How to prove that $\lim_{n\to\infty} \sqrt[n]{a^n+b^n}=\operatorname{max}(a,b)$?

How do I show that $$\lim_{n\to\infty} \sqrt[n]{a^n+b^n}=\operatorname{max}(a,b)$$ with $a,b\ge0$.  I tried to do this by dividing it in two cases, when $a=b$ and $a\gt b$.  In the case $a\gt b$ I factored $a^n$ like this: $$\lim_{n\to\infty} \sqrt[n]{a^n \left(1+{b^n\over a^n} \right)} = \lim_{n\to\infty} a\sqrt[n]{1+{b^n\over a^n}} = a\lim_{n\to\infty} \sqrt[n]{1+{b^n\over a^n}}$$  Then I expressed it in exponential way. $$a\lim_{n\to\infty} \left({1+{b^n\over a^n}}\right)^{1/n}$$  Now I need to prove that $\lim_{n\to\infty} \left({1+{b^n\over a^n}}\right)^{1/n}=1$ so the whole limit is equal to a. The problem is that I don't know how to take the limit of $\lim_{n\to\infty} \left({1+{b^n\over a^n}}\right)^{1/n}$ I tried to use the natural logarithm, but it ended up like this: $$\lim_{n\to\infty} \log\left({1+{b^n\over a^n}}\right)^{1/n}=\lim_{n\to\infty} {1\over n} \log\left({1+{b^n\over a^n}}\right)=\lim_{n\to\infty} {1\over n} \lim_{n\to\infty}\log\left({1+{b^n\over a^n}}\right)=0$$ What did I do wrong and how can I do it right?


Can every finite index subgroup of $\mathbb{Z}\times\mathbb{Z}$ be written as $\langle n\cdot e_1,m\cdot e_2\rangle$?

Can every finite index subgroup of $\mathbb{Z}\times\mathbb{Z}$ be generated by $n\cdot e_1,m\cdot e_2$ for some integers $n,m$ and some choice of generators $e_1,e_2$ of $\mathbb{Z}\times\mathbb{Z}$?


Trying to json_encode an array with a special character in it. The echo of the json is empty print_r shows the contents of the sql

Apologies if this is a silly question but I am learning at the minute and can not find the solution to this anywhere. I have a name in my database table containing é. I run my sql query, pull down the data, put it into an array and then attempt to echo the json encode bur I get nothing. I can print_r and see the contents of the sql result, so I know the data has been sent from the database. I've tried various things now including - json_encode($array, JSON_UNESCAPED_UNICODE). $ut=  utf8_encode($contents); making sure the header = header('Content-Type: application/json; charset=utf-8', true,200); When I use print_r where the é should be in the name I get a black diamond with a question mark in. So basically I think I need to convert the é to unicode in order to echo the json encode? Anyone any ideas? Here is an example of the code I am using after running the sql. $result = $conn->query($sql);      $data = array();      while ($row = $result->fetch_assoc()) {          $data[] = $row;     }      echo json_encode($data);  Maybe this will help someone in future. I solved it by changing $data[] = $row; to $data[] =  array_map("utf8_encode", $row);


Is physical contact/posession of a Horcrux required for resurrection?

Down in the comments of  I mentioned that I'd figure it'd be hard to resurrect someone if you couldn't get access to the Horcrux. @Acccumulation asked whether or not physical posession was required, and although I've always thought it was (seems like all the cases we see in the books do), I didn't know whether or not there was an official answer to this. So, is physical access to the Horcrux actually required, or could you just drop it into the ocean?


Social Security and Medicare taxes not withheld

I have been working with same employer in the US since the start of H-1B in 2016.  I just noticed that my W2 shows no SS and Medicare paid by employer. Since I applied for a change of status from F1 to H1, and they forgot to change in the payroll, I have filed my taxes every year and did not get anything from IRS.   Should I ask my employer to look into this or leave it to the IRS and the employer? I am concerned that if I go and tell them, it might backfire and they may look down upon me.  Do I owe anything to the IRS?


How can a deep neural network with linear activations be reduced to a two-layer model?

Wikipedia [1] has the following statement without citation or additional details: "If a multilayer perceptron has a linear activation function in all neurons, that is, a linear function that maps the weighted inputs to the output of each neuron, then linear algebra shows that any number of layers can be reduced to a two-layer input-output model." How does the linear algebra for this work? When it says "two-layer input-output model" for the reduced form, does it mean two hidden layers? Are there any other assumptions or details the Wikipedia statement leaves out (e.g. layers must have the same number of neurons in each of those layers, each hidden layer's weight matrix must be full rank)? [1]


How do I identify which Linux distro is running?

We have some new hardware in our office which runs its own customized Linux OS.   How do I go about figuring which distro it's based on?


I noticed that   sudo apt-get update   takes longer and longer, because i used  several   sudo apt-add-repository xxx   it seems like non ubuntu repositories are not as fast or dont have as much bandwith as the default ones.  How can i reset the repositories to the default ones, removing all the ones added by me? (not to worry, if ever need any of them i can add them later)


How can wifi penetrate through walls when visible light can't?

I did search the question on Physics S.E considering it would be previously asked. I found this  But in this question , the answers are w.r.t to or in comparison with microwaves , their absorption and certain other things. I didn't find a sort of general answer that could be the answer to the question. So the question is - wifi or radio waves  reach us through concrete walls . They also reach us through the ceiling (if some one is using it in the flat above ours ). Even through the air they travel such a lot , bending around corners or doors . Now I would not compare them to microwaves (because I don't want the answer in terms of properties of the material but physics). Visible light which is so much powerful than them can't penetrate black opaque paper leave alone the walls. Same is true for gamma rays (penetration through a very thick wall). So why then radio waves being so very less powerful than light  waves are able to travel through walls? There should be a general concept as to why the radio waves are able to pass through walls but microwaves or light waves cannot ! A linked question is also that sound travels much faster in solids(walls) but is not audible in it though it is in air. After reading @BillN's answer, it would be really helpful if any one could explain it in terms molecular resonance or crystalline structure or electrical conductivity or how does molecular resonance or crystalline structure or electrical conductivity cause this.


Can I Run 64 Bit Ubuntu OS On Intel® Pentium (R) Processor B940?

I have old notebook with Intel® Pentium (R) Processor B940. Can I run the latest 64 bit Ubuntu on my machine? This is detail of my machine taken on Ubuntu 16.04 LTS 32 Bit.


A sci-fi novel about augmented mental power

I read a sci-fi novel 14 years ago (April/May 2003) that haven't been able to find since then.  It was in a shared book locker in a reception battalion barracks at Ft. Leonard Wood, MO.  The book was a paperback, it may have been part of a series of at least two books, and i may not have read the first (unsure).  I think the cover was blue/yellow/green or something similar in a 90's styling (slanted text, text overlayed on full cover imagery).  Seems like it was published by one of the big science fiction publishers of the 90s.  It was extreme futuristic, multiple planets.  With humans being augmented at birth or shortly after with enhanced brain implants.  These augmentations enabled extreme levels of math, and the price the parents paid for these augmentations depended on their child's future success.  I believe the primary protagonist was a female.  If I recall correctly the story included items like the protagonist's augmentation was removed, and the protagonist was mentally hampered, and then a new one inserted, but it took a while for the brain to "wire it in" or something to that sort.  I don't actually remember the plot, just the technology.  Which seems like what Neuralink is trying to accomplish, but letting the brain do the heavy lifting and letting the augmentation be "additional processing power".  The cost of the implants were extremely high, like an entire adult's lifetime income or something similarity severe.  I believe the augmentation gave the protagonist probabilistic predictive power or some other extremely cool ability.  I seem to remember that the female protagonist was tutored by a famous mathematician, and when she got her second powerful implant she had to go back to him to retrain or for assistance.


How to distinguish vector space from $k$-algebra?

Let $A$ be a finitely generated $k$-algebra with no nilpotents. What do I need to show in order to prove it's a finite dimensional vector space over $k$?   For example, is it enough to show that $A$ has only finitely prime ideals and every prime ideal is maximal?


In one English student's book i encountered the following sentence: "The weather was no obstacle to my expeditions."  As i understand the essential constrain is: [1] Subject + is + no + noun  Apparently it's a kind of negation. But i can't find any grammar rule for this constrain.  It's similar to "The weather was not an obstacle to my expeditions.": [2] Subject + is + not + a + noun  Or "The weather had no obstacle to my expeditions.": [3] Subject + has + no + noun  But seems it doesn't fit into them. What a grammar constrain is it? Which one of ([2] or [3]) constrains is it closer to?


How to access a really old, untouched bank savings account?

I was just going through old things and found a Wachovia account opened for me by my aunt - specifically, I found the checkbook and transaction record. The transaction book is dated April xx, 1998 and has one record in it: "Happy Birthday", $50 deposit, $50 balance.  I vaguely remember having discovered this a few years ago, calling Wachovia, and confusing the operator on the phone with an account number which was not their usual format - she couldn't even type it into the computer, it was too short or something. She supposed that they changed their account number scheme some years in the past. I must have just put it away, and now I rediscovered it and want to give it another shot.  I suppose I will call Wachovia and try again, but is there anything else I can do to try and access this account? I don't know anything about the savings account (interest rate, etc.), but I have this fantastical thought that maybe the $50 has grown into a hefty chunk of money by collecting interest over these 13 years it's just been sitting there. Or maybe it was emptied and closed due to some stupid bank fees. Either way, I'd like to know what happened to it.  Is there any special course of action for this kind of thing?  Also, the address on the account is of course WAY old. I was 8 years old at the time (which is why I didn't know what to do with this, I just put it in a drawer with the rest of my stuff) and I've moved several times since then. I guess the chances of being able to get anything from this are very slim, but I want to pursue it anyway.


What is the difference between the different nVidia Quadro drivers?

I have a nVidia Quadro FX 1700 graphics card and there are different drivers offered at the nVidia driver page:   Quadro ODE Graphics Driver Quadro Performance Driver Quadro Partner Certified Driver   And 2 software specific drivers:   AutoCAD Performance Driver 3ds Max Performance Driver   So my question is: What is the difference between the 3 first drivers and which one is the best for gaming?  EDIT: The Driver I´m currently using is linked .


I know that we can call a C# method from a Java program.   I want to know if it will affect the performance of the Java program. Also, do you recommend using it or not?


I'm working on an ASP .NET MVC application, and i'm the inexperienced guy on a team of 3.  One of my colleagues, the most experienced guy on the team, is constantly using var when defining a variable, although the functions that he uses to load the variable return a specific type(int, string and so on), is this a good practice?  I confronted him with this question but the answer he gave me was "i don't know search for it...", the experienced guy answer, you know...  So, is this a good practice?  Thank you!


Non-abelian group in which $\forall_{a,b\in G} (ab)^3=a^3b^3$

Give an example of a non-abelian group, in which $(ab)^3=a^3b^3$ for every element $a,b$ in $G$.  I understand that such a group should be of order divisible by 3 (see ). Also, it is easily seen that $(ab)^3=a^3b^3 \iff (ba)^2=a^2b^2$. But I can't come up with one single example.


I work "in a grocery store" or "at a grocery store"

I am not a native speaker but both sounds good to me. Which one should be more accurate or in fact correct.


