So last week I was trying to install Ant, and accidentally deleted my environmental variable Path. I dont really know what I am doing. What effect will this have/what can I do to fix it?

I accidentally deleted the Path environment variable by creating a new one with Path name. How can I restore my old Path environment variable?


I recently read that the Wade Wilson character was in X-Men Origins: Wolverine, before he became Deadpool.  I had forgotten this because it has been a while since I saw that movie.  What other movies has the Wade Wilson character been in, and what is the brief synopsis of the cinematic back story of Wade Wilson? Are any of Wade Wilson's movie appearances in the MCU?

Right so seeing as the new Deadpool movie shows the origins of Deadpool: specifically, he got cancer... blah blah had to get him the healing factor from Wolverine.  But that makes no sense — they used the same actor, so I'm assuming there must be some connection, right... right?


i'm using Qchainage on a Polygon to Line layer, and in the input dialogue there's degrees instead of meters .. and i've used trial and error to find a suitable distance ... but the issue is that not all the created points are at the same distance from each other  my process goes as follows Creating a buffer >> polygon to line >> QChainage   is there a way to input meters ?

I have a series of layers of lines (shapefiles) in My Project. The CRS of some are different and to merge them they all must have same CRS.  When I use Processing/Toolbox/Qgis_algorithims/Reproject_layer the reprojection only works if it is allowed to save to temporary file somewhere (it will not change the CRS when I reproject if I try to save and replace it in My Project directory);   I must remove the original from the layer list and reproject the temp file (without changing the CRS) to get it into my project and name it appropriately.  Is there a better way to reproject a layer in Qgis?


I have windows 10 preinstalled on mine laptop. I love both ubuntu and windows so I planned to make DUAL boot my laptop. Then I have installed Ubuntu as 2nd OS to my LP. Everything was successful and I had configured the GRUB(Basics like time out and Default). Then I have to restart my computer and GRUB menu appears and I choose to use Ubuntu. After my work finished in Ubuntu, I wished to use Windows so I had restart my laptop and GRUB menu appears and chose Window. Suddenly I realized that I forgot some file to bring to Windows so that I wanted to go back to Ubuntu so again restated Laptop. After the restart, I came to know that there is no GRUB menu so that I tried to load using BIOS but I did not found Ubuntu there also.  Both the OS has booted using UEFI(Secure boot off). I have checked that the Ubuntu folder is there is the EFI folder(Checked through windows command prompt). Also made the GRUB as default I have Ubuntu partition also.

I have an HP 500-413nl (a desktop) and Windows 10 keeps changing the boot order in UEFI/BIOS every time, so that if I want to boot Ubuntu 16.10 (64-bit) I always have to press F10, thus entering the BIOS setup and changing boot order…  Is there a workaround for my PC? What should I do? I'm a little desperate.  P.S.: I have already disabled "Secure boot" and "Fast/quick boot" in the BIOS and "Fast startup" in Windows options / Control panel.


I have some confusion in Regex so I need help.my question is I am using the following Regex to prevent string should not start with some character and should not contain angular bracket.this regex also preventing next line as well so can u help me to modify it according to my need.  ^(?![@=+*-])(?!.*[<>]).*$   Thanks working example-->

For example, this regex  (.*)<FooBar>   will match:  abcde<FooBar>   But how do I get it to match across multiple lines?  abcde fghij<FooBar>


Why is birds which stay on electrical wire which current is being pass through doesn't get shock?

When we touch electric wires, we get shocked. Why don't birds sitting on electric wires not get shocked?


The new Disney canon includes Star Wars: The Clone Wars TV series, but are The Lost Missions (e.g. the unfinished season 6 of Star Wars: The Clone Wars) considered a full part of the Star Wars canon?

For all types of derivative works, namely:   Movies Novels Comic books Other written works (including RPG materials) Cartoons Video games Derivative movies (such as the infamous Ewok movies and even more infamous )   According to what rules does something become "canon" and who is responsible for the evaluation of a published work?


We put candle in electric field. My question is: Ions of flame move or ions of air? It is written that flame heat air molecules and convert them to ions, then positive ions of air heavier than negative ions therefor flame bends in direction of electric field. Is it correct?

Let me show a figure first about the shape of flame for a candle without any external electric field in the dark night:        Now consider the following physical configuration: If you put this lighted candle into the parallel plate capacitor, in which the electric field produced by it can be turned up or turn down arbitrarily.  So my question is: what's the shape of the flame of the candle when we keep the electric field stationary and how is it changed as we increased the field or decrease the field yielded by the parallel plate electrical capacitor?


Let $f$ and $g$ be two holomorphic functions on a complex region. If $\left |  f\right |^2 + \left | g \right |^2$ is constant, then show that both of them are constants. I have tried to use Cauchy Riemann eq. and Laplace eq., however I did not manage to solve the problem.

I need to prove that if $f,g$ are analytic in the unit disk, and $|f|^2+|g|^2=1$ for all $z$ in the unit disk, then $f,g$ are constant.  This is an exercise question so it should not be very hard, but I don't know where to start. Any hint is appreciated.


I'd like to know how to show that  $$\int_{0}^{\pi/2} {\sin(x)\;dx}=1$$  using Riemann sums.   If someone could please show me step by step and explain I would be very grateful! Edit: I did see the other question but I don't think I need to use trig identities on this. I'm still confused about how to go further than the setup.

How to find the integral $$\int_{\frac{1}{3}\pi}^{\frac{2}{3}\pi} {\sin(x)\;dx}=1$$ using Riemann sums?


When i zoom out even a bit, there's this mist that prevents me from seeing the object. Is there a way to disable it?

I'm having an odd issue - When I try to zoom in on a detail using my MMB, the "camera" in the 3D view seems to be cutting off the exterior surface of my object and showing me the inside instead. I'd expect this behavior, but only when I was much more zoomed in.  If I zoom out a bit (one click on the scroll wheel) then I can see the exterior as I intend.  Is there any way to adjust this behavior?  Thanks!


I want to show that the requrrence $T (n) = \sqrt{n} T(\sqrt{n}) + O (n)$ is in $O(n \log \log n)$  Here's my attempt:  If we expand the recursion tree, at a level $i$, there are $n^{1/2^k}$ subproblems each requiring work equal to $n^{1/2^k}$. There are $\log \log n$ levels in this tree.  So the summation is: $\sum_{i = 0}^{\log \log n} n^{1/2^{(k-1)}}$  Is this summation correct, and how can I show it is in $O(n \log \log n)$?

$$T(n) = \sqrt{n} T \left(\sqrt n \right) + n$$  Master method does not apply here. Recursion tree goes a long way. Iteration method would be preferable.  The answer is $Θ (n \log \log n)$.  Can anyone arrive at the solution.


I'm trying to prove the following Theorem from my Discrete mathematics lecture notes:   Let m $\ge 1$. If $a, b \in \mathbb{Z}_{m}^{*}$, then $ab \in \mathbb{Z}_{m}^{*} $.   Where,  $\mathbb{Z}_{m}^{*} = \{a \in \mathbb{Z}_m : gcd(a, m) = 1\}$   Since, $gcd(a, m) = 1$ and $gcd(b,m)=1$ my intuition tells me $gcd(ab, m) = 1$. However, I'm not sure how to prove $gcd(ab, m) =1$.   Can anyone give me a hint or post the proof of this?

Let $a,b,n$ be integers such that  $\gcd(a,n)=\gcd(b,n)=1$. How to show that $\gcd(ab,n)=1$?   In other words, how to show that if two integers $a$ and $b$ each have no non-trivial common divisor with and integer $n$, then their product does no have a non-trivial common divisor with $n$ either.     This is a problem that is an exercise in my course.   Intuitively it seems plausible and it is easy to check in specific cases but how to  give an actual proof is not obvious.


I try to insert a graphic but it does not work. I try the following one ;  \begin{figure}[!htb] \centering     \includegraphics[width=5in]{D:\Utilisateurs\e0g411j00nm\Dropbox\images/phasediagram1.eps}     \caption{Effects of ....}   \label{fig:SOvsBAU} \end{figure}   why it does not work ? All my documents are in the same file.

I know that includegraphics can be used in Latex to include images into the document, but how can I specify a path for that file?  \includegraphics[]{picture-name}   Instead of asdd.jpg I want to specify C:\Documents and Settings\Nina\asdd.jpg, because that's where the image is.


I am playing a Level 5 Monk/Aarakocra with the monk I get 1d6 + 5 (20 dex) but with Aarakocra’s talons I get 1d4 + 5. Does it become 1d6 + 1d4 + 5?

Do the claws of Tabaxi and Tortles change the unarmed attacks of monk to slashing damage, or is the damage separate? Does the unarmed slashing damage increase with the monk's level, as described on the monk table in the PHB?


Which browser will let me login say to website if I open number of different instances, with different login credentials(hence storing cookie to instance cache instead of global browser cache).

By default, all browser instances use the same cookie for the same site. Is there a browser that doesn't follow this?  Or is there a Firefox plugin that can "wear" different cookies for a specific site?


I have Ubuntu 14.04. I installed it on my computer but now would like to remove it to install Windows. I cannot  get the computer to boot from DVD so the windows install will not load. what can I do?

I have absolutely no experience with Linux, and I desperately need to get my computer back up and running again with Windows.  How do I remove Ubuntu and reinstall Windows?    Editor's note: many of the answers are about removing Ubuntu from dual-boot but keeping Windows (which is a bit complicated), while other answers are about removing Ubuntu from single-boot (which is easy: basically just format the disk while installing Windows). The question as written is ambiguous between dual-boot or single-boot.


One of our clients site need to be re-designed. The updates would be mostly presentational including graphics, page layout updates (re-order page elements), color, icons, fonts, making it responsive etc. There will be minor content updates, mostly correcting old data and add some new.  Currently site pages appear on Google search first page for key business phrases/words.  What precautions should be taken while re-designing website without affecting the search ranking?

What steps do I have to take in order to make sure that I keep my search engine rankings after I redesign or update my site?


One of my books gives the following proof that if the image of a sequence of real numbers $x_n$ has an accumulation point $x_0$, then there exists a subsequence $x_{n_k}$ convergent to $x_0$.  The sequence having finitely many values is a trivial case, so let's consider the case where there are infinitely many points in it.  We consider the intersections between the sequence and the balls of radius $\frac{1}{k}$, $k \in \mathbb{N}$, centered in $x_0:$ $$U_k =B_{\frac{1}{k}}(x_0) \ \cap \ \{x_n\}_{n \in \mathbb{N}}$$  Since $x_0$ is an accumulation point, $U_k$ contains infinitely many points of the sequence, for every $k$.  We define a subsequence as follows:   we choose any point in $U_1$ as our first point, call its index $n_1$; since there are infinitely many points in $U_2$, infinitely many of them have an index greater than $n_1$. Choose one and call its index $n_2$; ... since there are infinitely many points in $U_{k+1}$, infinitely many of them have an index greater than $n_k$. Choose one and call its index $n_{k+1}$; and so on.   The subsequence $x_{n_k}$ converges to $x_0$.  Is the Axiom of Choice needed to justify this definition procedure? I'm used to books always pointing out when they use AC, but in this case my book doesn't.  The book also doesn't mention it, but by the well-ordering of the naturals, the iterative process can be made more "canonical" and less "choosy" by always defining $n_{k+1}$ as the minimal element of the set $\{n \ | \ n>n_k \land x_n \in U_{k+1} \}$.  Would this make AC unneeded? Was it unneeded in the first place, even with the book's procedure?

