How many squares on a 5-foot grid does a 5-foot radius spell affect?

We had a situation come up regarding this term and how it affected spells.  In the spell Moonbeam, for example, it says a 5-foot radius cylinder appears. Does this mean that from the center of square it extends 2.5 feet into the next square hypothetically hitting up three squares or does this mean from the edge of one the target square to the five feet and five feet the other direction effectively covering only two squares for a total of 10 feet between total range of both squares?  I understand that radius means half the distance of a circle from the center point. The spell is not the issue but the understanding of radius as it pertains to the spell, as there are other spells that are worded similarly such as Fireball, etc.  Essentially we are asking, does the spell in the example effect one square or three? This would be saying the edge of the initial square is the point of origin and not the center of the square for the total distance of ten feet.  I had been working under the understanding that the radius is half of the distance and therefore dragging a ruler from the center of where I want the spell to take effect would get me the area of effect.  It's much easier to do this with Fireball, due to the larger area to effect, but this one has such a small area and therefore sparked the debate. We are using a grid system to mark the distance, etc. We play within the digital realm of roll20.com.


My problem is the following:  I decided to do an apt-get dist-upgrade. At first it said that it had to remove a lot of programs, which seemed a little suspicious, but I trusted the upgrade system. I said to myself "well, maybe there are dependencies issues, and it's easier for the update system to remove those programs and install the newer ones. We are in the year 2015, it probably knows what it's doing". Well, it didn't, since it deleted the OS basically.  So now my problem is the following: I can't recover my personal files because my home folder is encrypted, and I don't have the mount passphrase, only my user password. I searched all the web but I couldn't find anything that solved my problem. I tried booting from a live-cd and recover the passphrase with ecryptfs-unwrap-passphrase but it was worthless, because when I try, it asks me for my... passphrase (I tried my user password but it didn't work out). I also tried using  script, but it only outputs unrecognized characters.  I tried the approaches suggested  but eventually they didn't work out, basically when I'm asked for my passphrase, which I couldn't recover yet with any of those methods.  Any suggestions?    EDIT: @zhongfu  I did that, and I get the following:  INFO: Found [MYUSER]. Try to recover this directory? [Y/n]: y INFO: Could not find your wrapped passphrase file. INFO: To recover this directory, you MUST have your original MOUNT passphrase. INFO: When you first setup your encrypted private directory, you were told to record INFO: your MOUNT passphrase. INFO: It should be 32 characters long, consisting of [0-9] and [a-f]. Enter your MOUNT passphrase:   so we are back at square one. So I went to /media/xubuntu/f6c13be2-8045-4ec6-b1af-c1f2524de4ed/home/.ecryptfs/MYUSER/.ecryptfs and there is a file called wrapped-pashprasse, so apparently there is a wrapped passphrase, and I don’t know why it said that it couldn’t find it earlier. Next I did ecryptfs-unwrap-passphrase, I enter my account password, but I get the same result. I don't know what else to do.  I opened the wrapped passhprase file with gedit and got strange symbols mixed with hex values. If I could see correctly what characters the strange symbols are encoding, I could get the passphrase, but I don't know how.  I was thinking, maybe if I could get the binary representation of that file, I could convert those symbols into hex by myself, right?


Do we have the potential technology to harness the energy the Earth is constantly giving us?

Messing around with fun physics, and it got me thinking. I probably am not the only or the first one to think of it. I am wondering what more experienced physicists on this site can contribute to this thought experiment.  We are constantly moving because earth is constantly rotating on its axis. Using quick numbers and assuming.. a lot of things. Is there a way, and do we have the technology to harness the energy the earth constantly exerts on us?  I am a 95kg adult, and assuming I am at the equator I have a linear velocity of about 463m/s.  Using the $$v_{linear}=\frac{\Delta x} {\Delta t}= \frac{2 \pi R}{86400s} = \space \sim463\space m/s $$  This gives me a Kinetic energy of $\sim 1.03 \times 10^{7}J$  Spanning over the time period of a day on the earth, I assume, gives me about 118 watts of power per second.   What are some the pros and cons to this thought?


Is it possible to pass on Event exclusive moves through breeding?

Someone on a trading group offered me an 'Event Pikachu', which was a Pikachu that knows Surf (normally impossible to teach to Pikachu).  Unfortunately it was a previous Generation's Event, and as such doesn't count as a 'Kalos-Born' Pokemon for tournaments/rating battles and the like.  So assuming I got a hold of it, could I breed this Pikachu to get a Kalos-born Pikachu with Surf?


Is it possible to get data off of a dead PS3?

Is it possible to get the data off of the hard drive of a PlayStation 3 that has crashed? I have already voided the warranty so I am not worried about that and I have access to quite a few tools.   I have a new PlayStation and a few saves that were not backed up. I am not worried about them but if it is possible I would love to get it moved over.   The old PlayStation will not turn on at all and I think I am going to have to pull the drive. My main concern is if I am able to transfer the files without running into any issues. I have heard that some of the stuff is specific to each PlayStation, is that true?


" this kernel required an X86-64 CPU, but only detected a i686 CPU"

I recently decided to use Virtualbox to run Ubuntu, but I get the message     this kernel required an X86-64 CPU, but only detected a i686 CPU   I've already enabled virtualization in BIOS, but that doesn't seem to work. Many other solutions suggest that I should download the 32-bit version, and not the 64-bit. I'm not sure about that though, since my computer clearly says "64-bit operating system" under systems. But I might just be mistaken.


Why does Firefox developer edition use chrome:// urls to load scripts?

I just downloaded a copy of the new Firefox Developer Edition browser and started to fiddle around with the dev tools.  I noticed that some of the links and scripts were loaded over chrome:// urls, which I thought were registered for Google Chrome.    Here are some of those lines in specific.  <link id="favicon" rel="icon" type="image/png" href="chrome://branding/content/icon32.png"></link> <link rel="stylesheet" type="text/css" media="all" href="chrome://browser/content/searchSuggestionUI.css"></link> <link rel="stylesheet" type="text/css" media="all" defer="defer" href="chrome://browser/content/abouthome/aboutHome.css"></link> <script type="text/javascript;version=1.8" src="chrome://browser/content/abouthome/aboutHome.js"></script> <script type="text/javascript;version=1.8" src="chrome://browser/content/searchSuggestionUI.js"></script>   I wondered whether they were hijacking chrome assets, but after checking out one of those scripts, I found a Mozilla comment.  /* This Source Code Form is subject to the terms of the Mozilla Public  * License, v. 2.0. If a copy of the MPL was not distributed with this  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */   I don't know much about custom protocols or how they are registered or used. What's going on here?


Series of books featuring dragons, enchanted forests, magic swords, etc

When I was younger I read a series of 3 or 4 books involving largely traditional mages/dragons/enchanted forests.  I'd like to buy it for some of my younger extended family members but I can't remember the name of it.  Here's what I remember from this:   I read the last book first, in which the son of a woman turned out to be largely one of the main characters in the other books takes an enchanted sword into a forest on a quest to do something. At one point in one of the earlier books the group was travelling through a swamp like area to get to a tower where a witch(or mage lived). There was a king (possibly the son's father) who was frozen in a castle during the last book. The evil mages/witches would melt (but not die) when some spell was cast on them. I read the series circa 1992 (estimated), comparable to the DragonLance series it was geared towards a younger audience (I don't remember any sex/brutal slayings of anyone). I believe in the first book the mother of the son in the last book runs away from home and becomes something of a maid to a dragon. I can't remember if there were evil dragons or not, I seem to remember that at least some of them were good (or at least largely neutral).   If I think of any other details I'll add them.


Why is the potential drop zero across a wire of zero resistance?

Okay, even if the wire has zero resistance, then charges are being transferred in the direction of electric field, which means there must be a potential drop according to the distance travelled by the charges in the direction of electric field. But, in my book, as it is explained, it seems like the potential remains constant throughout the journey of the charge and that it abruptly changes when the charge reaches the other end of the battery. Well, that's just like saying that a body dropped from a height has an abrupt potential drop when it reaches the ground and has no potential drop along its journey if there is no air friction.  I think the potential drop still happens. The difference is only that in case of an ideal wire, the potential drop corresponds to the increase in kinetic energy of the electrons, because the electrons can accelerate forever in this case when there are no positive ions to collide to, while in case of a real wire, the potential drop mostly corresponds to the heat developed.


How can I view my partition sizes and mount points?

I'm running Ubuntu 16.04.3 LTS. The installation was done by a computer shop (I had a faulty hard drive, which they replaced). I'd like to see if they set up my partitions as I requested. How can I view the partition sizes and mount points?


Why does an open interval NOT have measure zero?

I am currently working on a proof that requires me to show that an open ball $B_{\epsilon}(x)$ has nonzero measure. I currently have the following proof in my book:  "The closed interval $[a,b]$ is not of measure zero."  Hence, if I take the contrapositive, does it follow that "if an interval doesn't have measure zero, the interval is open"? Is there a way for me to prove that the open interval on the line $\mathbb{R}$ is of measure not zero? Thanks!


Can't format or delete partitions in pendrive because of GPT table error

This is what I got while trying to format a partition in my pendrive:     Error deleting partition /dev/sdb1: Command-line parted --script "/dev/sdb" "rm 1"' exited with non-zero exit status 1: Warning: /dev/sdb contains GPT signatures, indicating that it has a GPT table.  However, it does not have a valid fake msdos partition table, as it should.  Perhaps it was corrupted -- possibly by a program that doesn't understand GPT partition tables.  Or perhaps you deleted the GPT table, and are now using an msdos partition table.  Is this a GPT partition table?      Error: Both the primary and backup GPT tables are corrupt.  Try making a fresh table, and using Parted's rescue feature to recover partitions.  (udisks-error-quark, 0)


How to declare a variable inside bash -c

I can't figure out how to declare a variable inside bash -c command.   bash -c "var=3; echo $var"


Let $p$ be a prime number. Prove that there exists $x∈Z$ for which $p|x^2−x+ 3$ if and only if there exists $y∈Z$ for which $p|y^2−y+ 25$.   I've copied the question verbatim from an elementary number theory assignment.  I'm not making much ground on it, but here's what I've determined so far:  Each equation is based on the following sequence:  x^2 - x: 0, 2, 6, 12, 20, 30, 42, 56, 72, ...   I'm not sure what to call this type of sequence, but I'm thinking of it as a sequence with an acceleration of $2$, as in, each number on the sequence is increased by a number which is increased by $2$ each iteration.  The only difference between the two equations is the starting point of the sequence: one starts at $3$ while the other starts at $25$.  This is how I have been thinking about the problem but unfortunately I think I'm working in the wrong direction.  If anyone could help me move in the right direction of this problem, I would appreciate it


Formula that returns the current day of the week

In Salesforce Trailhead there is one Challenge available. Please find the challenge description below  To complete this challenge, use some of the strategies and function you learned in this unit to return the day of the week as a text string.   The formula should be on the Contact object The formula should be of return type Text The formula should be named 'Day of the Week' with the resulting API name 'Day_of_the_Week__c'.     The formula should return the day of the week as a string—”Monday,” “Tuesday,” and so on   I tried the following formula  CASE(MOD( TODAY() - DATE(1900, 1, 6), 7), 0, "Saturday", 1, "Sunday", 2,"Monday", 3, "Tuesday", 4, "Wednesday", 5, "Thursday", 6,"Friday","")   It returns the following error     Challenge Not yet complete... here's what's wrong: The   'Day_of_the_Week__c' is not reporting the correct day of the week   (Monday, Tuesday, etc.)   What is the problem ?


