xelatex: I can't write on file `test.pdf'.

Every so often I'll be working and all of a sudden xelatex won't work, saying "I can't write on file `test.pdf'". But why not? Is it something I did? Did I insult xelatex? Now it won't even compile my test.tex.  This is XeTeX, Version 3.1415926-2.2-0.9995.2 (TeX Live 2009/Debian) (format=xelatex 2011.4.22). Ubuntu 10.04.  The input  \documentclass{article} \usepackage{fontspec,xltxtra,xunicode} \setmainfont{Inconsolata} \begin{document} hello world \end{document}   The error  LaTeX Font Info:    Overwriting math alphabet `\mathsf' in version `bold' (Font)                  OT1/cmss/bx/n --> EU1/lmss/bx/n on input line 4. LaTeX Font Info:    Overwriting math alphabet `\mathtt' in version `bold' (Font)                  OT1/cmtt/m/n --> EU1/lmtt/bx/n on input line 4.  [1 ! I can't write on file `test.pdf'. (Press Enter to retry, or Control-D to exit; default file extension is `.pdf') Please type another file name for output:  ! Emergency stop. <to be read again>                     \endgroup \set@typeset@protect  l.6 \end{document}  End of file on the terminal!   Here is how much of TeX's memory you used:  5003 strings out of 495724  81422 string characters out of 1189346  150108 words of memory out of 3000000  8144 multiletter control sequences out of 15000+50000  3664 words of font info for 17 fonts, out of 3000000 for 9000  28 hyphenation exceptions out of 8191  40i,4n,27p,455b,147s stack positions out of 5000i,500n,10000p,200000b,50000s No pages of output.   The inconsistency of it all  Ten minutes later (now), after tinkering around, it works. So I delete the contents of the file, and paste what I posted here, and, it works. Then I delete test.* except for the tex file, try xelatex again, and it doesn't work. The tinkering was to change the tex file to this:  \documentclass[12pt,letterpaper]{article}   \usepackage{fontspec}% provides font selecting commands  \usepackage{xunicode}% provides unicode character macros  \usepackage{xltxtra} % provides some fixes/extras   \setromanfont[Mapping=tex-text]{Inconsolata} \begin{document} hello world \end{document}   strace -f  Strace shows a memory error right before the "cannot create pdf" line. I'm experimenting with adding more swap. Currently my system is down its last 300-400 MiB of ram, and I'm seeing xelatex using upwards of 200 MiB. Which means a couple more browser tabs or another pdf window could foul things up..  clone(child_stack=0, flags=CLONE_CHILD_CLEARTID|CLONE_CHILD_SETTID|SIGCHLD, child_tidptr=0xb7887738) = -1 ENOMEM (Cannot allocate memory)`.


What would be an example of free module such that cardinality of linearly independent set is greater than the rank?

Let $R$ be a commutative ring and $M$ be a free $R$-module. Since $R$ is commutative, $R$ has the IBN property, hence the rank of $M$ is uniquely well-defined. So set $n:=\mathrm{rank}(M)$.      Let $A$ be an $R$-linearly independent subset of $M$. What is an example of $A$ such that $|A|>n$?   If $R$ is a division ring, it must be $|A|≦n$, but if $R$ is commutative, I think it is possible that $|A|>n$.


How can I check if iPhone has been manipulated or compromised firmware?

I would like to buy a secondhand or refurbished iPhone 7 or newer. Since I am not watching anything regarding the hacker's scene, I am not up-to-date. Is any newer version of the iPhone hacked? Is it possible to manipulate iPhone firmware?


Setting an additional modifier key for a custom layout

For anyone interested, and anyone who knows something about this, I have a question. Can I somehow use xmodmap or xkb to add a third modifier key to my keyboard layout? What I mean: If the layout allows it, you can use AltGr, Shift and the two's combination to get four characters out of each key when pressed, together with what they type on their own. Theoretically, if you were to bring in an additional modifier key (let us call it Meta, after a key from the Space Cadet keyboard), it could ramp up the number of characters per key to 8! 1: Typed Normally 2: +Shift 3: +AltGr 4: +Shift+AltGr 5: +Meta 6: +Shift+Meta 7: +AltGr+Meta 8: +Shift+AltGr+Meta Such a layout could be useful for a heavily multilingual situation, or scientific work requiring many different symbols. Sometimes, time might not allow to always go snooping around in the special character section. If anyone can tell me even just a theory on how to do something like this, I would be very glad. Looking forward to replies, and thank you in advance.


How to play torrented windows games on ubuntu 20.04

I Have been planning to completely to switch over ubuntu but I couldn't find any forum which gives step by step process to do so, I have no problem in playing steam games with help of proton but I couldn't find a way to play torrented games please help I know it could be done by lutris  but I couldn't find the option to select .exe


Different definitions of exterior derivative

In Sean Carroll's GR book, pg 84, the exterior derivative $d$ is defined as $$(dA)_{\mu_1\mu_2...\mu_{p+1}} = (p+1) \partial_{[\mu_1}A_{\mu_2...\mu_{p+1}]}\tag{2.76}$$ where $A$ is a $p$-form and the RHS is the appropiately normalized and antisymmetrized partial derivative. But on pg. 454, equation E.5,  he replaced the partial derivative with a covariant derivative: $(dA)_{\mu_1\mu_2...\mu_{p+1}} = (p+1) \nabla_{[\mu_1}A_{\mu_2...\mu_{p+1}]}\tag{2.76}$ Are these two definitions the same?


User "last seen" on March 17th, but has an answer from March 24th

has posted a answer on , but their profile page shows March 17 as "Last seen".    In this , you can click on "Newest" to view the bug clearly.  Is this a bug in the "Last seen" functionality?


Is there a word or expression for someone who knows various things, a little bit of everything, but is not specialised in anything?

Like a  but without being an expert in each subject.     A pantomath (pantomathēs, παντομαθής, meaning "having learnt all",   from the Greekroots παντ- 'all, every' and the root μαθ-, meaning   "learning, understanding") is a person whose astonishingly wide   interests and knowledge span the entire range of the arts and   sciences.   Update  I don't think this question is a duplicate of  as "not specialised" isn't a synonym of "superficially". Also the referred question has many answers not related to this one in terms of content and quality (as this one already has), and has been marked as a duplicate of ) so it won't make sense to mark this as a duplicate.


With reference to:    I removed the Cortana packages from my running Windows 10 using the method posted by magicandre1981 and using  win6x_registry_tweak.   My question is how can I re-install Cortana (or for that matter any other package removed similarly)?  I have opened up the install.wim image (converted from a Win 10 install.esd file) and found Cortana in the system apps folder, but don't know how / what to use to re-install it.  Any help please?


How to show that $\sum_{i=1}^n|\lambda_i|\leq \sum_{i,j}|a_{ij}|$?

I was asked by a student that     Given a matrix $(a_{ij})$ with its eigenvalues (with their multiplicities) $\{\lambda_i\}_{i=1}^n$, show that   $$\sum_{i=1}^n|\lambda_i|\leq \sum_{i,j}|a_{ij}|$$   Frankly speaking, I am not sure that it is true, but I cannot find any counterexample by try some easy example.


I have been racking my brain to understand the solutions of constrained stars and bars problems like:  $a+b+c+d = 19$;  $a,b,c,d \in \{0,1,2,3,4,5,6,7\}$  Finding the total number of solutions is really simple $\dbinom{22}{3}$.   What to do after that? I want to understand the entire procedure step by step.   Please do not mark it as a duplicate of .  Reasons:   The accepted answer's trick doesn't always work.   Another person (the answer with two upvotes) has just listed out the binomial coefficients and I can't even remotely understand what he has tried to do.   The second answer isn't my cup of tea.


What's a good way to run a point-to-point network speed test over a WAN?

I want to monitor my WAN speed between two offices, and be able to schedule it to run at certain times of the day.  I guess in its simplest form this is just a point to point copy, but I want to automate it so I can schedule it to run at certain times.   Are there any tools out there? I also wondered about doing this with Powershell.


Story about hunting giant lizards for hides on privately owned planet

In this question:  [  There is a comment about hunting giant lizards on a planet and exporting their hides.  I remember a story, possibly from Isaac Asimov's Science Fiction Adventure Magazine in the 1980s.  In an interstellar civilization, the protagonist runs out of luck on a planet and has to sign a contract to pay off his debts.  The contract requires him to hunt dangerous giant lizards on a neighboring, privately owned, planet.   The giant lizard hides are exported for use as industrial machinery belts, like buffalo hides were used in the 1800s.  The owner runs the planet like a company town, charging high prices for everything and paying little for hides, so while it is theoretically possible for a hide hunter to pay off his debt and leave, most get deeper and deeper in debt and are eventually killed by a lizard.  The protagonist eventually runs away with the owner's mistress, and the owner sends men to chase them.  The market for hides collapses when an artificial material is invented, and the planet owner goes bankrupt.  So can anyone identify that story?


c++20 Likely and Unlikely performance optimization

I read about the attributes likely and unlikely of c++20, and i want to ask if there are some reasonable and official data of performance advantages that this new attributes give to the execution. I mean there are examples execution test that give me a measure of how much this feature has impact on performance when the code is executed? I noticed that this attributes are often used in linux kernel development ( in C code ). So my question is: Does not the compiler optimaze the code sufficiently already? There are example or proof of the effective improved performances? Is this true for all kind of machine or some architectures need Likely/Unlikely for a good improvement? EDIT : I'm searching for Graph or data that demostrate the effeciency of this kind of suggestion to the compiler. ( I search online, but i don't find nothing good ) If someone know some paper, or similar can answer this question?


Do we fix divergence of the vector potential $A$, because $\nabla \cdot \nabla \psi \ne 0$?

Because $\nabla \times \nabla \psi = 0$, we can transform the vector potential $A \longmapsto A + \nabla \psi$, without changing the magnetic field. Is the reason we specify $\nabla \cdot A$ in the gauge theory, because $\nabla \cdot \nabla\psi\ne0$? Thus, we always can find a function $\psi$, such that $\nabla \cdot A$ equals to whatever we want.   A bit more elaborated:  Let's say I found $A$ and $\phi$, and $\nabla \cdot A \ne 0$. In principle, nothing stops me from finding a function $\psi$, such that $\nabla \cdot (A + \nabla \psi)=0$ (Coulomb gauge). But now my scalar potential will be modified. Then from Gauss' law: $\nabla \cdot( \nabla\phi+\frac{\partial \nabla\psi}{\partial t}- \frac{\partial }{\partial t}(A + \nabla \psi))=\nabla \cdot( \nabla\phi+\frac{\partial \nabla\psi}{\partial t})$. Thus, the new 4-potential in the  Coulomb gauge $(\phi,A)\longmapsto (\phi+\frac{\partial \nabla\psi}{\partial t},A + \nabla\psi)$. So, the freedom of choosing the divergence stems from the freedom of choice of $\nabla \phi$.


Input Unicode string in String.Format() method;

I want to input Unicode string in String.Format() method.  This is my code:  string filename = String.Format("Това трябва да е уникод {0}_{1}.doc", wayBillNum, DateTime.Now.ToShortDateString());  //File name for the exported word document HttpContext.Current.Response.AddHeader("Content-Disposition", "inline;filename=" + filename);   How to do this?