Bring up (missing) running python script in console / command prompt?

I don't know how to properly describe my situation in the title. I am connected to an ubuntu server via PuTTy. I then ran a python script that is using my GPU. I can verify this by typing nvidia-smi which shows up  +-----------------------------------------------------------------------------+ | Processes:                                                       GPU Memory | |  GPU       PID   Type   Process name                             Usage      | |=============================================================================| |    0      3979      G   /usr/lib/xorg/Xorg                           161MiB | |    0      4589      G   compiz                                       173MiB | |    0     17024      C   python                                     10461MiB | |    1     17024      C   python                                      3955MiB | |    2     17024      C   python                                      3925MiB | |    3     17024      C   python                                     10619MiB | +-----------------------------------------------------------------------------+   I also had another command prompt printing the output of the python script that it was running. The problem is, I got disconnected from the internet and thus the server and the console windows all closed. I don't know if my python script is still being run because when I typed nvidia-smi I get the same output as shown above i.e. it is implying that I the script is still running.  My question is, how do I bring up the console window printing the output of this script ?


Logics; Proof by contradiction (specific question)

In mathematics it is not possible to derive something wrong when my premise is true. So my question is, is this the reason when i do have a contradiction that i assume my premise had to be wrong, since then it is true again. So we always want true assumptions ?


how to delete privious year june files from the list

How to delete previous year June files from the list  #!/bin/bash echo "hi" path="/home/alert/VideoApplicationAPI.v1/logs" dayDiff=365  DATE=`date +%Y-%m-%d` for filename in $path/*.*; do     modDate=$(stat -c %y "$filename")      modDate=${modDate%% *}      echo $filename:$modDate     echo "( `date -d $DATE +%s` - `date -d $modDate +%s`) / (24*3600)" | bc -l done echo $DATE


A normed space is Banach iff its unit sphere is complete

Let $X$ be a non-trivial (other than singleton $x$) normed space. Prove that $X$ is a Banach space if and only if $\{x \in X \mid \|x\| = 1 \}$ is complete.


Can a holomorphic function satisfy $f(1/n)=1/(n+1)$?

Does there exist a function $f$ which is holomorphic on $B_0(2)$ (open disc of radius 2 in the complex plane) such that $f(1/n)=1/(n+1) \forall n \in \mathbb{N}$? At the moment I'm thinking not but a proof is seeming elusive. Any hints would be appreciated.


Even though moon and satellite orbit the planets in multiple planes why our solar system is co-planar? Not only that, ring systems of several planets are also co-planar. Is it the way they evolved with the time? Or is it the only possible way a planetary system can be formed?


I've just seen this question and noted in the comments a suggestion to post this on Code Review    I'm a little lost with the differences between the 2 SE sites? Is "Code Review" more about practices and general approaches (which is then ambiguous between "Code Review" and "Software Engineering") or is there a defined difference?   I have seen  which doesn't really answer the question as the lines are still hazy?   Can I assume that there are some cross over here (as there probably always will be) and the example above is one of these times and common sense can prevail (in that it would have been suitable in either CodeReview or SO)?


I am trying to design a pre-amplifer and just starting basic.   Using a low pass filter and a high pass filter with already determine cut off frequencies.   The problem is that I thought it doesn't matter how you cascade the filters as its super positioned (Both linear), however when I put the LPF then the HPF my cut off frequencies become all whack. When I put the HPF then the LPF it works perfectly, whats going on? I am pretty sure there's something simply I am not taking to account, making the low resistor and cap values to ground.  Low-pass filter:   High-pass filter:   LPF-> HPF Topology    HPF-> LPF Topology   Circuit:   Any help would be appreciated!


So I'm making a small game on Blender Game Engine and its racing. What i want is so that when a player presses w the car starts moving and slowly gains velocity. I know about the controller's that make an object move but i want to know how to make it BUILD speed as it progresses.(the reason i tagged this as python is because i am assuming this will take some python. Do i use Python for this)?


I cannot use the split_string function and I cannot alter the database to set the compatibility level to what I need.  I have a column with the following example values:  JohnDoe-123-fakestreet-02-2018-01-01-2018-12-03 SamSmith-ab1-concordia-16-2018-02-02-2018-11-03 JaneDoe-zxy-austin-11-2018-03-01-2018-03-16 HomerSimpson-999-Chicago-22-2018-04-01-2018-10-20 EricCartman-222-Madison-05-2018-05-01-2018-09-01   I need the 4th value in each row. I.e.:  02 16 11 22 05   How can I do this? Any suggestions?


How does rounding affect subsequent calculations?

When we are doing calculations in mathematics, we often express exact values, like $\sqrt 2$ or $\arctan (1)$, as decimals and round these to a finite number of decimal places/significant figures before using these approximations in subsequent calculations. We might also round off a very long but finite decimal and use it in subsequent calculations. My question is, what is the minimum number of decimal places/significant figures which all of my intermediate values must be rounded to if I want my final answer to be accurate to a particular number of decimal places/significant figures?  Example: I'm doing a $\chi^2$ test. I want to find $\chi^2$ exact to $1$ decimal place. The exact $\chi^2$ contributions are: $(0.56,0.32,1.76,1.99,0.72,0.88)$. If I sum these, the exact value of $\chi^2$ is $6.23$, which becomes $6.2$ rounded to $1$ decimal place. Now if I round the contributions to $1$ decimal place, so they become $(0.6,0.3,1.8,2.0,0.7,0.9)$, before I sum them, I get the sum to be $6.3$, which is not accurate to $1$ decimal place, as we have shown it should be $6.2$.  How can I be sure that my intermediate values are rounded with enough remaining decimal places/significant figures that my final answer is accurate to a desired number of decimal places/significant figures? Not just for this particular example, but for a general calculation.


I write an object to a file and then I read it.  Then I make "if" to compare object's arguments. For example "genreDescription" is "Action".   if (genreDescription == "Action" ) {   System.out.println("Some text");         }   Before import == and equals produce expected and the same result. After import equals work but == doesn't.  I tried removing blank spaces. I also manually updated object's "genreDescription" to "Action" right before if. It affects only String, because if "gendreDescription" is int like 6 then it's normal. Why?


Yesterday when I was biking my mountain bike on level paved path, I would pedal but get no power to the wheel.  To use a car analogy, it was as if I had the clutch in and was apply gas.  It seemed to happen most often after I coasted and then went back to pedalling.  I would pedal and realize that no power was going to the wheel.  The chain was definitely on the sprockets and moving. I could change gears no problem while I had no power.  Sometimes stopping the bike and starting again would work, or just trying again.  Needless to say, I'm taking it in as I'm not mechanically inclined, but I'm hoping to learn something.  Perhaps a link to a site that explains the problem?  So my questions.   What is going on?  I have heard of something called the "freehub".  I really don't know how bikes work though, so I'm hoping for an explanation of how one can pedal and give power to the wheel and then stop pedalling and the wheel just keeps moving (without the pedals moving).   If you are on a ride, is there any emergency adjustment to make?   For what it's worth, it's an old bike.  Circa 1993 Performance Mtn Bike.  So it's not too surprising that it's falling apart.  I haven't used it a whole lot, and have tried to wash and oil it, but I probably haven't taken the care that a biking aficionado would.  Also, besides losing power after coasting, one time I was pedaling and suddenly the pedals weren't powering the wheel.  I almost went over the handlebars!  So, I definitely want to get it fixed.  I'd just like to know a little bit about what is going on.  Thanks,  Dave.  Bonus question:  If there is enough info to make a diagnosis and you have ideas on costs to fix, perhaps you could comment on whether it's worth fixing.  Like I said, it's circa 1993 and cost about $450 then.  No shocks or anything.  Just 21 speed Mtn. Bike.


If RSA Signature is not Decryption, why is it not advisable to use same keys for enc/dec and sig/ver? What is the proof where you may be exposing your private key when you use the same one for decryption and signing? This is for RSA OAEP.


Proof of the statement 'World is not flat' by graph theory

In my graph theory book exercise,I found a problem that:  Prove that,World is not flat using Mathematics    This picture is used in the exercise,but no idea of applying it.


The path of image causing error at compiling

I have this path of one of my images:  \includegraphics[trim=0cm 0cm 0cm  0cm,clip,scale=.40]{Figures/Simulation_C_044 _023_4_21kV.pdf}   When I compile the code, it shows me that there is an error in the line of the path. When I changed the name of the figure with other name, it works fine.  Do you have any idea of solving this problem as I don't prefer to change the file names.


Can Google Sheets use date data validation to require one column's data to be more recent than another's

I would like my target completion column to have a date that is greater than in my start column.  Excel supports a date validation option but I do not see this in Google Sheets.  Is it there and I just don't know how to use it or is my only option to write an Apps Script add-on?


Why do surfaces act like barriers for electrons?

Say you have a conductor, filled with free electrons. The nuclei have a weak pull on the valence electrons so they are moving around in the conductor.  But the electrons don't leave the solid. If you bring a positively charged object near the conductor, the electrons might move to the other side of the object, but won't leave it, almost as if there's a "wall" blocking it.   Why do surfaces act like barriers/walls for free electrons?  I have gotten the following explanations:  1) They are attracted by the nuclei so they are pulled back.  My problem with this: Conductors have a weak attraction force on the electrons, so why does it take an extremely large force to counteract the pull by the nuclei? And also what makes the boundary so special?  If the electron can move within the solid freely, what makes it so much harder to move outside the solid, since the force by the nuclei is the same?  2) Think of the electrons as being held by the nuclei by a string. If you pull on it, you might be able to move the electron away but you would need a stronger force to break the "string" of the nuclei.  My problem with this: This analogy doesn't work. Elastic strings follow Hooke's Law:  $$F = kr$$ where $k$ is a constant and $r$ is the distance. As the distance increases, the force pulling back increases.  Electromagnetic forces however follow Coloumb's Law:  $$F = \frac{kq_1q_2}{r^2}$$  As the distance increases, force pulling back decreases.  I am not looking for a mathematical proof. I am looking for an intuitive explanation. Something like an analogy would help a lot, but any other explanation you feel would be more helpful is welcome.  Also note that I know that you can get electrons to leave a conductor, but this requires a high voltage.  Related:


pre_get_posts Tax Query not working for custom author page

I am using the theme TwentyTwelve and modified the standard post query in the file author.php with the following code:  function wpd_author_query( $query ) { //CODE to set $current_user_name here //This gets the author from the URL $author = get_user_by('slug',get_query_var('author_name')); $current_user_name = $author->user_nicename;      if ( $query->is_author() && $query->is_main_query()) {             // your code to set $current_user_name here             $query->set( 'meta_key', '_writer_relation_added_date_'.$current_user_name );             $query->set( 'orderby', 'meta_value_num' );             $query->set( 'post_status', $post_status );              $tax_query = array(                   array(                     'taxonomy' => 'writer',                     'field' => 'name',                     'terms' => $current_user_name                 )             );             $query->set( 'tax_query', $tax_query );     }                } add_action( 'pre_get_posts', 'wpd_author_query' );   However, the tax_query is not working for the author page. It is still not retrieving the posts in the writer taxonomy.  I did try applying that code for other pages such as is_home() is_archive() and it does work.  So, there must be a conflict in with wordpress and the author template page that is not allowing me to use the tax_query for retrieving posts in the writer taxonomy.