NullPointerException in getter with FirebaseDatabase, retrieving data causes NullPointExeption

I have this problem with my code I don't know what to do about it. I'm trying to get a text from my firebase database but I ran at NullPointerExeption. Can you help?  My codes:  ImageAdapter  This is the line where it calls NullPointerExeption:  holder.textViewDescription.setText(uploadCurrent.getDescription());  java.lang.NullPointerException: Attempt to invoke virtual method 'java.lang.String com.example.firebasecarview.Upload.getDescription()' on a null object reference  public class ImageAdapter extends RecyclerView.Adapter<ImageAdapter.ImgViewHolder> { private Context mContext; private List<Upload> mUploads;   public ImageAdapter(Context context,List<Upload> uploads){     mContext = context;     mUploads = uploads; } @NonNull @Override public ImgViewHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {     View v = LayoutInflater.from(mContext).inflate(R.layout.cardview,parent,false);     return new ImgViewHolder(v); }  @Override public void onBindViewHolder(ImgViewHolder holder, int position) {     Upload uploadCurrent = mUploads.get(position);     holder.textViewDescription.setText(uploadCurrent.getDescription());     Picasso.with(mContext).load(uploadCurrent.getImgUrl()).placeholder(R.mipmap.ic_launcher).fit().centerCrop().into(holder.imageView); }  @Override public int getItemCount() {     return mUploads.size(); }  public class ImgViewHolder extends RecyclerView.ViewHolder{      public TextView textViewDescription;     public ImageView imageView;      public ImgViewHolder(@NonNull View itemView) {         super(itemView);          textViewDescription = itemView.findViewById(R.id.card_description);         imageView = itemView.findViewById(R.id.imageView);     } }   Upload  public class Upload { private String mDescription; private String ImgUrl;  public Upload(){     //needed }  public Upload(String description,String imageUrl){     if (mDescription != null && mDescription.equalsIgnoreCase("")) {        mDescription = "no name";     }      mDescription = description;     ImgUrl = imageUrl; }  public String getDescription(){     return mDescription; }  public void setDescription(String description){     mDescription=description; }  public String getImgUrl(){     return ImgUrl; }   public void setImgUri(String imageUrl){     ImgUrl=imageUrl; }


Blacking out a part of a PDF, or redaction of text

What methods are there to blackout a part of a PDF?  I don't want to simply use Preview's annotation tools and then save the document, since then someone could open up the PDF and remove the annotation to reveal the part of the document which I'm trying to black out.


Check if elements of 2 lists are matching or not even if its uppercase or lowercase

Im having 2 lists. Looping list2 and checking if list1 elements exists in list2 or not.But my below code is checking for only exact match and not considering upper case or lower case elements like Date, CIRCUIT  list1 = ['circuit', 'Date', 'common', 'discover'] list2 = [('id-23', 'po'), ('id-24', 'date'),('id-25', 'CIRCUIT'), ('id-26', 'discover')]  for i, a in list2:     if a in list1:         kia = i,a         print(kia)   Output im getting is ('id-26', 'discover')  expected output should be ('id-24', 'date'), ('id-25', 'CIRCUIT'), ('id-26', 'discover')


$I$ is a separable closed ideal of $A$. Does $I$ always have sequential quasicentral approximate unit?

Let $e_\lambda$ be an approximate unit of $I$. Say $e_\lambda$ is quasicentral if for every $a\in A$, $e_\lambda a-ae_\lambda\to 0$. I have shown that when $A$ is separable, $I$ has sequential quasicentral approximate unit $\{e_n\}$ with $e_ne_{n+1}=e_n$. Here is the proof: Let $e_\lambda$ be an arbitary approximate unit of $I$. for $\lambda$ and $\mathcal F\subseteq_{finite}A$ , define $H_\lambda$ to be the convex hull of $\{e_\eta:\eta\geq \lambda\}$ and define $S_{\lambda,\mathcal F}=\{\bigoplus_{a\in\mathcal F} (ha-ah):h\in H_\lambda\}$. Then the norm closure $\overline{S_{\lambda,\mathcal F}}$ contains $0$. Therefore there is an element $h\in H_\lambda$ such that $\left\|\bigoplus_{a\in\mathcal F}(ha-ah)\right\|<1/n$, where $n=|\mathcal F|$. Denote by $h_{\mathcal F,\lambda}$ such $h$. Assume $h_{\mathcal F,\lambda}=\sum \alpha_ie_{\eta(i)}$ ,write $r(h_{\mathcal F,\lambda})=\max_i\eta(i)$, and define : $$(\mathcal F,\lambda)\leq (\mathcal G,\eta)\Leftrightarrow \mathcal F\subseteq \mathcal G\text{ and } r(h_{\mathcal F,\lambda})\leq \eta $$ Then $h_{\mathcal F,\lambda}$ is a quasicentral approximate unit. When $A$(or $I$) is separable, $e_\lambda$ can be chosen to satisfy that $\lambda\in\mathbb N$ and $e_ne_{n+1}=e_n$. Then $h_{\mathcal F,\lambda}h_{\mathcal G,\eta}=h_{\mathcal F,\lambda}$ when $(\mathcal F,\lambda)\leq (\mathcal G,\eta)$.Again since $A$ is seqarable, there are $\mathcal F(n),\lambda(n)$ such that $h_n=h_{\mathcal F(n),\lambda(n)}$ forms a sequential quasicentral approximate unit. However, if $I$ is separable while $A$ is not, I don't know how I can modify the proof to get a sequential quasicentral approximate unit with $e_ne_{n+1}=e_n$.


Can we make mailing address in contact object read only?

Is it possible to make mailing address in contact object read ony ?.  Tried to do from the layout but still the mailing address is editable.


Ubuntu boots from USB but get GRUB rescue after installation

I can boot Ubuntu from USB, but when I took the USB stick out of the laptop and booted again, I got an error saying   Error: unknown filesystem. grub rescue>   What can I do to fix this?


Strange output from RSAGA topographic wetness index?

I am trying to generate a topographic wetness index raster with the RSAGA package in R. The output I am able to generate does not make sense to me, as it has a large number of NA cells and I wonder if I am doing something wrong. I have put together a simple dummy example to illustrate what I mean.  Session info: I am running R 3.2.3 on Ubuntu 15.10. I have SAGA v2.2.0 installed, as well as RSAGA v0.94-5.   library(RSAGA) library(raster) library(maptools)  #get DEM for Switzerland alt <- getData('alt', country='CHE')  # write to SAGA format tempInfile <- 'saga_temp_twi_in' writeRaster(alt, filename=tempInfile, format='SAGA')  outfile <- 'saga_temp_twi_out.sgrd' call <- rsaga.wetness.index(in.dem='saga_temp_twi_in.sgrd', out.wetness.index=outfile, env=rsaga.env(modules='/usr/lib/x86_64-linux-gnu/saga/'))  #read resulting file back in res <- raster('saga_temp_twi_out.sdat')  par(mfrow=c(1,2)) plot(alt) plot(res)


Is icloud drive on desktop storing file on my locally or on the cloud?

Question is simple, i subscribe to a 200GB icloud drive. My desktop has 60GB available for storage (on SSD)  Will i be able to fill my icloud drive with data from my dying USB external drive, and can you explain me how to do that ? (i just put 20GB from my external drive to C:\mysuser\icloudrive\stuffs\ and now i only have 40GB available on my windows 7 C:\ ), 180Go remain to be transfert, how can i do that ?


How to share the "Look Back" video from Facebook?

On Facebook, there is a  looking back on your Facebook history. Apparently, some people have shared this video with their friends, however I and someone else cannot figure out how to do so. This URL is not unique, it's a global URL which shows the video of who's logged in. People say there's supposed to be a "share" link, but there are no links whatsoever. And, I can't share the URL because it would show them their own videos.  How do I share this video with friends on Facebook?  without using a screen recorder to capture it


sum of positive elements of relatively convergent series

If a series is relatively convergent, what can we say about the sum of all its positive elements? Will it be also convergent?


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


Showing that a group of prime order is in the center of a $p$-group.

Let $N $ be a normal subgroup of order $p$ contained in a group $G$ of order $p^n$. Here $p$ is a prime number. Then I have to show thst $N$ is in the center of $G$.  This is an exercise 15 in p.92 of Hungerford.   I thought of acting $G$ on $N$ but cannot find a way through.  Could anyone please help me?


Let $(u_n)_{n \ge1}$ such as $u_1=\frac12$ and $(\forall n \ge2):u_n=(1-\frac3{2n})u_{n-1}$. Find the value of $\displaystyle \sum_{n=1}^{\infty}u_n$. This is my try : We can rewrite it as $\displaystyle u_n=(-1)\cdot\frac{\frac32-n}{n}\cdot u_{n-1}\Rightarrow\prod_{k=2}^nu_k=(-1)^{n-1}\cdot\prod_{n=2}^n\left(\frac{\frac32-n}n\right)\cdot\prod_{k=2}^nu_{k-1}$. It is clear that $(\forall n \ge 0): u_n \neq 0$, thus we have $ \displaystyle u_n=(-1)^{n-1}\prod_{k=1}^n\left(\frac{\frac32-k}k\right)$. Using the fact that $\displaystyle \binom{p}{q}=\prod_{k=1}^q \frac{p+1-k}k$ with $p=\frac12$, we now have $\displaystyle u_n=(-1)^{n-1}\binom{\frac12}{n}$. Thus $\displaystyle \sum^\infty_{n=1}u_n=-(-1)^{-1}\binom{\frac12}{0}+\sum^\infty_{n=0}(-1)^{n-1}\binom{\frac12}{n}=1+\sum^\infty_{n=0}(-1)^{n-1}\binom{\frac12}{n}$, but here I'm stuck because i wanted to use the Newton's generalized binomial theorem yet it is not possible here.... Any help please ?


Grey out all unused vote buttons on old elections

I'm hoping this is a "quick fix", but it's far from a priority. A small change might help a lot here. I got some egg on my face yesterday when I . A new user thought the same thing and had asked in chat. It turns out that's by design  Look at the candidates you voted for. The '1st', '2nd' and '3rd' choice buttons look different there; here are the buttons on the candidate I voted for as second choice:  Unless I get shown a candidate I did vote for, my screen looks like this  While voted candidates show like this (note 1st and 3rd are greyed out)  I would like to see all the buttons, save ones I used to vote for, shown as greyed out. It would make it visually obvious that one cannot cast a new vote.


Abstract algebra: homomorphism and kernel from $\Bbb Z$ to $S_{3}$

1) Assume that there exist homomorphisms $f:\mathbb{Z} \rightarrow S_{3}$ where $\ker(f)\neq \mathbb{Z}$? What are the possible kernels? Explain. 2) Lest at least two non-trivial homomorphisms $f:\mathbb{Z} \rightarrow S_{3}$ whose kernel are not $\mathbb{Z}$.