When selecting the terms of subsequence from each bisections, I thought axiom of choice might be required. But I'm not so sure whether or not, so please tell me. [edited] I'm sorry for the lack of explanation. I want to prove this statement: Let $a_1, a_2, \ldots \in \mathbf{R}$, and $(a_n)_{n\in\mathbf{N}}$ is bounded, then $(a_n)$ has some convergent subsequence.  The proof is as follows. Since $(a_n)$ is bounded, for all $n\in\mathbf{N}$,   $a_n \in I = [b, c]$.  Now, let $I_0 = I$ and if $I_n = [b_n, c_n]$,  we define $d_n = (b_n+c_n)/2$ and  if infinite terms of $(a_n)$ is included in $[b_n, d_n]$(resp. $[d_n, c_n]$), we will define  $I_{n+1} = [b_n, d_n]$(resp. $[d_n, c_n]$).If both intervals contain infinite terms, let $I_{n+1}$ be $[d_n, c_n]$. For all $n\in \mathbf{N}$, infinite numbers of $m \in \mathbf{N}$ exist such that $a_m \in I_n$ suffices. We take the sequence of natural numbers $(n(k))_{k\in\mathbf{N}}$which suffices $n(0) < n(1) < \cdots < n(k) < \cdots$ following this procedure: Now we have already selected $a_{n(1)}, \ldots, a_{n(k)}$, there are infinite numbers of $m\in \mathbf{N}$ which suffices $n(k)<m, a_m \in I_{k+1}$, so let's take the minimum m out of it. Applying this process recursively, we obtain a infinite convergent subsequence(?). I think intuitively, by only repeating this process we can't obtain countable infinite terms of subsequence because we have to repeat infinite times.


The HTML5 clipboard is awesome, but I am looking for a way to make it safe.  The user is pasting text/html into my webpage. This allows them to paste images, tables, etc.  I am looking for a way to remove all scripts from the pasted content, before I add it to the page.  I need to remove <script> elements, as well as other ways of executing scripts like  <img src="x" onerror="alert('Hacked!')">   (and any others)  I do not want to remove style elements, or any other sorts of elements. (They are actually pasting into an iframe, so styles won't affect anything else.)

Does anyone know of an easy way to escape HTML from strings in ?  I need to be able to pass an arbitrary string and have it properly escaped for display in an HTML page (preventing JavaScript/HTML injection attacks).  I'm sure it's possible to extend jQuery to do this, but I don't know enough about the framework at the moment to accomplish this.


Prove the following for $\Re(z) >0$  $$ \log(\Gamma(z)) = 2\int_{0}^{\infty} \tan^{-1} \left(\dfrac{t}{z}\right)\dfrac{\mathrm{d}t}{e^{2\pi t} - 1} + \dfrac{\log(2z)}{2} + \left( z - \dfrac{1}{2} \right)\log (z) -z  $$  I found this identity on Wolfram Functions . I can't see where to start solving this problem.    I'm looking for elementary solution, I haven't learned about Complex Analysis or Abel Plana formula yet.  Please help. Thanks.

$$\log \Gamma (n)=n\log n -n +\frac{1}{2} \log \frac{2\pi}{n}+\int_0^\infty \frac{2\arctan (\frac{x}{n})}{e^{2\pi x}-1} \,\mathrm{d}x$$  Is an identity that is derived from using Sterling's approximation. I can't quite figure out how it was used, and was wondering for a proof.


I am looking for way to improve the way I read incoming data from the server. Right now I am using a while loop to catch the incoming data:  BufferedReader myReader = new BufferedReader(new InputStreamReader(mySocket.getInputStream()));             read=myReader.readLine();             String line;             while (!read.contentEquals("stop")) {                  read = myReader.readLine().trim();                 if((line=read)!=null) {                 Thread Comm = new Thread(new CommThread(read));                 Comm.start();                 }             }   I start a new Thread to handle incoming data (I want to send commands to the client) and prevent it from blocking the UI Thread. The Comm Thread will execute given commands.  I want the Bufferedreader to keep listening for new incoming data, but also I want to filter out the messages where nothing is coming.  Quick question: After the Bufferedreader reads an incoming message, is the message deleted from the InputStream?  Are there events like "OnRequestReceive" or something like that or am I bound to keep using while loops?

What are Null Pointer Exceptions (java.lang.NullPointerException) and what causes them?  What methods/tools can be used to determine the cause so that you stop the exception from causing the program to terminate prematurely?


I have downloaded a xml OSM file, but I would like to query by mouse possition a way Id, nodes Id, etc...  I only need to view it.  I'm exploring OpenTripPlanner, to be able to calculate routes with it I have my streets graph using a OSM file. I also intend to update ways speed limits using traffic data. I have the traffic data, and know it's position, now I need to find out the way Id at that position to be able to match it (so routing takes that into account).  I have QGis, but I have only been able to load all the nodes in the file, but not the complete graph (ways, etc...) and don't know how to query it (I need something similar to WFS).  Which is the more convenient way?, I'm using QGis but if there is a better tool feel free to mention it.    After a comment I tried loading the OSM file using layer > àdd layer>add vector layer` I have now loaded the data and I'm querying it in QGis, but how can I view the nodes in a way?  For example, I'm examining the way with id = 172550740, but how can I view the nodes (specially start and end nodes)?

In QGIS 1.8 I used the openstreetmap plugin to request data from the server, or open a .osm XML file, which produced 3 layers (polygons, polylines and points) in QGIS.  This was great (give or take the 64bit bug which highly affects the freshly mapped area I work on), but how do I do that in QGIS 2.x?   I can't find any updated documentation about it.  In the vector menu, I've tried importing from osm servers, I get a .osm file, but then I'm stuck. There's a menu option for loading an XML file, but it produces a spatialite db, which apparently only has non-geometry tables when I try to add it as a spatialite layer. If I open the attribute table, I can see node ids, ways and so on, but I can't figure out how to actually make use of them.  I've also tried adding a vector layer from a .osm XML file. I get a gpsbabel window that shows nothing, then finally an invalid data source message in QGIS.


I am interested in converting a polygon featureclass created via  from singleparts to multipart.  QGIS has a very handy tool called singleparts to multipart that does the job, however, I need to stay within the arcpy/Python realm.  The ArcGIS equivalent appears to be Dissolve, yet the tool does not preserve individual feature geometry when the polygons share a border.  The following is an example of the type of fishnet polygon data I am working with, which was generated from the below script.      import arcpy  # Create a fishnet with 9 columns and 9 rows # with origin at (1, 1) and output geometry is set to default (POLYGON) arcpy.CreateFishnet_management("C:/temp/fishnet2.shp", "1 1", "1 9", "1", "1", "9",     "9", "#", "NO_LABELS", geometry_type = "POLYGON")   How can I convert a fishnet polygon from singleparts to multipart using a scripting approach?    *Note. There is a similar question at GIS SE (), although it appears to be limited to desktop tools.  I am looking for any Python or arcpy-based approaches.

I have a set of parcels as illustrated in the image below. There are currently no multi-part features in dataset. What I would like to do is to merge (not the right word) all of the parcels with same address, say 421 for example. I want to have these three polygons as one multi-part polygon, that still has the same geometry, as in it doesn't dissolve the lines.     When I have tried this thus far, the lines dissolve resulting in only the boundary being preserved.     I feel like there is a super easy was to do this, but I can't find it. I have full access to ArcGIS Advanced and use it to manage the topology of this dataset.


How do I get MAC address of system using Angular, JavaScript, TypeScript or any other techniques.  I just want to store the MAC address of system for to just check whether that system used earlier or not.  Please help me out from this issue.

I know that we can get the MAC address of a user via IE (ActiveX objects).  Is there a way to obtain a user's MAC address using JavaScript?


I would like to create a mockups of custom flags "on-the-fly" on a website I'm working on. I thought one reasonable way to do that would be to take an image of a flag such as below, preserve/cut only the shadows and highlights, and then add that to a semi-transparent layer above the image I want to appear on the flag thus giving it a little faux depth.  However, every attempt I've made, mostly with the "Color Range/Shadows" selection too have not been sufficient. Is there a better way?  (not looking for PS plugins, mapping, etc. as again the mockup layering will be done on the fly in a web browser)

I need to export a png file with pattern or light effects. I have a tshirt shape with shadow effects on tshirt. The shadow effects has 75% fill and Multiply. If i add a background like color on back layer, it will show me the color of tshirt with shadow effects correctly. After save it in png, and import in new file, when i try to add a background layer on back, the color not is the same ( more lighter ).  How i can export the image with multiply effects or like this ? because i need to use it online on website but with same effects on photoshop.


Everytime I add a new element the page should scroll to the bottom of the inner div (having id = content). Right now scrollTo scrolls to the top of the outer div aka container    // css     .container{       background: #eee;       height: 800px;     }     .inner-div{       overflow-y: auto;       height: 100px;       background: #aaa;     }

   Some random data

   Some random data

   Some random data

   Some random data

   Some random data

   Some random data

   Some random data
   <button onclick="addItem()">   Add Item   </button>

I am creating a chat using Ajax requests and I'm trying to get messages div to scroll to the bottom without much luck. I am wrapping everything in this div: #scroll {     height:400px;     overflow:scroll; }  Is there a way to keep it scrolled to the bottom by default using JS? Is there a way to keep it scrolled to the bottom after an ajax request?


String s1 = "abcd5";  String s2 = "abcd"+"5"; String s3 = "adcd"+s1.length(); System.out.println("s1 == s2 : "+(s1 == s2)); System.out.println("s2 == s3 : "+(s2 == s3)); System.out.println("s1 == s3 : "+(s1 == s3));   Why first statement is true and rest are false. Is String concatenation with int behaves differently?

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


What is the best way to downsample photos to increase sharpness?  If I have a photo in raw format with a resolution of about 24MP. How do I best downsample it to increase sharpness if I think the original is soft? I’m avare that this will reduce maximum print size for a given dpi but I am wondering what the best downsampling method is.  My intuition tells me that scaling down by an integer factor using area avarage probably is quite good but can I use more information to get even better results?  Can the knowledge of raw pixel values before debayering be used for example?  This differs from this () question in that that question wants to preserv grain charachteristics which as far as I understand can be comparativly high contrast micro structure. While this question asks about how to increase sharpnes of soft photos (most likely from a soft lens) which is a more gradual smear.