Maybe once a month I need Photoshop.  Since it is rare, the cost seems like a disproportionate amount of money to spend by my startup.   I think the tasks I need to achieve when I'm converting a design to HTML/CSS/images are:   opening a PSD that a graphic designer sent me crop some images out of it, generally picking up the layer to have transparent backgrounds measure distances measure colors (RGB) measure font and font sizes maybe more that I'm not aware since I almost never do this kind of task   Is there some cheaper software for MacOSX that can do all of this so we don't have to buy Photoshop?


I am trying to create a portfolio website for a college class and want to sent up a contact page where people can sent me messages rather than just posting my personal email to the world.  the problem it, the mail keeps going to my junk folder.  can someone please help me figure out how to fix the problem?  I am new to coding and have to use the college's server, so I'm not sure how to correct the issue. Here is my code: <?php if(isset($_POST['sendEmail'])){    $to = "myemail@hotmail.com";    $from = $_POST['emailFrom'];    $subject =$_POST['subject'];    $message = $_POST['message'];    $headers  = 'MIME-Version: 1.0' . "\r\n";    $headers .= 'Content-type: text/html; charset=iso-8859-1' . "\r\n";    $headers  .= "From: $from\r\n";  try {     mail($to, $subject, $message, $headers);     $msg = "Your message was sent successfully!"; } catch(Exception $e) {         $msg = "An Exception was thrown: ".$e -> getMessage()."
"; }}?> <?php if (isset($msg)) {echo $msg;}?>


Deleted answer got stuck in server cache

:        It's way over two days and the link points to :        What caused the answer to get stuck in the list? Lots of posts get deleted and cleared from the list just fine so can't see what happened here.


Every homogeneous Riemannian manifold is complete.

I have to prove that every homogeneous manifold is complete.  Let $p,q$ points on a Riemannian homogeneous manifold. I want to prove that there exist a minimizing geodesic join $p,q$ or equivalently, that every geodesic can be extended forever, that is the same that the $\exp_p$ is defined to all $T_pM$ for at least one point $p$.  My idea is the following: We know that there is an open ball in $T_pM$ with some radius $\epsilon > 0$ such that $\exp_p$ is a diffeo in some open set on $M$. In particular, the image of the diffeo has the property that every point can be join to $p$ by a minimizing geodesic with length less than $\epsilon.$   Once $M$ is homogeneous, then every point admits a ball with the same radius and same property. This can seen noting that given two arbitrary point there is an isometry that "connects" both. Then I can transfer the geodesics from a point to another.  Ok, then:  For every point I can produce a ball with radius $\epsilon$ with the property that for every point on the ball there exist a minimizing geodesic join two points.  How can I conclude then that I can extend every geodesic? I know that for every point I can produce geodesics with the same length, how to finish?


What is the correct way to create a Persistent Ubuntu 20.04 Usb?

I want to create a persistent Ubuntu 20.04 on my 8GB USB stick. Currently I have both windows and ubuntu as base Os. Better with windows.


nginx - client request body is buffered to a temporary file

I get the following error in my log files every time I try to upload a large file.  a client request body is buffered to a temporary file /var/lib/nginx/body/0000000001   Although the file uploads successfully, I always get the above error.  I increased the client_body_buffer_size to 1000m which is what I expect the largest file uploaded to be. However, this is was just a guess and although I don't get that error anymore I am wondering if this is an appropriate value to set for the client_body_buffer_size?  I would appreciate it if anyone can shed some light on this directive and how it should be used.


I have a HP MFP127fw.  It's "supported" by Ubuntu 17.10 - except print jobs will not release from the print que because a special copywrited driver for HP is not installed.  I went through this with 16.10 and had to install a small HP driver that I found with Synaptic.  Then the jobs would release. It isn't part of HPLIPS.  Apparently Ubuntu 17,10 version doesn't run synaptic due to Wayland.  Where can I find this driver?


solving the integral $ \int_0^\infty \dfrac{\sin xt}{x(x^2+1)} dx $

How to solve the following integral by differential equations techniques? $$ \int_0^\infty \dfrac{\sin xt}{x(x^2+1)} dx $$


LibreOffice icon tips shows incomplete text/info

I have LibreOffice 5, and since I installed Ubuntu 16.04 LTS, LibreOffice's icons tips show it's text/info incomplete.  I can't find a way to fix it.  I've tried: Tools > Options > Libre Office > View  There I turn on/off the "Screen font anti-aliasing", fixing it temporarily, but after closing LibreOffice the problem returns.  Any idea of how to fix it definitely?  Image of the problem:


Why are some weapon fusions blocked out with a question mark?

In the weapon fusion menu, some combinations of items contain an "X" in their location box, and both their name and display image are just quesiton marks (??? and ? respectively). I'm unable to combine these items, but my instincts tell me that there is something more to this.   Is there some restriction that prevents me from combining certain items until later in the campaign (and if so, what is it, and how do I remove it)? Or are some items just not able to be fused?


Is the uncertainty principle just saying something about what an observer can know or is it a fundamental property of nature?

I ask this question because I have read two different quotes on the  that don't seem to match very well. There are similar questions around here but I would like an explanation that reconciles these two interpretations specifically:   Feynman talks about the uncertainty principle in one of his lectures and mentions it as the reason why electrons don't crash into the atom's nucleus: If they did they would have an exact location and momentum which is not allowed by the uncertainty principle. In saying this it is clear that the uncertainty principle is a fundamental property of nature because it has an effect on where an electron can reside. Recently I read - somewhere else but I forgot where exactly - an account of the uncertainty principle where there was explained how we can measure position of a particle by firing another particle into it, the collision disturbs the velocity of the observed particle therefore we can not know its momentum anymore.   Now, 2) very much seems like a limitation of what the observer can know, while 1) attributes a fundamental property of nature to it (electrons don't crash into the nucleus). What is the correct way to think about this?


Show that normable eigenstates are not degenerated in 1D

I'm given a particle in a piecewise continous potential $V$ and am supposed to show that normable eigenstates of the Hamilton Operator are not degenerated. My approach was to find two eigenfunctions $\psi_1(x)$ and $\psi_2(x)$ that have the same eigenvalue and the show that they are linear dependent. Plugging into the Schrödinger equation led me to $\psi_1(x) \psi''_2(x) - \psi_2(x) \psi''_1(x) =0$. For linear indepence this equation would only be true for $\psi''_1$ and $\psi''_2$ both being zero, so I thought it's somehow possible to show that they are not zero to show the linear dependence. But I'm stuck so far. The only further assumption I have is that the first differential of the functions is limited for $|x| \to \infty$.


Is it possible to read and write Word (2003 and 2007) files in Python without using a COM object? I know that I can:  f = open('c:\file.doc', "w") f.write(text) f.close()   but Word will read it as an HTML file not a native .doc file.


What's the blue pentagon for in Pokemon XY?

On the Pokemon status screen, underneath the Pokemon and to the left of the custom markings, is a small blue pentagon:  This doesn't seem to be present on Pokemon obtained through the Pokemon Transporter from Gen V:  I've looked into it myself, and popular opinion seems to be that it's either some kind of "Legitimate Pokemon" mark or simply to indicate that the Pokemon originates from Gen VI. The latter seems far more likely to me, but do we know for sure what this blue hexagon means?


If $L$ is a straight line then what is the topology that $L$ inherits as a subspace from $\mathbb{R}_l \times \mathbb{R}$ and as a subspace of $\mathbb{R}_l \times \mathbb{R}_l$ .  I know that the basis of $\mathbb{R}_l \times \mathbb{R}$ is $(a, b] \times (a, b) $ and so the basis of $(\mathbb{R}_l \times \mathbb{R} ) \cap L$ is $((a, b] \times (a, b) ) \cap L$. I know that the basis of $\mathbb{R}_l \times \mathbb{R}_l$ is $(a, b] \times (a, b] $ and so the basis of $(\mathbb{R}_l \times \mathbb{R} ) \cap L$ is $((a, b] \times (a, b]) \cap L$. Am I on the right track? I need some hints from here. (not the full answer)


In what circumstances will a bank waive the annual credit card fee?

I've had my credit card for two years. I use it extensively for all kinds of purchases and I have never gone over my limit or incurred a late payment fee. The card has an annual fee and I was wondering if there are any circumstances when a bank might waive the fee, given that I have proven I am a reliable customer and make extensive use of it.


$\mathbb{Q} \simeq \mathbb{Q}^*_+$ isomorphism

Is it true that $(\mathbb{Q},+) \simeq (\mathbb{Q}^*_+, \times)$? If yes then is there any constructive isomorphism?


How to create separate profiles for Firefox Developer Edition and Firefox?

I need to run Firefox Developer Edition (67.0b3.) and Firefox (regular version) simultaneously, but whenever I try to run the second instance I get this error message:     Firefox is already running, but is not responding. To open a new   window, you must first close the existing Firefox process, or restart   your system.   I remember that when I first installed Firefox Developer Edition, there was an option in the Settings to use separate profiles for Firefox Developer Edition and Firefox. Now I don't see that option in the settings.  How to achieve that profile separation? Maybe it can be done by manually editing profiles.ini?


As I understand another = an + other, which has turned into a single word through the history of English. As a consequence, it refers to a single object (another car = one car, another bite = one bite). But I wasn't sure about the expression "Another four chickens". The expression sounds good to my ears, but bad to my (little) grammar knowledge.  My two questions are:        Is it correct?   If so, when can another be used for plural?


Prove that the given series of functions is continuously differentiable.

$f(x)= \Sigma_{n=1}^{\infty} \frac {\sin nx^2}{1+n^3}$, $x\in {\mathbb{R}}$  I can show continuity by using uniform convergence and the Weierstrass M test. But I don't know how to do differentiability. Any help would be highly appreciated. Thank you.


This might be a conceptually stupid question, but it also might not and since I am still a student I think I should I have no problem asking.  Imagine you have a method that if given certain conditions it will throw an NumberFormatException. I want to write a Unit Test to see if the exception is being correctly thorwn. How can I achieve this?  P.S. I am using JUnit to write the Unit Tests.  Thanks.


How can you go through single-height blocks?

This has been a constant source of annoyance for me. Scattered around the castles are darker walls where projectiles and - occasionally - players can squeeze through. Often there is the explicit expectation that you should be able to squeeze through such an opening, but nothing I've done so far seems to do the trick.    A specific room in the Forest that would have you go up and then down at the other side has such an area at the bottom that you can dash through. This seems to work nowhere else, however.  So: how do you do that? Is it the flexibility perk? Is it some kind of NG+-only rune? Is it some weird input combination? Is it something awfully obvious?


I have made a command  \newcommand{\mysec}[2]{%  \textbf{#1} \\ #2 }   I use it with \mysec{A}{B}.  But sometimes I also want a third parameter. I could make a whole new command for those situations where I need 3 parameters. But I thought if I could handle it with an optional parameter in my original command?  So I have to check if the third parameter is set and how to print if it is set.