How to create a new user with restricted network access

I want to create a new user (or group), so that any application running with this user can't connect to the network.  @Michael Kjörling I have followed your suggestion(with Ubuntu 12.04 64bit) and got some error information:  $ sudo iptables -A OUTPUT -m owner --uid-owner xyz ! -i lo -j REJECT --reject-with network-unreachable iptables v1.4.12: unknown reject type "network-unreachable" Try `iptables -h' or 'iptables --help' for more information.  $ sudo iptables -A OUTPUT -m owner --uid-owner xyz ! -i lo -j REJECT  iptables v1.4.12: Can't use -i with OUTPUT  Try `iptables -h' or 'iptables --help' for more information. $ sudo iptables -A OUTPUT -m owner --uid-owner xyz ! -j REJECT  iptables v1.4.12: cannot have ! before -j Try `iptables -h' or 'iptables --help' for more information.   Finally, the following one works. But I'm not sure if there is anything wrong.  $ sudo iptables -A OUTPUT -m owner --uid-owner xyz -j REJECT  $


If an object was sliding on an infinitely long friction-less floor on Earth with relativistic speeds (ignoring air resistance), would it exert more vertical weight force on the floor than when it's at rest?


I'm trying to crack a cypher that I believe is Vigenère encrypted and I'm currently stuck.  I calculated the key length by finding repeated sequences in the cypher and calculating the the common factors.  Word    distance factors agzd    16       2,4,8,16        zna     92       2,4,23,46,92 zdc     54       2,3,6,9,18,27,54 csio    44       2,4,11,22,44 omy     46       2,23,46 zab     5        5   I assume the key-length is 4 as these are the once that are common factors, but from here on trying to map the correct caesar shiffre for each position I'm stuck.  Can somebody confirm that my key-length calculation has no errors which would explain why I can't solve the cypher.  Here is the cypher:  jD 2GSA 7HNA ZNA w.m. V7KXA 36HBM MKE5 /H SGP9 +R GKKJ 2I A4OTC KDBCUR. 19+R 8Y TKJ JG4 IGO6 6U4T OJ hH/BIK. 196 qFKT+9 BNJK ZD6+Q AGZD. kJ'R EaOP6 4NCR ZK 36 / AGZD6C/HOIE2D. x0ZNAC2S8IO8DI HB xX8D4D 0XK O66M 0Y MN62S 8TZABBD2Za8BI. lBJ HA+DF 6UU/ 2J /FOZDC6S8I OJ kDC8G OO 2BLCYZ O66M 0Y G 925F4 UL J2JHCTGH FHH3K


Ubuntu Server 16.04.3 cannot Update/Download/Install

When I run sudo apt-get update this is my output:  Err:1 http://security.ubuntu.com/ubuntu xenial-security InRelease     Temporary failure resolving 'security.ubuntu.com'   Err:2 http://us.archive.ubuntu.com/ubuntu xenial InRelease     Temporary failure resolving 'us.archive.ubuntu.com'   Err:3 http://us.archive.ubuntu.com/ubuntu xenial-updates InRelease     Temporary failure resolving 'us.archive.ubuntu.com'   Err:4 http://us.archive.ubuntu.com/ubuntu xenial-backports InRelease     Temporary failure resolving 'us.archive.ubuntu.com'   Reading package lists... Done   W: Failed to fetch   http://us.archive.ubuntu.com/ubuntu/dists/xenial/InRelease    Temporary failure resolving 'us.archive.ubuntu.com'   W: Failed to fetch http://us.archive.ubuntu.com/ubuntu/dists/xenial-updates/InRelease    Temporary failure resolving 'us.archive.ubuntu.com'   W: Failed to fetch http://us.archive.ubuntu.com/ubuntu/dists/xenial-backports/InRelease    Temporary failure resolving 'us.archive.ubuntu.com'   W: Failed to fetch http://security.ubuntu.com/ubuntu/dists/xenial-security/InRelease    Temporary failure resolving 'security.ubuntu.com' W: Some index files failed to download. They have been ignored, or old ones used instead.  I'm new to servers and have run into this issue. I've managed to get SSH up and running and am attempting to install Apache. Nothing will install. I am new to Linux servers. I have only worked with Windows Servers before.   Let me know if any other info would be helpful.


Scroll top after popping up a new window. - Jquery

So currently on button click I'm popping up a new window that goes to some website. But not only do I need to pop open to this new site but I also need to scroll down a little on the popped up screen. Here is what I'm currently doing:  $(document).ready(function () {   $('.popup').click(function(event) {     event.preventDefault();     window.open("https://www.spmet.aspx", "popupWindow", "width=1400,height=600,scrollbars=yes");     setTimeout(function() { scrollTo(0,150) }, 1000);   }); });   This currently opens the window successfully but how do I amend a change that will scroll to a particular spot in the site.


Abelian $p$-group with unique subgroup of index $p$

Let $G$ be a finite abelian $p$-group with a unique subgroup $H$ of index $p$. It is a fact that $G$ is cyclic. This can be deduced from the classification theorem for finite abelian groups by writing $G$ as a product of cyclic groups and noting that $G$ does not have a unique subgroup of index $p$ unless there is only one such group. I am wondering if there is a nice proof of this result which does not use the classification theorem. Does anyone know of one?


How to change display language in psql shell?

Here is a picture showing what it looks like:    My system language is English, I set locale to English when I install Postgres.  Not sure what happened.  I've googled around can't find anything relevant  Is there any way I can change it to English?  Thank you！


How to detect encoding in a markdown file using program effectively , to get same encoding as shown in notepad++ ?

I have a set of markdown files to be passed to jekyll project , need to find the encoding format of them i.e UTF-8 with BOM or UTF-8 without BOM or ANSI using a program or a API .   if i pass the location of the files , the files have to be listed,read and the encoding should be produced as result .  Is there any Code or API for it ?   i have already tried the sr.CurrentEncoding for stream reader as mentioned in  but the result varies with the result from a notepad++ result .  in notepad++ , the file encoding is shown as utf-8 , but from the program , the result is ANSII .   but i should get same result from both ways , so where the problem has occurred?


How to change the light grey text that many web sites seem to use these days?

Of late, I've noticed that many web sites seem to be using light grey text for many sections of their sites. Some such sections include - the text (link, usually) that shows in the status bar at the bottom of the browser when you hover the mouse over a link on their page, the indicator text in form fields to be filled in (e.g. the word "email" in the email address field), and many other elements on the page.  That light grey makes it much less readable.    Not sure whether is a new trend, or something to do with my browser settings (I haven't changed them lately, AFAIK), or Google Chrome, which is my browser. This is on Windows 7 running on a Dell Vostro laptop. I added the info about the laptop because I suspect the problem may even be due to my hardware settings, since I found the default brightness to be too high after I bought it, and changed it via Control Panel.  Would like to know what are some of the things I can check or change to solve this.  Thanks.


Does Google Maps respect the  definition in KML?

I'm using the GGeoXml object to overlay KML on an embedded Google Map. I need to customize the popup balloon for placemarks, so I'm trying to use the  element:  <?xml version="1.0" encoding="utf-8"?> <Document xmlns="http://earth.google.com/kml/2.0">     <name>Concessions</name>           ...  </Document>   This works as expected in Google Earth, but the embedded map API appears to ignore this altogether. I suppose I could just leave out the <name> element altogether and just put everything in HTML inside the <description> element, but I'd like to be able to take advantage of the  element to display custom data in a structured way.


sum of noncentral Chi-square random variables

I need to find the distribution of the random variable  $$Y=\sum_{i=1}^{n}(X_i)^2$$ where $X_i\sim{\cal{N}}(\mu_i,\sigma^2_i)$ and all $X_i$s are independent. I know that it is possible to first find the product of all moment generating functions for $X_i$s, and then transform back to obtain $Y$'s distribution. However, I wonder whether there is a general form for $Y$ like the Gaussian case: we know the sum of independent Gaussian is still a Gaussian, and thus we only need to know the summed mean and summed variance.   How about all $\sigma^2_i=\sigma^2$? Will this condition make a general solution?


String literals inside functions: automatic variables or allocated in heap?

Are the string literals we use inside functions automatic variables? Or are they allocated in heap which we have to free manually?  I've a situation like the code shown below wherein I'm assigning a string literal to a private field of the class (marked as ONE in the code) and retrieving it much later in my program and using it (marked as TWO). Am I assigning a variable in the stack to a field in ONE? Can the code be referencing to a dangling pointer which in this case worked because the program was small enough?  I've compiled and ran it, it worked fine but I'm having a strange crash in my actual program where I'm assigning string literals to fields of the class like this and I suspect the case I mentioned above.  #include <iostream>  using namespace std;  class MemoryLeak { private:     char *s; public:     MemoryLeak() {}      void store()     {         s = "Storing a string"; // ONE     }      char *retrieve()     {         return s;     } };  int main() {     MemoryLeak *obj = new MemoryLeak();     obj->store();     cout << obj->retrieve() << endl; // TWO     delete obj;     return 0; }   Should I be declaring the variable "s" as a char array instead of a pointer? I'm planning to use std::string, but I'm just curious about this.  Any pointers or help is, as always, much appreciated :) Thanks.


Systemd user timer only runs when logged in

I have as file sync script I want executed periodically every 1 min or so. Since I may need separate instances for different users I run it as a user instead of root. The issue I have is that it seems only executed when logged in. That is the timer is started and remains started but the script does not execute until the moment I enter user/pass in the terminal or am already logged in. Why does this happen? What is causing it and how to make it run in the background like any other systemd timer?  Systemd service:  [Unit] Description=******  [Service] Type=oneshot ExecStart=/usr/bin/*****  [Install] WantedBy=******.timer   Systemd timer:  [Unit] Description=**********  [Timer] OnStartupSec=1m OnUnitActiveSec=1m Unit=********  [Install] WantedBy=timers.target   Timer start command:  systemctl --user start *******.timer


I tried to prove  $$\sum\limits_{r=0}^n\binom{n}{r}=\sum\limits_{r=0}^n \frac{n!}{r!(n-r)!} =2^n.$$  I used induction method:   Assuming $$\sum\limits_{r=0}^n \frac{n!}{r!(n-r)!} =2^{n}.$$  Proving $$\sum\limits_{r=0}^{n+1} \frac{{(n+1)}!}{r!(n+1-r)!} =2^{n+1}.$$  I got $$\sum\limits_{r=0}^{n+1} \frac{{(n+1)}!}{r!(n+1-r)!} =\sum\limits_{r=0}^{n+1} \Bigl(\frac{n!}{r!(n-r)!}+\frac{n!}{(r-1)!(n-r+1)!}\Bigr),$$ and an invalid term appeared: $(-1)!$.  How does one prove this identity, and what's wrong with my method?


Can you Start Skyrim 'silent' without the launcher showing up?