Parse a html string for latex expressions using C# regular expressions

I have the following html string that I need to parse for all latex expressions using regular expression.  A latex expression is anything that is delimited by $$ or \$. For example, $$x^2-x+1 = 0$$ and \$x=34\$ are latex expressions in html string below..
$$x^2-x+1 = 0$$

Another example of inline Latex is \$x=34\$.$$x^2-5x+3 = 0$$
 What are the roots of following equation: \$x^2 - 2x + 1 = 0\$?
   My aim is to get all latex expressions in above string. For this I have used these regular expressions. (I have used the online regex tester at [Regex Storm].   ((\\$)[\W\w]+(\\$)){1} to get latex expressions delimited by \$ ((\$\$)[\W\w]+(\$\$)){1} to get latex expressions delimited by $$   Even though I am getting a match with above regular expressions as in screen shots below, but its not matching multiple regular expressions.  Question  What is missing in my above regular expressions that is causing it to not match the multiple latex expressions that are present in the given html string?  First Regular expression matches   Second Regular expression matches


Evaluation of $\sum_{k=0}^n{n\choose k}^2u^k$

I am trying to evaluate the finite sum \begin{equation} f(u)=\sum_{k=0}^n{n\choose k}^2u^k,\quad 0<u\le1 \end{equation}  In an first attempt, I think of the generating function \begin{equation} (1+x)^n(u+x)^n = \sum_{k\ge0}{n\choose k}x^k\sum_{k\ge0}{n\choose k}u^kx^{n-k}=\cdots+x^n\sum_{k\ge0}{n\choose k}^2u^k+\cdots \end{equation}  which means that $f(u)$ is the coefficients of the term $x^n$.  Expanding $(1+x)^n(u+x)^n$ into $[1+(1+u)x+x^2]^n$, and using the multinomial expansion, I get an expression for the coefficient of $x^n$. However, such an expression is more complicated than $f(u)$. It seems I am making the problem even more difficult.  Can someone help me find the value of $f(u)$.  Thank you.


Consider the function $f: (0, 1) \to \mathbb{Q}$ defined by $$f(x) = \begin{cases} 0, & x\text{ irrational} \\ 1/q, & x = p/q\text{ in lowest terms.} \end{cases}$$ The problem is to show that $\lim\limits_{x \to a}f(x) = 0$, using $\delta$-$\epsilon$, for all $a \in (0, 1)$. That is, for all $\epsilon >0$ there is a $\delta > 0$ such that for all $x$ satisfying $0 < |x - a| < \delta$, $|f(x)-0| <\epsilon$.  If $x$ is irrational, this is trivial. Edit: as discussed in the comments, this isn't as trivial as I thought it was.  But what if $x$ is rational? Then $f(x) = 1/q$ as shown above, so $$\left|\dfrac{1}{q}\right| < \epsilon\text{.}$$ I'm used to $\delta$-$\epsilon$ problems where I can "work backwards" to find $\delta$, but obviously $1/q$ isn't a function of $x$, and I'm lost as to what to do here. I sort of understand the discussion in Spivak, but I'm not quite getting how the discussion helps me find $\delta$, so I thought someone here could enlighten me.  As mentioned in the comments, I don't agree that this is a duplicate.


Where can I find X-01 power armor pieces?

I've been playing Fallout 4 for quite a while now and I haven't got any X-01 power armor pieces yet. I've only got the helmet from the brotherhood ship. I'm level 32 and I haven't got one set yet.   I've checked the following locations: 35 Court, Federal Surveillance Center K-21B in the Glowing Sea, the pond around Jamaica Plain and Nordhagen Beach. What I found was T-51, T-45 and T-60. Where can I find X-01 pieces scattered around the map?


I've started taking security more seriously lately. (Why only now you may ask? Because I'm a trusting fool that's why.) I've now got emails signing automatically and encrypting where I have their key.   Previously I only did this when necessary, but I'm trying to breed a sense of change around me and taking my own medicine seems sensible. I have no issue with GPG in Thunderbird, Outlook, or on Android with K9 Mail & APG, but I have no idea how to handle GPG on IOS.   I can't accept there's no way, it seems ridiculous, or maybe I'm approaching the problem wrong and there is a more appropriate route than GPG that's better supported?


Configure forward search with Texmaker + SumatraPDF

Texmaker has a Built-in pdf viewer which supports synctex forward/inverse search out of the box. This Built-in viewer can be displayed embedded or in a separate window, external viewers always have a separate window. As I have two screens, I am using the two-window layout.  Now I would like to switch to  as external viewer, but cannot find how to configure Texmaker to get Forward search working. I have filed a  to add that information to the  already. Does someone here know how to do it? Probably using some ...


Why is it commonly said Angular momentum for ground state is zero (for system with rotation invariant potential)?

Neglecting any effect of spin,it is a well known fact,that orbital angular momentum of a system in ground state is zero.(For potential $V=V(r)$ .)  The angle-angular momentum uncertainty,gives $\Delta{L}\Delta{\phi}\ge\hbar/2$ , where $\Delta$L=$\sqrt{<L^2>-<L>^2}$.Now,<$L^2$>=$l(l+1)=0$(Since,$l=0$ for ground state).Therefore the uncertainty relation to be valid, expectation of Angular momentum <$L$>should be non-zero,and...non-real too!Why is this happening?


Showing pop up when internet connection is lost in php

I have simple php mysql data running page. with bootstrap.  How can i display an error when connection is lost?  How about popping up and modal as connection is lost & also trying to get connection & as connection gets back the modal disappears.   I have following modal:

              <button type="button" class="close" data-dismiss="modal"> x </button>
ERROR

You have lost connection
 Trying again...


iPad app where possible draw, save for reuse and drop 'objects' on canvas for prototyping and to make mockup

For prototyping / mockup needs, I want an iPad app where it's possible to draw, save and drop 'templates' on a canvas. Something similar to , where there is a collection of components that can be placed on canvas, but with the ability to create my own components by drawing and saving for later reuse.


Assuming I already have a D, P, Q, etc of an RSA key: How do I now sign a message? If it matters – the message is around 100 bits.  I don't know much about cryptography, but I can get these numbers generated by a computer. Unfortunately, in my scenario – I can't use the built-in functions to use these numbers.


Link to the pending review after the edit is submitted

Thanks for your Edit!   This edit will be visible only to you until it is peer reviewed.   I'm sure you've seen that, somewhere at some time in the past.  Those who know, can go to their own profile, activity, suggestions (or all) and then click on the suggested edit link for the most recent edit.  Granted, thats a few clicks.  For those that don't know all the ins and outs of the profile, this is just a statement that reads much like "Thank you for your call, your call is important to us."  The request is to provide a glimpse into the "where is this suggested edit" in the process? Just make that "peer reviewed" a link to the review task that was generated.  It becomes much easier for those who go back to the post and wonder why the review is taking so long on a site and it helps introduce the peer review process (this isn't random people clicking random buttons most of the time).


Installation of Ubuntu 13.04 desktop (i386)

I am trying to install "ubuntu-13.04-desktop-i386.iso" on a Dell optiplex gx270.  I used "Universal-USB-Installer-1.9.3.5" to get it on an external Seagate Freeagent USB harddrive.  No problem.  I attach to Seagate to the desired computer to install Ubuntu and it boots to the USB with no problem.  The screen hangs with the Ubuntu logo for a while, then I get the error message:  (initramfs) unable to find a medium containing a live file system   Please can anyone help me with this?


What is the distribution of the sum of non i.i.d. gaussian variates?

If $X$ is distributed $N(\mu_X, \sigma^2_X)$, $Y$ is distributed $N(\mu_Y, \sigma^2_Y)$ and $Z = X + Y$, I know that $Z$ is distributed $N(\mu_X + \mu_Y, \sigma^2_X + \sigma^2_Y)$ if X and Y are independent.  But what would happen if X and Y were not independent, i.e. $(X, Y) \approx N\big( (\begin{smallmatrix} \mu_X\\\mu_Y \end{smallmatrix}) , (\begin{smallmatrix} \sigma^2_X && \sigma_{X,Y}\\ \sigma_{X,Y} && \sigma^2_Y \end{smallmatrix}) \big) $  Would this affect how the sum $Z$ is distributed?


Can my surname under which I publish differ from the one on my passport?  I was thinking of publishing under "Miller-Hendrix" instead of just "Miller".


I am a bit confused by how Python handles variable scope. Below is a simple example that I created to explain the varialbe scope. When I execute the code below, the reference error surprisingly happens at the line print(x) instead of x = x + 1. def foo():     print(x)     x = x + 1  x = 0 foo()  I would assume at the line print(x), Python should have access to the x in the global scope, no? (In fact, if we comment out the line x = x + 1, the code actually runs) How exactly does the Python intepreter work here?


To find the probability whether $X$ is rational

I was thinking whether I can replace this sum by an integral , because I can't think of a distribution whose mgf looks like this. Please Help!


Force iPhone to remember "don't trust" setting when connecting to computer

Every time I plug my iPhone into one of my computers to charge it, it prompts me to trust or don't trust. How do I force it to remember he don't trust setting? I don't want this specific computer to ever be trusted, and I don't want it to ask me every time.  All searches I've found relate to how to reset the warning dialog in case you've chosen the wrong option by mistake.  It's running iOS 10.3.3


Can I get all boarding passes on an India-Germany-USA multi-leg flight?

I have a flight from Mumbai to North Carolina.  It will start from Mumbai to Frankfurt  Frankfurt to Munich  Munich to Charlotte.  Can I get the boarding pass for all flights from Mumbai airport, if not can I get both the boarding pass from Frankfurt (Frankfurt to Munich and Munich to Charlotte)


I forgot the password to my ssh. I am planning to remove the files (id_rsa, id_rsa.pub and known_hosts) in the directory and starting from scratch. I haven't been using ssh since the whole heartbleed thing and I've cleared out the stuff in the keys before but I think I did it wrong.   My question is how do I recreate the files properly and set up ssh to stop asking me for passwords when I'm connecting to git or other things?


use of package bbold and mathbb at same time

Using the package bbold changes the look of \mathbb{R} which I dont want. However, I do want the look of \mathbb{1} from the package bbold. Is there some way to have both or am I too greedy :)  \documentclass[10pt,a4paper]{article} \usepackage[utf8]{inputenc} \usepackage[T1]{fontenc} \usepackage{amsmath} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{graphicx}  %\usepackage{bbold}   <------ CHANGE HERE      \begin{document}          $\mathbb{1}$              $\mathbb{R}$      \end{document}


Should smilies be turned into images in questions and answers?

A lot of mention has been made of the seriousness of Stack Overflow (and presumably Server Fault). Would it be a good idea to turn  :-) into actual images as per  in questions and answers?


"Step over" when debugging multithreaded programs in Visual Studio

One thing that annoys me when debugging programs in Visual Studio (2005 in my case) is that when I use "step over" (by pressing F10) to execute to the next line of code, I often end up reaching that particular line of code in a totally different thread than the one I was looking at. This means that all the context of what I was doing was lost.  How do I work around this?  If this is possible to do in later versions of Visual Studio, I'd like to hear about it as well.  Setting a breakpoint on the next line of code which has a conditional to only break for this thread is not the answer I'm looking for since it is way too much work to be useful for me :)


At the moment I'm trying to prove the statement:     $K_n$ is an edge disjoint union of Hamiltonian cycles when $n$ is odd.   ($K_n$ is the complete graph with $n$ vertices)  So far, I think I've come up with a proof. We know the total number of edges in $K_n$ is $n(n-1)/2$ (or $n \choose 2$) and we can split our graph into individual Hamiltonian cycles of degree 2.   We also know that for n vertices all having degree 2, there must consequently be $n$ edges. Thus we write $n(n-1)/2 = n + n + ... n$ (here I'm just splitting $K_n$'s edges into some number of distinct Hamiltonian paths) and the deduction that $n$ must be odd follows easily.  However, the assumption I made - that we can always split $K_n$ into Hamiltonian paths of degree 2 if $K_n$ can be written as a disjoint union described above - I'm having trouble proving. I've only relied on trying different values for $n$ trials and it hasn't faltered yet. So, I'm asking:     If it is true, how do you prove that if $K_n$ can be split into distinct Hamiltonian cycles, it can be split in such a way that each Hamiltonian cycle is of degree 2?