I understand the differences between RAW and JPEG. But why does my DSLR offer me the opportunity to shoot RAW plus JPEG simultaneously. What benefits does this offer over RAW only, especially since I process my RAW files in Lightroom and the originally 'camera saved' jpegs would not reflect the changes. (I export jpegs for screen viewing after LR adjustments). What am I missing?


Question about the defination of the first order Language

I see the different definitions of $\mathcal{L}$ . First one is in the book :A First Journey through Logic it says the language consists two parts:logical symbols and non-logical symbols. the non-logical symbols consists three part: $\mathcal{C}^{\mathcal{L}}$,$\mathcal{F}_{n}^{\mathcal{L}}$,$\mathcal{R}_{n}^{\mathcal{L}}$,$n\in \mathbb{N^{*}}$, which each mean the set of constant symbol,the sequence of set of function,the sequence of set of relation. And the second one is in the book:Lectures on Inﬁnitary Model Theory the definition is:the second part just consist: a set of function symbols, relation symbols and constant symbols.  So, I want ask is the the sequence of set of function or the sequence of set of relation requires countable?


10th of June i've made an update and now I'm no more able to login. Unfortunately I don't know wat was included in this update. My PC looks like logging in, but, after a few seconds, it comes back to the login screen and ask me again and again the password (or to select another account).


Is there a limit to a total number of months a holder of UK multiple entry visitor visa can spend in UK per calendar year?

A relative of mine has received a multiple-entry UK visa for 2 years. Is there a particular limit on how many months in total per year she can stay in UK? The way I understand the current rule is that such visitors can enter UK as many times as they want as long as they do not stay for longer than 6 months per single visit. However, does this mean that if she stayed with us for 5 months and went back home for 1-2 months, she could come and stay for another 5 months? I heard that it is advisable to spend only 180 day per calendar year in UK and not more, but I could not find that rule in any official UK Home Office documents. Thanks in advance for any info about this.


Can't come even near to the solution.. Can somebody take a look?

Fermat's little theorem states that if $p$ is a prime number, then for any integer $a$, the number $a^p − a$ is an integer multiple of $p$. In the notation of modular arithmetic, this is expressed as $$a^p \equiv a \mod p.$$  Use Fermat's little theorem to prove that:  Given prime number $p$, show that if there are positive integer $x$ and prime number $a$ such that  $p$ divides   $\frac{x^a – 1}{x – 1}$, then either $а= p$ or $p \equiv 1 \mod a$.  I tried to connect  $\frac{x^a – 1}{x – 1}$ to the theorem, but without any success..  Anything will help.. Thanks in advance


Show that $\lim\limits_{y\downarrow 0} y\mathbb{E}[\frac{1}{X};X>y]=0$.

Let $(\Omega,\mathcal{F},\mathbb{P})$ be a probability space, and let $X$ be a nonnegative random defined on this space. For any $A\in \mathcal{F}$, let $\mathbb{E}[X;A]:=\mathbb{E}[X\mathbb{1}_{A}]$, where $\mathbb{1}_{A}$ denotes the indicator random variable on $A$. Without assuming $\mathbb{E}\left[\frac{1}{X}\right]<\infty$, show that  \begin{eqnarray} \lim\limits_{y\downarrow 0} ~~y~\mathbb{E}\left[\frac{1}{X};X>y\right]=0. \end{eqnarray} Any initial ideas will be greatly appreciated.


Install Android. v 4.0.4 on a STAR H3000+

I've got mobile "STAR H3000+" (a rip off iPhone5) with Android v4.0.4. I just wanted to ask if it is possible to install Android v4.2. or newer. Does anyone know how to do it?


What is the highest possible profile level?

What is the highest Steam profile level? I've seen people with levels like 142 and they still have a next level indicator on their profile. Is there an end to this?


C#, get object indexes from List, by multiple conditions using Linq

linq expressions is to complex for me when i need to do complex searches over list.  let's say i have List  public class Object {     var length;     var height;     var depth; }   How to filter objects id by max length, if there are more than one index, then filter by max width, if there are more than one index, then filter by   max depth, if there more then one index return first one.   i found max values:   float maxWidth = boxes.Max(x => x.width); float maxHeight = boxes.Max(x => x.height); float maxDepth = boxes.Max(x => x.depth);   then i used for loop to get values. And it's ok, but after each loop i have to create another list to get another value and etc.  private GameObject largestSurfaceBox() {      //find max length.width, height box     float maxWidth = boxes.Max(x => x.GetComponent<Box>().dimensions.x);     List<GameObject> maxWidthBoxes = new List<GameObject>();      for (int i = 0; i < boxes.Count; i++) {         if (System.Math.Abs(boxes[i].GetComponent<Box>().dimensions.x - maxWidth) < float.Epsilon) {             maxWidthBoxes.Add(boxes[i]);         }     }      float maxHeight = maxWidthBoxes.Max(x => x.GetComponent<Box>().dimensions.y);     List<GameObject> maxHeightBoxes = new List<GameObject>();      for (int i = 0; i < maxWidthBoxes.Count; i++) {         if (System.Math.Abs(maxWidthBoxes[i].GetComponent<Box>().dimensions.y - maxHeight) < float.Epsilon) {             maxHeightBoxes.Add(boxes[i]);         }     }      List<GameObject> maxDepthBoxes = new List<GameObject>();     float maxDepth = maxHeightBoxes.Max(x => x.GetComponent<Box>().dimensions.z);      for (int i = 0; i < maxHeightBoxes.Count; i++) {         if (System.Math.Abs(maxHeightBoxes[i].GetComponent<Box>().dimensions.z - maxDepth) < float.Epsilon) {             maxDepthBoxes.Add(boxes[i]);         }     }      return maxDepthBoxes[0]; }   How to do that elegant linq way with if statements if possible?


In the history of mathematics, has there ever been a mistake?

I was just wondering whether or not there have been mistakes in mathematics. Not a conjecture that ended up being false, but a theorem which had a proof that was accepted for a nontrivial amount of time before someone found a hole in the argument. Does this happen anymore now that we have computers? I imagine not. But it seems totally possible that this could have happened back in the Enlightenment.   Feel free to interpret this how you wish!


The master method - why can't it solve $T(n) = 2T(\frac{n}{2}) + \frac{n}{\log n}.$ What's the issue with the master theorem? Why is there like different concepts on different channels? What formula applies? what is "polynomial check"? when does the k method apply? There are so many questions in which some say master theorem cannot be applied but some give out the answers. I m pretty confused right now - what to follow?


Create and manage a group using the Facebook API

I am new to Facebook application development and I am looking for a way to create and manage a group using the the Facebook API. There is a get and get list call but I have not found a way to manage groups.


I have hp laptop with intel processor with Ubuntu 14.10 preinstalled in it which is customized. I want to remove that customization and make it original as earlier. SO I want to reinstall Ubuntu in it. Please send me a link to download Ubuntu and install it on Ubuntu os (for reinstallation).


Prove that a holomorphic function with postive real part is constant

Suppose that $f$ is holomorphic on $\mathbb C$ and that $\Re(f(z))\ge 0$ for all $z$. Show that $f$ is constant. [Hint: consider $e^{−f(z)}$.]   My thoughts: If $\Re(f(z))\ge 0 $ holds, then $e^{−f(z)}$ is a bounded holomorphic function (do I need to prove this or is it obvious?) So then by Liouville's Theorem $e^{−f(z)}$ is constant.   But then I'm not sure how to rigorously go from this $\exp(−f(z))$ back to $f(z)$.   Could anyone help me piece this together please?  Thanks


What is the function of shortcut "Alt + PrtSc + b"?

I find a shortcut Alt+PrtSc+b which can let my ubuntu reboot,  but what is the really function of the shortcut?


Can someone help me find the continued fraction expansion for $\sqrt{7}$ just like I did for below.  For $\sqrt{3}$ I did this:  I was given that $x = \sqrt{3} -1  $  $x = \frac{1}{1+\frac{1}{2+x}}  $  take the second   $x = \frac{1}{1+\frac{1}{2+x}}  $  $x = \frac{1}{\frac{2+x+1}{2+x}}  $  $x = \frac{2+x}{x+3} $   $x(x+3) = 2+x  $  $x^2 +3x = 2+x \Rightarrow x^2+2x-2=0  $  find x,then we are done   how to write  $x =\sqrt{3}-1$  in continued fraction using  $x = \frac{1}{1+ \frac{1}{2+x}}  $  $\sqrt{3}-1 = \dfrac{1}{1+ \dfrac{1}{2+\dfrac{1}{1+\dfrac{1}{2+\dfrac{1}{1+\d  frac{1}{2+\dfrac{1}{1+\dfrac{1}{2+\dfrac{1}{1+\dfr  ac{1}{2+..}}}}}}}}}}$  I just sub x value each time it will never end   $\sqrt{3}-1 = \dfrac{1}{1+ \dfrac{1}{2+\dfrac{1}{1+\dfrac{1}{2+\dfrac{1}{1+\d  frac{1}{2+\dfrac{1}{1+\dfrac{1}{2+\dfrac{1}{1+\dfr  ac{1}{2+..}}}}}}}}}} $  so   $\sqrt{3} = 1 +\dfrac{1}{1+ \dfrac{1}{2+\dfrac{1}{1+\dfrac{1}{2+\dfrac{1}{1+\d  frac{1}{2+\dfrac{1}{1+\dfrac{1}{2+\dfrac{1}{1+\dfr  ac{1}{2+..}}}}}}}}}} $  So it would be <1;1,2,1,2,1,2>


Is there a systematic way of solving cubic equations?

In my text book, to solve cubic equations, I need to    find by trial & error what $f(a)$ will make the equation 0. The factor will be $(x-a)$ then the other factor will be $Ax^2+Bx+C$ then I can solve using compare coefficient   But for te first part, is there any other way apart from trail & error? Or is there some technique to guess the factor of an equation?   The question I am currently doing happens to be $2x^3+3x+4=9$   UPDATE:  $2x^3+3x+4=9$ should be $2x^3+3x+4=9x^2$   UPDATE 2  So I am going to try substituting   $x=\pm{1}, \pm\frac{1}{2}, \pm{2}, \pm{4}$  When $x=-\frac{1}{2}$, one of the provided answers,   $2(−0.5)^3−9(−0.5)^2+3(−0.5)+4=-18.75\neq 0$   did I make a mistake?


Semplification using Vandermonde determinant

My task is to simplify at most the following polynomial $f \in\mathbb{Q}[x_1,x_2,x_3,x_4]$ (I must then write it as alementary symmetric polynomial)  $f:=\frac{\det\begin{pmatrix}1&x_1^2&x_1^3&x_1^4\\1&x_2^2&x_2^3&x_2^4\\1&x_3^2&x_3^3&x_3^4\\1&x_4^2&x_4^3&x_4^4 \end{pmatrix}}{\det\begin{pmatrix}1&x_1&x_1^2&x_1^3\\1&x_2&x_2^2&x_2^3\\  1&x_3&x_3^2&x_3^3\\1&x_4&x_4^2&x_4^3 \end{pmatrix}}$  Clearly the denominator is equal to $\prod_{1≤i<j≤4}(x_j-x_i)=(x_4-x_1)(x_4-x_2)(x_4-x_3)(x_3-x_2)(x_3-x_1)(x_2-x_1)$ being a Vandermonde determinant.  The problem is the numerator, I tried to compute it, but even after a long computation i can't see an easy way to determine the fraction. I was wondering if also the numerator is correlated with a Vandermonde matrix somehow, or if there is something I'm missing. Thank you in advance.