I just got a brand new Nexus 4 phone and am a bit dissappointed that it doesn't support USB OTG. One reason is that is doesn't supply 5 V out of its USB port, as opposed to other Android devices I tested.*  Since I have an extra USB OTG cable lying around, I am thinking about modding it to supply the 5V from somewhere else (e.g. from a USB power supply adapter). How would I do that?   I think I should connect Vcc from the power cable to Vcc from the child, and also  connect all the grounds together (so that host (the Nexus 4) and child have the same 0V potential, relative to which D+ and D- are measured). (Is that sufficient to pull host and power supply to the same potentials? What potential do I end up with anyways? I find that a bit confusing.) Do I connect the host Vcc with the power supply+child Vcc, or do I leave it dangling? It seems there is no power on it anyway, so I can regard it as not connected (in USB mode). Is there anything special I have to do with the Sense, D+, or D- pins, or can I leave them connected as they are?   Sorry if this is a stupid question!  Here is a schematic of a regular USB (OTG) cables for reference:  From     *) There might be other problems related to its Slimport feature, though.


In Terminal how do you run a sudo command with an & at the end without prior authentication?

I have been using an & at the end of some commands, to free up the terminal. However, if it requires sudo, it doesn't work. I can get around this by running a random sudo command before it, but this is a pain, and I could also type the password in the command but this is insecure. Is there any alternative way of getting these commands to work.  Thanks.


How to insert number of records in one table with respect to each of the value of a column i another table

I have a table name TABLE1 in which I have a column YEAR where I an storing the year information like 1990 , 2000 ,2001 etc. I have another table TABLE2 in which I have the Year column and other columns as well.  Now I want to select each year from the TABLE1 and then insert some record into the TABLE2 like...  Year     Information 1990     abc 1990     lmn 1990     xyz 2000     abc 2000     lmn  2000     xyz   How can I get this I do not know how I will use the while loop or how I will get the each row from select statement and then pass it to the insert statement.


How to export Blender 2.8 for Elements 3D/After Effects (+ Node material)?

I'm new to Blender, but thanks to a few tutorials online, managed to create a cool fireball effect I'd like to utilize in one of my upcoming videos (hence Elements 3D / After Effects).  But, despite exporting the object and loading the mtl files into Elements 3D, all I get is the following:    The animation works great, and I'm getting the opacity, but that's about it.  To help clarify, below are some screenshots of what I'm trying to produce... but everything about the material was created using a node tree, which might be the issue?  Desire Result:   Full Node Tree:   Zoom in:   Just to show material location (within isosphere)   Any help would be greatly appreciated! I tried learning how to bake this using a YouTube tutorial, but I think because I'm not using Principled BSDF, it's not working? I'm honestly unsure. Sorry for such a newbie question!


Proof of : $x^{n}\equiv x^{\varphi(m)+[n \bmod \varphi(m)]} \mod m$

There is a lesser known generalization of Euler's Theorem. Here 'x' and 'm' are NOT COPRIME and $\,n\ge \log_2 m.\,$ I stumbled upon this on this site :   The "derivation" can be found towards the end of the above link; but i can't seem to wrap my head around it. It would be really great if it could be explained a bit better, probably with an example.


How to calculate the probability that one random variable is larger than another random variable?

Suppose we have two random variables $Z$ and $U$, the random variable $Z$ follows the exponential distribution and the random variable $U$ follows the general distribution $G$. The probability that $Z$ is greater than $U$ is calculated as follows: $Pr\{Z>U\}=\int_{0}^{\infty} Pr\{Z>U|U=u\} dG(u)$ Unfortunately, I can not understand why such a relationship exists. On what principle can this equation be obtained?


Will Canadian citizens be denied entry to Canada during COVID-19 border closure?

I am a Canadian citizen currently in the United States.  After calling CBSA at 1-204-983-3500, they indicated that returning to Canada right now would be considered "non-essential". Does that mean as a Canadian citizen, I would be denied entry to Canada? Wouldn't this be illegal/unconstitutional to deny a Canadian citizen entry to Canada?


How to change the default font and size in Notes on El Capitan?

Editing DefaultFonts.plist doesn't seem working anymore on the pre-release build 15A279b of El Capitan:  sudo vim /Applications/Notes.app/Contents/Resources/en.lproj/DefaultFonts.plist   It still shows that the file is readonly. I guess it's because the new  feature.  Is there another way to change the default font in Notes app?


$\int_{-2}^2 \sin\left(x^5\right)\, e^{(x^8)\sin(x^4)}\,dx\;$: integration by parts or substitution?

$$\large\int_{-2}^2 \sin\left(x^5\right)\, e^{(x^8)\sin(x^4)}\,dx$$  I think I should solve it by parts but I'm really confused. It seems as a hard question.


Is it possible to use a laptop charger in other laptop with different specifications?

Possible Duplicate:             Let's say I have my laptop charger that uses 19.5V and 3.9A and I want to use it in other laptop that has no charger but it needs just 19V and 3.16A, I've studied a little of electtronics and I know that the amperage doesn't affect because the computer will use just the necessary, but I'm not really sure about the voltage.  I read  post and I know the polarity is the same and the connector fits, but it doesn't say anything about voltage, I also know if the voltage of the charger were lower than the specification it'll not be a problem, but what about this little almost insignificant difference??


Showing the sum of n independent Bernoulli trials follows Binomial distribution

Suppose $U_1,...,U_n$ are independent Bernoulli random variables taking values $0$ or $1$ with $Pr(U_i=1) = \theta$ and $Pr(U_i=0)=1-\theta$ Let $S = U_1+...+U_n$ be the number of $U_i$ equal to one.  Show $S \sim Binomial(n, \theta)$  I'm unclear as to what I need to show in order to achieve this. Would it be enough to show: $(1)$ That the sample of space of $S$ is the same as a Binomial variable with such parameters. $(2)$ The probability of each element of the sample space and hence the probability distribution of $S$ is also the same as a Binomial variable with such parameters. Or is there something specific way to show that $S$ is a Binomial random variable?


When installing Ubuntu I didn't know the passwords wouldn't show so I just kept hitting random keys. Now I don't know the password

this is my first Ubuntu - Linux installation. I didn't know the password field would be invisible so I kept hitting random keys, and I'm guessing I also hit Enter twice because I received an error: Passwords don't match, try again? I pressed Y, but the process of installation kept going and I couldn't type the password I wanted to.   I've checked how to remove or change the password but I can't access recovery mode since my laptops' screen is dead (i use a monitor instead). I have tried holding shift down like 100000 times but I can't access recovery mode, plus the computer boots pretty fast so it makes it even harder.  How can I solve this issue?  I installed Ubuntu 20.04 LTS, Windows version is the latest one (2004). I enabled the "second screen only" option so my laptops screen won't turn on, but when booting it still does. It turns off once the Windows login screen is shown and from then I can use my monitor. Just in case, I use a Dell Latitude E7240.  If Kernel version is useful: Linux 4.4.0-19041-Microsoft. I really don't know anything about Linux and Ubuntu, just wanted to have it installed and after that I had planned to do some research, but it seems like I had to be done before installation.


Is it possible to exclude a domain name in robots.txt?  I have a single Drupal site with multiple domains pointing on it. For example our dev and staging server are being crawled by Google when our .htaccess password protection is disabled.  I don't intent to block any access in our development server but to tell search engine bots to stop indexing all the contents when the domain is/are dev or staging.   Basically I am seeing some of the links pointing in dev servers when I search some of my content in Google.  Is there any way or any module that could handle this?  EDIT:  Here's how I ended. Inside theme_preprocess_html().  // Avoid search engines to index dev and stage domains.   $restricted_domains = array('dev.mydomain.com', 'stage.mydomain.com', 'editorial.mydomain.com');    if (in_array($_SERVER['HTTP_HOST'], $restricted_domains)) {     $meta_robot = array(       '#tag' => 'meta',       '#attributes' => array(         'name' => 'robots',         'content' => 'noindex, nofollow'       ),     );     drupal_add_html_head($meta_robot);   }


It seems you have seen this question posed by many users. But still i want to clear my doubt Regarding Implication in Mathematical Logic which is $p \to q$   I have clearly understood these:  $1.$ If $p$ is True, $q$ is True, Then the Implication is True  $2.$ If $p$ is false, $q$ is False, Then the Implication is True  $3.$ If $p$ is True, $q$ is False, Then the Implication is False  But why If $p$ is False and $q$ is True, The Implication is treated as True.  One example I convinced myself with is:  If $x=2$, Then $x^2+1=5$  Where $p$ is the statement $x=2$ and $q$ is the statement $x^2+1=5$  Now if $p$ is false, Then still $q$ can be true, since $x=-2$ will help to make $q$ True.But there are infinite values of $x$ which makes $q$ false, hence majority of values of $x$ are making $q$ false. Hence the Implication is TRUE.  Now i started to think about a different example Viz:  If $x \gt 7$, Then $x \gt 5$  Now if $p$ is false There are infinite values of $x$ making $q$ True that is all numbers $ x \in (5 \:\: 7]$   Also $q$ is false for all $x \in (-\infty \:\: 5]$   Since density of numbers in second interval is more, The Implication Should be TRUE again.  Is this the Reason when $p$ is False and $q$ is True, Implication is considered TRUE?, since when $p$ is false the number of reasons for $q$ being true less than number of causes making $q$ false?


Call a function specified in variable in javascript

I have a input hidden type which specifies the function that needs to be called. How can I do it using Javascript/Jquery  <input type="hidden" name="extrafunction" id="extrafunction" value="edit_data_provider/DataProviderChange1" />   and in Javascript file          var fullfunctionName = $('#extrafunction').val();         var control_name    = fullfunctionName.split('/')[0];         var function_name   = fullfunctionName.split('/')[1];         if(control_name == client_control_name)         {             //The function call which is in function_name var should come here          }


Might the use of the word "where" be inapt in these three sentences?

The question found  triggered a question in my mind. Lately I've been noticing how people tend to use the word where in a way which to me seems inapt. Some examples:   Anorexia is a condition where a person, usually a young female, has such a poor body image that she virtually starves herself to death.  A phobia is where you have a fear of, say, clowns, and this fear seemingly has no rational basis.  The abused dog suffered from hypothermia, a condition where the body's core temperature drops to a near-fatal level.    Wouldn't the words in which (or when, in the case of the hypothermic dog) be a better fit than where in the first and third examples?   Anorexia is a condition in which a person . . ..  The abused dog suffered from hypothermia, a condition in which . . .. Or, The abused dog suffered from hypothermia, a condition when . . ..    Wouldn't the word when, or the words a condition in which, be a better fit than where in the second example?   A phobia is when . . .. Or, A phobia is a condition in which . . ..   I'm not suggesting my substitutions are necessarily the best or that they exhaust the number of possibilities, but isn't the use of the word where inapt in my examples? If so, why? If not, why not?


How can we find the maximum current a source can provide,say if my device need 1amp and the source can provide 2 amps in the rated voltage will my device only draw 1 amphere or will it draw 2 amp in this case is there any chance my device may burn out of over current.