Are there any geocoding plugins for QGIS that interpolate along linear features instead of querying web services?

I am curious if there are any tools for QGIS to facilitate geocoding tabular data using a local linear features layer (ie, a street map with street name and address ranges - similar to geocoding in ArcGIS). I am aware of Alessandro Pasotti's GeoCoding plugin, but it queries Google Maps/OpenStreetMap rather than interpolating along line segments of a user-provided layer.  One reason I am interested in this approach is that for some projects it is desirable to have geocoded points placed exactly on features from other project-specific layers, such as the street maps provided by local services or municipalities, which may not necessarily match the positions returned by web services.  Any ideas - or any input in case I have a go at writing a solution from scratch?


I have a workgroup of ten computers connected to internet on a broadband ADSL line via a 24 port switch. There is no server.  The internet bills have gone so high that I want to eliminate seven to email only and no internet leaving three that can have access to internet.  How can I accomplish that?


Unable to access the HardDisk drive in Ubuntu 16.04 LTS

I recently installed Ubuntu along with Windows 10. It is working perfectly till today. But I updated my Ubuntu 16.04 form Software Updater and restarted my system.  After restarting I am getting following Error while opening other disk drives (named 136 GB Volume).    Please notice that I am able to access these drives(NTFS partitioned) before updating the system but now it is showing error.  Now I am having access to Computer drive only (that is EXT4).  Please help me to solve this issue. As I am new to Ubuntu.  Thanks!


"Seeing someone slowly lose interest in you is one of the worst things."?

I'm new here and the sentence "Seeing someone slowly lose interest in you is one of the worst things." Same with "Watching someone die.." Why are the verbs "lose" and "die" in their base form? Also are "seeing" and "watching" gerund or progressive?


Many other languages posses the ability to suppress diagnostic messages on specific sections of their source code, while still reporting these messages in other sections.  For example, in C++ with gcc one can use #pragma GCC diagnostic commands to turn compiler messages on and off, and Java has the @SuppressWarnings annotation.  Does LaTeX posses a similar feature or another way to disable diagnostic messages in a specific section of code?    As a specific example, I have some code that triggers these warnings:  paper.tex:8: LaTeX Font Warning: Font shape `U/fontawesometwo/m/it' undefined(Font)     using `U/fontawesometwo/m/n' instead on input line 8. paper.tex:20: LaTeX Font Warning: Font shape `U/fontawesometwo/b/n' undefined(Font)     using `U/fontawesometwo/m/n' instead on input line 20.   How can I turn off this warning, but only for those two specific lines of that specific file?  Note that I am not looking for the 'correct' way to fix warnings, I am only looking for a general method to suppress warnings.


Get a return value from dynamically calling java class

I need to get a retrun value from dynamically calling java class by passing a variable values to that calling method. I try to use the java.lang.reflect.Method;  PredictionManager pm = new PredictionManager(); Class invokeclass = pm.getClass();  Class[] cArg = new Class[1]; cArg[0] = Integer.class;//Instances.class;  Method lMethod = invokeclass.getMethod("showLong", cArg); Object aaa= lMethod.invoke(pm, cArg);   in there I need to pass the value as a argument. but this method needs to give the parameter type. not the parameter value.  What can I do?


What is "playing too long"? How much is too long?    How long is "rest for a few minutes"?  What is the purpose of this feature? Player benefits? Account maintenance?


I am very new to Linux, Ubuntu and this forum.  Is it possible to install Ubuntu (19.04 or 19.10) so that the entire disk is used?  I just ran into a disk space error extracting a theme to /usr/share/themes. Can the entire disk be used like in windows so I never have disk space issues? I am currently using 19.10.  Do I have to reinstall to make this happen?  EDIT: I guess I didn't really know what to ask.  I needed to know how to set up the partition table to use the entire disk.   this website explained it very well and included other info I needed to know.


mod_rewrite: Redirect https://example.com to https://sub.example.com

I have an domain example.com running on an Apache Server and I want to redirect every call to  to .  I have a Virtual Host configured like this:  <VirtualHost _default_:80>         ServerName sub.example.com         RewriteEngine On         RewriteCond %{SERVER_PORT} !^443$         RewriteRule ^/(.*) https://%{HTTP_HOST}/$1 [NC,R,L] </VirtualHost>  <IfModule mod_ssl.c> <VirtualHost _default_:443>         RewriteEngine On         RewriteCond %{HTTP_HOST} ^https://%{HTTP_HOST}/$1         RewriteRule ^(.*)$ https://cloud.%{HTTP_HOST}/$1 [R=301,L]          ServerName sub.example.com         ServerAdmin gnarf         DocumentRoot /var/www/subfolder         <Directory />                 Options FollowSymLinks                 AllowOverride None         </Directory>         <Directory /var/www/>                 Options Indexes FollowSymLinks MultiViews                 AllowOverride None                 Order allow,deny                 allow from all         </Directory>         ErrorLog ${APACHE_LOG_DIR}/error.log         LogLevel warn         CustomLog ${APACHE_LOG_DIR}/ssl_access.log combined         SSLEngine on         SSLCertificateFile    /etc/apache2/ssl/ssl.pem         SSLCertificateKeyFile /etc/apache2/ssl/ssl.key         <FilesMatch "\.(cgi|shtml|phtml|php)$">                 SSLOptions +StdEnvVars         </FilesMatch>         <Directory /usr/lib/cgi-bin>                 SSLOptions +StdEnvVars         </Directory>         BrowserMatch "MSIE [2-6]" \                 nokeepalive ssl-unclean-shutdown \                 downgrade-1.0 force-response-1.0         BrowserMatch "MSIE [17-9]" ssl-unclean-shutdown         <Directory /var/www/subfolder>                 Options Indexes FollowSymLinks MultiViews                 AllowOverride All                 Order allow,deny                 Allow from all                 Satisfy Any         </Directory> </VirtualHost> </IfModule>   I tried to add the rewrite conditions into the default-ssl file, but when I reload the configuration this error occurs:  Reloading web server config apache2                                                                              [Sat Mar 22 22:57:11 2014] [warn] _default_ VirtualHost overlap on port 443, the first has precedence   So I removed the default-ssl. How do I get apache to take my rewrite conditions?  Thanks,  Ira  Edit:  To make my problem more clear.. The Reloading error ist not my real problem, it was just to clarify my tries so far ;)  http://example.com <- shows /var/www content = OK https://sub.example.com <- shows /var/www/sub content = OK https://example.com <- also shows /var/www/sub content = Not OK, I want this rewritten to https://sub1.example.com   But I don't know how and where to write this rule.


Set default value in people picker javascript/jquery

I want to set current logged in user to people picker by javascript.  I can retrieve the value of user(lets say in var user).But how to set it to people control. Any help is much appreciated.


I've made a very simple (inaccurate) program that calculates your age. I want to make it accurate by calculating leap years and taking into account that every month has a different amount of days. Any help how to do that and where to start? Thanks!   using System;  public class Program {     public static void Main()     {         float currentDay = 22;         float currentMonth = 2;         float currentYear = 2020;          Console.WriteLine("Enter your date of birth: (eg: 13/04/1998)");         Console.Write("Day: ");         int dayNum = Convert.ToInt16(Console.ReadLine());         Console.Write("Month: ");         int monthNum = Convert.ToInt16(Console.ReadLine());         Console.Write("Year: ");         int yearNum = Convert.ToInt16(Console.ReadLine());          float birthDay = (currentDay - dayNum) / 365;         float birthMonth = (currentMonth - monthNum) / 12;         float birthYear = currentYear - yearNum;          float age = birthYear + birthMonth + birthDay;          Console.WriteLine("Your age is: " + age);        } }


What is the benefit of being on an eSport team for a non team based game?

Many professional gamers are on a team for whatever game they play.  This makes sense for games like League of Legends where you play with your team mates, but what about games like Hearthstone where the games are always played 1v1?   Why not just compete/play independently?


Why cannot I obtain a valid SVD of X via eigenvalue decomposition of XX' and X'X?

I am trying to do SVD by hand:  m<-matrix(c(1,0,1,2,1,1,1,0,0),byrow=TRUE,nrow=3)  U=eigen(m%*%t(m))$vector V=eigen(t(m)%*%m)$vector D=sqrt(diag(eigen(m%*%t(m))$values))  U1=svd(m)$u V1=svd(m)$v D1=diag(svd(m)$d)  U1%*%D1%*%t(V1) U%*%D%*%t(V)   But the last line does not return m back. Why? It seems to has something to do with signs of these eigenvectors... Or did I misunderstand the procedure?


convert C style comments to C++ style using sed

I'm trying to convert single line 'C' style comments to 'C++' style.  The 'sed' below isn't bad, but of course it fails if any leading code (code before the comment) has any ' / ' in it at all:  sed -i 's,\(^[^\/]*\)\/\*\([^\*]*\)\*\/[ ]*$,\1\/\/\2,' filename   What I wish I could do is this:  ... [^\\/\\*] ...   i.e. negate ' /* ' which doesn't work of course, but after several hours of searching, I can't find a simple explanation of how to do that properly :(  It doesn't seem like it should be rocket science.  For example, these strings:   blah blah        /* comment */ blah blah / blah /* comment */ blah blah        /* comment */ blah blah blah / blah /* comment */ blah    ... should convert thusly:  blah blah        // comment  blah blah / blah // comment  blah blah        /* comment */ blah  (this CAN'T be converted) blah blah / blah /* comment */ blah  (this CAN'T be converted)   ... obviously no conversion can take place if there is code AFTER the 'C' comment.  I will do a close visual comparison between the file, before and after, so there's no need to handle ' /* ' inside a literal, nor do I want to convert anything multi-line.   Note I think of this as a 'negation' problem but maybe there is another way.  I  just need to capture everything before a ' /* ' and I don't care how.  FOLLOW UP ON ANSWER BELOW  Well damn! I see that I've completely misunderstood something fundamental:   .*/\*   ... reads: "anything except slash star followed by slash star", so actually I get my 'negation' for free :-)   So, going even further than Barmar:  sed -i 's,^\(.*\)/\*\(.*\)\*/\s*$,\1//\2,' filename   ... will even catch this:  blah / * blah        /* co / mme * nt */   and output this:  blah / * blah       // co / mme * nt    Enlightenment.


Show that a polynom is inversible when its coefficients are nilpotent

I have to prove that a polynom $f = a_nx^n+...+a_0 \in R[x] $ (the polynom ring) is inversible, if and only if $a_0$ is inversible and all $a_i$ are nilpotent. It is obvious that $a_0$ is inversible, but I have no idea how to prove the rest.  Also, I'm wondering if $ a\neq 0, \exists b\neq 0 \quad \text{such that}\quad ab=0\quad $   always implies that $a$ is nilpotent.


The Sorcerer's Destined Bloodline gave at level 1 the Touch of Destiny ability.     Touch of Destiny (Sp): At 1st level, you can touch a creature as a standard action, giving    it an insight bonus on attack rolls, skill checks, ability checks, and saving throws equal    to 1/2 your sorcerer level (minimum 1) for 1 round. You can use this ability a number of times per day equal to 3 + your Charisma modifier.   So the definition says that "You can touch a creature" but doesn't exclude you of the possible creatures. Am I misinterpreting, or can you indeed cast it on yourself?  I understand it would be pretty useless in fight, since you would have used your single action to buff yourself for one round (for a sorcerer level below 3), but could you use it to help in a skill check, like lockpicking out of fight?