"I've been doing this (for) a week" -- When do you leave out the 'for' when talking about duration, and when do you not?

The other day I heard someone say:       They've been going out a week; I mean, that's not (a) serious (relationship).     I wondered if she was speaking correctly, which is presumable, since she was a native American English speaker. But more often I here the for when people talk about duration. So is it also possible to leave out for? Maybe only in the informal register?   EDIT: There was a heavy stress on the word week. Does it play a role in this matter?  EDIT#2: ... OK. It's more suitable as an answer.


How to put a default text in empty page?

I am currently writing my thesis and for that I use a default template found on internet. It use \cleardoublepage apparently. I have an issue because this template add empty page by default and my company ask me to put the default text "This page is empty" for security reason.   I am wondering if it possible, by adding a simple code some where, to add that text on all empty pages ?  Thanks a lot,  Cheers,  Eliott


Can I get to Germany from Norway with a single entry Schengen visa while having a flight transit in UK?

I have a single entry visa to Schengen countries(type c). I will be traveling to Norway from Toronto, Canada. I will stay for a week, then I will travel to Germany. My flight from Norway to Germany will have a transit in London. Will this be a problem with my Single Entry Visa? Will I be able to enter Germany even if I have a transit in London?


Terminal sometimes fails to find executables on local directory

I can open my terminal emulator via a keyboard shortcut or through the apps finder that executes the exo-open --launch TerminalEmulator command. My terminal starts and I can cd to any directory and execute any binaries located on any bin directory on my system.  But whenever I launch it by right-clicking any directory on thunar and using the Open terminal here option it sometimes can't find any executable on my local binaries directory (~/.local/bin/). Simply put:   Open terminal via app finder, command launcher, keyboard shortcut, … → It can find local executables. Open terminal via context menu on Thunar → It sometimes can't find local executables.   This happens on any terminal (xfce4-terminal, xterm, gnome-terminal). My machine is running Fedora 20 XFCE with thunar version 1.6.3-2.  I can't say for sure since when this started happening, because it has been some time, but this became more frequent in recent days. Also, I have to mention that once my terminals can find executables on my local bin directory and I add a new one, it won't find them again, until some time passes - no matter if it was launched via the thunar's context menu or not.  Has anybody noticed this behaviour too? Can somebody shed some light on what's happening here?  Update:  I've noticed that my .bash_profile file is what adds my local bin directory to the $PATH environmental variable:  PATH=$PATH:$HOME/.local/bin:$HOME/bin export PATH   And when I run a login shell (not started via the context menu), it executes .bashrc and then .bash_profile, so I proceeded to move those two lines from my .bash_profile to my .bashrc and now everything works fine.   So the question now is: why does the context menu command (which is the same as the normal command) somehow make my terminal to be launched as only interactive and not as a login terminal?


Why isn't the word "white" capitalized when referring to the race?

I was surprised to find that there's a growing convention of capitalizing the word "black" when referring to the race, i.e.:  A Black person.  I thought this was wrong, because I thought it was only proper nouns, like cultures, nationalities and ethnicities, that were to be capitalized. Black denotes a race, and nothing more, as there are many nationalities, cultures and ethnicities that fall within the black race. Calling black a culture or ethnicity would be reductive. However, this capitalization rule apparently applies to race as well; see the 10th item . If this rule is in fact true, then that means black is to be capitalized when denoting a person of the black race. It also means that white is to be capitalized when denoting a person of the white race. Caucasian, which is a word denoting a race, is capitalized. It is a synonym to white. So, if Caucasian is capitalized, and if people want black to be capitalized when referring to race, why isn't white supposed to be capitalized? Is white not a race? I'm no biologist, nor anthropologist, but if white is too genetically broad to be considered a race, then I'm pretty sure black would be too. EDIT: As user Cascabel pointed out in the comments, Caucasian is derived from the Caucasus Mountains, which is a place, and therefore a proper noun. Therefore, regardless of what capitalization rules one employs, Caucasian has to be capitalized, and is therefore not necessarily an example of people capitalizing racial classification. EDIT 2: CMS have changed their preferred capitalization rules as of the 17th edition, which means that the answers to the linked  that this post was designated a duplicate of, are no longer valid.


Significance of "thin" in thin film interference

What is the significance of the word "thin" in thin film interference. Will the phenomenon not occur when the film is thick or not of order of magnitude of wavelength of light ( thin films are of order of magnitude of light). Thick films may too produce various path differences and thus varying phase differences. Then why is the phenomenon not specified for thick films?


What is exactly copied during class slicing?

#include<iostream> using namespace std;  class A {     public:         A():m(1){};         int m; };  class B : public A {     public:         B (): A(),m(2),n(3){};         void print(){cout<<'?';};         int m,n; };  int main (int, char *[]) {     B b;     A a1 = b;     cout<<a1.m<<endl;       // This prints out 1 instead of 2.       return 0; };  Brief code explanation: I declared and defined two class A and B, where B inherits from A. Class A and B both contains member variable m. When I say A a1 = b;, I understand that member variable n of instance b won't get copied to a1, because of class slicing. My question is why member variable m is not copied as well? (My thought is like: Both instance a1 and b contain member variable m, so when initializing a1 with b, the copy constructor of a1 will be called, and member variable within class A will get copied from b.)   Is that correct? More generally, during class slicing, what exactly is copied to the recipient?


Kernel density estimation for a variable with lots of zeros

I am trying to estimate the kernel density for number of days a child is sick. Around 73% of children report not being sick, i.e. zero. How do I estimate a kernel density for this censored variable using Stata?


Differences between reconstruction- and generation-level variables in HEP data

I am working on a CMS - related project where the ROOT trees contain both reconstruction-level and generation-level particle variables (like mass). However, I don't know the basic difference between the two or when we prefer using one type of variable over the other?


I am currently using this php code to send a mail from a form on my website, and it works fine, with one exception : when we receive the email it shows as sent by "webmaster@mydomain.com" instead of the user's email.  This is the php :  if(isset($_POST["submit"])){ // Checking For Blank Fields.. if($_POST["vname"]==""||$_POST["vemail"]==""||$_POST["vphone"]==""||$_POST["msg"]==""){ echo "Fill All Fields"; }else{ // Check if the "Sender's Email" input field is filled out $email=$_POST['vemail']; // Sanitize E-mail Address $email=filter_var($email, FILTER_SANITIZE_EMAIL); // Validate E-mail Address $email=filter_var($email, FILTER_VALIDATE_EMAIL); if (!$email){ echo "Invalid Sender's Email"; } else{ $subject = "Contact site"; $message = "\n\nMessage from: ".$_POST["vname"]."\nPhone: ".$_POST["vphone"]."\nEmail: ".$_POST["email"]."Message:\n\"".$_POST["msg"]."\""; $headers = 'From:'. $email . "\r\n"; // Sender's Email $headers .= 'Cc:'. $email . "\r\n"; // Carbon copy to Sender $message = wordwrap($message, 70); // Send Mail By PHP Mail Function mail("contact@mydomain.com", $subject, $message, $headers); echo "Email sent !"; } } }


In Interstellar, after young Murph places the watch on the bookshelf in her bedroom, her father - in the same bedroom but from another dimension - moved the second hand and recorded data in a Morse-signal message on it. Many years later, the second hand still signals the message, grown-up Murph finds the watch and takes it with her to NASA and there she translates the message back into the data needed.  If we assume the watch had a long lasting battery, then I still see some problems with this plot:   From what we know from the explanation in the movie itself is that the only thing capable to travel from them in the 4th or 5th dimension to present Earth is gravity. Gravity is a vertical force on Earth. It pulled dust from the air to the floor in a barcode-like pattern. So how can it adjust the horizontal position of the second hand of the watch? Like a magnet? And how is a multiple of those movements of the second hand recorded on the watch? How does it play the message for all these years, again and again. Not only in Murph's bedroom, but still at NASA too?   Normally I would answer this myself by saying that it is film, it is science fiction, everything is possible, and there is no need to question things we cannot explain. But this movie certainly has the intention of being truthful to science, to explain what is going on and this particular director has a reputation of telling stories that in one way or another always has plausible explanations for plot-hole-like aspects.


In the beginning, there were several times when Kousei was playing the piano, and he suddenly felt that he was at the bottom of the ocean and couldn't hear what he was playing. Why did that happen, and was he able to hear himself play at the end?


How can I show the details from the highest zoom of OSM webmaps in QGIS for printing?

I would like to compose a large format map for printing in QGIS with the highest detail possible.  My process looks like this,    Install "QuickMapServices" plugin Click the "QuickMapServices" button and choose OSM >> OSM Standard Pan to my selection area New print layout (ctrl + p) and make a name add item >> add map (its now at the zoom where I want more detail displayed and I don't know what to do).


Now that gravitational waves have been discovered, what does their particle version look like?

Duality dictates that gravitational waves should have a particle counterpart too, right? Will this in any way help solve the big problem of quantum gravity?


Is my question appropriate for Stack Exchange? If so, where should I ask? If not, where else can I ask?

My question is this: What is it like working in the IT security field and what skills are required?  I was looking for a "career" site but there doesn't seem to be one so I thought instead of the Information Security site. After looking at questions asked there, I didn't think mine would be appropriate.  Also, if my question is unappropriate for Stack Exchange, is there a place I could ask it?  I'm not even sure Meta is the right place for this question but I couldn't find a .


\documentclass[12pt]{article} \usepackage[paperheight=9in,paperwidth=13.24in,margin=0in]{geometry} \usepackage{pstricks} \usepackage{graphicx} \begin{document} \thispagestyle{empty} \psset{unit=1in} \begin{pspicture}(13.24in,9in) \psframe[fillstyle=solid,fillcolor=Maroon](0,0)(13.24,9)  \end{pspicture}  \end{document}   I am following a tutorial outlined here:   I am following the Robbers book.  Everything seems fine until I paste the \psframe[fillstyle=solid,fillcolor=Maroon](0,0)(13.24,9)  What could be the problem?


How to install Chrome to a custom location?

How can I install Google Chrome to a custom location, instead of its default usr/bin?  And where does Chrome keep user settings?


Null Pointer Exception with entrySet() on HashMap

I want to iterate through the HashMap and this is part of the code:  HashMap<Long, Integer> users = ((HashMap<Long, Integer>) getArguments().getSerializable("HashMap"));  Iterator it = users.entrySet().iterator();      04-25 19:13:31.070: E/AndroidRuntime(1446):   java.lang.NullPointerException: Attempt to invoke virtual method   'java.util.Set java.util.HashMap.entrySet()' on a null object   reference   I looked at the users variable and it does contain a table with keys and values.


Artifacts when switch to camera view and render. 3d view looks OK

This is the picture of 3d viewport   Then I switch to Camera view (artifacts can be seen in both viewports).   And the render   You can see, that the size of the model is big (though I tried to scale it down to check and it didn't help). Also the camera is in orthographic mode with a big Scale. Blender 2.79 internal.  Texture is not UV mapped, but generated (sphere). And it looks different in viewport when material and render view. In case if it matters.  Any ideas?