Let X be an uncountable set. And let $$\mathcal{A} =\{A\subset X: A \text{ is countable or } X-A \text{ is countable}\}.$$ Then it can be shown that $\mathcal{A}$ is a $\sigma$-algebra. Define $\mu:\mathcal{A}\rightarrow [0,\infty]$ by $\mu(A)=0$ if $A$ is countable or 1 otherwise. The task is to show that $\mu$ so defined is a measure on $\mathcal{A}$.  It is clear that $\mu(\emptyset)=0$. Now we want to show that $\mu$ is countably additive on disjoint sets from $\mathcal{A}$. I'm first trying to show this for two disjoint sets $A$ and $B$ in $\mathcal{A}$. I am running into a problem if I assume that both $X-A$ and $X-B$ is countable.  For if this happens then, $B\subset X-A$ implies $B$ is countable. But both $B$ and $X-B$ cannot be countable, since then $X=B\cup (X-B)$ will be countable, running contrary to the assumption that $X$ is uncountable. How should I address this case?


I know that sites have two main stages once they leave Area 51: beta and graduated.  In order for a site to graduate from beta, it must meet a few requirements such as   A certain number of questions per day (10 I think) A certain number of users above a specific reputation level   However, I was wondering if a site that has graduated, Movies & TV for example, could be reduced back down to beta level if they drop below these requirements?


How to apply layer style to one object and apply it to multiple layers

I think what I may be looking for exists in Fireworks maybe, but I haven't messed with it. Basically, is there a way to make a style sheet for an object?  Say I have an object and I apply x layer styles to it, then I want all those layer styles on multiple objects throughout a document. Then I want to change the strength of a drop shadow, how would I set it up so all I had to do is change the drop on the master file and it would apply to all with this "style" set on it?


Can someone call themselves Dr. so and so (ABD)?

Someone in my profession is referring to themselves as Dr. so and so (ABD). It is my understanding that they are not a Dr. since they have not completed the dissertation process. Doesn't it seem fraudulent to refer to yourself as Dr. without completing a doctoral program?


I am passing a parameter     public void addStudent(String studentName)      {          if (studentName != null)      {    int[] array = new int[NUM_QUIZZES];         for (int i = 0; i < array.length; i++)      {          array[i] = MIN_GRADE;         }         quizMarks.put(formatName(studentName), array);        }         }   > new student, marks set to 0   /**    * returns the quiz marks for a given student    * @param student    * @return the array of quiz marks for this student   */ public int[] getQuizzes(String student)      {        int[] array = quizMarks.get(student);        if (student != null)      {         for (int arrays : array)     {     System.out.println(arrays);         }        }   return array;    }     I want  to get the marks displayed, but it gives me Exception in thread "main" java.lang.NullPointerException at StudentDatabase.getQuizzes(StudentDatabase.java:68) : line 68: for (int arrays : array)


SOQL results returning RecordTypeId which is not included in query

I am running this script from developer console.  List<Account> lstAccount = [SELECT Id, Name, BillingStreet From Account LIMIT 1]; System.debug(lstAccount);   Debug Log:     23:47:04:012 USER_DEBUG [5]|DEBUG|(Account:{Id=0019000001nNLGEAA4, Name=Acct_nm001, BillingStreet=xyz Road, RecordTypeId=01290000000iaNiAAI})   I never queried for RecordtypeId in SOQL, but it is included in the list.  Although, if I run the query from the query editor, it is not showing RecordtypeId column.   Is this by design? Then why not Salesforce is not providing us audit fields in the first scenario.


Find all roots of $\,x^2\!\equiv x\pmod{\!900}$, i.e all idempotents in $\Bbb Z_{900}$

I need the idempotent elements of $Z_{900}$ $2^2\cdot 3^2\cdot 5^2=900$ Of course there's $$0 \pmod 4 \\ 0 \pmod 9 \\ 0 \pmod {25} \\ $$ and $$ 1 \pmod 4 \\ 1 \pmod 9 \\ 1 \pmod {25} \\ $$ I found the answers by making a C++ program to test all numbers, but I don't know how to quick solve on paper. This is the output of the program $(0, 0, 0) \rightarrow 0 \\ (1, 1, 1) \rightarrow 1 \\ (0, 0, 1) \rightarrow 576 \\ (0, 1, 0) \rightarrow 100 \\ (1, 0, 0) \rightarrow 225 \\ (1, 1, 0) \rightarrow 325 \\ (0, 1, 1) \rightarrow 676 \\ (1, 0, 1) \rightarrow 801 \\$


How do we prove $\int \frac{\ln(1+x)}{x}dx = -\sum_{k=1}^{\infty}\frac{(-x)^k}{k^2}$?

After working on the integral $\int_{0}^{1} \frac{\ln(1+x)}{x}dx$ for a couple of hours, I became convinced its antiderivative was not elementary. So I looked it up on Wolfram Alpha, and it found that  $$\displaystyle{\int \frac{\ln(1+x)}{x}dx = -\sum_{k=1}^{\infty}\frac{(-x)^k}{k^2} = -\text{Li}_2(-x)}.$$ How does one prove this result? I have no idea where to even begin...


almost all is in the title : imindq asks an url when attempting to add a picture to a node.  I would like to add a local picture...  I tried something like this :      file:///sdcard/pictures/position_-2101364257.jpg   but it does not seem to work.  thank you


I have the following code to reverse linked list But I am getting NPE at         head.next = prev; How can I resolve it?      ListNode l = new ListNode();             l.insert(4);             l.insert(10);             l.insert(12);              l.show();             l.reverse();             l.show();  public void reverse() {         ListNode nextNode = null;         ListNode curr = head;         ListNode prev = null;          while (curr != null) {              nextNode = curr.next;             curr.next = prev;             prev = curr;             curr = nextNode;         }          head = curr;         head.next = prev;      }


Is there an ideal PWM frequency for DC brush motors?

I'll be using a microcontroller to create a PWM signal for motor control. I understand how PWM and duty cycle works, however I am unsure about an ideal frequency. I do not have my motor in yet, so I can't just test it and find out.  The picture depicts a graph of RPM vs Voltage. It's linear from 50 RPM @ 8 V to 150 RPM @ 24 V. I will not be varying voltage, just the time it receives a given voltage. So can I assume a linear response? At a 10% duty and 24 V supply it would run at a speed of 15 RPM? If it makes a difference, I'll include the setup. I am running 24 V directly to an H-bridge that controls the motor. Obviously I have two PWM pins going from the MCU to the gates of the two enable MOSFETS.


How do I enable comments for user profiles?

With users being entities in D7 I assumed the user type would would have built in "comment" option. That doesn't seem to be the case. I just want to allow users to leave comments on the user profile page. Is there a simple way to doing that?


The use of "were- should- had” at the beginning of sentences instead of “if”

Conditionals in English are usually formed by using if with normal word order; but for the three past (subjunctive) forms were, should, and had, it is also possible to express the conditional through subject–auxiliary inversion alone, with no if in the conditional clause.  Does forming conditionals in this manner differ semantically from if-conditionals? Is some aspect of the conditional statement or the conditionality emphasised more in one version than in the other? Or are there differences in how and when they are used? Or are they simply completely interchangeable?  For example:     If I were you, I would try it again   Were I you, I would try it again      If I had seen it, I would have told you   Had I seen it, I would have told you      If you should drink, don’t get behind the wheel   Should you drink, don’t get behind the wheel


How do you make the Windows 8 Metro Photo Viewer open up faster?

I just installed Windows 8.1. Every time I try and open an image, the photo viewer metro app  fills the screen for about a second before the image is displayed.  Is there any way to make the app start up faster?


I've discovered that you can \pause within a tikzpicture, which works well until I switched the theme to one with a footline.  I've created a "test case" that illustrates the problem.  \documentclass{beamer} \providecommand\thispdfpagelabel[1]{} % Not sure what this does but our installation requires it. \usepackage{tikz} \usetheme{Madrid} % Has a footline.  \begin{document}   \begin{frame}     \frametitle{test}     \begin{tikzpicture}       \node at (0, 1) {Hello};       \pause       \node at (0, 0) {World};     \end{tikzpicture}   \end{frame} \end{document}   This creates two slides, but the footline is only drawn on the second (the headline/title appears on both). Is there anything I can do about this?


How does the variance-covariance matrix change when I create a linear combination of two variables?

Suppose I have four normal r.v (X,Y,W,Z) and the variance-covariance matrix is know. If I create a new r.v J=aX+bY (a and b are scalar), what is the new variance-covariance matrix? Thank you


How to evaluate $\int_0^1\frac{\log^2(1+x)}x\mathrm dx$?

The definite integral  $$\int_0^1\frac{\log^2(1+x)}x\mathrm dx=\frac{\zeta(3)}4$$  arose in my answer to . I couldn't find it treated anywhere online. I eventually found two ways to evaluate the integral, and I'm posting them as answers, but they both seem like a complicated detour for a simple result, so I'm posting this question not only to record my answers but also to ask whether there's a more elegant derivation of the result.  Note that either using the method described in  or substituting the power series for $\log(1+x)$ and using  $$\frac1k\frac1{s-k}=\frac1s\left(\frac1k+\frac1{s-k}\right)\;$$  yields  $$ \int_0^1\frac{\log^2(1+x)}x\mathrm dx=2\sum_{n=1}^\infty\frac{(-1)^{n+1}H_n}{(n+1)^2}\;. $$  However, since the corresponding identity without the alternating sign is used to obtain the sum by evaluating the integral and not vice versa, I'm not sure that this constitutes progress.


Sizes of icons for SE network sites are not equal

The sizes of one icon for a StackExchange site (English Language Learners) is bigger than another (LEGO).  Should this be the same size in the iOS app?


C++ Template Function - Undefined Reference Error

I'm learning to use templates within C++ for defining generic functions. I'm having issues with getting a simple program to compile. I keep getting an error saying that the function call in main is an undefined reference.  I'm probably making a fundamental mistake somewhere in how I declare the template. Possibly with try to pass a const reference.   Please be gentle, I haven't coded C++ in a few months.  Thanks, -Izzo  main.cpp  #include <iostream> #include <Probability.h>  using namespace std;  int main() {      int hoor[] = {3, 3, 1, 1};      cout << "Hello world!" << endl;     Probability prob;      prob.ExpectedValueDataSet(hoor);  }   Probability.h  #ifndef COFFEEDEVMATH_PROBABILITY_H #define COFFEEDEVMATH_PROBABILITY_H   class Probability {     public:         Probability();         template <typename T> void ExpectedValueDataSet(const T& data);      protected:     private: };  #endif // COFFEEDEVMATH_PROBABILITY_H   Probability.cpp  #include "Probability.h" #include <iostream>  Probability::Probability(void) {     //ctor }  /* Expected Value */ template <typename T> void ExpectedValueDataSet(const T& data) {     bool error = 1;     typename T::iterator it;     double avg = 0;       for(it = data.begin(); it != data.end(); it++)     {         avg = ((it - data.begin())*avg)/avg + data[it]/it;// Do nothing for now         std::cout << avg;         std::cout << "/n";     }   }


I need to fill a box up with objects. See picture. I'm totally new to Blender and haven't found any answer to this question online. Its mostly how to fill (cover with a face) or animations with rigid body, so if someone could point me in a direction it would be great! Thanks in advance.


How can I set IP on Debian for multiple interface?

