seconds as I understand it.    Would this work?


Did Neo die in the end of the Matrix trilogy?

Towards the end in The Matrix Revolutions, Neo is jacked by the machines into the Matrix to fight Agent Smith. During the fight, Smith seems to have killed Neo then we see the machines pumping a charge into Neo to revive him. Neo however doesn't seem to be active inside the Matrix anymore and just explodes into light.  We then see his physical form being set down by the machines. Is Neo at this point actually dead or is he just unconscious?


Light is clearly affected by gravity, just think about a black hole, but light supposedly has no mass and gravity only affects objects with mass.  On the other hand, if light does have mass then doesn't mass become infinitely larger the closer to the speed of light an object travels. So this would result in light have an infinite mass which is impossible.  Any explanations?


When I \cref an algorithm, it shows "algorithm 1". Is it possible to ref an algorithm with its numbering and caption? Like "algorithm 1 foo", where "foo" is the caption of algorithm 1. Thanks a lot


Prove that $p\mid \binom{p}{k},\ 0< k< p$

Prove that:   $$p \,\,\left|\, {p \choose k} \right., \quad 0< k \lt p$$   if $p$ is prime.   how to prove that with direct proof?


Constructing a Galois extension field with Galois group $S_n$

Given a field $F$, can you necessarily construct a field extension $E \supset F$ such that $\operatorname{Gal}(E/F) = S_n\,$?


Show $A\cap(B\cup C)=(A\cap B)\cup (A\cap C)$

For sets $A,B,C$ not equal to $\emptyset$ prove that $$AXB=BXA$$ $$\iff$$ $$A=B$$


My almost 5yr old son won't poop in toilet..about to start school

I have 4 kids, (12,7,5) are boys and an almost 3yr old girl. The oldest two were completely potty trained around 3yrs old. My biggest problem right now is my almost 5yr old son who still to this day won't poop in the toilet. I have tried candy, stickers, everything. I have tried underwear, and there's always poop in it. He is still wearing pull ups. He will 'hide' in his room, then come out smelling really bad. I would love to put him in kindergarten in the fall...I just can't do it with him pooping in his pants. Half the time when I ask him 'do you have poop in your pull up' he says 'no' and I check him and he's dirty. Please any suggestions would be greatly appreciated.