Is the set $A=(sin(nt))_{n=1}^{\infty}$ totally bounded?

By Arzela-Ascoli, if I show that A is bounded and equicontinuous. Then, it is totally bounded. I have no problem showing that it is bounded. But I do not know how to determine it is equicontinuous or not. Can you help me? Thanks for any help.


How do I unsubmit my own edit from review?

I made an edit that was submitted for review and quickly noticed I made a mistake. How can I unsubmit it?


Get the Latest date from the Three columns

ID     Date1           Date2            Date3    158    5/3/13 15:11    2/20/13 11:38    2/20/13 11:38   I want to get the latest date from this three columns.


Let $(G, *)$ be a group and $a$, $b$ belongs to $G$. Suppose that $a^2 = e$ and $a*b^4*a = b^7$. Prove that $b^{33} = e$. I dont know how to proceed.


Can I leave the Schengen point of entry in less than one day to travel to another Schengen country? This is my first time.


I noticed a pretty unfixable error in one of my answers today and thus went to delete it. However, on the Android mobile app, the only options were to share, edit, or flag the post (no deletion). Would it be possible to add the delete option to posts as well on the mobile app?


Find all ring homomorphisms from $\Bbb Q$ to $\Bbb R$

My question is find all homomorphism $ f: \Bbb Q \to \Bbb R$.  I think I should use ring isomorphism theorem to do this problem, but I just don't know how to do this.


I'm trying to build an application. It requires the next libs: libev(x86-32) libev(x86-64) libev-devel(x86-32) libev-devel(x86-64) for Ubuntu I run:  sudo apt-get install libev-dev   and get libev4 and libev-dev. But if I run  sudo apt-get install libev-dev:i386   it wants to remove old libev. I need all these libraries to compile versions for different platforms. How to install them all?


Received message stating I failed too many review audits?

When clicking on the "review" tab today, I saw the following message:     You have failed too many recent review audits – looks like you might need a break. Come back in 4 days to continue reviewing.   While I suppose I don't mind taking a break, I don't particularly remember failing any audits recently, so I'm not really sure why I've been banned.  Is there any way to check what behaviors might have gotten me banned so I can (at the very least) avoid doing whatever it is I did in the future?


Can a 4-length road ever be Longest Road in Settlers of Catan?

Suppose I have an 8-length road and Longest Road, but later someone splits my road in half with a settlement, leaving me two 4-length roads.  Assuming no one else has a longer road than me, do I lose Longest Road, given that my road no longer has a length of at least 5?


How can I start up an application with a pre-defined window size and position?

I'm wondering is there any way to achieve the affect of the Ctrl-Alt-Keypad shortcuts in Unity using terminal commands instead? I want a command that sets a gui window to half the size of the screen, either left or right aligned.  By way of background, I'm writing a script that runs after log in. It uses Zenity to ask whether or not I want to open my development environment (GVim and IPython side-by-side). I have been trying to achieve two equal-sized windows for these programmes by using set lines= columns= in my .gvimrc and c.IPythonWidget.width = and c.IPythonWidget.height = in my ipython_qtconsole_config.py. However, there are problems associated with this approach.


Can you apply CRT to the congruence $84x ≡ 68$ $(mod$ $400)$?

this might be a (very) stupid question, however I need to ask it (why?). I have the congruence $84x ≡ 68$ $(mod$ $400)$ from: , where the solution is given. However, I tried to solve this using the Chinese Remainder Theorem and got the wrong answer. So my question is, can I use CRT to solve this and if so please provide an answer, if I can't use CRT why not, what condition is not fullfilled?  Ok, I might not have been clear. When applying CRT I get: Primefactorization of $400 = 2^4*5^2$ then:  $84x ≡ 68$ $(mod$ $2^4)$ ↔ $4x ≡ 4$ $(mod$ $2^4)$ ↔ $x ≡ 1$ $(mod$ $2^4)$ $(1)$ $84x ≡ 68$ $(mod$ $5^2)$ ↔ $9x ≡ 14$ $(mod$ $5^2)$ ↔ $x ≡ 21$ $(mod$ $5^2)$ $(2)$  From (1) and (2) I get: $x = 1 + 16s ≡ 21$ $(mod$ $25)$ → $s = 20 + 25*t$ → $x = 321 + 400t$ which is wrong :(  Where am I going wrong?  Regards


biblatex prints editor twice in bibliography

MWE Bib: @inproceedings{Gossart:10, author = {Gossart, D and Meskens, N and Guinet, A}, editor = {Camarinha-Matos, L M and Boucher, X and Afsarmanesh, H}, title = {{Strategic and Tactical Bed Management in Belgium and France}}, booktitle = {Collaborative Networks for a Sustainable World}, year = {2010}, address = {Berlin}, publisher = {Springer}, pages = {243--250} }  code: \documentclass[listof=totoc, bibliography=totoc, index=totoc]{scrbook}  \usepackage[backend=biber, style=apa, sorting=ynt, bibencoding=utf8]{biblatex} % Keller 11.1. \addbibresource{library.bib} \begin{document} \chapter{Variables influencing on the tactical decision level}\label{chap3} blablabla \autocite{Gossart:10} \begin{refcontext}[sorting=nyt] \printbibliography \end{refcontext} \end{document}  output: Bibliography Gossart, D., Meskens, N., & Guinet, A. (2010). Strategic and Tactical Bed Management in Belgium and France (L. M. Camarinha-Matos, X. Boucher, & H. Afsarmanesh, Eds.). In L. M. Camarinha-Matos, X. Boucher, & H. Afsarmanesh (Eds.), Col- laborative networks for a sustainable world, Berlin, Springer.   Why on earth do the editors show up twice here?


Convergence of a Sequence Involving arctan - Is my solution correct?

Here's my question:     Let $(a_{n})$ be a sequence where $(a_{1}) > 0$, defined as:   $$(a_{n+1})=\arctan*(a_{n})$$ for all $n$.   Prove that $a_{n}$ has a limit $L$ and calculate it.  Solution:   Prove that x>$arctan (x)$ for all x. Prove that above we can conclude that $a_{n+1}<a_{n}$, since they are equal we multiply $a_{n}$ by $arctan(x)$. $arctan(x)=0 \space iff \space x=0$, and that doesn't happen here since $a_{1}$ is positive. Therefore, we can use the follwoing theorem:      Let r be a number such that $r \in \Bbb R$ and $0<r<1$, so:   $$IF \space\space \left|\frac{a_{n+1}}{a_{n}}\right| \le r \Rightarrow \lim \limits_{n\to\infty}(a_{n})=0$$    Sorry for the last theorem - I don't know how it's named in English (I'm not a native speaker).  Is my solution correct?  Thanks,  Alan


Why is a nuclei with too many neutrons unstable?

I understand that a nuclei with too many protons is unstable as the electromagnetic repulsion becomes too strong to be balanced by the strong nuclear force.   However in the case of there being too many neutrons, surely the addition of neutrons should be adding extra strong nuclear force without extra electromagnetic repulsion, which should make a nucleus more stable. Why is this not the case?


Is it possible to experimentally show that observable universe is much larger than ~93B ly?

Thought experiment:   Entangle a pair of particles.  Package one half of each pair in a special package, and send it out in a nano-spaceship keep the other half of the pair of entangled particles here on earth accelerate nano-spaceship to 99.99999999999999% of the speed of light using a number of    Due to Lorentz ,  $$ L = L _\text{0} \sqrt {1 - \frac {v^{2}}{c^{2}}} $$  In one years time, the spaceship would have traveled 93B ly away from us (in the spaceships relative frame)  After one year of travel, the spaceship could be preconfigured to detect the CMB in the direction of travel, and then trigger their quantum entangled particle to send a '0' or a '1' depending on whether the CMB was detected.  Repeat this process using any number of spaceships in any number of directions, and soon you would experimentally show how big the universe really is.  Any problems?


Shift-arrow not working in emacs within tmux

I recently started using tmux (was a screen user before) and I'm loving it, except for one small problem. I use emacs within my tmux session and I am used to using Shift-arrow keys to move between emacs windows (not tmux windows). When running within tmux, these bindings seem to stop working entirely (it's like they don't register to emacs at all). If I exit tmux and just run emacs in my shell, they work fine.   I'm using iTerm2, ssh'd into a Linux box, running tmux/emacs there. I have the Shift-arrow key bindings set up as follows in my .emacs:  (global-set-key "\M-[1;2A" 'windmove-up) (global-set-key "\M-[1;2B" 'windmove-down) (global-set-key "\M-[1;2C" 'windmove-right) (global-set-key "\M-[1;2D" 'windmove-left)   When not running in tmux, I can confirm those are the right character sequences for the shift-arrow key combinations by doing C-q in emacs and then pressing the key sequence. Within tmux, even that doesn't work because it doesn't seem to see any input from the shift-arrow keypress (it just sits at the C-q prompt).   Looking at the key bindings for tmux, I don't think anything is bound to Shift-arrow keys and even if it was, they would only register after entering the prefix (which is bound to C-o in my case).   Any idea on how to make the shift-arrow keys work again within tmux?


Does general relativity make time travel impossible or just very difficult?

I was hoping to get some technical answers to this question, and was really asking because I thought it'd be a fun question. Have at it folks.


How to protect an employee's wages before the company declares bankruptcy?

I work for a company which is behind on my salary.  The company might file for bankruptcy: how do I claim my salary before then?   This question is different from other postings. We are discussing how to get wages for employees before the company files for bankruptcy.


How to excludes my visits from Google Analytics?

I have integrated Google Sites website with Google Analytics and I access the website frequently to add more content. I want Google Analytics to track visits from real visitors only. How can I configure it to exclude or filter out my visits?


I am forced to manually document a legacy enterprise database. Are there some standard good practices or tools to do this?  To give you some more context, I have recently been given restricted access to a legacy enterprise database. There is very little documentation. I don't have permissions to view system tables or generate ER diagrams. I am exploring/using the database and manually documenting it as I go.   I would like to represent the schema with code (manually) in such a way that it can be parsed, say, with Python, to generate an ER diagram?  Are there tools to do this kind of thing? Or standard good practices to document the schema, annotate definitions and common keys etc?  I'm imagining some kind of a tree or graph like data structure that can be used to encode the schema, parsed with Python etc, and used to generate ERDs, etc, outside of the db management tool; (since I don't have permissions to do this inside the db management tool (Oracle SQL Developer)).


If information is conserved, why did the early universe had lower entropy than now?

If information and entropy are equivalent, and information is a conserved quantity because of unitarity, what does it mean to say that entropy is growing since the big bang (I know why it grows, I'm not getting how to conciliate the two affirmations).  I undestand the process by which entropy grows, and I know why information (quantum states) are conserved. What I am not getting is how these two facts are reconcilable with each other, since information is equivalent to entropy.


Why do I get this "Context = NullPointerException" error in my homework?