I want to put in place a network balancing cluster for a web server on Debian. So I must use 2 network adapters for this service. The first one will be for the local network and the second one will be for a separate cluster network.   network 1: 172.16.0.0  network 2: 192.168.17.0  I modified this file /etc/network/interfaces like this:  #interface 1 allow-hotplug enp0s3 iface enp0s3 inet static  address 172.16.17.229 netmask 255.255.0.0 broadcast 172.16.255.255 gateway 172.16.0.1 dns-* options are implemented by resolconf package, if installed dns-server 172.16.17.20  #interface 2 allow-hotplug enp0s8 iface enp0s8 inet static  address 192.168.17.229 netmask 255.255.255.0 broadcast 192.168.17.255   After configuring the second interface, I am not able to ping www.google.com. I want to know where the problem comes from.  *I have restarted the computer and still not able to.


Is it possible in pdo to have a query with a operator like + - * or / ?  The solution is to put spaces between the ? and the operators  this will not work  $table01.Amount - ?*?   This works  $table01.Amount - ? * ?   the query  UPDATE account SET account.Amount = account.Amount - 1000000*0.03 WHERE account.Id = 23;   throws an error but putting this query into the database clients gives me no error  $sqlAccountUpdate="UPDATE $table01                 SET                  $table01.Amount = $table01.Amount - ?*?                 WHERE                 $table01.Id = ?;"; try  { $stmtAccountUpdate = $pdo->prepare($sqlAccountUpdate); $stmtAccountUpdate->execute([$_POST['new_account_initial_deposit'], $deposit_fee, $accountid]); } catch(Exception $e)  { echo 'Exception -> '; var_dump($e->getMessage()); }   the error I get is caused by this this is the line that gives the error:  $table01.Amount - ?*?   I know I can work around it by calculating the values before the prepared statement and using 1 variable instead of doing the calculation in the prepared statement.  this works  $initalFee=$_POST['new_account_initial_deposit']*$deposit_fee; $sqlAccountUpdate="UPDATE $table01                 SET                  $table01.Amount = $table01.Amount - ?                 WHERE                 $table01.Id = ?;"; try  { $stmtAccountUpdate = $pdo->prepare($sqlAccountUpdate); $stmtAccountUpdate->execute([$initalFee, $accountid]); } catch(Exception $e)  { echo 'Exception -> '; var_dump($e->getMessage()); }


Topological equivalence between $\mathbb Q^2$ and $S\subset\mathbb R$

I'm wondering if the metric spaces $S:=\{x+y\sqrt{2}:x,y\in\mathbb Q\}$ and $\mathbb Q^2$, with metrics induced by $\mathbb R$ and $\mathbb R^2$ respectively, are topologically equivalent. I know that the function $f:\mathbb Q^2\to S$ defined by $f(x,y):=x+y\sqrt{2}$ is bijective, but how can I show that $f$ is continuous / not continuous?


Human & Alien captured, observed by higher beings

From a collection of short stories I read at least 30 years ago. :/  This is going to be incredibly vague, so apologies in advance.  A human and alien (blob/octopus-like...I think) from warring races are captured by an unidentified higher intelligence and put in an enclosure (more like a zoo habitat rather than a prison cell). They are separated by an invisible barrier and can see each other.  I think they were both trying to escape or trying to figure out how they could kill the other first. There was a bulldozer/loader type vehicle they could use at one point to build a shelter (or something).  I believe they were crafting makeshift weapons as well. There was no communication between the two as far as I remember.  The main tension in the story seemed to be was the race to get to the other first.  This has been stuck in my head forever. I know its a very common theme.  The short stories may have included Asimov.


How to make looping/cyclic clock-hand animation seamless?

I am making a (non realistic) clock hands animation. But there's a slight pause at the end of the loop. I have copy/pasting the first frame to last, making the graph cyclic, using the steps modifier, but none of them seems to work for me. :(    Also, how do I create and upload those nice gif captures I often see here in theis forum? Is there a native method to capture gifs from blender and host to here?  UPDATE: In the other thread marked as duplicate of this one, the 'set keyframes as linear option' solves this issue, but not completely. There is still a tiny pause at the end of the loop, probably due to the end keyframe sharing the same values as the first. But if I duplicate the first frame to the last, the entire clock animation rewinds at the last frame, and then starts again normally.


Next is a riddle that I found interesting and I decide to share it with you. Try solve it by yourself before reading the answer.  A merchant has 13 fair gold coins with one fake among them. The fake coin have been made by a skillful thief and look identical to the real coins, except for it's weight, its different, it might be lighter or heavier then the real one. The merchant has a balance that allows him to compare the weight of two groups of coins. Can he distinguish the fake coins from the fair coins with only 3 weights?   13 coins 1 of the 13 is fake Fake coin is lighter or heavier 3 weights


Number of Divisors of $N = 3^55^77^9$ of the form $4n+1$

I need to find the number of divisors of $N = 3^55^77^9$ that are of the form $4n+1$, $n\geq 0$.  My try:  I noticed that $5$ itself is a number of the form $4n+1$ so all of its power satisfy the required condition, so number for the exponent of $5$ will be $7+1 = 8$.  Also, even powers of $3$ and $7$ satisfy the required condition.   But, I also noticed that odd powers of $3$ and $7$ multiplied together also satisfy the given condition as $(4m+3)(4k+3) = 4q+1$. How would I take that into account?


I wonder if you have a more practical way of doing the following:   Indent the text in 4cm Maintaining justified alignment The text should occupy all available space except the edges and 4cm   Something like the image below (the right alignment is bad)   It is possible to do this also using two minipage, but it is still not very practical


Since the change, I've clicked on the bounty link a couple of times, when I meant the comment link, my eyes/hand just automatically go to 'the link at the bottom'. How about putting the bounty link opposite (on the right) rather than below?  Just a thought.


About This Mac → Storage suggests more space in on the SSD than is actually being used

I've got a 480 GB SSD in a MacBook Pro running OS X El Capitan 10.11.6. I have recently reformatted the drive and clean installed the OS.  I have very limited programmes installed on this machine and all my files are managed by Dropbox, using their , which stores all your files in the Dropbox cloud and downloads them locally as and when you need them.  What's strange is that although I've got a 480 GB SSD, and only using c. 25GB as confirmed by the total at the bottom of Finder (see attached screenshot), if I go to About this Mac → Storage, it says I've used about 210 GB, mostly all photos and movies.  Any idea why this would be?


How can I calculate the average age of survey respondents?

A question in my survey asks about the age of respondents. Respondents are asked to choose one of these four ranges:  18-29 30-49 50-64 65 and over  How can I calculate the average age of respondents?


How do I install Brother HL-2280dw network printer?

New to Ubuntu (using 15.04) and trying to install a couple of Network printers I have. Brother HL-2280dw, and Brother MFC-J870dw. I downloaded the Linux deb drivers from Brother's support site and the application installer will give a message to not install.  Why?  Also tried directly by connecting to the network printer, and letting Ubuntu look for drivers and install from a free site it recommended, but during the installation it froze, and I had to reboot.


Show Kripke's model proving that the following formula isn't tautology in intuitionistic logic. $ \neg ( p \wedge q ) \implies (\neg p \vee \neg q) $  Please help/hint me ;)


cannot access array from index i-1 through Null Pointer exception

I'm working on a 2D array. The problem is really simple but I can't figure it out. When I try to access the value from index array[i-1][j] it is throwing a Null Pointer exception. While it seems completely legitimate to me to access a index like array[2-1][2] . Why it is not working? Is there any logic behind why I can't access array from one back index OR am I doing it wrong please explain.  Code to declare and initialize array:  this.Result = new Integer[len][6];   Code where Null pointer exception occurring:  for(int i=0;i<Result.length;i++) {     if(i==0){         Result[i][4]=0;     }     else if(Result[i][1]!=null) {         Result[i][4]=(Result[i-1][2]+Result[i-1][3])+Result[i][2];     } }   Thanks in advance and please ignore grammar mistakes.


How do I perform an action on all files with a specific extension in subfolders in an elegant way?

My current best bet is:  for i in $(find . -name *.jpg); do echo $i; done   Problem: does not handle spaces in filenames.   Note: I would also love a graphical way of doing this, such as the "tree" command.


$\log x =Cx^4$ has only one root. Find C.  I don't know how to solve this problem. Do you take derivative on both sides?  I am thinking C equals 0. Am I correct on that?


Why did "they" rely on cooper and his daughter to save themselves in Interstellar

If "they" were our descendants who transcended to the 5th dimension, "they" are practically a Godlike civilization compared to us, then why did they developed this complicated plan rather than simply communicating with NASA and send the equations to save the earth? I mean, Cooper nearly died on several occasions, and if these guys are our descendants, they were practically playing roulette with their own survival.


Why does lastModifiedById is same on Trigger.OldMap and Trigger.NewMap in before update trigger

I am writing a before update trigger on case object. And I am debugging the LastModified by ID in case of Trigger.oldMap and Trigger.newMap.  I was expecting them to be different values.  But I am getting the same values in both the cases (In case of Before update trigger).  But, if I compare other fields that are modified like subject, I am getting the different values in both the maps. I am not able to understand the reason for the same. Has anyone ever faced the same issue?


What will happen if a stick and a beam of light is to race

I don't know whether the question is asked before on not on this website as I can't found it anywhere so I have to ask. What will happen if a place a long stick with a length of a light year. Rather othe dimensions not matter just the sri k is a s long as a light year. Now I have placed a switch just in one end of the stick 1 cm apart. And the other end is on earth. Now my question is that what will happen if I push that stick and send a beam of light simultaneously toward thar stick who will win. The stick or the beam. I know the light will win but can you explain the phenomenon.


I began an iPhone project the other day with a silly development code name, and now I want to change the name of the project since it's nearly finished.   But I'm not sure how to do this with Xcode, trying the obvious of changing the application's name in the info.plist file, causes the signing process to go wrong (I think...) and my app won't launch giving me a Launcher error.  I guess I could make a new project and copy paste everything over, but it seems so primitive that I'm hoping for a more civilized solution.


How to extract X Y coordinates and RGB from pixels using python in QGIS?

I'm trying to white a Python plugin in QGIS (2.2) to get, for each pixel of a raster image, its X Y coordinates, as well as, its RGB (3 bands) values.  At first I opened the raster file using: rlayer = QgsRasterLayer(rfileName, rbaseName)  Now I don't know how to get, for example, for pixel (1,1) its coordinates (X,Y) and its RGB color values.  Anybody could help me?  I know that I'll need to implement a DO WHILE, but I don't know the commands to extract this information of each pixel.  Thanks in advance, Mateus


Random numbers created when doing arithmetic's on float in c

I am very new to c but I have to create a program for school and for that, I need to know how many decimal numbers are in a number but when I try this a bunch of random numbers come from the 4th dimension and I don't know how to fix it, can anybody help me? Here is the code:  int main(void) {   float test = 1.567;   while (test != 0){     test = test * 10;       test = test - (int)test;     printf("%f\n",test);   } }  Edit: I'm running on windows 10, and I'm using repl.it to program and run it. This is the output I get 0.670000 0.700001 0.000008 0.000076 0.000763 0.007629 0.076294 0.762939 0.629395 0.293945 0.939453 0.394531 0.945312 0.453125 0.531250 0.312500 0.125000 0.250000 0.500000 0.000000  Edit 2: The assignment is that we have to create a program where you have to enter an amount of money and it tells you how many 2 euro coins, 1 euro coins, etc. you need to get that amount and because you can't have 4.63454 euro I wanted to make sure that you can only enter 2 decimal numbers otherwise it would throw an error. So TLDR: you enter the number via the keyboard, but the same thing happens then.