I'm mixing analog with digital photography — I tend to take better photos when I can't look at a small digital screen, unconsciously forcing me to take the picture before I shoot instead of checking afterwards if it succeeded. I also like the grain film gives me.  However, most shots aren't worth spending much time in the darkroom, and scanning them is a lot faster. I'm wondering how best to convert the film to digital.  Scanning at lower than maximum (non-interpolated) resolution of my image scanner tends to exaggerate the contrast of the grain and screw up the mid-tones because of that.1 On the other hand, the resulting size of the scans are major overkill in most cases (I don't print them at A0 size), so I want to downscale the pictures. However, the grain confuses most methods and results in loss of detail and/or loss of the characteristic grain. For example, bicubic sharper tends to result in a "bigger" grain than the original. Now, the best compromise I've found so far is simply using bilinear interpolation, but I doubt that this is the best method to preserve both overall details and the look of the grain.  In short: when processing the scanned negative, how do I "best" preserve both image quality and the characteristic look of the grain?   As Stan Rogers pointed out below, there's a difference between truly scanning the grain of the film, and scanning the "grainy" character of film at lower resolutions. This question is about the latter; Stan Rogers explains how to do the first.  I'm looking for alternatives to the standard Photoshop options to try out, and reasons for each. Is the fact that every film has a different grain characteristic a problem? Are customized advanced noise reduction methods perhaps an option?  1. I'm using a Minolta DiMAGE Scan Elite 5400, using the software provided by Minolta.  As requested, here is a scanned picture with different resize methods. Just scanned this, scanning a B&W negative to get better tonality range. I turned off grain dissolver, automatic dust and scratch removal, etc, for obvious reasons. On the right the pictures are upscaled again with Nearest Neighbor. I set the 8 bit scan to 16 bits before downscaling, assuming it reduces risks of banding if I choose to mess with curves, channel mixers, etc. No other modifications (usually I first retouch dust & scratches, and in the end channel mix the picture to B&W, then switch to 8 bits again).


I have a simple bootstrap html layout setup, which contains 2 buttons #add and #take. When calling their functions before from the $(document).ready function, everything works, but since I will need to reuse the functions anyway I decided to put them outside.  Now when I click the button nothing happens. Can somebody please tell me what I'm doing wrong?    html:

       Session length:       25 min       <button id="add" class="btn btn-info">+</button>       <button id="take" class="btn btn-info">-</button>

25:00

       <button id="start" class="btn btn-success">Start</button>       <button id="reset" class="btn btn-danger">Reset</button>

   js:  function addMinute() {   time + 60; }  function removeMinute() {   time - 60; }  function updateSession(a) {   $(".session").empty();   $(".session").append(a + " min"); }  $(document).ready(function() {    var time = 1500;    $("#add").click(function(time) {     addMinute();     updateSession(time);   }) //end add.click }); //end document.ready

What is the scope of variables in javascript? Do they have the same scope inside as opposed to outside a function? Or does it even matter? Also, where are the variables stored if they are defined globally?


which of the following series converges uniformly for $x\in (-π,π)$. 1.$\sum_{n=1}^\infty \frac{x^n}{n^n}$.     2.$\sum_{n=1}^\infty \frac{1}{((x+π)n)^2}$  I was trying to  put putting $x = 0$,then both are uniformly convergent.I'm confused. Please give me hints or any idea, or tell me the solution.I would be much thankful.

For $x\in (-\pi, \pi) $, I want to know whether the following series following series are uniformly convergent on  $(-\pi,\pi) $: 1. $\sum _{n=1}^{\infty}{(\frac {x}{n})^n} $ 2. $\sum_{n=1}^{\infty}{\frac {1}{((x+\pi)n)^2}}$. I think series in 2 has to be uniformly convergent for, $|\frac{1}{((x+\pi)n)^2}|$ $\leq $ $\frac {1}{n^2} $ and as $\sum {\frac {1}{n^2}} $ is convergent, by Wierstrass M-test the series in (2) is uniformly convergent. But I don't how to proceed for the series in (1). Any help please!  Also tell if my answer to the (2)nd is correct.


I have two objects called Opportunity and Tournee, with a date field and date field is a formula field which subtracts 10 days from date field in Opportunity and the trigger create events based on this dates and shows them in a calendar. Now, what I found is Tournee trigger is not being called on its date formula field update. Now how do i create Tournee events based on its date field?

Assume we have ObjectA__c with Field1__c and ObjectB__c with formula field Field2__c which is formula to ObjectA__r.Field1__c.  I expected change of record field Field1__c of ObjectA__c would cause trigger on ObjectB__c to fire with changed Field2__c field, but this doesn't happen.  Can anyone explain why? Alternatively, can anyone share link to docs where is behavior is explained?


The word "D'Arvit" in the Artemis Fowl series is the cuss word in Gnommish, used in dire situations by the protagonists. But the  (which was used as a source for the answer to , answering that the alleged Gaelic source below might be what is meant) claims (NSFW link!):     Despite popular belief D'arvit was not the creation of popular Irish author Eoin Colfer. In the Aran islands their is a legend that a dark banshee (Banshee which goes against the laws of magic) will rip your soul from your body when your alone regardless of whether your dieing or not and u feel a chill run up your spine a dark banshee is near and the only way to protect yourself would be to utter "Dh'ábhoit". The folklore was told all over the provinces of Connacht and Munster but during the English conquest by Henry the VIII. It was anglicized as "d'arvit".which is pronounced the same as the original and now its mainly used in Gaeltacht of Connacht as a form of a curse or cuss, in english or Gaelic (Irish).   Urban Dictionary is hardly a reliable source, true, but I can't seem to find anything either in support or refuting this.  Did Eoin Colfer coin the word or not? How accurate is the claim that it came from Gaelic?

D'Arvit is the most commonly used Gnommish word in the Artemis Fowl series. We know it's a swear word from the first time it's introduced:  “D’Arvit!” growled Root. (There is no point translating that word as it would have to be censored.) -- Artemis Fowl, Chapter 5: Missing in Action (emphasis mine)  And from one of the later books:  “Hurkk,” said Artemis half-choking with surprise. “D’Arvit,” swore Holly. “I think we all know what D’Arvit means,” said No.1. “But hurkk is not English. -- AF and the Time Paradox, Chapter 5: I Now Pronounce You (emphasis mine)  Is the actual meaning of the word D'Arvit ever revealed or implied? Perhaps some hints are dropped from which its general ballpark can be deduced (e.g. is it sexual? does it refer to bodily waste?) Or perhaps Colfer has said something about this in an interview?


I need to pass the loop index (i) to the xhr function so I can update the upload progress of each file.  for (var i = 0; i < files.length; i++) {     var file = files[i];                             var formData = new FormData();     formData.append('photos', file, file.name);      $.ajax({         url: 'index.php?option=com_photos&task=photos.uploadFiles',         type: 'POST',         xhr: function() {         },         success: function () {         },         data: formData,     });  }   SOLUTION:  I found out the answer of the question. To access the data param you need to use this.data etc..

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


I accidentally wiped /etc/default/grub with a mistyped :w !sudo tee %. Is there a way to regenerate its content? Is the original available somewhere to copy?

I'm currently working on a project that needs kernel boot parameters added during a custom adapted Ubuntu installer (based on 14.04.3).  I know that   they belong into GRUB_CMDLINE_LINUX_DEFAULT in /etc/default/grub. one can add configuration files to /etc/default/grub.d in order to influence the generation of /etc/default/grub. the default grub seems to be available as /usr/share/grub/default/grub. grub-mkconfig then takes the scripts from /etc/grub.d and settings from /etc/default/grub and generates /boot/grub/grub.cfg.   My current problem is the following: Two of my packages and mdadm place files into /etc/default/grub.d, all of them altering GRUB_CMDLINE_LINUX_DEFAULT. But for some reason, one of my files gets ignored. And I can't really find when or by what /etc/default/grub is created initially created or how I could regenerate it.


Let $Q_n(x)$ be the degree $n$ polynomial   $$ 1+\frac{x}{1!}+\frac{x^2}{2!}+\frac{x^3}{3!}+\cdots +\frac{x^n}{n!} $$   How many real roots does the equation $Q_n(x)=0$ have?     My attempt:  It is obvious that $Q_n(x)$ will have all its real roots in the negative part of the real line if there is any. Also, we notice that if $n$ is odd, then there is at least one real root by the . So I conjecture that there is exactly one root for $n$ odd and there is no root for $n$ even.   However, I don't know how to analyze $Q_n(x)$. All I can do is to take derivative and this does not provide more useful information. Any hint is appreciated! Thanks.

Find the number of real roots of $1+x/1!+x^2/2!+x^3/3! + \ldots + x^6/6! =0$.  Attempts so far: Used Descartes signs stuff so possible number of real roots is $6,4,2,0$ tried differentiating the equation $4$ times and got an equation with no roots hence proving that above polynomial has $4$ real roots. But using online calculators I get zero real roots. Where am I wrong?


When I read a (math or statistics) textbook, sometimes I do not understand some of the equations or proofs in the book. Is it OK to take a picture of the page in the book (or ebook) that has the equations or proofs, and include it in the question as a supplemental matreial? Does this violate any copyright law?

I read a book that answers one of my questions, and I would like to quote it as an answer. Is that illegal?    Thanks.


I know that given a commutative ring with unit the sum of two radical ideal is not a radical ideal. I would want to know if for example in the ring of polynomial in $n$ variables with coefficient in the field of complex numbers is true that given two radical ideal their sum is again a radical

What is an example of the radical of a sum of ideals not equal to sum of the radical of the ideals?


Why is it not necessary to include the return statement while using int main() in some compilers for C++? What about Turbo C++?

What is the correct (most efficient) way to define the main() function in C and C++ — int main() or void main() — and why? And how about the arguments? If int main() then return 1 or return 0?  There are numerous duplicates of this question, including:       — For C++, with a very good answer indeed.     Related:


Through the book series there have been examples of charms stopping when its creator dies (Harry could move again after Dumbledore fell in HBP), but also of charms continue working (Protection of Privet Drive in DH, protection of Grimmauld place against Snape by Moody).  Is there further information what kind of magic is influenced by the death of its creator and which isn't?

Looking at the questions and answer to these two questions.  &  and neither mentions the longevity of magic. I recall several instances of magic failing to last; the money that was spread at the  and the broken  on.  If I recall correctly when Voldemort died, the curses on several people were lifted.  I don't recall if any other spells fell apart with his death.  Is there any canon evidence on the the length of time a spell will live?