I am doing a tutorial for homework, which is to build an Instagram app. The tutorial is about two years old and I am having some problems with the coding.  I am having the following error and am not sure why.    java.lang.NullPointerException: Attempt to invoke virtual method 'android.content.Context android.content.Context.getApplicationContext()' on a null object reference   My UniversalImageLoader class  public class UniversalImageLoader {      private static final int defaultImage = R.drawable.ic_android;     private Context mContext;      public UniversalImageLoader(Context context) {         mContext = context;     }      public ImageLoaderConfiguration getConfig(){         //File cacheDir = StorageUtils.getCacheDirectory(mContext);         ImageLoaderConfiguration config = new ImageLoaderConfiguration.Builder(mContext)//<--the error is in this line                 .memoryCacheExtraOptions(480, 800) // default = device screen dimensions                 .diskCacheExtraOptions(480, 800, null)                 .threadPriority(Thread.NORM_PRIORITY - 2) // default                 .tasksProcessingOrder(QueueProcessingType.FIFO) // default                 .denyCacheImageMultipleSizesInMemory()                 .memoryCache(new LruMemoryCache(2 * 1024 * 1024))                 .memoryCacheSize(2 * 1024 * 1024)                 .memoryCacheSizePercentage(13) // default                 .diskCacheSize(50 * 1024 * 1024)                 .diskCacheFileCount(100)                 .diskCacheFileNameGenerator(new HashCodeFileNameGenerator()) // default                 .imageDownloader(new BaseImageDownloader(mContext)) // default                 .defaultDisplayImageOptions(DisplayImageOptions.createSimple()) // default                 .writeDebugLogs()                 .build();          return config;     }   in HomeActivity:(and OnCreate)[in every Activity I call it like this]  initImageLoader();    private void initImageLoader(){         UniversalImageLoader universalImageLoader = new UniversalImageLoader(mContext);         ImageLoader.getInstance().init(universalImageLoader.getConfig());     }


how to check if char is letter or number

I am doing some html encode in js.   Looks like that I don't want to encode letters and numbers.   export const encode = (str) => {   if (!str || str === '') return '';   var buf = []    for (var i = str.length - 1; i >= 0; i--) {     buf.unshift(['&#', str[i].charCodeAt(), ';'].join(''))   }   return buf.join('') }   This is how I encode.  Now, if character is a english letter, or france or russian letter, i don't want it encoded. So I think I am left with this: encode anything that is not letter/number and also [a-Z] regex mightn't be enough, because what if it's a russian letter? I wouldn't want it encoded.  Any regex idea?


Name the book where the setting is a giant ship with a planet inside

Here's what I remember:    Takes place in the future on a giant, bigger-than-a-planet spaceship found and now run by humans Humans are genetically altered and/or are enhanced with nanotechnology and have essentially become immortal and can be healed from almost any wound The surface of the ship is inhabited by former humans who have mutated into a new species, and live their entire lives in a kind of space suit The plot involves the discovery of a small planet within the ship that the protagonist is stranded on along with many others, and they form a civilization and live there for centuries   Anyone know the name of this book?  I can never remember it.


How to set rotation of a projectile in a parabolic arc in Box2D?

I have trouble making my projectile - in this case an arrow - rotate as it should when it's travelling in a parabolic arc. It doesn't rotate at all while travelling, only until it collides with something.  Below is the relevant code I'm using.   public class Arrow extends BodyDef{  private Body body;  public Arrow(float x, float y, float halfWidth, float halfHeight, float rotation, float velocity) {     type = BodyDef.BodyType.DynamicBody;     position.set(x, y);     angle = rotation;      body = Box2DTest.world.createBody(this);     PolygonShape shapeShaft = new PolygonShape();     shapeShaft.setAsBox(halfWidth, halfHeight);      /* Creation of the shaft of the arrow */     FixtureDef fixtureShaft = new FixtureDef();     fixtureShaft.shape = shapeShaft;     fixtureShaft.density = 6.5f;     fixtureShaft.restitution = 0.4f;     body.createFixture(fixtureShaft);      /* Creation of the tip of the arrow, note the higher density */     PolygonShape shapePoint = new PolygonShape();     float[] shapePointV = {             halfWidth, halfHeight * 2,             halfWidth * 1.5f, 0,             halfWidth, - halfHeight * 2};     shapePoint.set(shapePointV);      FixtureDef fixturePoint = new FixtureDef();     fixturePoint.shape = shapePoint;     fixturePoint.density = 26.0f;     fixturePoint.restitution = 0.05f;     fixturePoint.friction = 0.5f;      body.createFixture(fixturePoint);      body.applyLinearImpulse(MathUtils.cos(rotation) * velocity, MathUtils.sin(rotation) * velocity,              body.getWorldCenter().x, body.getWorldCenter().y, true);      //body.applyTorque(-90.0f, true); <-- My attempts to fix this but still doesn't work well     //body.applyAngularImpulse(-0.5f, true);     shapeShaft.dispose();     }  }   The Box2DWorld is initialized as such:     world = new World(new Vector2(0, -9.8f), true);   Here's a picture explaining how it looks and what I want to achieve (Courtesy of vilbeyli in github):   I have also attempted to apply the initial impulse in the bottom-left corner of the arrow but the resulting spin is very imprecise and random.    Why doesn't the heavier tip make the arrow rotate by itself? How can this be fixed?


Extrude and subdivide without using tris

How do I extrude this top so the mesh will form a complete dress. More precisely, after applying the mirror modifier, each horizontal loop contains N=24 vertexes. To get good results from the cloth simulator, I want the skirt to have at least more vertexes around each horizontal loop so I need to branch each vertical edge to create more vertexes in the loop below. Is it possible to join two loops with N and kN vertexes without using a "tris bridge". That is, I want to stick to quads.  Update:  I figured out that I can multiply by three using the following pattern  |      | +------+  \    / \   +--+   +  /|  |\ / + |  | + | |  | | +-+--+-+   By only branching every other edge, it is possible to multiply by two.  This technique results in some bad quads. Is more regular tris a better approach then?


Why does StackOverflow make you wait 2-x minutes before you can accept an answer?

Hi,  It is kind of an annoying feature that I have to wait to accept an answer after I upvote it.  Why is it done like that?


Proving an elementary inequality of real vectors related to the p-Laplacian

How would you prove the following inequality? $$  \left|\left|a\right|^{p-2}a-\left|b\right|^{p-2}b\right|\leq C_p\left|a-b\right|^{p-1} $$ where $a,b\in\mathbb{R}^{n}$ and $C_p>0$ is some constant depending only on $p$, $1<p<2$. The inequality is mentioned in  on page 43 but proof is omitted. The same notes have a collection of inequalities at chapter 10, in particular the following inequality for euclidean inner product product is given $$ (\left|a\right|^{p-2}a-\left|b\right|^{p-2}b)\cdot(a-b)\leq C_{p}\left|a-b\right|^{p} $$  but I'm not sure how to deduce the first inequality from this.


$$\left\lfloor \frac{1}{\sqrt{1}}+\frac{1}{\sqrt{2}}+\frac{1}{\sqrt{3}}+\frac{1}{\sqrt{4}}+...+\frac{1}{\sqrt{1024}}\right\rfloor =?$$  I can't find $$? \leq  \frac{1}{\sqrt{1}}+\frac{1}{\sqrt{2}}+\frac{1}{\sqrt{3}}+\frac{1}{\sqrt{4}}+...+\frac{1}{\sqrt{n}} \leq ?$$ I remeber there was a sharp bound , Am i right  ? I am thankful if someone help me to find the bound  , or give another idea Last question : Is it possible to find $\frac{1}{\sqrt{1}}+\frac{1}{\sqrt{2}}+\frac{1}{\sqrt{3}}+\frac{1}{\sqrt{4}}+...+\frac{1}{\sqrt{1024}}$  by integral  ?


how to install Apache ActiveMQ on Ubuntu 16.04

Were can I find instructions on installing Apache ActiveMQ on Ubuntu 16.04.  Thanks


I have no idea how to calculate (I know that the answer is 1 but why ?). Maybe with a theorem or with trigonometric properties ...     $$ \lim_{m\to\infty} \frac{\int_0^{\pi/2}(\sin x)^{2m}dx}{\int_0^{\pi/2}(\sin x)^{2m+1}dx} $$


I am trying to learn filters. In the following circuit, the author says that negative and positive feedback are used. I couldn't understand what the circuit parts do. Actually I got the negative feedback highpass parts but the low pass part is a little different from normal filters because C2 doesn't bind with ground.


can i use iMac (Retina 5k, 27-inch, Late 2015) as target monitor?

i have an iMac 2020 and a late 2015 iMac. I wish to know if it’s possible to use the latter as target display monitor. and if yes, which cable should i buy? thanks


If $gcd(a,b)=d$ and $a^2+b^2=c^2$, show that $gcd(a,c)=gcd(b,c)=d$. This is what I have so far. We know that $d|a$ and $d|b$ which implies that $d|c$, but that is not enough to show that $gcd(a,c)=gcd(b,c)=d$, only that they are at least $d$. Also $a^2=c^2-b^2$ and $b^2=c^2-a^2$. Any hints or solutions are greatly appreciated.


How to run a scheduled job every 1 minute , and automatically start the re-scheduled automatically?

How to run a scheduled job every 1 minute , and automatically start the re-scheduled automatically again and again same process. I am trying this example below way. But it can't reschedule automatically and time interval also not clear. Could you please give me an example another way.  Global class SchedulebatchAccountUpdate1 Implements Schedulable {     global void execute(SchedulableContext sc) {     batchAccountUpdate1 c = new batchAccountUpdate1();     Database.executeBatch(c);     }   Public static void SchedulerMethod() {         String sch = '0 0 * * * ?';     system.schedule('My Jobs scheduled name', sch, new SchedulebatchAccountUpdate1());     } }


$p^2+1=q^2+r^2$. Strange phenomenon of primes

Problem: Find prime solutions to the equation $p^2+1=q^2+r^2$  I welcome you to post your own solutions as well  I have found a strange solution which I can't understand why it works(or what's the math behind it.) Here it is through examples  Put $r=17$(prime) Now $17^2-1=16\times 18=288=2 \times 144$ (a particular factorization)  $\frac {2+144}{2}=73$  $\frac {144-2}{2}=71$  Solution pair $(p,q,r)=(73,71,17)$  Put $r=23$,  $23^2-1=22\times 24=8\times 66$  $\frac {8+66}{2}=37$  $\frac {66-8}{2}=29$  Solution pair $(37,29,23)$  It works for each prime except for $2,3,5$ Which generate  $(2,2,1),(3,3,1),5,5,1)$  Please explain me how it's working


How can you prove that $S_n$ is generated by $(1\space 2)$ and $(1\space 2\space 3\space ... \space n))$ for $n\geq 2$?


How can I make a group of blurry colors in Illustrator?

I have downloaded an asset that shows as the picture attached.   The image is slightly warped with the warp tool (U) (may not be the correct translation as English is not my main language).   I wonder how could be this done, as I'm double clicking it but I'm unable to get deeper in layers. Is it an imported picture?


I have an mysql Server on hostD. I can access hostD through hostC, hostC through hostB, hostB through hostA and I access hostA using putty on my home device  home(windows)-->hostA-->hostB-->hostC--hostD(mySQL Server)   My goal is to access the server from my home device.  Another challenge is that I don't have any root access on A,B and C. Now I've been experimenting with the '.ssh/config' file and this is what I got so far:   Host BTunnel   HostName hostB   LocalForward 3306 localhost:3306   Host CTunnel   HostName hostC   LocalForward 3306 localhost:3306   Host DTunnel   HostName hostD   LocalForward 3306 localhost:3306   This way I can connect from Putty--> hostA and type in consecutively:  ssh BTunnel ssh CTunnel ssh DTunnel   To get a tunnel from A to D. But I would like to have a solution, where I only type in 1 command from host A to get a Tunnel to D, maybe by chaining up the existing host aliases.  Can anyone offer a solution?