70s/80s scifi movie: astronauts return to future earth

I remember seeing a movie when I was young (around late 80s) about a couple of astronauts returning to Earth. They either had some kind of an accident or fluke as there was some sort of time travel going on (or maybe parallel universe?) and they returned to a future Earth. (Note, future as in present day, like traveling from the 60s to 80s, not futuristic scifi-movie type future.)  I can't remember if there was any huge post-apocalyptic stuff but I remember at least two male astronauts walking in a desert and finding a can of coca-cola and going something like "at least we know we are in America" but they had never seen (aluminium) cans before and then they wondered what the can was made of as "it's too light to be metal" or something similar.  I remember enjoying the movie but sadly this is all the info I can remember.  It is NOT the following:   Operation Ganymede Planet Earth Genesis II Strange New World


login loop even after remove nvidia driver

I've got infinite loop problem after installing CUDA (which automatically install nvidia driver). I have tried removing nvidia driver with   sudo apt-get remove --purge nvidia-* sudo apt-get install ubuntu-desktop   and removing /etc/X11/xorg.conf, but the problem is still not solved. I have also tried logging into tty and run startx from there, but with no luck.   My laptop has a Intel integrated graphics controller, and a nvidia Geforce 970M video card. Right now when I run lspci, I can see it's running on the Intel graphics controller.  Any idea how to solve this login loop problem?  The message in ~/.xsession-errors is listed below:  Xlib:  extension "GLX" missing on display ":0". Script for ibus started at run_im. init: gnome-session (Unity) main process (1761) terminated with status 1 init: unity-settings-daemon main process (1752) killed by TERM signal init: logrotate main process (1652) killed by TERM signal init: update-notifier-crash (/var/crash/_opt_google_chrome_chrome.1000.crash) main process (1691) killed by TERM signal init: update-notifier-crash (/var/crash/_usr_lib_x86_64-linux-gnu_indicator-application_indicator-application-service.1000.crash) main process (1696) killed by TERM signal init: xsession-init main process (1748) killed by TERM signal init: hud main process (1757) killed by TERM signal init: Disconnected from notified D-Bus bus init: unity-panel-service main process (1766) killed by TERM signal Xsession: X session started for root at Wed Nov 11 05:49:16 EST 2015 localuser:root being added to access control list Script for ibus started at run_im. Script for ibus started at run_im. Xlib:  extension "GLX" missing on display ":1". Xlib:  extension "GLX" missing on display ":1". Xlib:  extension "GLX" missing on display ":1". gnome-session-is-accelerated: No hardware 3D support. gnome-session-check-accelerated: Helper exited with code 256 Xlib:  extension "GLX" missing on display ":1". Xlib:  extension "GLX" missing on display ":1". Xlib:  extension "GLX" missing on display ":1". gnome-session-is-accelerated: No hardware 3D support. gnome-session-check-accelerated: Helper exited with code 256 x-session-manager[2248]: WARNING: software acceleration check failed: Child process exited with code 1 x-session-manager[2248]: CRITICAL: We failed, but the fail whale is dead. Sorry....


How to derive the formula for the sum of the first $n$ odd numbers: $n^2=\sum_{k=1}^n(2k-1).$

How to derive this formula?   $$n^2=\sum_{k=1}^n(2k-1).$$


I am writing my own library and i have a text file which i need to load into a variable. I know i can do this using Jquery but i would really like to know how this is done using java script native. I couldn't find any good resources for this so here i am :/  Soooo how do i replace this code with javascript?  $('#result').load('txt.txt', function() {   alert('Load was performed.'); });   I actually need the text to be in a variable and not an element.


python3-django is a package available in the repos for Ubuntu 15.04. It isn't in the default repos for Ubuntu 14.04. How can I install it in Ubuntu 14.04?


If I spinned a fan in a vacuum it will keep spinning forever. Why can we not make energy out of it?

Suppose we created a vacuum and spinned a turbine inside it with some amount of force. According to newton's second law it will keep spinning as there is no air resistance, so why can we not make electricity out of it?


How can I both decrease image width with 50% and increase its height to 150%?

I've tried to use scale, but it doesn't work in this case. Have you guys any idea how can I achieve this?


I know Java well. Which caveats and resources will help me cross to the other side (C#) as painlessly as possible.


How to remove apps that are remembered by App Store?

Over the past few years, I have downloaded various apps onto my iPhone from the App Store.  I have noticed that the App Store remembers the apps that I have downloaded.  So, for instance: If I download an app and then delete it from my phone and go back into the App Store, the download icon is different (it doesn't say "+Get" like apps that I have never downloaded before, instead it will have an icon of a cloud with an arrow pointing downwards).  How to I get the App Store/iCloud to forget these programs?


Dealing with difficult male players, when you're a new female player?

There was quite a bit of discussion about this after I posted , so I thought I would do as advised and re-ask the question in a new topic.  I will be playing D&D 5th edition soon with a group of all male players. This will be my first time playing D&D (or anything even remotely similar) and as the only female player this group has ever had, I'm quite worried about how to deal with integrating into the group. I'm interested in playing with this group because I'm very close to the DM, and I don't really know any other groups in the area. (The ones that I do are a bit too eager for a female player. I would rather deal with hostility.)  My main concern are two of the players that I know are difficult to deal with, as a girl.  One, from all my experiences with him, is extremely sexist and loves to put girls 'back into their place' and to let them 'know where they belong'.  He makes a point of it by calling me 'it' in real life, as, according to him, my unusual name isn't really a name and as such it isn't worth addressing me by.  The other I don't know well, but from what I've heard from the DM, is a sadist and likely to target and attempt to kill or seriously injure my character.  I'm extremely shy and I don't tend to speak up for myself, but I don't want to be put of from trying more RP games because of a bad first experience.   What's the best way to deal with difficult players, as a female that's new to the game?


Why is there no antiderivative to the integral of sin(x)/x

I have been baffled for a while now because no antiderivative has been found for what seems to be a simple enough Integral on the surface.   $$\text{Si}(x)= \int \frac{\sin(x)}{x} dx $$  Is this due to the fact that we do not know what its sum approximates? Namely :   $$\sum_{k=0}^{\infty} \frac {(-1)^k x^{2k+1}}{(2k+1)(2k+1)!} = \text{Si}(x) $$  I have noticed that Si(x) , Ci(x) , Ei(x) all contain sums in their definitions which follow the pattern.  $$ \sum_{k=t }^{\infty}\frac{\text{something}}{a \cdot a!}$$  Do we simply not know what these sums approach  or do not know how to tackle the integral form, or is it impossible to give the antiderivative in terms of elementary functions??   Thank you very much for your time and help.


Note I am looking a proof using Peano's axiom as I am working on the Natural Numbers, not the Real Numbers.  I need help proving "For each x,y,z in N, if $x<y$ then $x+z<y+z$  This must be done using Peano's axioms and the definitions of addition, multiplication, and ordering.  I have tried induction on z, and the base case works out but I run into an issue when it comes to the inductive part seeing as I am no longer dealing with equality.  I think induction is the correct way to approach this proof, however I become stuck once I reach a certain point in the proof.


I've got a bunch of files named with a the pattern 99 - DescriptiveName.txt and I'd like to remove the number from the front so I just have DescriptiveName.txt.  How can I do this? Can I do it from the command line or is there a utility that can do this?


How to type the symbol of viscous stress tensor?

How to insert the symbols shown below in LaTeX?


I have some big problems with my packages in my Ubuntu 16.04 Xenial. In the last few days I've changed my sources.list a lot and I've added some bunches of PPAs. Now I'm lost and don't know what to do.  I think I'm an intermediate Linux user. I started to use Debian 2 or 3 years ago, but I have problems everyday. In some months I had to format my machine more than 3 times due to problems with packages, drivers and multi-architecture.  This problem started when I tried to install VLC media player. They showed me that I have dependencies with libgles1-mesa and the system can't solve by itself. Then it asked me to try apt-get -f install to force the installation of dependencies, but my system can't solve this again.  After a lot of changes and attempts, I couldn't solve my problem, so here is some information about my status. I hope someone can help me to fix this.  I'm sorry about this, but my system is in Brazilian Portuguese. [Edit: the below is partially translated.]  uname -a  Linux Max-Notebook 4.8.0-45-generic #48~16.04.1-Ubuntu SMP Fri Mar 24 12:46:56 UTC 2017 x86_64 x86_64 x86_64 GNU/Linux   sudo apt-get install vlc  Reading package lists... Done Building dependency tree Reading state information... Done You might want to run 'apt-get -f install' to correct these: The following packages have unmet dependencies:  libgl1-mesa-glx : Depends: libglapi-mesa (= 17.0.1+git20170319+17.0.07adc57f-0ubuntu0ricotz~xenial) but 11.2.0-1ubuntu2 is to be installed  libglapi-mesa : Breaks: libglapi-mesa:i386 (!= 11.2.0-1ubuntu2) mas 17.0.1+git20170319+17.0.07adc57f-0ubuntu0ricotz~xenial está para ser instalado  libglapi-mesa:i386 : Quebra: libglapi-mesa (!= 17.0.1+git20170319+17.0.07adc57f-0ubuntu0ricotz~xenial) mas 11.2.0-1ubuntu2 está para ser instalado  libgles2-mesa : Depende: libglapi-mesa (= 17.0.1+git20170319+17.0.07adc57f-0ubuntu0ricotz~xenial) mas 11.2.0-1ubuntu2 está para ser instalado  vlc : Depende: vlc-nox (= 2.2.2-5ubuntu0.16.04.1) but will not be installed        Depende: libgles1-mesa (>= 7.8.1) mas não será instalado ou                 libgles1        Depende: libsdl-image1.2 (>= 1.2.10) mas não será instalado        Depende: libva-drm1 (>= 1.1.0) mas não será instalado        Depende: libva-x11-1 (>= 1.0.3) mas não será instalado        Depende: libvlccore8 (>= 2.2.0) mas não será instalado        Recommends: vlc-plugin-notify (= 2.2.2-5ubuntu0.16.04.1) mas não será instalado        Recomenda: vlc-plugin-samba (= 2.2.2-5ubuntu0.16.04.1) mas não será instalado E: Unmet dependencies. Try 'apt-get -f install' with no packages (or specify a solution).   sudo apt-get -f install  Lendo listas de pacotes... Pronto Construindo árvore de dependências        Lendo informação de estado... Pronto Correcting dependencies... failed. Os pacotes a seguir têm dependências desencontradas:  libgl1-mesa-glx : Depende: libglapi-mesa (= 17.0.1+git20170319+17.0.07adc57f-0ubuntu0ricotz~xenial) mas 11.2.0-1ubuntu2 está instalado  libglapi-mesa : Quebra: libglapi-mesa:i386 (!= 11.2.0-1ubuntu2) mas 17.0.1+git20170319+17.0.07adc57f-0ubuntu0ricotz~xenial está instalado  libglapi-mesa:i386 : Quebra: libglapi-mesa (!= 17.0.1+git20170319+17.0.07adc57f-0ubuntu0ricotz~xenial) mas 11.2.0-1ubuntu2 está instalado  libgles2-mesa : Depende: libglapi-mesa (= 17.0.1+git20170319+17.0.07adc57f-0ubuntu0ricotz~xenial) mas 11.2.0-1ubuntu2 está instalado E: Erro, pkgProblemResolver::Resolve gerou falhas, isto pode ser causado por pacotes mantidos (hold). E: Impossível corrigir dependências   cat /etc/apt/sources.list  deb http://security.ubuntu.com/ubuntu/ xenial-security main universe restricted deb http://br.archive.ubuntu.com/ubuntu/ xenial-updates main universe restricted deb http://br.archive.ubuntu.com/ubuntu/ xenial main universe restricted   If you need any information just ask me.  I can't format my notebook because I'll have a lot of problems again to install and configure Android Studio, Java, Netbeans, Vagrant, Composer, Git, VirtualBox, Astah, and a lot of other softwares.  Thanks guys!