How do I apply this kernel patch to /net/ipv4/ip_gre.c?

I've been googling for a while about how to do patch linux kernel but still have no clue. My intention is to do a patch to /net/ipv4/ip_gre.c . the patch is from here http://patchwork.ozlabs.org/patch/264994/  diff --git a/net/ipv4/ip_gre.c b/net/ipv4/ip_gre.c     index 855004f..c52fee0 100644     --- a/net/ipv4/ip_gre.c     +++ b/net/ipv4/ip_gre.c     @@ -572,7 +572,7 @@  static int ipgre_header(struct sk_buff *skb, struct net_device *dev,         if (daddr)             memcpy(&iph->daddr, daddr, 4);         if (iph->daddr)     -       return t->hlen;     +       return t->hlen + sizeof(*iph);          return -(t->hlen + sizeof(*iph));      }   doing patch command still no success. so i tried change the line just like decribed in the patch to the file i wanted to patch, delete the (-) and add (+) line.  does the ip_gre.c file need to be compiled again??


Minimum principle is following: Let $M$ be a closed convex nonempty subset of Hilbert space. Then there exists $x\in M$ which have a minimum norm.  Assume that $M$ is not convex subset. What is a counterexample, when there have not the element with minimum norm in space $\ell^{2}$?


Prove that $y'=-y^3+\sin x $ has a unique solution satisfying $y(0)=y(2\pi)$

Prove that the ordinary differential equation $$y'=-y^3+\sin x $$ has a unique solution satisfying $y(0)=y(2\pi)$ It's really hard for me to figure out the existence and the uniqueness. I don't have any clue about this problem. Maybe we can let $u(x)=y(x+2\pi)-y(x)$, then $u(x)$ should satisfy $u(0)=0$ and some differential equations.


Scale (resize) large images (graphics) that exceed page margins

Background  A large number of screen captures have been scaled 300% at 288dpi. They appear correctly when embedded in OpenOffice, but not LyX.  Problem  Images that do not extend beyond the margins (small images) appear perfectly. Images that are too big extend beyond the margins.  Attempt #1  \setkeys{Gin}{width=1.0\textwidth}    However, that code scales the smaller images to also fit the width, which is undesirable. (The smaller images become distorted.)  Attempt #2  Didn't attempt this, but it looks useful.  % Redefine includgraphics for avoiding images larger than the screen size % If the size is not specified. \let\py@Oldincludegraphics\includegraphics  \newbox\image@box% \newdimen\image@width% \renewcommand\includegraphics[2][\@empty]{%   \ifx#1\@empty%     \setbox\image@box=\hbox{\py@Oldincludegraphics{#2}}%     \image@width\wd\image@box%     \ifdim \image@width>\linewidth%       \setbox\image@box=\hbox{\py@Oldincludegraphics[width=\linewidth]{#2}}%       \box\image@box%     \else%       \py@Oldincludegraphics{#2}%     \fi%   \else%     \py@Oldincludegraphics[#1]{#2}%   \fi% }   Source:   Attempt #3  % Resize figures that are too wide for the page \let\oldincludegraphics\includegraphics \renewcommand\includegraphics[2][]{%   \makeatletter%   \def\maxwidth{\ifdim\Ginnatwidth>\linewidth\linewidth%   \else\Ginnatwidth\fi}%   \makeatother%   \oldincludegraphics[width=\maxwidth]{#2}%   Packages  Using graphicx.  Other package suggestions are welcome.  Question  Without adding LaTeX code to every image that exceeds the margins, what can be done to resize just those images that are too big?  Example  The following image is an example of many, many images that must be scaled back to fit the page width:    Related


The book of Thoms Jech on set theory mentions some equalities involving $\aleph_{\omega}$:  $\aleph_\omega^{\aleph_1} = \aleph_\omega^{\aleph_0} \cdot 2^{\aleph_1}$ If $\alpha < \omega_1$, then $\aleph_\alpha^{\aleph_1} = \aleph_\alpha^{\aleph_0} \cdot 2^{\aleph_1}$. If $\alpha < \omega_2$, then $\aleph_\alpha^{\aleph_2} = \aleph_\alpha^{\aleph_1} \cdot 2^{\aleph_2}$  How can the above equalities be proved?


Is There a Better Way of Checking Nil or Length == 0 of a String in Ruby?

Is there a better way than the following to check to see if a string is nil OR has a length of 0 in Ruby?  if !my_string || my_string.length == 0   return true else   return false end   In C# there's the handy  string.IsNullOrEmpty(myString)   Anything similar to that in Ruby?


Easy command or package for properly formatted integrals?

I like to format my integrals so that there is less space between the integral sign and the integrand, more space between the integrand and differential, and so that the differential is upright. However, it is tedious to type out the formatting repeatedly. I wrote a command,  \newcommand{\intf}[4]{\int_{#1}^{#2} \! #3 \, \mathrm{d}#4}   So that the properly-formatted integral is easier to type, e.g. typing in \[ \intf{a}{b}{x^2}{x} \] gives    However, this command requires 4 inputs. If I didn't want the upper or lower limits, I could omit their inputs but I would still need to write out the brackets, e.g. \intf{}{}{x^2}{x}. In the long run, however, this gets tedious as well, and looks messy in the code! It would be super if I had some command where I could just write ^ and _ as necessary, e.g. \intf^{b}{x^2}{x}  So, I'm wondering two things: (a) Is there some preexisting package that has a pre-formatted integral command? (b) Is there an easy way to change the above command so that it can take modifications such as ^ and _ as required?  Thanks!


Should a question mark appear at the end of a question, and before the second quotation mark?  An example is:      "How are you feeling today," he asked.   I'm getting conflicting advice.


Problem with Stack Overflow reputation league

I was quite impressed when I saw this week's Stack Overflow leaderboard:    But the user's reputation activity doesn't quite match:    What's going on?


I am switching from windows 8.1 to ubuntu which ubunutu you prefer me to choose? Laptop info(intel i7 3rd ino, 8gbRAM radeon graphics, samsung)


Array gets mutated after array element is passed into splice() method as arguement

I was trying to solve the Water Connection Problem I have an inputs array const inputs = [     [7, 4, 98],     [5, 9, 72],     [4, 6, 10],     [2, 8, 22],     [9, 7, 17],     [3, 1, 66] ]  when I pass an element of that array's inner array into splice() method like newArray.splice(-2, 0, item[1]) the original one, input[item] is getting mutated. Here is the full code   const inputs = [   [7, 4, 98],   [5, 9, 72],   [4, 6, 10],   [2, 8, 22],   [9, 7, 17],   [3, 1, 66] ]  const starts = inputs.filter(element =>   !(inputs.map(item => item[1]).includes(element[0])) );  const arrayAppender = (array, element) => {   const newArray = element;   let elementAdd;   let traversalDone = false;   while (!traversalDone) {     elementAdd = false;     array.some(item => {       if (newArray[newArray.length - 2] === item[0]) {         newArray.splice(-1, 0, item[1]);         newArray[newArray.length - 1] = newArray[newArray.length - 1] > item[2] ? item[2] : newArray[newArray.length - 1];         elementAdd = true;         return true;       }     })     if (!elementAdd) traversalDone = true;   }   return newArray; }  console.log(starts.sort().length);  starts.forEach((element, index) => {   starts[index] = arrayAppender(inputs, element);   console.log(starts[index][0], starts[index][starts[index].length - 2], starts[index][starts[index].length - 1]); });    at the end of execution inputs[1] changes from [5, 9, 72] to [5, 9, 7, 4, 6, 10] when I tried to see what causes the change, newArray.splice(-1, 0, item[1]) ; this line of code was what's triggering it (found using debugger). The code is working and doing what it's supposed to do, But I'm very much curious to see what's causing the above mentioned odd behavior and how can this be solved. Thanks in advance.


Perfect power of $2$ in whose decimal representation, each digit is also a non-negative power of $2$

Let $A:=\{n \in \mathbb N : 2^n=\sum_{j=0}^k 10^j2^{n_j} , $ for some integers $   0 \le n_j \le 3  , j=0,...,k $ with $ k>1\}$ ; then is the set $A$ finite or infinite ? I have been unable to find any number other than $7$ in  $A$ . Please help . Thanks in advance .


By the fluctuation-dissipation theorem (detailed-balance for Langevin equation), $$\sigma^2 = 2 \gamma k_B T$$ where $\sigma$ is the variance of noise, $\gamma$ is a friction coefficient, $k_B$ is Boltzmann's constant, and $T$ is temperature. So in principle, one can have $\gamma\neq 0$ while $T=0$ and $\sigma=0$.  Is it indeed possible to experimentally achieve a system whose temperature and noise approach zero, but whose friction coefficient $\gamma$ does not approach zero?   If yes, what would be an example of such a system? What is the physical source of friction for such a system? If not, why not? Is there some sort of "quantum" correction to the fluctuation-dissipation theorem that rules out such zero-noise, non-zero friction systems?


nomencl package : sort by order of appearance

In the nomencl package, how can I make the symbols print by order of appearance in the LaTeX code?


My laptop only has a 28 GB hard drive with Ubuntu installed. I would like to install Windows 10 as well but there is no room on the hard drive. How do I install Windows 10 onto an EXTERNAL hard drive  EDIT: I want to dual boot with Ubuntu on the internal drive and Windows 10 on the external drive


When I make a tile-based map editor in C#, I tend to iterate over the X,Y axes and call Graphics.DrawImage() to blit a single tile in place, from a tileset Bitmap onto a map Bitmap. This process takes several seconds to complete, so I only do it once when loading a new map or changing its tileset. Any edits from there on are relatively fast blits of only the edited tile.  Now, I sat back earlier today and thought about my options. Graphics.DrawImage() is the only one of the three (the others being DrawImageUnscaled and DrawImageUnscaledAndCropped(?)) that allows the specification of a source origin. DrawImageUnscaled() was much, much faster, but always blitted from the top-left of the source bitmap.  In sharp contrast with the speeds of QuickBasic PSET versus POKEing the video memory, or VB6's PSet versus WinAPI's SetPixel, a simple Get/SetPixel loop was as fast as a DrawImageUnscaled call, but did the cropping that only DrawImage would otherwise do.  This is fast enough for now, but I was wondering how something like direct image manipulation could speed it up even more? Something with LockBits perhaps, a function I know next to nothing about?


Photons from stars--how do they fill in such large angular distances?

It would seem that far-away stars are at such a distance that I should be able to take a step to the side and not have the star's photons hit my eye. How do stars release so many photons to fill in such great angular distances?


What is the appropriate place to ask for advice on which technology or plugin to use for a specific purpose?

I am developing a website in  and am looking for the appropriate front-end and back-end plugins to crop, rotate, and resize images. I have enough experience on Stack Overflow to know that such a question is not appropriate for that forum. What would be the appropriate place to ask for help with what plugins and libraries to use on a project?


Why doesn't 32-bit Eclipse run in 64-bit Ubuntu?