Show that if $ R $ is an integral domain then a polynomial in $ R[X] $ of degree $ d $ can have at most $ d  $ roots.  Thoughts so far:  I feel like I might be missing something here. If $ R $ is an integral domain, then so is $ R[X] $. The factor theorem gives a correspondence between roots and factors. Clearly (is this clear?) a polynomial of degree $ d $ can't have more than $ d $ irreducible factors.


Python check if a directory exists, then create it if necessary and save graph to new directory?

so I want this to be independent of the computer the code is used on, so I want to be able to create a directory in the current directory and save my plots to that new file. I looked at some other questions and tried this (I have two attempts, one commented out):       import os     from os import path     #trying to make shift_graphs directory if it does not already exist:      if not os.path.exists('shift_graphs'):         os.mkdirs('shift_graphs')      plt.title('Shift by position on '+str(detector_num)+'-Detector')     #saving figure to shift_graphs directory     plt.savefig(os.path.join('shift_graphs','shift by position on '+str(detector_num)+'-detector'))     print "plot 5 done"     plt.clf   I get the error :   AttributeError: 'module' object has no attribute 'mkdirs'   I also want to know if my idea of saving it in the directory will work, which I haven't been able to test because of the errors I've been getting in the above portion.


Custom Tools not Saving in Toolbar on Startup/ Normal.mxt?

I am trying to save some tools that I have created into the default toolbar layout that is present when ArcMap 10.1 is launched.  It is possible to change the arrangement of toolbars, add new ones and even add in existing tools, but any custom tools I set in the commands category "geoprocessing tools" are gone and do not appear in the toolbar. How can I save these custom tools to the default layout that appears on startup?  Update:  Saving a document with the custom tools added and reopening it preserves the tools, but opening a template (10.1 mxd) containing the tools, then opening and older document will cause the tools to disappear. Oddly enough, any other changes made after the custom tools were added are preseved.  Update (03/18/2014):  I have upgraded to 10.2 and this has still not been fixed. I did not see this issue in the 10.21 changelog so I doubt it will address it. For those interested in this issue, I have started a forum post on the ESRI forums .


Different random seeds lead to big classifier performance difference

I've a dataset for binary classification. I tried various algorithms using Weka. Then I noticed that if I change the seed of the random number generator I get different classification accuracy results. For example in one run I get 65% and in another run I get 72% accuracy. In all runs I use 10-fold cross validation. Is this variation in accuracy results normal? Or any idea on what might be the cause of the variation? Thanks


Part time job offer where employer's customers sends money to my bank account and I send it to my employer

I am a teenager looking for a job to earn some side income while studying, but I am very uneducated on bank transfers and such. I found this job offer and I do not know if this is legitimate or a scam, so help would be greatly appreciated.   This was the job offer: Employer from another country has many customers in my country and wants an assistant to receive their money and transfer to him, and assistant would get tips for every transaction.   It is an easy job and pays well so it feels like something too good to be true, but I am quite 'dumb' in this topic so I cannot make the correct judgement. Is this legitimate or a scam?


I am writing a platform independent Java console tool and within which will have to execute some commands in separate independent terminal at runtime.  However, I need to know which terminal should I be using gnome-terminal or xterm. i.e. the one available on that particular system. Since there are many different linux variants are available. I want to support at least the most obvious ones.  Normally in Java System.getProperty("os.name") returns Linux but it doesn't tell you if its Ubuntu or any other Linux varient. So It is difficult to know which terminal to start at runtime. Whether gnome-terminal or xterm or if there is anything else as well that I don't know.  Working sets:  In Windows:  cmd /c start java -jar jarTool arguments   In Ubuntu:  gnome-terminal --execute java -jar jarTool arguments   or  xterm -e java -jar jarTool arguments   Also just for additional information,I am using Runtime.getRuntime().exec(args or commands) to start terminal from Java program at runtime.


I have a script which has an array called metaData that includes product IDs and quantities. It looks like this:  "PRD 6060BNDISHRT-CHARCOAL-SMALL": 3, "PRD 6060BNDISHRT-CHARCOAL-MEDIUM": 3, "PRD 6060BNDISHRT-CHARCOAL-LARGE": 4, "PRD 6060BNDISHRT-CHARCOAL-XL": 3, "PRD 6060BNDISHRT-ALLOY-SMALL": 0, "PRD 6060BNDISHRT-ALLOY-MEDIUM": 2, "PRD 6060BNDISHRT-ALLOY-LARGE": 1, "PRD 6060BNDISHRT-ALLOY-XL": 3, "PRD 6060BNDISHRT-BLACK-SMALL": 1, "PRD 6060BNDISHRT-BLACK-MEDIUM": 0, "PRD 6060BNDISHRT-BLACK-LARGE": 0, "PRD 6060BNDISHRT-BLACK-XL": 4, "PRD 6060BNDISHRT-CABERNET-SMALL": 2, "PRD 6060BNDISHRT-CABERNET-MEDIUM": 2, "PRD 6060BNDISHRT-CABERNET-LARGE": 3, "PRD 6060BNDISHRT-CABERNET-XL": 2, "PRD 6060BNDISHRT-NAVY-SMALL": 3, "PRD 6060BNDISHRT-NAVY-MEDIUM": 3, "PRD 6060BNDISHRT-NAVY-LARGE": 0, "PRD 6060BNDISHRT-NAVY-XL": 3   This code:    var stockChicago = metaData;   alert(stockChicago);   results in the above list (or as much as will fit in the alert box).  Now, if I do this, I should get the result of the value for that key (it's the second one on the list), right?:    var stockChicago = metaData["PRD 6060BNDISHRT-CHARCOAL-MEDIUM"];   alert(stockChicago);   I expect the response to be "3," but instead, I just get "undefined." I've tried it without the quotes and have searched everywhere I can think of to figure out what I'm doing wrong. Like I said, I figure it's something very simple, but for the life of me I can't figure it out!


How do I create a sparse file programmatically, in C, on Mac OS X?

I'd like to create a sparse file such that all-zero blocks don't take up actual disk space until I write data to them.  Is it possible?


I've got a huge list of date-times like this as strings:  Jun 1 2005  1:33PM Aug 28 1999 12:00AM   I'm going to be shoving these back into proper datetime fields in a database so I need to magic them into real datetime objects.   This is going through Django's ORM so I can't use SQL to do the conversion on insert.


can't install with usb pen drive, SYSLINUX problem

i'm on ubuntustudio and i want to format my hd and try kubuntu (install in my acer notebook, no partion, no double operating system problem, only istall it) i've downloaded iso file ( kubuntu-10.10-desktop-i386.iso ), insert usb pen drive, then: system > administration > startup disk creator erased usb pen content, and "make startup disk" finally, reboot computer with pen inside usb port  normal boot didn't start (as expected) but only black screen with this signal:  SYSLINUX 4.03 2010-10-22 EDD Copyright (c) 1994-2010, H. Peter Anvin et al unknown keyword in configuration file boot:   i've tried different usb pen stick and different iso files (ubuntu, kubuntu, netbook edition).. always same problem (sometimes only the first line without "unknow keyword in conf file" error)  some advice?? sorry for my bad english


What is exactly the difference between $\forall x \neg P(x)$ and $\neg \forall xP(x)$?

Could you explain what is the difference  between $\forall x \neg P(x)$ and $\neg \forall xP(x)$  or $\exists x\neg P(x)$ and $\neg \exists x P(x)$ ?


On my new tablet I installed the gmail app and also configured the builtin app. Now I get two notifications for each email. How can I get rid of the builtin email app which does not seem as good as the gmail app?


A and B are similar if and only if $\text{rank}(A)=\text{rank}(B)$?

Suppose that $A$ and $B$ are linear transformations (on the same finite dimensional vector space) such that $A^2=A$ and $B^2=B$.  Is it true that $A$ and $B$ are similar if and only if rank($A$)=rank($B$)?  As far as I can tell, it is true.  What I have for the forward direction is this:  $A=C^{-1}BC$  $CA=BC$  And by a theorem, we can say, rank($CA$)=rank($BC$).  Further, by the same theorem, we can say, rank($A$)=rank($B$) because $C$ is invertible.  I'm stuck on the reverse direction though.  I can put an invertible $C$ in there, but past that, I don't think I can make the assumption that $CA=BC$.  Thanks.


I'm having some trouble with ajax element, that when i add new element, i will inject new click function to that element, but he also add to the exist elements, so that some elements will call my function triple times or more.  So i wonder:  How to remove exist custom 'click function' and replace new one?  I know .off()but he remove all other functions of my elements so hover() still remove too.


I just ran into a situation whereby I need to use a timedelta. I have only used timedelta once before, and I am using that piece of code as a reference point.  timedelta(**{unit_of_measurement:quantity_of_units})   I am simply curious what the **{var1:var2} part of the code is called?  I am new to Python, so I am not sure if it is exclusive to timedeltas, datetime, or Python in general. There is no mention of it in the datetime documentation. I have tried searching Google, but it returns completely irrelevant results.


Secret sharing scheme with ability to add or update share number

I would like to have a secret sharing scheme with the following properties:   Generate secret $S$ a split it to $N$ shares $(s_1, s_2, ..., s_N)$  Require $k$ of $N$ shares in order to reconstruct secret $S$ Update $N$ to $N+1$ and generate new share $s_{N+1}$ (everything remains the same, $N$ shares not changed)   The scenario is that I use Shamir secret scheme to split secret $S$ into for example 4 parts and require 2 of them to be present in order to reconstruct $S$. In that case if I would like to reconstruct S then I have to also input scheme type, i.e. 2 of 4.  What if I need to update number of parts but need to preserve existing shares and be able to reconstruct the same secret $S$? Is there a way how to do it?


Is there a way to group options in a selectList

Is there a way to group options in an apex:selectList  I have in my page        <apex:selectList styleclass="form-control rec" size="1" id="country"  >               <apex:selectOption itemValue="" itemLabel="--Please Select--"/>               <apex:selectOptions value="{!CountryName}" />               <apex:actionSupport event="onchange"  reRender=""/>       </apex:selectList>   In the controller I have      public List<SelectOption> getCountryName(){       List<SelectOption> options = new List<SelectOption>();        for(Country__c con :[select Id,Name from Country__c where Region__c=:'Americas' order by Name]){       options.add(new SelectOption(con.Name,con.Name));       }   Is there  a way I can group the selectOptions based on region like with a grouping label  similar to html <optgroup label="Americas">  Also is it possible to do something like the below code in case I'm not able to group them using salesforce   <select id="country" >     <option value="">--Please Select--</option>     <optgroup label="Americas">     <apex:selectOptions value="{!CountryName}" />      </optgroup>   </select>


Standardizing variables with negative values in R

Because my dependent variables in a multiple linear regression model are in different units, some coefficients are > 10,000 and others less than 0. I need to standardize them by using the scale function on R, but because some of my data is negative, it's impossible to take log of some of the variables which I need to do before standardizing. Is there any other step I can take? Can I standardize without log transformation first?


I have a div in my HTML page. I am showing this div based on some condition, but the div is displaying behind the HTML element where I pointed the mouse cursor.  I have tried all values for z-index from 0 - 999999. Can anyone tell me why this is happening?  Is there any minimum or maximum value of Z-INDEX property of CSS?    .divClass {      position: absolute;       left: 25px;       top: 25px;       width: 320px;      height: 300px;       z-index: 1000;  }

            <asp:HyperLink ID="lnkProgram" runat="server"></asp:HyperLink>

            Some Data

     I am showing and hiding the div with .divClass onclick via the <asp:hyperlink> using jQuery.