How to run a script with systemd right before shutdown?

What do I need to put in the [install] section, so that systemd runs /home/me/so.pl right before shutdown and also before /proc/self/net/dev gets destroyed?  [Unit] Description=Log Traffic  [Service] ExecStart=/home/me/so.pl  [Install] ?


Looking for good introductory treatment of meta-analysis

A (non-statistician) colleague has been encountering meta-analyses in papers he reviews for medical journals and is looking for a good introductory level treatment so he can educate himself.  Any recommendations?  Favorites?  Books, monographs, nontechnical survey articles would all be fine.  (Yes, he's familiar with the Wikipedia entry and other stuff readily accessible by a Google search, such as .)


How does a particle know it should behave in such and such manner?  As a person, I can set mass is so and so, charge is so and so - then set up equation to solve its equation of motion but who computes that equation of motion for a particle in real life?   I, as a person, employ smart 'tricks' such as principle of superposition to avoid having to calculate super complicated situation (calculating electrical force by a shape where large circle is hollowed out in the off-center) but if I were to calculate this in a brute force manner, this would take long time for me to calculate. However, nature doesn't seem to face these types of problems.   Given a school of fish, the ones at the edge will sense threat and gives signal to those near them and so on but this analogy doesn't seem to make sense for physical objects generally considered in general physics problems. Am I asking the wrong type of question? Would appreciate input on this.


Looking for games with drop-in drop-out mechanic

When playing video games, I often prefer games that are easy to drop in and drop out of.  Games like Team Fortress 2 where players are always respawning so the new player isn't set back, especially if most people are ignoring the goal.  With board games I sometimes see two problems:  Sometimes the game stretches on longer than one player can afford or care for (I usually have a 1 hour rule for myself).  Sometimes the game has already been started and another prospective player shows up.  In these circumstances it would be nice if a game carried on even though players might start or stop playing at any time.  Are there any board games out there with good drop-in drop-out mechanics?


Blackscreen after GRUB screen right after upgrading Ubuntu 18.04

I have a problem with my installation of Ubuntu. I installed it fresh using a live USB stick to another USB stick with fast boot and secure boot disabled.  I'm using an Asus Zenbook UX562F with an integrated GTX 1050 Max-Q. After the installation, I installed Nvidia-390 and updated the kernel with ukuu to 4.20.17 to fix no sound issue.  After the reboot, everything went well and I did:  apt-get update apt-get upgrade + J   All was done well, so I restarted and on the next boot after selecting Ubuntu in GRUB it gave me a long black screen (violet screen) where nothing changes after so much time.  I tried to add nomodeset and noveau.modeset=0 single and together but didn't help so I don't know what to do.  Edit:  I had a random lucky boot but was not able to repeat it. (Just to add this Information.)  Trying the solutions on  didn't work for me.  I tried purging nvidia and install old driver nvidia-375 but still no boot.  I also installed Ubuntu on my internal SSD where I ran into the same issue: -booting after installation - works -booting after upgrading the kernel to 5.1.4 - works -booting after dist-upgrade - get stuck after grub  Lucky boots were reproducable but rare so TTY solutions are possible to apply  Starting with nomodeset and noveaus.modeset=0 is also not possible what makes me think it's not an nvidia issue  Edit:    When I got a lucky boot some error messages I have taken a picture of them:


Was Yoda wrong about the limits of telekinesis?

In Empire Strikes Back, Yoda  that an object's size doesn't matter and that the difficulty of levitating an X-Wing was only in his mind. If the upper limits of telekinesis are determined by belief, what's to stop a Jedi/Sith from pulling a moon out of orbit, moving an entire solar system, or splitting an atom with the Force?


If photons don't have mass, how can they accelerate objects?

As far as I know photons don't have mass but they do have momentum ($p=mv$). Scientists say that if we put a shiny (reflective) shield of large radius in the vacuum of space, then light from sun will will start moving the shield. How can these two facts be commensurate?


What's a good book on advanced linear algebra?

I'm taking an advanced linear algebra course and I'm a little confused about books. The teacher said we could use any book we wanted to, but he recomended just Hoffman and Kunze and also Kostrikin, however, those seem to be not quite sufficient since it seems he's teaching in a little more advanced way.  Indeed in the first class he proved from Zorn's Lemma that every vector space admits a basis and in the second class he defined direct product, direct sums (both internal and external), proved the rank nullity theorem and some other things. Most of things he did in a very general context (families of vector spaces indexed by some arbitry set of indexes and with dimensions being finite or infinite).  I'm looking for a good advanced book on linear algebra to review what he did in class, but the books he recommend do not go so far if I'm right. I've studied multilinear algebra once with Kostrikin's book, but he never generalized things to arbitrary families of vector spaces and things like that.  Which books at this kind of approach are recommended?  Thanks very much in advance!


As shown in the picture I just want to make those 3 ends more round like a half circle maybe, but when I try to do that with Effect → Stylize → Round Corners it deforms/warps the whole object?   Why does it do this and how can I fix this or is there maybe another way to make the corners round (I know you can click on the round corner button thingy but that doesn't make them round enough)


About embryonic and genetic evidence of evolution?

My question here is about evidence for evolution from Embryology and from Genetics.  Mammals do have similar Embryos, but is it the case that for each species there is an embryonic development that occurs in earlier species, has such relationship been observed? What I mean for example if we generally conceive of having species$Sp_1,Sp_2,...,Sp_n$ where each $ Sp_{i+1}$ being evolved from $Sp_i,$ then is it the case that the embryonic development stages of $ Sp_{i+1}$ contains some of the embryonic development stages of all of its ancestor species.  Similar question to 1 but regarding Genetics, is it the case that every species has a genetic thumbprint of its ancestors that lie there in the non-functional sections of its DNA, i.e. is it the case that all the genetic history of our evolution is recorded in the non-functional section of our DNA. So do human DNA have some portions of the DNA of some dinosaurs for example?


Inconsistent default site in the dropdown menu on the reputation leagues

When you go to the reputation leagues of a site, there is a drop-down menu that allows you to change quickly to another site. For example, on :  and on :  So it seems that the default site on that drop-down menu is the site we are currently on. Makes sense. But if we now go to , we see this:  Wait, why is Stack Overflow there as default site? But it gets even stranger if we go to :  or to :  What does Biblical Hermeneutics have to do with Board Games? Or CiviCRM with Spanish Language? How is this "default site" chosen? It is not like this breaks any functionality or hurts anyone. But it seems to be an inconsistency, and I am for sure interested in knowing the "pattern".


Don't return results until jQuery dialogbox closes?

I am trying to return results based on jQuery dialog selection. I kept alert msg before sending return statement. How to hold results to return until I do something in dialog box? value will be 'true' or 'false'              function ConfirmDone() {             var results;             $('

').appendTo('body')                .html('

Are you sure you want to lose unsaved changes?

')                .dialog({                    modal: true, title: 'Delete message', zIndex: 10000, autoOpen: true,                    width: 'auto', resizable: false,                    buttons: {                        Yes: function () {                            $(this).dialog("close");                            results=true;                        },                        No: function () {                            $(this).dialog("close");                            results=false;                        }                    },                    close: function (event, ui) {                        $(this).remove();                        results = false;                    }                });             alert(results); //This is calling same when dialog shows up             return results;          }   Whats wrong here?  update:  I am not sure. call back function can apply to my code? As @Barmar mentioned in duplicate post  update  @Ajax.ActionLink(     new { CommunicationLocation = commemail.Location,  CommunicationType = "email" },             new AjaxOptions()              {                  HttpMethod = "Post",                  UpdateTargetId = "DivEmailContainer",                  InsertionMode = InsertionMode.Replace,                  OnBegin = "return ConfirmDone(function(success) {alert('You said: ' + (success ? 'Yes' : 'No'))});"                },                new { @class = "linkbutton" })                }       $(document).ready(function () {                 $("#deletedialog").dialog({                     autoOpen: false,                     modal: true                 });             });             function ConfirmDone(callback) {                  $("#deletedialog").dialog({                      buttons: {                          "Delete":{ text: "Delete",                                     class: "btn btn-success",                                     click: function () {                                         $(this).dialog("close");                                         callback(true);                                     }                          },                          "Cancel": {                              text: "Cancel",                              class: "linkbutton",                              click: function () {                                 $(this).dialog("close");                                 callback(false);                             }                         }                      }                  });            $("#deletedialog").dialog("open");


How can I calculate the sum of the following series?

I am trying to calculate the sum of S=(1-1/2 +1/3-1/4+...). I used wolfram Alpha but the answer makes no sense to me.    Thank you in advance.


My question is simple, but I cant find solid answer for this. I can make hole in face like this:  But it makes a lot of 3 polygons faces. or make hole like this:  Is it better to make holes in few seconds like on first picture with a lot of 3-gons or is it right to take time and make it like on second picture with all 4-gons? and why? I looked at some youtube videos or websites, but they make hole and dont really say anything about topology.


output ascii art in a red color on terminal

so i wanted to make a MR ROBOT default banner, but i don't know how to make the output in a red Color in terminal, could somebody please help?  also does anybody have the Original MR ROBOT ascii art? if so please drop it here.  ps: using kali linux 2018.1 release


Any strong consistent tutorials for beginners?

1st I hope this is the right place, because it's a little hard to find a place where you can ask simple question. Like there is no registration in blender forums and I don't know why.  2nd I have a question and I hope get good and informative answer to it.  So. Hi again. I was looking in google and youtube for good tutorials for beginner. I mean not "how to create a box" or "animate your box". I was looking some strong and new tutorials like "how to create animated girl" or "how to create a realistic weapon and texture it". But I didn't found anything good. I found only scattered tutorials without any explanations. Well "Blender Guru" I liked in youtube. But it's too little tutorials there. I'm ready to pay some money monthly like 10$ you know. And I saw I can pay it in blender clouds. I tried to find some free information in there where to start and etc. But I didn't found any consistent tutorials like what you can do when you create this girl or this weapon. Like in example "If you create a weapon not let's go animate it to shoot!" you know. So I wan't to ask should I spend money in blender clouds? Or you know better place? Any information from you practice would be most amazing thing in today for me! So thank you and waiting for answers in this place :). I hope this place is really good! :) BTW sorry for bad English!  EDIT: from some comments of you i found in resources blender101, is it right place would be? Because it cost a little.