Should the caret point down when the menu is down, or point up? See example.

When looking an expandable panel, such as those which one might find in an accordion and considering the situation where the arrow is positioned on the right hand side of the element which is to open, which of the following two arrow directions is the most likely to imply to the user that the panel content opens below the heading:         – Wireframes created with   To be precise, I am looking specifically for answers that concern controls where the arrow moves on click to indicate something opened and ends up in the down pointing position to indicate that the panel is open.


I have several CSS files under a folder contains 0.2rem or 0.5rem 0.6rem, now I want them to be all divided by 2, become 0.1rem and 0.25rem, 0.3rem. How can I use awk or sed or gawk to accomplish this?  I tried the following command but have no success:  find . -name "*.css" | xargs gawk -i inplace '{gsub(/([0-9\.]+)rem/, "(\\1 * 0.5)rem"); print $0}'

I am looking for a bash command that will multiply only numbers from a text file. Below is the content of my text file. I need multiply all numbers by 100.      0 4530000 sil 4530000 11100000 ow 11100000 6320000 p 6320000 7600000 ah 7600000 8410000 n 8410000 12100000 sil   For single line with only number,I am using something like this below  for file in *.txt; \ do y=`sed -n '1 p' "$file"`;    z=$(bc<<<"$y*100")    sed $file -i -e 's/'"$y"'/'"$z"'/' done   But I dont know how to do it for multiple lines, with alphabets in them. Number of lines in my file are not fixed, each file has different number of lines with max being 8


I am looking for a technology stack that would allow me to have some sort of OSM-driven custom map with as-easy-as-possible editing via a web frontend. I would require this for creating custom fictional maps for roleplaying games, so they wouldn't have any connection to the real world at all.  As for editing capabilities, I'm eyeing openstreetmap.org's current default web editor, iD. But to be honest, I have no idea what software I would need to make it all work together. I also have only limited knowledge when it comes to setting up virtual machines. If a ready-to-go appliance exists somewhere (or something that requires only trivial extra effort), I would be super grateful.  Edit/clarification: by "fictional map" I mean exactly that, a completely made-up map that very likely doesn't re-use a single node from Earth's actual map but instead is made-up from ground zero. I intend to use OSM for this, mostly because of the easily transferable data format, my (limited but still somewhat present) acquaintance with editing and the vast landscape of readily available mapping/rendering tools. I do intend to use most tags as they would be used on OSM, so editor presets are fine as they are for Earth's non-fictional map.  Edit/clarification #2: it should be web-based as we're physically scattered through-out the world. If we only passed an .osm file around, I fear that we could bump into very inconsistent vaguely different versions of said fictional map too easily.

I'm embarking on a new web map project that seeks to display simple geometries (lines, points, polygons) and rasters/basemaps. Ideally, the map will also allow authorized users to add/remove/edit geometries and their attributes.  What are the available options for the storage of data (e.g. SQL Server Spatial)?  What are the available options for the presentation of data (e.g. ArcGIS Server)?  I'm new to web mapping and am attempting to build a solid understanding of the available options and their pros/cons.


The javascript code I'm refactoring for work often declares functions as variables and then defines them in a $().readyblock. To be clear, this is what the code is like:  var myFunction;  $().ready(function(){     myFunction = function() {     //function body     } });   What are the advantages of this practice with respect to a normal function declaration and definition? Are there any or is it just a syntactic difference? I searched through other questions and didn't seem to find anything.

I've recently started maintaining someone else's JavaScript code. I'm fixing bugs, adding features and also trying to tidy up the code and make it more consistent.  The previous developer used two ways of declaring functions and I can't work out if there is a reason behind it or not.  The two ways are:  var functionOne = function() {     // Some code };     function functionTwo() {     // Some code }   What are the reasons for using these two different methods and what are the pros and cons of each? Is there anything that can be done with one method that can't be done with the other?


Partly inspired by the question about , this question concerns both the spells Raise Dead and Revivify, which both state that they return dead creatures to life, but (respectively):     This spell closes all mortal wounds, but it doesn’t restore missing body parts. (PHB, Raise dead)   and     This spell can’t return to life a creature that has died of old age, nor can it restore any missing body parts. (PHB, Revivify)   I started wondering what qualifies as "missing." It seemed clear to me that a character couldn't be Raised or Revivified if you had their decapitated body but no head (unless they could survive without it), but what if you had both? If a creature had its head cut off, and you placed that severed head on top of its body, wound to wound (presumably facing the correct direction), would Raise Dead or Revivify be able to bring them back to life, or would the head be considered "missing"?

I have a bit of confusion about the  spell.  It states that it can raise a creature from the dead, but cannot do so if major organs needed for life are missing (such as a head).  Killing anyone though will likely severely damage or destroy major organs.  Jabbing a sword through someone's heart will leave it in little pieces.  Can that heart reform itself if Raise Dead is cast?  What if an enemy purposefully grinds it up as best as possible in the chest so nothing is really left except fragments?  What if they remove the main heart muscle?  Also, with the head issue - what if someone is beheaded, but the head is held onto the body and the spell is cast?  How about if someone is cut in half lengthwise by a nasty trap and then held back together?  I'm sure that'd do major organ damage, but if both halves were available?  Some of these particular situations may be arising soon, as you might guess.  Best if I know ahead of time what my PCs can fix.


I have hired a design company to help with our logo colors. I picked the  Pantones we wanted (3165c and 7408c).  When I did a search on Pantones website it gave values for Hex, RBG, and CMYK conversions. Sure enough they match when I use them. This new company gave me a brand identity guideline and their numbers for those values are different.  He keeps telling me his are right and mine are wrong. What am I not understanding? Specifically, for Pantone 3165c it gave me:  RGB: 0-79-89, HEX: 004f59, and CMYK: 100-16-33-66.  Their brand guidelines give  RGB: 0-79-88, HEX: 004f58, and CMYK: 100-53-53-33.  His last email said that photoshop converts the Pantone to the values he gave me and those are accurate. I don't understand why he is going with those values and not the ones I have. What am I missing or not understanding?

I figured out that there are possibly more than one methods to convert RGB to CMYK.  Using Adobe Illustrator CS6 (Mac) the color conversion is completely different as the conversion via Wolfram Alpha. I used the simple cyan (CMYK 1,0,0,0). I already know that most computer displays use RGB to outline the color and I cannot “trust” the CMYK color on my display.  But how to correctly convert a RGB to CMYK color and why displays Wolfram Alpha the color completely different as Illustrator does? Wolfram Alpha shows the cyan very light whereas Illustrator shows it darker. Which one is more “correct”?  I want to have a corporate color and use it on the Web and for some print products. Assuming that my display is calibrated and I like a specific color. Is it better to choose a RGB color and then convert it to CMYK or vice versa?  And how to ensure that the color looks the same everywhere?


Good day. I have code that converts results data frame to CSV. I have another code that in samae script that allows  to name the csv file.When program runs user is asked to name the csv file and its generated.Question is how can i have a mechanism in the case that user enters the same name of an existing file stored in pycharm file that prompts the user that file name exists already and enter another one.  I have tried to use if statements that check if strings is equal to existing file without success.  filename=str(input('Insert file name')) results=pandas.dataframe() results.to_csv("%s.csv"%filename)   I expect the code to check when use inputs name to check in directory if file name already exists

How do I check whether a file exists or not, without using the  statement?


I want to install Ubuntu in a PC with no internet access.  I want to have a local copy of the repositories in an external HD drive. This external HD drive is formatted as NTFS and has about 1 TB of free space.  How much space will I need to have a full copy of the repositories? Where and how do I download it? How do I set it up so that when I plug in the external HD, my PC sees it as the source repository?  Update: I have been reading , and I downloaded all the files inside  (binaries for architecture amd64). I think I've done something wrong, because it totals to only about 50 MB. Isn't it supposed to be around 50 GB?

I have a friend who has got a computer that is not connected to the Internet. Is there any way to install software offline easily?


Trying to install Ubuntu on a HP Netbook Mini 210-4150NR( 1GB RAM)  I have installed ubuntu 12.04 LTS using uNetbootin and USB installer on USB. Changed the boot sequence in BIOS to load from the USB and it is recognising the USB.  On starting it shows the following message and is stuck at a blinking underscore:  SYSLINUX 4.03 2010-10-22 EDD Copyright (C) 1994-2010 H. Peter Anvin et al  based on various threads in this forum I tried formatting the USB flash drive as NTFS and installing and restarting but the BIOS did not recognise the same & went ahead to load windows.  I tried downloading a fresh iso using the link from the USB installer app, but the same result.  I tried the solution given at but to no avail  -   Please help with installing ubuntu on my netbook. ( I am using a PNY 8GB USB flash)

I am trying to install linux on my laptop, a Toshiba Satellite C6550-S5200. I did it once but something happened so I removed it then I had to destroy all data on hard drive so now I have nothing on it. Well I got a iso file burned to a CD and to a flash drive. With the flash drive I get.   SYSLINUX 4.06 EDD 4.06-pre7 Copyright (C) 1994-2012 H. Peter Anvin et al  With the CD it will start booting it but somewhere loading it up, the dots turn all orange and stay that way and my CD drive turns quiet.  Oh and some more info the images work because I tried loading them up on another pc and it worked just fine.  I manage to get the CD to boot I just had to let me pc boot up first then insert the CD and have it boot the CD then. Once I get done installing ubuntu it works fine but I have to leave the PC on 24/7 for if I turn it off the PC will freeze 5-10 seconds after booting back up no matter how I install it.


I understand that light passed through the objective lens of the telescope produce an image that is real and inverted, and have a height which is measured as the distance between the focal point and the principal axis, but my question is: Why? If all the light is concentrated onto the focal point, then why does the height matter, because wouldn't the light rays coming from a given object be focused on to a single point? Please help me understand the lapses in my logic.  Thanks for any help you can give me, I really appreciate it!

How do lenses produce 2-dimensional images, if a lens bends all incoming rays of light to intersect at the focal point? Shouldn't this produce a single dot of light on a screen placed at the focal length?  This is basically the standard diagram that always shows up in textbooks:    I know this doesn't happen in real life--I used to use telescopes pretty frequently for work. The most in-focus image would be the one with the smallest diameters for the stars, which, of course, we think of point sources at infinity. But--the light from all stars (despite being at infinity) is not all focused at a single point. Instead, each star's light is focused at its own $(x,y)$ point on a 2D image.  I can't reconcile the theory as I understand it with any of my real-life experience with optics. What am I missing?