What are the ways to add new weapon allowances to Decisive Strike/Flurry of Blows?

For thematic reasons, I am wanting to make a Zatoichi-style character based on using  and Decisive Strike monk alternate feature from the PHB2. The only catch is that Decisive Strike says:     . . . make one attack with an unarmed strike or a special monk weapon . . .   What are all of the official ways to add a weapon to the list of ? I have found only one in the Shou Disciple prestige class (Unapproachable East, p.32), but doing so would mean the earliest the character could use decisive strike with a katana would be level 10. I would like to be doing it no later than level 5 if such an option exists.  Note that, for the purposes of this question, anything that works for "Flurry of Blows" can be interchanged with "Decisive Strike" (e.g. the "Martial Flurry" ability of a Shou Disciple gains ability to use other weapons with "Flurry of Blows," but that is fine).


Requirement in our app is to provide a UI control for user to select 'from' month/year and 'to' month/year over multiple year. With validations like 'to' month cann't be less than 'from' month.  Example:- User should be able to select Feb-2013 to Mar-2014 Or just Jun-2014 to Jun-2014, etc.  The most simple UI I can think of is by using four combo dropdown to select fromMonth, fromYear, toMonth and toYear.    Some drawbacks of this patter are:-   User need to click 4 *2 = 8 times to select from and to. Time period selection or magnitude is not intuitive, (No visual way to tell 6 months or full year is selected) To know the full range of months and years available, user need to click all four combos.   Please let me know of any better UI pattern or controls for above requirements.


Prove by induction that $n < 2^n$ for all $n \ge 1$

I'm trying to do homework problems and for the most part I've been getting the results. For this one though, I am having some trouble since its $2^n$ and I can't relate it properly:     Prove using simple induction that $n < 2^n$ for all $n \ge 1$.   So obviously, the basis step holds as $1 < 3$. Now, I assume that $n = k$ holds as well and have to prove for $n=k+1$. This is the step I am having trouble with as I cannot relate the induction hypothesis with what I want to end up with. Can anybody show me a model solution for this one? I think my trouble comes because of the $2^n $


If derivative of function is less than or equal to 4, prove the existence of point $c$ so $f(c)=c^2$.

I am struggling to construct a simple proof of the following.  Suppose $f(x)$ is differentiable for any real value $x$ and that $f'(x) \le 4$ for all real values of x. Prove there is at most one real value $c>2$ such that $f(c) =c^2$.  I am completely lost on where to start on this proof and any help would be greatly appreciated!


How do I use the SVD in collaborative filtering?

I'm a bit confused with how the SVD is used in collaborative filtering. Suppose I have a social graph, and I build an adjacency matrix from the edges, then take an SVD (let's forget about regularization, learning rates, sparsity optimizations, etc), how do I use this SVD to improve my recommendations?  Suppose my social graph corresponded to instagram, and I was tasked with the responsibility of recommending users in the service, based only on the social graph.  I would first build an adjacency matrix $\mathbf A$ $(m\times m)$, take the SVD, $\mathbf A = \mathbf{U s V}$, choose the first $k$ eigenvalues, then what?  I would presumably create a new set of matrices: \begin{align} \mathbf U_{new} &\sim m\times k  \\ \mathbf s_{new} &\sim k\times k  \\ \mathbf V_{new} &\sim k\times m \end{align} then what does one do?  I've looked on the web, and most links focus on calculating the SVD, but no one tells you what to do with it. So what should I do?


Help I can't input values in database if my input has (') sign  if I go to chrome I can input it to my database but if I put (') sign it produce error  <form action="addsong.php" method="POST">
Add A Song

         <textarea type="text" class="seach-field title" name="title" placeholder="Title" required></textarea>         <textarea type="text" class="seach-field" name="verse1" placeholder="Verse 1" required></textarea>         <textarea type="text" class="seach-field" name="verse2" placeholder="Verse 2" ></textarea>         <textarea type="text" class="seach-field" name="verse3" placeholder="Verse 3" ></textarea>         <textarea type="text" class="seach-field" name="refrain" placeholder="Refrain" ></textarea>         <textarea type="text" class="seach-field" name="chorus" placeholder="Chorus" required></textarea>         <textarea type="text" class="seach-field" name="bridge" placeholder="Bridge" ></textarea>

         <button type="submit" class="search-btn noEnterSubmit" name="add-song">Add</button>         <button type="reset" onclick="window.location.href = 'index.php';" class="cancel left">Cancel</button>
 </form>   this is my addsong.php  *   $conn = mysqli_connect('localhost:3306', 'root', '', 'copy_cat');      $titles = $_POST['title'];     $v1 = $_POST['verse1'];     $v2 = $_POST['verse2'];     $v3 = $_POST['verse3'];     $refrain = $_POST['refrain'];     $chorus = $_POST['chorus'];     $bridge = $_POST['bridge'];       $query = "INSERT INTO songs (title,verse1,verse2,verse3,refrain,chorus,bridge) VALUES ('$titless','$v1','$v2','$v3','$refrain','$chorus','$bridge')";     $query_run = mysqli_query($conn, $query);      if($query_run)     {         $_SESSION['success'] = "Song Successfully Added";         header('Location: index.php');     }     else{         $_SESSION['status'] = "Song Not Added";         header('Location: error.php');      }


How to customize Linux without sudo/root access?

In my company I do not have sudo or root access to the Linux server but I still want to install my softwares and customize it to my taste.  What is a good practice to install applications to your 'user' directory that won't require root/sudo access. I've ran into multiple problems when trying to do this, that's why I don't want to focus this question to one particular application, but a general thumb rule on how to go about this process so that you don't create more problems than you solve.  Linux Info:  cat /etc/*-release SUSE Linux Enterprise Server 10 (x86_64) VERSION = 10 PATCHLEVEL = 3 LSB_VERSION="core-2.0-noarch:core-3.0-noarch:core-2.0-x86_64:core-3.0-x86_64"


I've been coding for a while and it's just struck me, what's better to use in terms of SEO:  Hello   or  Hello


How to define permissions in a Menu Deriver?

Pre-note: usually my questions aren't as vague as this one. This time though I am pretty lost in the lack of documentation, so I think I don't even completely understand the context of what I'm asking. I am looking into code that wasn't written by me and it builds a menu using a Deriver (Drupal\Component\Plugin\Derivative\DeriverBase). It's method getDerivativeDefinitions creates a list of links. The actual menu is then loaded in the page using a block. Now the menu that's being build is a menu of static links. Some of the links require that the user either has certain permissions, or has certain account checkboxes ticket. Currently these checks are being performed inside the getDerivativeDefinitions method, but that doesn't seem to work because the method is called once during a cache rebuild and then no more. Adding user as a cache context doesn't seem to change anything. Example code:   public function getDerivativeDefinitions($base_plugin_definition)   {     $links = [];     if (!$this->account->isAnonymous() && !$this->account->get('field_something')->isEmpty()) {       $links['Some link'] = 'https://some-url';     }     if (!$this->account->isAnonymous() && $this->account->hasRole('some_role')) {       $links['Something'] = 'https://some-link';     }      $menu = [];     foreach ($links as $key => $link) {       $menu['app_links' . $key] = [           'title'     => $key,           'menu_name' => 'menu-name',           'url'       => $link,           'options'   => ['attributes' => ['target' => '_blank']],         ] + $base_plugin_definition;     }      return $menu;   }  I would expect the actual link definition to have some kind of access-callback key or something like that, but I can't find that either. Does anyone know how to fix this?


What does "dual statement" mean exactly in category theory?

I have long been confused about this notion. I know that for a statement within a single category, forming the dual statement is just reversing every arrows. But what about a statement concerning several categories and functors between them?   Mac Lane suggests reversing all arrows in all categories and leaving the functors invariant in his book "Categories for the working mathematician" (page 32), but it seems that Mac Lane himself doesn't always follow this discipline (when he states "the dual of Yoneda Theorem", he doesn't reverse the arrows in $\mathbf{Set}$ !) Can anyone give me a formal definition of "dualize a statement in category theory"?


Only through struggles (you can OR can you) solve this problem. Which order is the correct?

I'm writing a description for my game's store page, and I'm having a bit of a trouble with a sentence:  Use plants and animals, collect and channel water... However only with strategy and optimisation you can solve all the levels.  Is the "you can" in the correct order there? Or should it be "can you"? Or this sounds ugly in both ways, and I should restructure it? This question already makes it a bit suspicious so I would be happy if you could suggest something else. Thanks!


I am trying to prove: $A$ compact, $B$ closed $\Rightarrow A+B = \{a+b | a\in A, b\in B\}$ closed (exercise in Rudin's Functional Analysis), where $A$ and $B$ are subsets of a topological vector space $X$. In case $X=\mathbb{R}$ this is easy, using sequences. However, since I was told that using sequences in topology is "dangerous" (don't know why though), I am trying to prove this without using sequences (or nets, which I am not familiar with). Is this possible?  My attempt was to show that if $x\notin A+B$, then $x \notin \overline{A+B}$. In some way, assuming $x\in\overline{A+B}$ should then contradict $A$ being compact. I'm not sure how to fill in the details here though. Any suggestions on this, or am I thinking in the wrong direction here?


How to resolve 'Unknown data property commerce_product' when adding a product in Drupal Commerce?

I'm wondering if someone can help: I'm trying to add Drupal Commerce into an existing Drupal site, so I've followed the steps  and managed to install all modules without problems.  The issue I'm having is when I view a product I've added. Please note that I've added the product type. I can also add the node, but every time I try to view it I get this error (in the reports/error):     EntityMetadataWrapperException: Unknown data property   commerce_product. in EntityStructureWrapper->getPropertyInfo() (line   336 of   /my/local/server/php/mysite/sites/all/modules/entity/includes/entity.wrapper.inc).   I did follow all the steps in the tutorial. When I tried to view the product like in the video I get the error.  Any ideas?


What are the drawbacks of moving an app to SD card?

Since I upgraded to Android 2.2, I noted some minor disadvantages of moving an app to SD card, like having to wait the SD card to be mounted after a reboot to be able launch the app.  What other disadvantages are there?


python copy string from position to position

I've got a string test_string like 'Hello, two is a number'" and I want to copy the characters between position 7 and 12. In the programming language I use:  test_string = 'Hello, two is a number' new_string = string_copy(test_string, 7, 12)   the value of new_string would be ' two i'. My example might be a bit stupid, but does a function exist in Python equal to string_copy?


Why does my logo look terrible and blurry on Instagram and Facebook?

I am not a graphic designer at all. The first logo I made was in Photoshop for my Etsy store. Now I want to move off Etsy but can't make my own website until I have good quality graphics.  So I made the logo as a vector in Inkscape.  It looks fine but as soon as I set it as my Instagram logo or anything, it looks super blurry and awful. I have tried different formats and making it the size px instagram requires, but it always comes out looking the same.   I've attached the png and also a screen shot of how it looks on Instagram.


How to pan my view around in a blender game?

How can I pan my camera around in a blender game? I want to be able to use camera controls in my blender game Like panning 360 around with the right mouse button. My view does not need to pan up or down, just needs to rotate around the view like to say I have a cube to represent my character! I want to be able to pan the view around it.