What is the motivation behind axiomatically forcing the underpinning group of a ring to be abelian? Noncommutative rings are vastly more complex than commutative ones, so I am assuming that allowing the additive operation to be noncommuting would just make matters worse. Is there something deeper here, or is this a restriction for the sake of convenience and simplicity?


I'm trying to get bold vectors in a superscript, but for some reason this won't happen when using the cmbright package (I like the font).  Is there a way to get it to behave?  Code:  \documentclass[12pt]{article} \usepackage{amsmath} \usepackage{cmbright}  \begin{document}  This is a bold vector \begin{equation}     \mathbf{p} \end{equation}  This is a plane wave \begin{equation}     \psi=Ae^{i(Et-\mathbf{p}\cdot\mathbf{x})} \end{equation}  \end{document}


I have to import a number of text files into SQL Server tables, and some of the text files have columns where all the rows appear to be mostly, if not all, null values.  Is there any simple way to write a query that will list all the columns in a table that have nothing but null values?


I am writing a seminar paper with latex, and currently working on Appendix. The problem is, that i want the title and the explanation of the table be on top of the page, but somehow LaTeX shows it other way around. Could you please help me, or tell what I am doing wrong in my code?       \documentclass[12pt,a4paper,twosided]{article}     \usepackage{amsmath}     \usepackage{amssymb}     \usepackage{graphicx}     \usepackage{setspace}     \usepackage[inner=2.5cm,outer=2.5cm]{geometry}     \usepackage{natbib}     \usepackage{hyperref}     \allowdisplaybreaks     \begin{document}     \onehalfspacing     \rmfamily       \section*{Appendix}      ln(ABCP $Out_{t-1}$) is lagged log ABCP outstanding, and  $\Delta$ ln(ABCP       $Out_{t-1}$) is lagged log net ABCP issuance (the lagged change in log ABCP outstanding). Panel A uses the ABCP – T-bill spread as the independent variable, while Panel B uses the OIS-T-bill spread. The sample runs weekly from July 2001-June 2007. YM denotes year-month fixed effects, while WOY denotes week-of-year fixed effects. Robust standard errors are reported in parentheses, except for the specifications without fixed effects. *, **, *** denote significance at the 10\%, 5\%, and 1\% levels respectively. \\     \begin{table}    \centering    \begin{tabular}{|c|c|c|c|c|c|}    \hline    \multicolumn{5}{c}{Panel A: ABCP - T-Bill Spread} \\    \hline     ABCP - T-Bill $Spread_{t-1} $&$0.013$***&$0.0012$*** &$0.010$*** &$0.012$***     &$0.011$**\\    &$(0.002)$&$(0.004)$&$(0.002)$& $(0.004)$&$(0.004)$ \\    ln(ABCP $Out_{t-1}$)&&&$0.002$&$-0.360$***&$-0.439$***\\    &&&$(0.002)$&$(0.061)$& $(0.066)$\\    $\Delta$ ln(ABCP $Out_{t-1}$)&&&$0.138$**&$0.007$ & $0.073$\\    && &$(0.066)$&$(0.074)$&$(0.082)$ \\    Constant&$-0.001$**&$-0.001$ &$-0.026$ &$4.874$*** & $5.991$***\\     &$(0.001)$&$(0.001)$&$(0.030)$&$(0.830)$ & $(0.896)$\\     \hline    $R^2$&$0.164$&$0.045$ &$0.172$ &$0.243$ &$0.362$ \\    N&$303$&$303$ &$301$ &$301$ &$301$ \\    FE&--&$YM$ &-- &$YM$ &$YM,WOY$ \\    \hline    \multicolumn{5}{c}{} \\    \hline    \multicolumn{5}{c}{Panel B: OIS - T-Bill Spread} \\    \hline      OIS - T-Bill $Spread_{t-1}$&$0.012$***&$0.009$** &$0.009$*** &$0.013$***    &$0.012$**\\     &$(0.002)$&$(0.004)$&$(0.002)$& $(0.004)$&$(0.005)$ \\     ln(ABCP $Out_{t-1}$)&&&$0.002$&$-0.359$***&$-0.434$***\\      &&&$(0.002)$&$(0.068)$& $(0.071)$\\      $\Delta$ ln(ABCP $Out_{t-1}$)&&&$0.125$**&$0.014$ & $0.091$\\     && &$(0.069)$&$(0.083)$&$(0.086)$ \\      Constant&$-0.001$**&$-0.000$ &$-0.022$ &$4.862$*** & $5.919$***\\       &$(0.000)$&$(0.001)$&$(0.031)$&$(0.923)$ & $(0.969)$\\       \hline       $R^2$&$0.169$&$0.028$ &$0.178$ &$0.224$ &$0.358$ \\       N&$287$&$287$ &$286$ &$286$ &$286$ \\       FE&--&$YM$ &-- &$YM$ &$YM,WOY$ \\      \hline      \end{tabular}      \caption{ABCP Net Issuance and Spreads}\label{pred}     \end{table}        \end{document}


Recommendations for statistical mechanics book

I learned thermodynamics and the basics of statistical mechanics but I'd like to sit through a good advanced book/books. Mainly I just want it to be thorough and to include all the math. And of course, it's always good to give as much intuition about the material.  Some things I'd be happy if it includes (but again, it mostly just needs to be a clear book even if it doesn't contain these) are:   As much justifications for the postulates if possible, I'm very interested in reading more about how Liouville's theorem connects to the postulates. Have examples of calculating partition functions, hopefully not just the partition function for the ideal gas.


My form in view is   <?php        $attributes = array('id' => 'myForm');       echo form_open_multipart('', $attributes); ?>
         Main Image         <input type="file" class="form-control-file" id="image" name="image" aria-describedby="fileHelp">

         <button type="button" class="btn btn-primary" id="add">ADD</button>         <button type="reset" class="btn btn-primary">Reset</button>
 <?php echo form_close(); ?>        And my script is as follows      And my addArticleData function inside the controller form contains  if(isset($_FILES["image"]["name"]))       {          $config = array(             'upload_path' => "images",             'allowed_types' => "*",             'overwrite' => TRUE,             'max_size' => "2048000", // Can be set to particular file size , here it is 2 MB(2048 Kb)             'max_height' => "768",             'max_width' => "1024"         );         $this->load->library('upload', $config);         if($this->upload->do_upload('image'))         {             $data = array(                  'image' => $this->input->post('image')              );             //print_r($data);             if($this->modal->insert($data, 'admin')) {                 echo "DATA INSERTED SUCCESSFULLY";             }         }         else {             echo "ERROR";         }     } else {         echo "FILE NOT SET";     }   The problem is that whenever I tried to execute this script it alerts FILE NOT SET. And if I print $_FILES using print_r($_FILES);exit; it alerts an empty array.   Further if I try commented print_r($data);exit; and remove all the lines preceding it then  it alerts the name of the image uploaded as C:\fakepath\image.png  I just can't understand why this is not working. Please HELP


Which naming convention do you use and why?  I like to use employeeNameTextBox, because:   It seems more natural from an English language perspective. I find it's easier to look up with Intellisense. The convention is similar to the convention used for events (MouseClickEvent, MouseClickEventHandler) and dependency properties (VisiblityProperty).   Note:  I am using the full name rather than an abbreviation (such as "tb"), because it is in line with MS's naming conventions that say to avoid using abbreviations.


Which Random Forest hyperparameters to tune with Grid Search and which are the best initial hyperparameters values?

I want to use Grid Search for finding optimal hyperpameters for Random Forest. My questions are:  Which Random Forest hyperparameters are considered important for tuning? Which initial Random Forest hyperparameters values for Grid Search do you recommend?


Triangle inequality for metric on real-valued sequences

I am doing the following exercise from my functional analysis course.     Prove that $$d(\{x_n\},\{y_n\}):=\sum_{n\geq 1} 2^{-n} \dfrac{|x_n-y_n|}{1+|x_n-y_n|}$$   is a metric on $\mathbf{R}^{\mathbf{N}}$.   Is this some kind of known norm? I tried looking on the internet and I found similar expressions with the name F-norm. Any information on this norm is helpful.  Currently, I am stuck proving the triangle inequality for this metric. This must follow from the triangle inequality for $|\cdot|$.   I think it is equivalent to proving that   $$\frac{|x_n-z_n|}{1+|x_n-z_n|}\leq \frac{|x_n-y_n|}{1+|x_n-y_n|}+\frac{|y_n-z_n|}{1+|y_n-z_n|},$$  which is in turn equivalent to   $$1+\frac{1}{1+|x_n-z_n|}\geq \frac{1}{1+|x_n-y_n|}+\frac{1}{1+|y_n-z_n|}.$$  Reformulating, I am trying to prove that if $a,b,c\geq 0$ and $a\leq b+c$, then $1+\frac{1}{1+a}\geq \frac{1}{1+b}+\frac{1}{1+c}$. I am not really good at inequalities, can someone give a hint?


Prove $\int ^{\pi/2}_0 \frac{\sin^m x}{\sin^m x+\cos^m x}dx=\frac{\pi}{4}$

Prove $$\int ^{\pi/2}_0 \frac{\sin^m x}{\sin^m x+\cos^m x}dx=\frac{\pi}{4}$$ for all real values of $m$.


I am trying to setup a membership system, and want to implement a start and end date. I think I have successfully implemented the starting date, however, I am having a tough time with the expiration date (1 year later). The expiry should be stored in a text field which is a String, thus it needs to be converted. However, on compilation, I am presented with a NullPointerException.   center.add(createLabel("Membership Date Created")); center.add(memDateCreatedTxtFld); SimpleDateFormat sdf = new SimpleDateFormat ("E yyyy/MM/dd"); Date date = new Date(); memDateCreatedTxtFld.setText(sdf.format(date));  center.add(createLabel("Membership Date Expiry")); Calendar cal = Calendar.getInstance(); Date today = cal.getTime(); cal.add(Calendar.YEAR, 1); Date nextYear = cal.getTime(); String reportDate = sdf.format(nextYear); memDateExpiryTxtFld.setText(reportDate); center.add(memDateExpiryTxtFld);   For example, since today is 2019/02/01, the expiry should be on 2020/02/01.


Can you detect telepathic messages in your head, like the Sending spell, via Detect Magic?

An enemy casts  to communicate with a player from far away. In this example, the player character doesn't know anything about the sending spell and he might think he is just hearing voices or going crazy. Another player casts  to scan the area. Can this player detect the presence of the telepathic message inside the first player's head as an evocation spell via detect magic?


Why don't electrons moving around in a orbit produce electromagnetic waves in their natural state?

If moving electrons produce changing electric field, and if changing electric field produces magnetic field, every electron must produce an electromagnetic wave. This means an atom in its natural state must emit light or other waves in electromagnetic spectrum. But why doesn't this happen?