I installed 64-bit Ubuntu 12.04 on my desktop and the Eclipse Kepler 32-bit version, considering it should support backwards compatibility with 32-bit apps, but it does not. After a lot of attempts nothing worked out like running it from the terminal, reinstalling JDK, etc. Ultimately I installed 64-bit Eclipse, it runs flawlessly, and then I installed ADT-20.0.3 and Android SDK which gives me the error: unable to find adb version..error 13, I tried the solutions from googling like adding path in .bashrc file [Environment variable] and permission to to adb directory chmod 777 but it didn't work out. I think I just might have to revert back to the 32-bit version of Eclipse. Please explain why there are so many issues with 64-bit Eclipse not being compatible with 32-bit apps.


I am trying to find $$\lim_{n\rightarrow \infty}\prod_{k=2}^{n}\frac{k^3-1}{k^3+1}.$$I have no idea how I can start. Please help me.  Thanks!


Merging polygons at county level to state level?

I have a shapefile that represents counties (admin 2) only, but I need to create a state level (admin 1) polygon file (I'm using QGIS). I will need to sum up (or average) the relevant data at each district level as well.   There are far too many counties to do this manually, so does anyone know of an automated way to roll up to a higher administrative level like this?   I am new to QGIS.


I can't find an answer to this after searching meta and : how do "typo" tags get killed off? For example, currently there are tags for  and , which are both obviously typos. .  So, how do we get rid of these? My take so far is that it is partly automatic, like "tags that are x days old with no posts are closed automatically," and partly a moderator activity. Is this correct?  Closely related: is there any way for users to suggest destruction of a tag that is obviously irrelevant or a typo other than (1) a meta "burninate" post or (2) marking it as a synonym of a legit tag, which just perpetuates the typo's existence?


When doing a search, posts with MathJax code are wrongly formatted.  In this example  all the results look ugly. When taking a closer look at the first post, I notice that the first $ is not regocnized by MathJax as a math-begin, while the second $ (that should denote math-end) is taken as the beginning of math.    Another example:


Appalling browser performance despite fast 3G connection

This is a recent problem that is making me punch holes through walls. Two points up front -   My connection speed is fine. Using the various speedtest tools out there, it is consistently over 1mbps, 6mbps+ on a good day. My download speeds and file transfers (P2P, torrents, ftp etc.) are similarly fine.   My browser performance (whether FF, Chrome or Opera) however is decidedly NOT fine. Over the last few weeks it has been in the toilet. HTTP is bad and HTTPS is worse.  I used curl as described at -    to try and see what the problems may be. These are the outputs -  bob@beelzebubba:~/curl$ curl -w "@curl-timing.cfg" -o /dev/null -s http://www.google.com/    DNS lookup                          :  0.162   Connect to server (TCP)             :  0.442   Connect to server (HTTP/S)          :  0.000   Time from start until transfer began:  0.442   Time for redirection (if any)       :  0.000   Total time before transfer started  :  0.752           Total time                   :  0.752          Size of download (bytes)     :  260          Average d/l speed (bytes/s)  :  345.000  bob@beelzebubba:~/curl$ curl -w "@curl-timing.cfg" -o /dev/null -s https://www.facebook.com/    DNS lookup                          :  0.230   Connect to server (TCP)             :  0.729   Connect to server (HTTP/S)          :  1.620   Time from start until transfer began:  1.620   Time for redirection (if any)       :  0.000   Total time before transfer started  :  2.079           Total time                   :  2.080          Size of download (bytes)     :  0          Average d/l speed (bytes/s)  :  0.000  bob@beelzebubba:~/curl$ curl -w "@curl-timing.cfg" -o /dev/null -s https://www.google.com/    DNS lookup                          :  0.118   Connect to server (TCP)             :  0.435   Connect to server (HTTP/S)          :  1.375   Time from start until transfer began:  1.375   Time for redirection (if any)       :  0.000   Total time before transfer started  :  1.825           Total time                   :  1.825          Size of download (bytes)     :  263          Average d/l speed (bytes/s)  :  144.000   Generally terrible. My questions are -   What could cause this out of the blue? How can I fix it? There is very little of help googling.   Yes I've cleared caches, nuked cookies, started browsers in safe mode etc.


Maxwell Lagrangian where $F$ and its derivatives are the variables (i.e., without replacing $F={\rm d}A$)

The way the electromagnetic Lagrangian is usually constructed is by noticing that the EM fields are always constrained to satisfy ${\rm d}F=0$ (half of Maxwell's equations). We can immediately solve this constraint equation through $F={\rm d}A$. Then the following action,  $$ S[A,{\rm d}A] = \int {\rm d}A \wedge \star {\rm d}A, $$  leads to the remaining Maxwell's equations.  That's fine, but I want an action where $F$ is the dynamical variable and the constraint ${\rm d}F=0$ isn't solved a priori, but rather follows by introducing a Lagrange multiplier $\lambda$. Concretely, I want an action of the form,  $$ S[F,{\rm d}F,\lambda]=?, $$  such that:   From varying $F$, we get the equation of motion ${\rm d}\star F=0$. From varying $\lambda$, we get the equation of motion ${\rm d} F=0$.   Is such a thing possible?  EDIT: The linked answer doesn't satisfy my demands. While it derived ${\rm d}F=0$ by varying a Langrange multiplier, which I'm allowing, it also derives the equation of motion ${\rm d}\star F=0$ by varying a Lagrange multiplier. I do not want this. The eom should come by varying $F$.


Trying a VPS (hosting).  I have installed Ubuntu 16.04 and created a user admin. Now I'm trying: ssh admin@185.149.129.42 The prompt becomes just a $.  I try:   sudo su root   The prompt has become   root@simple_project:/home/admin#   This line is in white letters.  I try:   su admin   The prompt is in green letters:  admin@simple_project:~$    Well, in other words three cases:   white $;  white root; green admin.   I was somehow confused by case 1 for example. And I did:   su root  su admin  And I get my green letters up to the colon:  admin@simple_project:~$   This looks more familiar than just a bear $.  Could you tell me what these three cases mean? If they really mean anything.


How do I find:  $$\prod_{n=1}^\infty\; \left(1+ \frac{1}{\pi ^2n^2}\right) \quad$$  I am pretty sure that the infinite product converges, but if it doesn't please let me know if I have made an error. Also, could I have a nice explanation as to how would someone arrive to the answer.  Thanks alot.


Is it possible to let a user change value of a single field in their account profile without going to the user edit page?

On my site, users have several single-value boolean checkboxes as part of their profiles.  In various places on the site, I want to let users toggle one of these fields on or off without going to the user edit page.  I'm using Panels, so I'd like to somehow embed a way to edit just the value of a single field into a given page/panel.  What I tried:   Use the Field Permissions module to block access to the field. Create a flag with the Flag module. Let users flag or unflag themselves. Make rules with the Rules module to set the value of the field based on the user flag.   This works, but it's very cumbersome to set up and tricky to maintain.  It also prevents users from editing the value on the user edit page; they have to use the flag instead.  So I'm wondering if there is a more straightforward way to do what I want.  This is similar to , but that question is about modifying the user account page.


What are all the solutions to the functional equation $f(ax)=bf(x)$, where $a,b>0$, and $f$ is continuous, strictly monotone and increasing, and $x$ ranges over the reals?  references? proof?  Thanks    Additional details following the first response:  It is easy to see that the function $f(x)=c\cdot x^\alpha$, with $\alpha =\log b/\log a$ and any constant $c$ is a solution for the functional equation.  Also, the $c$ can be different for the positives and the negatives.  So, if $x^\alpha$ is not monotone itself, we can create a monotone solution by gluing together a positive $c$ for the positive side with a negative $c$ for the negative side.  Is this correct?  My question is if these are all the solutions, and if this is appears in the literature.    Thanks.


Single Photon Single Slit Interferometry

If just a single photon hit a single slit interferometer, what would happen? Would you just see a dot on the screen, or would there be a diffraction pattern? Furthermore, if you had a double slit interferometer but also had which-path information would there still be a diffraction pattern even though there is no interference?


Want to download an app from Kenya in the app store

Possible duplicates of       Nevertheless, as the answers provided in the previous threads were not satisfying for me, i wanted to ask again in case anyone had an updated answer. I want to download  on my phone but it is not available in my country.  Does anyone have any suggestions?


A friend has asked me to perform maintenance oh his computer. The described symptoms point to a performance issue with the hard drive. I want to objectively confirm this suspicion by measuring the performance of his 5400 RPM disk.  Which tools would you recommend for this job? Are there any (published) standard guideline numbers that I could use for the purpose of comparing my findings?


What is a product's normal price called?

Say a product is normally priced at $14.99, but at various times it goes on sale. Regardless of it's price at any given time, what would the $14.99 price be called?  In other words, I'm looking for the opposite of the sales price.


Can't explicitly instantiate a templated class

In "header.h"  template <typename T> struct Foo {     void func(); };   In "Source2.cpp"  #include "Header.h" #include <iostream>  template <typename T> void Foo<T>::func() {     T a = 5;     std::cout << a;; }   In "Source1.cpp"  #include "Header.h"  template struct Foo<int>;  int main() {     Foo<int> b;     b.func(); }   Linker error: LNK2019   unresolved external symbol "public: void __thiscall Foo::func(void)" (?func@?$Foo@H@@QAEXXZ) referenced in function _main    Is this not the right way to explicitly instantiate a class?


Error with Oracle VM VirtualBox: VT-x is not available (VERR_VMX_NO_VMX)

I've recently installed Oracle VM VirtualBox on my Windows 10 computer, and I'm trying to make an Android Virtual Machine. The problem is that when I go to start the VM, it displays the following error:  VT-x is not available (VERR_VMX_NO_VMX).  Result Code:    E_FAIL (0x80004005)   Component:  ConsoleWrap   Interface:  IConsole {872da645-4a9b-1727-bee2-5585105b9eed}   I've already checked that my CPU is compatible with VT-x, and it's activated in the BIOS (In my case, I activated VT-d because there isn't an option for VT-x, but I've read that they're the same thing. If I'm wrong please correct me). I also have disabled Hiper-V, but it didnt' work.  Do you have any ideas on what's the cause of this problem?  Edit:  I have a Gigabyte GA-H270M-DS3H motherboard with the F7 BIOS Version. I have an Intel I7 7700 (not K) CPU  Regarding , I've tried everything there, except for turning on VT-x on the BIOS, because I don't have the option, and because I thought that VT-d was the same thing. If not, how do I turn on VT-x?


Why is there more steam after a pot of water *stops* boiling?

I have a pot of vigorously boiling water on a gas stove. There's some steam, but not alot. When I turn off the gas, the boiling immediately subsides, and a huge waft of steam comes out. This is followed by a steady output of steam that's greater than the amount of steam it was producing while it was actually boiling.   Why is there more steam after boiling than during boiling? Also, what's with the burst of steam when it stops boiling?


Let φ : $\mathbb{R}^n → \mathbb{R}$ be a $C^1$ function such that $∀t ∈ \mathbb{R}$ we have $φ(tx) = t^{42}φ(x)$. Prove that $∀x ∈ R^n$,   $x·∇φ(x) = 42φ(x)$.  If someone could help me out with this problem that'd be great.


App.xaml file does not get parsed if my app does not set a StartupUri?