Let x,y be positive, constant nambers so:  $a_1=x, b_1=y$ and $a_{n+1}=(a_n+b_n)/2,\; b_{n+1}=\sqrt{a_nb_n}$  Prove that $a_n$ and $b_n$ have the same limit.  From inequality of arithmetic and geometric means, I know that $b_{n+1} \le a_{n+1}$ . I assume from it that $b_n \le a_n$  I can prove that $a_n $ monotonically dicreasing  and $b_n$ is monotonically increasing. But how can I prove that $\lim_{n\to+\infty} (b_n-a_n)=0$? If I prove it I can use Cantor's intersection theorem.  Sorry for inncorrect sintax and language.

I am given this problem: let $a\ge0$,$b\ge0$, and the sequences $a_n$ and $b_n$ are defined in this way: $a_0:=a$, $b_0:=b$ and $a_{n+1}:= \sqrt{a_nb_n}$ and $b_{n+1}:=\frac{1}{2}(a_n+b_n)$ for all $n\in\Bbb{N}$    To prove is that both sequences converge and that they have the same limit. I don't know how to show this. I have spent 2 hours on this, no sign of success


I have a road network shapefile of a city. I want to extract those roads which have 80ft or more than that width. Is there any tool in ArcMap to extract the data?

I have a shapefile of lakes with lots of polygons. The features I am interested in are only big lakes. Is there any way to subset only the polygons I am interested in from the shapefile using ArcMap?


This animation in wikipedia can be done with Latex in a pdf document? The problem is if it takes up vertical space, the text below has to scroll. Note that animation is unfold and not embed.  For example:     Any hint, would be appreciated.

(This is an end-of-year crazy question)   Is it possible to embed a (scrollable) frame or a PDF inside a PDF? If so, how to do it in (pdf)LaTeX?  This is something pretty common in HTML (see for example ). Here it is a webpage with PDF frames   Here it is a fake screenshot so you get the idea.  Portable and non-portable (e.g. only-Acrobat) answers are welcomed.     Example of a down arrow below a frame. The up arrow can be on top of the frame and the triangles point up.


I've published my scientific results one year ago, but I didn't apply for patent at that time. Can I still patent it?

After working on a project some times, some results are obtained and we decide to publish it. I know publishing a paper and applying a patent can actually happen in the same time, but is there any difference for their priority?   For example, if I obtain a patent first for my results, will it make it more difficult to publish the same results in academic paper, or vice versa?   If I do it together, will there be any conflict between them?


I'm fairly new to Linux and just want to be able to see the disk usage and mounted drives in the same way that I can when I open 'My Computer' in Windows. Is there a file explorer for Ubuntu with this kind of interface?

In prior versions, I would open Nautilus and check the statusbar, which would tell me how much free space there is. Now, the statusbar isn't shown by default. I know you can enable it from the View menu, but 99% of users won't do that (and I'd rather not do that, if possible). So, is there some new recommended way to keep tabs on hard drive usage? Or is there maybe some other method that I should have been using in the past but never noticed?


I want to receive $comment_id in my custom function in my plugin. I mean when a user submit a comment, I need to pass $comment_id to add_custom_comment_page(). How can I do that?  inside my plugin:   $this->loader->add_action('comment_post',$plugin_public,'add_custom_comment_page');  function add_custom_comment_page() {     $comment_id = comment_ID();    add_comment_meta($comment_id, 'id', $id);  }

I added custom checkbox to the comment form. I am trying to write the post ID of this comment in the database. But without success. I'm trying with something like this:  add_action( 'comment_post', 'save_chbox_in_db' );  function save_chbox_in_db() {      $post_id = ??? // Can't get id...      insert_to_db ( $email, $post_id ); // custom function }   I tested these options:  global $post; $post_id = $post->ID();  global $wp_query; $post_id = $wp_query->post->ID;  $post_id = get_queried_object_id();  $post_id = get_the_ID();   As a result, I get zero or nothing. Where is the problem? Something with "comment_post" action? Or do I make some stupid mistake?


Since the update to 1.5 to 1.6, I haven't had any sound. I've tried the fallowing:  Deleted .minecraft folder Redownloaded the new launcher Replaced lwjgl with the version used in 1.5 (doesn't work because new launcher auto-updates it back to the latest) Changed resource packs. F3+S Checked sound files and options  None of which fixed it. :( From what I gather, this isn't the same issue some folks on Windows have had, because none of their fixes work for me. So I assume this is a Linux issue with java.  This is on Ubuntu 13.04 64bit, and I'm using the latest openjdk.

How to correctly install Minecraft, including setting any needed packages or apps to install it and to troubleshoot the most common problems that Ubuntu users face when trying to use Minecraft.  I am trying to install and run Minecraft without first having to install the Oracle version of Java. I want to use the OpenJDK version that comes with Ubuntu and as a last resort, use the Oracle one.  I also want to know a list of problems related to Minecraft in Ubuntu and the possible solutions to them.  A step by step guide on how to install Minecraft would also help.


Based on the understanding that Newtons third law states for every action there is an equal and opposite reaction, when a car moves forward under driving force, air resistance and friction act equally in the opposite direction, leading to the car moving at a constant speed with no resultant force.  If this is the case, how is it possible for a car to accelerate?  Presumably the only way for a car to accelerate would be for the force acting in the forwards direction to be greater than the forces acting opposite to it. How would this be possible if the forces acting in the opposite direction must also be equal?   Is it true that air resistance etc takes time to become equal to the force driving the car forward, so by constantly increasing the force in the forwards direction the opposite force is unable to equal it simultaneously?  I am not sure this explanation is correct, so I would appreciate some help on the matter!   *To clarify, I can understand movement if you separate it from acceleration, in that the force from the ground is equal and opposite to the tyres, causing the car to move forward, the problem arose with the presumption that air resistance must equal the force the earth is exerting on the car, and not the force the car is exerting on the air. The question flagged as a duplicate had a similar problem but I believe with a significantly different example and slightly different line of questioning.

Given Newton's third law, why is there motion at all? Should not all forces even themselves out, so nothing moves at all? When I push a table using my finger, the table applies the same force onto my finger like my finger does on the table just with an opposing direction, nothing happens except that I feel the opposing force. But why can I push a box on a table by applying force ($F=ma$) on one side, obviously outbalancing the force the box has on my finger and at the same time outbalancing the friction the box has on the table? I obviously have the greater mass and acceleration as for example the matchbox on the table and thusly I can move it, but shouldn't the third law prevent that from even happening? Shouldn't the matchbox just accommodate to said force and applying the same force to me in opposing direction?


I am trying to do an apt-get update in one ec2 instance and I get the following error:  W: GPG error: http://us-east-1.ec2.archive.ubuntu.com precise-updates Release: The following signatures were invalid: BADSIG 40976EAF437D05B5 Ubuntu Archive Automatic Signing Key <ftpmaster@ubuntu.com>   I tried to apt-get clean and remove /var/lib/apt/lists and then re create it but this did not work. Tried adding signature with   apt-key adv --keyserver keyserver.ubuntu.com --recv-keys 40976EAF437D05B5   But this did not work either. Any ideas?

I frequently cross this issue, and always have to google for an answer. Does anyone have a permanent fix for BADSIG errors from apt-get?     W: GPG error:    lucid   Release: The following signatures were   invalid: BADSIG 54422A4B98AB5139   Oracle Corporation (VirtualBox archive   signing key)


I like to sync directories from my Imac & MacBook . What is the recommended method?

I need software that would detect changes in directory (A) every 5 seconds or so and upload/delete changed files from/at (B) remote directory.  I found non-commercial software, . I am wondering if there are any commercial alternatives?


Are the words everybody and everyone interchangeable?

Are there any subtle differences between "somebody" and "someone", or can they be used completely interchangeably? Similarly, can you imagine a situation in which you would prefer "anybody" to "anyone" or vice versa?


I want to use comma (,) as decimal separator. The problem is that it is typeset with wrong font (Computer Modern, I suppose), not with the normal font defined using mathspec package. I have tried icomma package and siunitx package but they don't affect the font.  Here is a minimal code to try. The last two "1,5" examples have wrong comma font.  \documentclass{article} \usepackage{mathspec} \usepackage{icomma} \usepackage[locale=DE]{siunitx}  \setmainfont{DejaVu Serif} \setmathsfont(Digits,Latin,Greek){DejaVu Serif}  \begin{document}  1,5  \( 1,5 \)  \( \num{1,5} \)  \end{document}

the following MWE  \documentclass{minimal} \usepackage{mathspec} \setmainfont{DejaVu Sans} \setmathsfont(Digits,Latin,Greek){DejaVu Sans} \setmathrm{DejaVu Sans} \begin{document} \(\mathrm{e}^{\mathrm{i}\pi}=-1\) = -1 \end{document}   typesets with xelatex into    How can I turn the = and - signs in math mode to DejaVu Sans ?


I tried to start bounty here:    But I got this strange error after I submitted:    Any idea?

An attempt to set a bounty on any question results in 404 at the URL   {site}/posts/bounty/start/{post-id}    {post-id} being the actual post id.   I haven't tried every SE site, but given that this occurs on Mathematics and here on Meta...


I have this cron:  00 0 * * * root /home/bitnami/backup.sh > /home/bitnami/backup.log   The Backup script contains:  #!/bin/bash  cd /tmp file=$(date +%Y-%m-%d).sql mysqldump \   --host localhost \   --port 3306 \   -u user \   --password="123" \   bitnami > ${file} if [ "${?}" -eq 0 ]; then   gzip ${file}   aws --region us-west-2 s3 cp ${file}.gz s3://backups/fc-wiki/   rm ${file}.gz else   echo "Error backing up mysql"   exit 255 fi   Which works fine when executing it by hand (sudo .\backup.sh)  When the crontab runs it only logs the following error in backup.log: Error backing up mysql  Is there a problem how I'm setting up the cron tab with the piping to log perhaps? Even without the piping it doesn't work.

This is a  about using cron & crontab.   You have been directed here because the community is fairly sure that the answer to your question can be found below. If your question is not answered below then the answers will help you gather information that will help the community help you. This information should be edited into your original question.  The answer for 'Why is my crontab not working, and how can I troubleshoot it?' can be seen below.  This addresses the cron system with the crontab highlighted.


If the light is a wave, how does one explain the rectilinear propagation of light? This is related to how the diffraction pattern vanishes and light cast sharp shadows on the screen. An appreciable bending/deviation of light across the edges of the slit in single-slit diffraction requires a narrow slit. But I don't find a satisfactory explanation anywhere.  I have tried to understand this by imagining a wide slit to be made up of a series of a large number of narrow slits but failed to explain why there is more bending for narrow slits.

I'm a newbie with physics but I'm wondering how a ray of light can essentially be represented. I have always known that a ray of light proceeds in a straight line until it encounters another object (or material) that refracts/reflects it. But a light ray should be part of an electro-magnetic wave, is this correct? If it is so, it should obey to the  and this doesn't seem to me to describe a straight line ray.  I'm having problems visualizing how light is emitted and how it relates with the wave equation. Can someone with a clear understanding of the problem explain it to me in simple terms?


I just wanna know what does Object S[] mean in this code? This is a snippet of a source code for Stack in array. Is this a data type? What does it return? and what type of data should be entered? public class ArrayStack implements Stack {  public static final int CAPACITY = 1000; public int capacity; Object S[];

I have recently been thinking about the difference between the two ways of defining an array:   int[] array int array[]   Is there a difference?


$sql="SELECT * FROM customers";  if ($conn_id=odbc_connect("testconn","user1","user1")){   echo "connected to DSN: $dsn <br>";    if($result=odbc_do($conn_id, $sql)){   } }   I have a database which is utf-8,I am using the below PHP code,it is not displaying the Chinese character.I have tried with other ODBC clients,connecting to same odbc datasource and they are able to display Chinese character.I have tried suggestion mentioned here But still I am not able to display Chinese character

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


A paper stated $| e^{iwx} - 1 | \le 2 |w| \, |x|$ without any further explanation. I struggle to find an explanation because Euler's formula doesn't help.   Can you give me a give why this statement might be true?

Could you help me to prove  $$ |e^{i\theta} -1| \leq |\theta| $$  I am studying the proof of differentiability of Fourier Series, and my book used this lemma. How does it work?


The book reads, “Various class features, spells, and other abilities let you take an additional action on your turn called a bonus action. This isn’t a feature, spell, or other ability, it is an action."  So, does this mean I can’t use it as a bonus action unless I have a Feature, Spell, or Other Ability that grants it? Or should they be counted as "Other Abilities" and anyone can use them as a bonus action if they want to? The DMG just said Action or Bonus Action; are these convertible in either direction?

The  description of casting times says that spells with a casting time of "bonus action" require a bonus action to cast (p. 79, emphasis mine):  Most spells require a single action to cast, but some spells require a bonus action, a reaction, or much more time to cast. Bonus Action A spell cast with a bonus action is especially swift. You must use a bonus action on your turn to cast the spell, provided that you haven't already taken a bonus action this turn. You can't cast another spell during the same turn, except for a cantrip with a casting time of 1 action.  It's pretty clear that bonus actions aren't automatic (p. 69):  You can take a bonus action only when a special ability, spell, or other feature of the game states that you can do something as a bonus action. You otherwise don't have a bonus action to take.  So to cast a spell like Healing Word (p. 93), do I  need to be granted a bonus action that I can use, or do I have a bonus action I can use?  I guess I'm unclear on whether I need to have a bonus action before I can spend it on something, or whether having an ability, spell, or whatnot that can be done as a bonus action grants me the bonus action I need to use it.


I tried to solve it as follows: We have  $$(x,y) \in A\times (B \setminus C) \iff$$ $$x \in A \ \text{and} \  y \in (B \setminus C) \iff$$ $$(x \in  A) \ \text{and} \  (y \in  B \ \text{and} \  y \notin C) $$ $$(x \in A) \ \text{and} \ (y \in B \ \text{or} \ y \in C')$$ $$[(x \in A) \ \text{and} \ (y \in  B)]\ \text{or}\ [(x \in A) \ \text{and} \ (y \in C')] $$ $$(x,y)  \in A\times B \ \text{or}\ [(x \in A) \ \text{and} \ (y \in C')]$$  But beyond this not able to proceed.

I have to prove the equation  $$A\times (B\setminus C) = (A\times B)\setminus (A\times C)$$ knowing that $$A\times B = \{<a,b> |\: a\in A \wedge b\in B\}$$ which I attempted to do the following way: Let's take any x. Then $x\in A\times (B\setminus C)$ iff  $$(\exists a\in A)\: (\exists b\in (B\setminus C))\: (x=<a,b>)$$ $$\equiv \exists a\exists b \:(a\in A) \wedge (b \in B \:\wedge b \notin C) \:\wedge x=<a,b>$$ $$\equiv \exists a\exists b \: (a \in A\: \wedge b \in B\: \wedge x=<a,b>) \: \wedge (a\in A\: \wedge b\notin C\: \wedge x=<a,b>)$$ Further transformations lead me to $(A\times B) \times(A\setminus C)$, which is not the thing I was meant to prove. I need an advice how should I do it the right way, because I cannot find any solution.


I cant manage to get the right render settings for this image.   if you look at the render closely you cant see the poor quality. The denoiser in blender makes the image look smudged.  Here's the project file. You can mess around with it and see the results you get. Let me know what you did so I can make my render better.

Since the Denoise feature was added to Blender I only use the default setting with it and it really does the work. But sometimes the denoise is noticable on some of my renders. How can I overcome the blurred effect? Denoising for me is a big help because my system is quite aged.


When I subtract 4.7 from 2.3, I get a number with 16 decimal places, instead of getting a specific number with one decimal place. How come it doesn't give you a specific answer?

Consider the following code:   0.1 + 0.2 == 0.3  ->  false   0.1 + 0.2         ->  0.30000000000000004   Why do these inaccuracies happen?


If $a, b, c$ are sides of a triangle, how can I prove that $$\frac{a}{b+c-a} + \frac{b}{a+c-b} + \frac{c}{a+b-c} \ge 3$$

Let $a$, $b$ and $c$ be the three sides of a triangle. Show that $$\frac{a}{b+c-a}+\frac{b}{c+a-b} + \frac{c}{a+b-c}\geqslant3\,.$$  A full expanding results in: $$\sum_{cyc}a(a+b-c)(a+c-b)\geq3\prod_{cyc}(a+b-c),$$ or $$\sum_{cyc}(a^3-ab^2-ac^2+2abc)\geq\sum_{cyc}(-3a^3+3a^2b+3a^2c-2abc),$$ but it becomes very ugly.


Can anyone give me step by step instructions on how to get Ubuntu 16.04 LTS onto a memory stick please?

How do I make an Bootable Ubuntu USB containing the the latest version of Ubuntu?  For completeness, how would I be able to do this on Ubuntu, Windows, OS X or another Linux distro?


I am trying to remove trailing whitespaces of a string in a concise/efficient way.   Let's say I have the string:  string input= "2 2 +                 "   I used this in an attempt to make it input = "2 2+"    std::string::iterator end_pos = std::remove(input.begin(), input.end(), ' ');   input.erase(end_pos, input.end());   cout << input << endl;   However, it removed all the whitespaces.   How would I implement it so it only removes trailing whitespaces?

I'm currently using the following code to right-trim all the std::strings in my programs:  std::string s; s.erase(s.find_last_not_of(" \n\r\t")+1);   It works fine, but I wonder if there are some end-cases where it might fail?  Of course, answers with elegant alternatives and also left-trim solution are welcome.


Is the save file kept in Rockstar's cloud service, or is it stored locally on the hard drive?

For GTA 5 (on PC), if I have a save file, will it automatically back-up to either the Steam or Rockstar cloud, or do I have to save it manually? If it have to save it manually, will you please provide the default directory for saves?


I have two small equations that I want to put into two columns, to save space. From this:   To this:

The align command from amsmath allows me to put two equations side-by-side:  \begin{align} x = y && a = b \end{align}   Unfortunately for my purposes, this shows both equations under one equation number:  x = y    a = b   (1)   Is there any way to give them individual numbers, so that the output looks  like this?:  x = y (1)    a = b (2)


I have Ubuntu 14.04 LTS as Dual-Boot with Windows 7 and everything worked superb. Then as I booted my PC GNU Grub rescue popped up and told me, that it couldn't find my SSD.  But as I booted into the Boot selecter of the BIOS it worked great and both OS's would boot without porblems. But it annoys me, that I have to boot into the Boot Selector everytime and I don't want to delete Ubuntu.  Thanks for your answers :)

I installed Windows 7, which ate Ubuntu's boot file. When starting up the computer, it now goes straight to Windows, without giving me the option of booting Ubuntu.   How can I get Ubuntu back?


Evaluate $$\cos \frac{\pi}{7} \cos \frac{2\pi}{7}\cos \frac{4\pi}{7}.$$  The first thing i noticed was that $$\cos \frac{\pi}{7}=\frac{\zeta_{14}+\zeta_{14}^{-1}}{2},$$ where $\zeta_{14}=e^{2\pi i/14}$ is the 14-th root of unity.  Substituting this into the expression and simplifying, the expression is then transformed to $$\frac{1}{4}Re (\zeta_{14}+\zeta_{14}^3+\zeta_{14}^5+\zeta_{14}^7).$$  But then i have no idea how to get the real part of that thing. I only observed that $\zeta_{14}^7=-1$ and all the terms are primitive 14-th roots of unity. Please helps. Thanks!

Factor $z^7-1$ into linear and quadratic factors and prove that  $$ \cos(\pi/7) \cdot\cos(2\pi/7) \cdot\cos(3\pi/7)=1/8$$  I have been able to prove it  using the value of $\cos(\pi/7)$. Given here


I have a table which was imported from MS-SQL, it has about 1.9 million rows. After importing I realized that a lot of the rows are duplicates and there are no primary key constraints.   The rules to check for constraints are:   Check the email address.  If no duplicate is found in the table, leave the row as it is. If email address matches then compare the columns in both. Select one of the two as the row that will be kept i.e. TO_KEEP, the other will be deleted i.e. TO_DELETE. If there is any column in TO_DELETE that has some value but there is no value in TO_KEEP the update the TO_KEEP row with the value from the matching column in TO_DELETE.    I need help with writing a query for that. It's beyond my current skills. I wouldn't mind if I get some pointers which can make it easier as to how the query can be structured and which ones to use.

I have a table item having just one column name:-  name ----- toys shirt mobile Shirt speaker Toys ....  ....   I am trying to delete duplicate rows except one duplicated record with the help of below query  DELETE FROM ( SELECT `name`,`rownumber` FROM (SELECT GREATEST(0,@num := IF(`name` = @NAME,  @num + 1, 1),LEAST(1, LENGTH(@NAME := `name`))) AS rownumber,`name` FROM  item ORDER BY `name`) AS result1 ) AS result  WHERE rownumber >1   The Inner query (Starts from SELECT name and ends with result1) returns individual auto incremented number for each repeating group but when i run entire query then it does not work.  I would like to know what changes i need to make in the inner query (contained in round braces) to delete duplicate rows.


Can you give me a hint to how to approach the problem.How one can show that $2^{35}-1$ is a multiple of 31 and 127?


I know it is very simple but something is going amiss.  We can see here that $\log(1+\dfrac{1}{n})=\displaystyle \int_{n}^{n+1}\dfrac{dt}{t}$  if $t \in[n,n+1]$, $\dfrac{1}{n+1}\le\dfrac{1}{t}\le\dfrac{1}{n}$  I want to show that $\dfrac{1}{n+1}\le\displaystyle \int_{n}^{n+1}\dfrac{dt}{t}\le\dfrac{1}{n}$.  Can I straight infer that? If so what is the logic behind it? I was thinking of using $\displaystyle \Sigma_{i=1}^{n}$ and sandwiching $\displaystyle \int_{n}^{n+1}\dfrac{dt}{t}$ between. But confused !