Background: I'm creating a WPF app using MVVM, and using a DI container to build my ViewModels  My App.xaml looks like this:  <Application x:Class="WpfApp.App"     ...xmlns etc...     StartupUri="MainWindow.xaml">     <Application.Resources>         <app:ServiceLocator x:Key="serviceLocator" />     </Application.Resources> </Application>   MainWindow.xaml looks like this:  <Window x:Class="CompositeMefWpfApp.MainWindow"     ...xmlns etc... >     <Control.DataContext>         <Binding Path="MainWindowViewModel" Source="{StaticResource serviceLocator}" />     </Control.DataContext>   Now, this all works fine, but the StartupUri is hardcoded into the XAML, which I don't want. Following guidance of several blogposts and articles I found, I removed the StartupUri, and tried to create the MainWindow by hooking OnStartup in App.xaml.cs, like this:  protected override void OnStartup( StartupEventArgs e ) {     base.OnStartup(e);     new MainWindow().Show(); }   The problem is, the app crashes when trying to show the window, with this exception:     Cannot find resource named '{serviceLocator}'. Resource names are case sensitive.  Error at object 'System.Windows.Data.Binding' in markup file 'WpfApp;component/mainwindow.xaml' Line 8 Position 45.   As far as I can tell, the <Application.Resources> section is simply not being read out of the xaml file. I can put some code in the OnStartup to add the resource programatically like this:  Resources.BeginInit(); Resources.Add("serviceLocator", new ServiceLocator()); Resources.EndInit();   However that's an ugly hack, and doesn't help me if I wanted to put something else in the app.xaml file later on :-(  Should I be hooking some other event? Is there a way around this?


I've got a form that people can fill out and the results of the form are displayed on a page. The form is limited to 2000 characters, however there's nothing limiting how many line breaks there can be, so someone could just put one character per line and get 2000 line breaks, which clutters up the page pretty badly. I'm looking to limit the number of lines that they can type into the textarea so the limits are 2000 characters or 40 lines, whichever comes first.  I would also need this to be protective of people pasting large amounts of text into the form as well. I looked at a lot of other posts about this but none of the answers worked when I tried them. Thanks!


Need Drivers for D-link DWA 525 PCI Wireless adapter

I'm using Ubuntu 12.10 32-Bit Edition. I have racently purchased D-link DWA 525 PCI Wireless Adapter. But i can't find the drivers for the adapter. I have been searching in internet for a while. Tried many options, including ndiswrapper.  When i run lspci command, it detects and shows as below.  04:00.0 Network controller: Ralink corp. RT5360 Wireless 802.11n 1T/1R   My kernel version was 3.5.0-18-generic.  After i have upgraded my kernel to 3.7.3-030703-generic and now the device detects as    Network controller [0280]: Ralink corp. RT5360 Wireless 802.11n 1T/1R [1814:5360]     Subsystem: D-Link System Inc DWA-525 Wireless N 150 Desktop Adapter (rev.A2)[1186:3c05] Kernel modules: rt2800pci   But still there is no sign of the wireless interface in Network Connections window or in iwconfig. And the interface is not functional yet.  The output of iwconfig is         lo no wireless extensions.   eth0      no wireless extensions.   The output of ifconfig is  eth0      Link encap:Ethernet  HWaddr 00:27:0e:05:5c:e1             inet addr:192.168.1.2  Bcast:192.168.1.255  Mask:255.255.255.0           inet6 addr: fe80::227:eff:fe05:5ce1/64 Scope:Link           UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1           RX packets:38317 errors:0 dropped:0 overruns:0 frame:0           TX packets:34741 errors:0 dropped:0 overruns:0 carrier:0           collisions:0 txqueuelen:1000            RX bytes:38422211 (38.4 MB)  TX bytes:4955007 (4.9 MB)  lo        Link encap:Local Loopback             inet addr:127.0.0.1  Mask:255.0.0.0           inet6 addr: ::1/128 Scope:Host           UP LOOPBACK RUNNING  MTU:65536  Metric:1           RX packets:3499 errors:0 dropped:0 overruns:0 frame:0           TX packets:3499 errors:0 dropped:0 overruns:0 carrier:0           collisions:0 txqueuelen:0            RX bytes:342593 (342.5 KB)  TX bytes:342593 (342.5 KB)


What is the best method with which to approach the following integral?     $$\int_0^1 \frac{3x^3-x^2+2x-4}{\sqrt{x^2-3x+2}}dx$$   Thanks


I'm new to php and struggling to find out how to hide the div if there are no tags on the page. This is my code:

<?php the_tags(); ?>

  Some help please? Thanks.


How to connect to WiFi from the command line?

Other posts seems to be addressing more complicated network connection issues from the command line.  The Unity panel Network indicator/button doesn't respond too well sometimes - it keeps trying to connect to a network even when i click on "disconnect", stuff like that.  So I want to go command line for the control.  I don't like GUIs anyway.  Is there not some simple command line tool which can do something like the following?  wifi connect MyNetworkNameA wifi disconnect wifi connect MyNetworkNameB


Can someone explain to me how to use golden ratio for layout purposes in Indesign?

I'm willing to understand how to use golden ratio for layout purposes in Indesign. I've found a couple of 'explanations' over internet but they are too enigmatic and I can't really see the possible usage of it in Indesign projects. I know that other people are doing it so it's possible. Can someone explain it to me ?


How does light combine to make new colours?

In computer science, we reference colours using the RGB system and TVs have pixels which consist of groups of red, green and blue lines which turn on and off to create colours.  But how does this work? Why would certain amounts of red, blue and green light make something seem yellow? Is this a biological thing, where our brain performs some kind of averaging operation, or are the waves actually interacting to make light of a new wavelength?  It seems RGB is a "universal triplet", as every colour within the visible spectrum can be created by combining the three in different intensities. Is RGB the only such triplet? If so, why? If not, what features must a triplet of colours have to be universal?


Proving $\lim_{n\rightarrow\infty} n(2^{1/n} - 1) = \log 2$

How do you prove $\lim_{n\rightarrow\infty} n(2^{1/n} - 1) = \log 2$ ?  Background: in computer science, if you allocate CPU time to $n$ processes by , all the processes get sufficient amount of time when the quantity $U$ called CPU utilization is less than or equal to $n(2^{1/n} - 1)$.  It is monotonously decreasing and tends to $\log 2$ when $n\rightarrow\infty$, so if $U \le \log 2$, you can be sure all the processes will be given sufficient CPU time.


Equivalence of the definition of the Subbasis of a Topology

I came to know about 2 definitions of a subbasis of a topology. 1. A collection of subsets of X viz. S is said to be a subbasis of a topology T on X if S covers X and the finite intersections of elements of the subbasis form the basis elements (H.L.Royden). 2. If we consider the all the topologies on X containing S, then their intersection is also a topology on X and it is the smallest topology containing S. Then S is said to be a subbasis of the smallest topology, and the topology is said to be generated by S.  Now I want to prove their equivalency, i.e. S is a subbasis of a topology T iff T is generated by S. I have tried in the way: First let T is generated by S. Then by 2nd definition T is a topology containing S. Let B be the set of all finite intersections of elements of S.Then S is a subset of B and B is a subset of T (as T is a topology). LET T1 be the collection of possible unions of elements of B, we will show that T = T1. After this I am not able to proceed. Also I am unable to sketch the converse part. If something is wrong, please let me know, and also I hope to get help. Thank You.


Artin's "Algebra", on pg.157, mentions that "glide reflection" is a part of the list of rigid motions in a plane.   The other rigid motions on the list are rotation, translation and reflection.   Why does glide reflection have to be added separately? Why can it not be considered a composition of reflection and translation?  Thanks in advance!


$A_1 \times ... \times A_n$ is countable if $A_1, ..., A_n$ are countable

Suppose that $A_1, ..., A_n$ are countable sets. Show that the cartesian product $A := A_1 \times ... \times A_n$ is countable. My attempt: Sets are said to be countable if they are finite or if they have the same cardinality as some subset of $\mathbb{N}$ (i.e. we can find some bijection $f: A \rightarrow S$ or $f: S \rightarrow A$ where $S \subset \mathbb{N}$). Assume that $A_1, ..., A_n$ are countable sets. Then, there exists bijections $fi: \mathbb{N} \rightarrow A_i$ for $i = 1, ..., n$. Define $g: \mathbb{N} \rightarrow A$ as follows My issue arises here in finding such a bijective function without it being too complicated. How would I go about finding one? I am also open to any suggestions. Any assistance is welcomed.


Find web page(s) that links to a specific page in Google Search

I got an article from some page, I don't know which. Is there some Google search way of finding the parent page?  Say for example from page A I navigated to page B. Page B is a PDF document. How to instruct Google search to search for pages that link to page B?


How to make wifi hotspot in Ubuntu? I am having connected with wifi Internet and want to create wifi hotspot so that other devices gets connected with internet.


Title “References” is missing in elsarticle class

I am beginner in LaTeX, and I am trying to use BibTeX to create a reference, I am using  MiKTex 2.9 and TeXstudio 2.5.1 . I am trying to include references to my .tex file using BibTeX.   I created a .bib file (mybib.bib) in TeXstudio using the BibTeX format  %%%%%%%%%%%% mybib.bib %%%%%%%%%  @BOOK{AsmussenandAlbrecher2010,   author  = {Asmussen, S. and Albrecher, H.},   title   = {Ruin probabilities},   edition = {2nd ed.},   address = {Singapore},   publisher = {World Scientific},   year    = {2010} }  @ARTICLE{Botta1987,   author  = {Botta, R. F. and Harris, C. M. and Marchal, W. G.},   title   = {Characterisation of generalised hyperexponential distribution functions},   journal = {Stochastic Models},    volume  = {3},   year    = {1987},   pages   = {115-148} }  @BOOK{ChaudhryandTempleton1983,   author  = {Chaudhry, M. L. and Templeton, J. G. C.},   title   = {A First Course in Bulk Queues},   address = {New York},   publisher = {Wiley},   year    = {1983} }  I include mybib.bib in my .tex file test_els.tex  %%%%%%%%%%%%%%%%%%%%%%%%%%%%% test_els.tex %%%%%%%%%%%%%%%%%%%%%%%%%%% \documentclass[preprint,12pt]{elsarticle}  \begin{document} \section{Introduction} Several researchers studied ruin probability, but for a survey see\cite{AsmussenandAlbrecher2010}. For bulk arrival queues see \cite{ChaudhryandTempleton1983}  \bibliographystyle{model1-num-names} \nocite{*} \bibliography{mybib} \end{document}  I use PDFLATEX->BIBTEX->PDFLATEX->PDFLATEX and the output produced references cited in the text, but the title references is missing. Where is the mistake? Please help.


What imgur domains/sub-domains need to be unblocked to allow images to show

As I have seen in other posts, i.stack.imgur.com is blocked by numerous companies' firewalls including my own. I have started the process to get the restriction lifted but to increase the likelihood of it being granted, have only requested that i.stack.imgur.com be unblocked.  Staying within the context of SO, imgur and the hosting arrangement SO has with them, are there any other sub-domains/domains that I should be requesting be unblocked? i.e. p.stack.imgur.com or *.stack.imgur.com?  I'm not sure if images can still be embedded/hotlinked in posts from other image hosts or not but if they can I'm not interested in unblocking those hosts, just the addresses used by SO for imgur.  Cheers :)