One of fundamental inequalities on logarithm is: $$ 1 - \frac1x \leq \log x \leq x-1 \quad\text{for all $x > 0$},$$ which you may prefer write in the form of $$ \frac{x}{1+x} \leq \log{(1+x)} \leq x \quad\text{for all $x > -1$}.$$  The upper bound is very intuitive -- it's easy to derive from  as follows: $$ \log(1+x) = \sum_{i=1}^\infty (-1)^{n+1}\frac{x^n}{n} \leq (-1)^{1+1}\frac{x^1}{1} = x.$$  My question is: "what is the intuition behind the lower bound?" I know how to prove the lower bound of $\log (1+x)$ (maybe by checking the derivative of the function $f(x) = \frac{x}{1+x}-\log(1+x)$ and showing it's decreasing) but I'm curious how one can obtain this kind of lower bound. My ultimate goal is to come up with a new lower bound on some logarithm-related function, and I'd like to apply the intuition behind the standard logarithm lower-bound to my setting.


I have vague memories about a novel or series of novels I borrowed from the library as a teenager (1990s). The protagonist was a young woman (pretty sure) who was exceptional. Civilization basically ended (nuclear war maybe). One significant trial she went through involved controlling an orbiting shuttle, trying to dock with a space station (maybe an orbiting Russian weapon?). Then somehow she transferred to a fantasy setting and became a dragon?  Update: A few more details I remember: The story starts out in the USA of the present (meaning the late 80s or early 90s, probably). The protagonist somehow receives early warning or is sheltered from the early parts of the apocalypse (nuclear or biological warfare I think) and goes to space to try to prevent further destruction.

This was a novel I read years ago.  I have no idea what the cover art was because the cover was missing.  The novel is about a girl who survives World War III.  I remember the war was (mostly) biological, and a bacterial strain became nasty when exposed to radiation.  One of the details I remember is that she is basically a mutant and immune, like a small portion of other people in the  world.  She has a genius intellect, is a black belt, and has a blue parrot.  She takes off to search for other survivors in a 4 wheel drive van.  The entire story is told as a series of journal entries in a very terse style.  It was a good book, but I can't seem to remember what it was called or who wrote it.


If $a+b+c=1$ and a,b,c＞0 prove $\dfrac{b^2}{a+b^2}+\dfrac{c^2}{b+c^2}+\dfrac{a^2}{c+a^2} \geqslant \dfrac{3}{4}$. I tried with CS Engel form,homogenization but ina anyway i can't prove inequality. Can someone helpp?

If $a$,$b$ and $c$ positive real numbers such that $a+b+c=1$, prove $\dfrac{b^2}{a+b^2}+\dfrac{c^2}{b+c^2}+\dfrac{a^2}{c+a^2} \geqslant \dfrac{3}{4}$. I have tried several methods to solve this,but can't get any result. Any idea?


There's length contraction and time dilation when traveling in a straight line, but what if a spherical object like a white dwarf through some interaction rotated at a speed near the speed of light? What would be the effects? Would it appear smaller from all directions or just along its equator? Would time slow down around it or just its surface? Or would nothing happen at all because angles aren't dimensional units?

Assume we have a ball with diameter 1 meter and mass 1 kg rotating at 99,5% speed of light (Suppose I'm an observer placed above the ball, I see under me a disk wich external  speed is 99,5% the speed of light)  Then we accelerate such ball to 99.5% of speed of light, to make clear from wich position we look at the ball when it's moving so fast I did a picture (there's a black ring around the ball, as you se the rotational axis is vertical to our observer)    I'm interested in a full explanation of what we observe (measured rotation speed, color etc.) and why that happens, as far as I know we should not measure something moving faster than light but I'm not sure how relativity constraints would alter the "measured state" of the ball as long as we accelerate it.  What we see change while the ball accelerates?  EDIT:  A precisation, I assume the ball is spherical when I start rotating it before even moving, this is because commenters made me to note that shape may change.


I need some advice/help with my Schengen visa renewal.  I am currently in France and will end my season on 31 October on my current boat. Afterwards I will be joining another boat in France on a new contract.  My visa is valid until March 2018 and I still have 80+ days left to stay within the Schengen area.  I would like to know if it is possible for me to renew my visa in Europe or do I need to travel back to South Africa, and is it possible to renew/lengthen my visa while mine is currently still valid and I have days left?  Thank you in advance.

My daughter applied at the Italian Consulate in Philadelphia, and they gave her two entries for 20 days (we thought it was for 20 days each entry). She was in Italy 12 days, then went to England for 1 week and flew to Venice to take a 10-day cruise. She couldn't make it because they said she has only 8 remaining days, but she still has a land tour already paid this week.  What can she do? Can she extend the Schengen visa for 12 more days? Right now, she is in Madrid, but next week she has to fly from Barcelona to Paris to start with the tour. What would happen if she decides to take the tour with the expired visa? She is a US permanent resident.


Problem  How to calculate center of each custom tile as a point (x,y) or (x,y,z) where z is zoom level, in a projection: EPSG:3857?  What I know about the tiles   Originally they are served as TMS They represent png images 256*256 They are in projection: EPSG:3857 In OpenLayers2 they were coded like TMS layer In OpenLayers3 (v.3.8.2) they are coded like XYZ layer (that includes -y) as shown in this example:   -    var baseLayer = new ol.layer.Tile({       source: new ol.source.XYZ({         url: 'http://path/to/the/tiles/base/{z}/{x}/{-y}.png'       })     })

Problem  The picture is just an example of my case, but I am left with blank space on the left when I load all the tiles and I get error message in the console:   Failed to load resource: the server responded with a status of 404 (Not Found) http://path/to/the/tile//base/8/6/53.png  etc.     I could guess and limit the extent of the layer, but I would really like to know is there any way to calculate it and also be able to get rid of the error message.  What I know about the tiles?   Originally they are served as TMS They represent png images 256*256 They are in projection: EPSG:3857 In OpenLayers2 they were called like TMS layer In OpenLayers3 (v.3.8.2) they are called like XYZ layer (that includes -y):     var baseLayer = new ol.layer.Tile({   source: new ol.source.XYZ({     url: 'http://path/to/the/tiles/base/{z}/{x}/{-y}.png'   }) });   Thoughts and questions   How can I calculate extent of the tiles? Or in another words how can I find out zmin zmax xmin ymin xmax ymax or whole range of x/y?  What does x/y really represent? Are they coordinates of the left bottom corner or center of the tile? In which direction does x/y increase? How can I figure out x/y of at least one of the tile, for example left bottom one?    (I have modified the question for better understanding of the problem)


I'm currently updating my StackExchange Careers profile with some updated information. But in fact, I have the option to change the language in the bottom part of the page, but it will just change the Display language of the page not the way I can edit my profile.   This means I just can generate a single language profile which is displayed in german on the german page and in german on the english page. Or the otherway round, english in english and english in german.  Is there any way to generate a real multilanguage profile?

I just accepted an invitation to , and thought that it would be just great if there was any possibility to write my profile in multiple languages.  I know English is kind of vernacular in Programming languages, but I have the habit to write CV, list of publications, etc., in both my native language (a.k.a. French) and English, and think this is an excellent practice.  Could it be possible to write a profile in several languages, and depending on the recruiter's profile, to display such or such language ?


I have an array like this:   array(1) {   [0]=>   string(16) "1785328791698338" }   And other array like this:  array(7) {   [0]=>   string(17) "10207252567926988"   [1]=>   string(17) "10208823390691752"   [2]=>   string(17) "10209064245580796"   [3]=>   string(16) "1274474365912572"   [4]=>   string(16) "1294280923934896"   [5]=>   string(16) "1317727711586522"   [6]=>   string(16) "1785328791698338" }   I should check if some of the elements(in this case only one, but it can vary) from first array are same as some elements in second array, and if they are, to remove them from first array. I tried doing it this way, but it does't work:  function findSameValuesOfArrays($arrayOne,$arrayTwo){          $newArray=array();          foreach($arrayOne as $a){             $newArray[0]=$a;          }          foreach($arrayTwo as $b){             $newArray[1]=$b;          }          if (strpos($newArray[1],$newArray[0])) {             return true;          }      }   This is just to find if there are same elements, and then i would probably unset key where those values are. But function returns NULL.

Is there an easy way to delete an element from an array using PHP, such that foreach ($array) no longer includes that element?  I thought that setting it to null would do it, but apparently it does not work.


I'm on Blender 2.91 and I'm trying to make a simulation with Suzanne being pushed around by liquid. No idea how I'd approach that though. Obviously I'm making it a rigid body and a fluid obstacle, but what should I do from there? There's no FLIP two way coupling option, is there?

Apologies if this doesn't light correctly, I omitted the HDRI I was using to save space for upload and download of the .blend. Plug in your HDRI of choice and the scene should look fine (or turn off HDRI and light as you desire!).  I'm trying to turn a physics object through contact with the Mantaray liquid simulation and it's not working.  The simulation particle system is set to render as a simple object with a sphere rigidbody with sphere collision.  The domain also has a passive rigidbody and collision system - added this out of desperation, and it doesn't seem to be doing much.  The water wheel is a Fluid effector set to collision.   The water wheel also has an active rigidbody and collision system set to mesh - which doesn't seem to be doing much.  The wheel attached to the pole behind it with an empty set to Generic physics constraint (having some problems getting that to rotate reliably on the Y axis, but that's not the main problem).  Can anybody tell me how to get this waterwheel spinning with Mantaflow?


What is better option to improve RAM performance eon MacBook 13Inch Early 2011:  Removing the original Apple RAM Memory slots of 2GB each (2 slots - each 2GB) and inserting brand new 2 slots of 4GB each  OR adding 2 new slots of 2GB each ?  And, what is the best Non-Apple brand for compatible Memory Slots ?  thank you in advance  Finn

I bought a Mac (13", early 2011) almost 5 years ago. When I first got it, it was running under OS X 10.7 and it was pretty fast. I've being upgrading it ever since and it's now running under Mac OS X 10.11.  I guess it didn't totally survive the upgrades because, today, there's a lot of bugs, freezes, lags, "spinning beach ball" appearing,... for example, when I write something on a normal program/editor, the cursor freezes for a few seconds, then catches up to what I'm writting.  As you can guess, that's really annoying! I've been thinkning about upgrading the hardware but I don't know what to do: should I change the RAM to 8 GB - 1 333 MHz (currently my computer has 4 GB - 1 333 MHz)? Or should I upgrade to an SSD (which is pretty expensive and difficult to install)?  Thank you very much.


I have plotted this distribution, representing the degree distribution of the amazon co-purchase network (2003) graph. Sadly, I do not know how to interpret this. Do you know which distribution this is?

I have plotted this distribution, representing the degree distribution of the amazon co-purchase network graph. Sadly, I do not know how to interpret this. Do you know which distribution this is?


The indefinite article "an" is used when the following word starts with a vowel sound. For example one write "an adjective" but "a noun".   However, when an abbreviation is used, should this be based on the expanded meaning, or on the letters of the abbreviation.  Specifically, one writes "a noun phrase". However, here on ell.se, the abbreviation "NP" for 'noun phrase" is commonly used. If this were pronounced by sounding out its letters, as "En-Pee" it would call for "an". If it were read as "noun phrase"  it would call for "a". Should one write "a NP" or "an NP" here on ELL?  I incline to "a NP" and i used that in  just a few minutes ago, but I am not at all sure.

Taking notes, I was going to write this:     therefore p′ is a shortest path.   But the topic is APSP which stands for "all pairs shortest paths" so I decided to just write SP instead and...  Is it written with a like this     therefore p′ is a SP   or with an like this (because in my head I would "read" the S)     therefore p′ is an SP


This question was part of my algebra quiz and I was unable to solve 2 options out of 4. So, I am asking it here for help.  Let R be a finite non-zero commutative ring with unity. Then which of the sattements are true?   Any non zero element of ring is either a unit or a zero divisor.  There may exist an element which is neither a ring nor a zero divisor.   I studied algebra from Joseph Gallian. Can you please tell how should I approach this particular problem as I am really confused if there exists an element which is neither unit nor zero divisor. I can't think of any idea. Thanks

Let $R$ be a finite ring with unity. Prove that every nonzero element of $R$ is either a unit or a zero-divisor.


I currently have 500 rows of data. I want to use the first fifty rows, then skip 50 rows and so on. How do I go on about doing this?

I need a good explanation (references are a plus) on Python's slice notation.   To me, this notation needs a bit of picking up.   It looks extremely powerful, but I haven't quite got my head around it.


I have read that there is no integer type in Javascript, only floating point double-precision (64 bit) type. I understand that because of that there will be some floating point arithmetic errors introduced even when comparing integers.  However, I don't understand why the three comparisons below would yield different results:  var aInt = 1 + 2; var bInt = 3; console.log("Comparing integers: "); console.log(aInt === bInt); // Prints true  var aNum = 0.1 + 0.2; var bNum = 0.3; console.log("Comparing 0.1 + 0.2 === 0.3: "); console.log(aNum === bNum); // Prints false  var aNum2 = 1.0 + 2.0; var bNum2 = 3.0; console.log("Comparing 1.0 + 2.0 === 3.0: "); console.log(aNum2 === bNum2); // Prints true   I would have expected all the above comparisons to evaluate to false.

Consider the following code:   0.1 + 0.2 == 0.3  ->  false   0.1 + 0.2         ->  0.30000000000000004   Why do these inaccuracies happen?


Grub> Possible commands are:      { commands......}  Grub> ls (Proc) (hd0) (hd1,gpt2) (hd1,gpt2) Grub> ls (hdx,y) Device (null): filesystem type ext* - last modification time 2020-11-05    06:55:31 Thursday, UUID 1995259e-0866-4c30-a45c-e9c5b4d28945 - partition start at 525315kiB - Total size 976236544kiB Grub> sudo  Error: can't find command 'sudo'.

I want to delete the swap partition to free up space to increase the root partition, but accidentally when I restarted Ubuntu I got this:    I have made a live Ubuntu to solve this, but I can't close grub rescue. How to close grub rescue and solve this problem?  This is the output of GParted:


I have a small (32x32) grey rectangle that I converted into bitmap:     I want to convert the black areas into vector polygons.  Is this possible somehow?

I've made some high resolution pixel art in PS by drawing it down at the pixel level and then increasing the image size with the nearest neighbor setting to keep it crisp. In the web browser, however, I need to display these images as icons with a dynamic size, so I can't just size the images correctly to begin with, and the broswer seems to blur the images when rendering them smaller, while vector images seem to stay more crisp as they shrink.   So I'm wondering if there's a way to convert the pixel art neatly into vector. I'm aware of the trace function in illustrator, but it seems to do a rough job iirc.


I'm looking for a story where it's being told from the "alien's" perspective about them observing Earth in its primitive times via telescopes from systems away.  They see us at our worst with war, violence and decide that we need to be purged for the good of the universe or something.  As the missiles are flying they keep observing and see us mature compassion and stuff but it's too late to stop the attack.  The attack hits and then they receive a message from Earth saying we're coming for you.

The story is basically told from an alien's point of view. Essentially they observed us from far off, deemed us as violent and a danger to the universe, and set course (asteroid or something) to kill us. They kept observing and saw all the art and beauty we created and realized we were actually not so bad, but by then they couldn't stop it. So it was sort of also an apology letter to Earth in the end.  First read it like a year ago online and I can't find any trace of it anymore, nor can I recall the site it was on. Anyone know what short story this is?


Prove there exists a countable set $C$ containing an uncountable family $F$ of subsets such that if $A,B$ are in $F$ and $A \cap B \neq \emptyset $, then either $A \subset B$ or $B \subset A$. I tried to show this by giving an explicit example, consider the set of integers $\mathbb{Z}$ and take it's power set $\mathcal{P} (\mathbb{Z} )$, I know that $\mathbb{Z} $ is countable and $\mathcal{P} (\mathbb{Z} )$ is uncountable , can you help?

How to find an uncountable subset of $P(\mathbb{N})$ such that every two elements of it can be compared. In fact, give an uncountable subset of $P(\mathbb{N})$ such that has totality property. We mean by $P(\mathbb{N})$, the powerset of natural numbers set $\mathbb{N}$.


I am a new Latex user and I have this question: What are the classes and packages that must exist in a simple Latex file?   Books recommendation are so appreciated.

I'm getting the impression from reading the answers written by some of the real experts here that there are quite a few little packages that just tweak LaTeX2e's default behaviour a little to make it more sensible here and there.  Rather than try to pick these up one by one as I read answers to questions (and thus risk missing them), I thought I'd ask up front what LaTeX2e packages people load by default in (almost) every document.  As this is a "big list" question, I'm making it CW.  I don't know if there are standard rules across all SE/SO sites for such questions, but on MathOverflow the rule is generally: one thing (in this case, package) per answer.  I guess that if a couple of packages really do go together then it would be fine to group them.  This is perhaps a little subjective and a little close to the line, so I'll not be offended if it gets closed or voted down!  (But please explain why in the comments.)  Also see our community poll question:


In a VMs network settings:   Right click settings,  then in the resulting Settings dialog select Network from the side bar  And click any Adapter N tab,  If I set the Attached to: drop down to Internal Network   Will the VM be able to access the external network?  Or will I need another adapter type for that that will cause the vm to function as a gateway of some sort?

In a VMs network settings:   Right click settings,  then in the resulting Settings dialog select Network from the side bar  And click any Adapter N tab,  If I set the Attached to: drop down to NAT   Will the VM be able to access the host machine?  Does it get a specific IP with NAT?


I would like to change the material of two faces of a cube to be glass as opposed to changing the entire cube to be made from glass. Is this possible to achieve or does each object have to be wholly comprised of 1 material?

I am doing  Blenderguru tutorial to work on my modelling skills. At about 28:30 min in the tutorial it is demonstrated how to assign a material to a selected part of the mesh (another material is already assigned to the object). Now I have read  post and I think I have selected the right area (with face select) and assigned the new material but it does not work. Why ?


I'm most likely going to be defending my master's thesis by December of this year, so I can graduate. Depending on the results, my work could be submitted for publication or not. My program is relatively new and small. I'm going to be applying soon to PhD programs at different schools or contacting different professors with labs before December. If I get accepted, I'll be starting in Fall 2017. My undergrad and grad GPA are good and I might need to retake the GRE in order to increase my math score. Can I get some tips or advice on how to become a better PhD applicant? Or, is there anything else I might be missing before applying?  Thanks.

When applying to a PhD program in the US, how does the admissions process work? If an applicant is weak in a particular area, is it possible to offset that by being strong in a different area?  Note that this question originated from this . Please feel free to edit the question to improve it.


I'm trying to put together a comprehensive regex to validate phone numbers. Ideally it would handle international formats, but it must handle US formats, including the following:   1-234-567-8901 1-234-567-8901 x1234 1-234-567-8901 ext1234 1 (234) 567-8901 1.234.567.8901 1/234/567/8901 12345678901   I'll answer with my current attempt, but I'm hoping somebody has something better and/or more elegant.


Evaluate the following integral $$\int 4 \sin^4 x \cos^3 x \,dx$$  I can do simple integration problems, but problems like this seem to stump me, I created this problem so I could solve and compare it to another similar problem for my study guide, where should I start?

Suppose $\displaystyle P(x,y)$ a polynomial in the variables $x,y$.   For example, $\displaystyle x^4$ or $\displaystyle x^3y^2 + 3xy + 1$.  Is there a general method which allows us to evaluate the indefinite integral     $$ \int P(\sin x, \cos x) \text{d} x$$   What about the case when $\displaystyle P(x,y)$ is a rational function (i.e. a ratio of two polynomials)?   Example of a rational function: $\displaystyle \frac{x^2y + y^3}{x+y}$.    This is being asked in an effort to cut down on duplicates, see here:   and here:


I'm watching them demolish a building near me and thought that the JCBs were rather animalistic – almost dinosaur-like.  Anyway, it just got me onto thinking that it's not anthropomorphy if I want to give a non-human (animal) trait to an inanimate object.  Another example is that the comedian Isy Suttie once described an elderly person, hunched over and using a pair of walking sticks as resembling an insect (except she was funny). I suppose this is the same thing.  The only thing I can think of that might fit is "xenopomorphism".  Any ideas?

I am writing a paper about Art Spiegelman's Maus, specifically the metaphor that Spiegelman creates by depicting his obviously quite human characters with the heads of various animals, or a couple times animal masks. The metaphor is used at times to bestialize/animalize the acts of the Nazis and, in some cases, to show the arbitrary nature of the classes/groups/divisions they and others applied to human beings.  I considered "chremamorphism," but this describes the attribution of the characteristics of an object to, or the objectification of, a human. I also considered "animalize" and "bestialize," but those describe some of the effects that can be produced by Spiegelman's metaphor, not the metaphor itself - in many scenes in the book, the characters are extremely human, and I think that the negative or degrading connotations of these words makes them inappropriate for this use. Nor do "anthropomorphism" or "personification" fit, because Spiegelman is not applying human characteristics to animals but the other way around. None of the words that I can think of quite fit.  What is a word that accurately describes Art Spiegelman's depiction of obviously human characters as having animal body parts or wearing animal masks in the comic book Maus?