Expected number of tries required for consecutive successes

(This is not a homework question; I just want to understand how this works)  Let's say I am playing a game, where I need to flip a coin. I need to get $X$ number of heads in a row in order to win. The coin is unbalanced, and has $p$ probability of landing on heads and $1-p$ probability of landing on tails. Consecutive flips are independent of previous ones.   The game ends when I flip $X$ heads in a row; if I flip only heads the game ends in $X$ flips, if I flip $X-1$ heads, then one tail, then $X$ heads, the game ends in $2X$ flips.   What is the expected value of coin flips? What is this distribution called?    I understand that this can probably be defined as some sum of binomial distributions; just curious if there's another way to do it.


How single external ip can route to mutiple servers behind the router?

Lets not talk on the of scale of big data center. Keep it simple. Every users gets an internet connection from an ISP. And if i want to run a web server. I usually forward the packets from my router to the desired computer. This is called as port forwarding.  Lets take for instance, I have two servers in my lan. I want both the servers to be actively responding. I have a single external ip say 182.22.XXX.XXX. I can only port forward to one computer. How can i port forward the same port 80 to two computers in the lan. can how does the person outside the lan differentiate the computers that is inside the lan. since we have only one external ip in our case??


Why is it “Who be ye?” and not “Who are ye?” in archaic forms of English?

When I was , I stumbled upon the phrase “Who be ye?”. But why is it “Who be ye?” and not “Who are ye?”? The modern equivalent of “ye” would be “you”, wouldn’t it? “Who be you?” would be considered incorrect, whilst “Who are you?” would be perfectly fine.


In the Android app, the "x more comments" phrase is cut off by the button next to it, "Add a comment":    It looks like the rest of the phrase is underneath the button and there is some space to the left of the phrase. Can we shift the "x more comments" phrase more to the left so it doesn't get cut off by the "Add a comment" button? At the very least, please allow the phrase to not be cut off by the "Add a comment" button somehow.


Object moves back into origin everytime i open the blender file

When i open the blender file the object seems to move back to origin and scales back down.... I tried to apply location but it gives me an error. Any idea whats happening or what can i do to fix it ?


I'm totally new to blender and I start trying to do a wizard hat. Since I started, I manage to do pretty much every thing I wanted to do. But I'm starting to struggle. So what I'm trying to do is pretty obvious, I'm trying to "glue" my plane star on my 3D hat. I tried "Boolean Union", big failure. And I didn't try to merge on vertices because I don't know how to create a 5 vertices stars on my rounded 3D model. I didn't find any tutorials or documentation, that's why I writting here, I tried to do it my way but maybe it's not a good one. If any of you got an idea on how to do that, I'll appreciate ! Cheers.


Can Plant Growth be repeatedly cast on the same area to exponentially increase the yield of harvests there (more than twice)?

I was looking into getting the spell  because we work with some agrarian societies in our campaign.  If you cast the 8-hour version that enriches plants in a 1 mile radius to double their next harvest over the same 1 mile every day, what stops it from increasing the harvest exponentially by further enriching the crops?  The theory being that even using a weekend of casting we could give a city/farmer x8 the harvest instead of just x2.


Why do I get a converging result when pressing cosine multiple times on a calculator?

I'm trying to comprehend the following: If I choose any starting value (e.g. 1) and keep clicking on cosine on the calculator (in radian mode), it gives me a result of about 0.739085...(I believe it's the result of cos(x) = x), but when I repeat the same procedure using sin and tan, I get something completely different (looks like for sin it's converging to 0 while for tan I get very wild results).  Thanks for your help.


I am new to the Ubuntu. I have installed the ubuntu 12.04 from the usb drive. But it needs the usb drive every time to open and run.  Please suggest me a solution to overcome.


Suddenly created meshes are invisible (even though they are checked as visible), cannot create any new objects now

as the title states I am suddenly unable to create any new objects, when i select a mesh from the "create" bar nothing noticeably happens, other than the object name appearing in the list in the top right hand corner of the screen, i cannot edit the object, view the object, or do anything at all to it, this happened suddenly part way through a project and has caused me to be unable to continue, it's driving me nuts and I cannot for the life of me see why this has suddenly happened, im sure i must have accidentally pressed a keyboard shortcut for something, but i do not know what, any ideas?


How to Fix corrupted pen drives during bootable creation process?

I want to re-format it and,  I have tried almost everything! tried diskpart method,3rd party software method, tried to format in safe mode, tried to format in ubuntu too... every time it shows same error : 'Disk is write protected'  please help me to recover my pendrive!


I am provided with a multi-set, let's say S with elements as [num1, num2, num3] and these elements are integers (both negative as well as non negative). As this is a multi-set, elements in the multi-set can be present multiple times. I need to choose an element from this multi-set and multiply it with -1. I need to perform this operation m times. I want to find out how many multi-sets are there which can be made from this multi-set. This is home work, so really sorry but I am not able to proceed. I need some help in this. Please give me some hints. I am providing one example.  S = [2, 3, 2] and m=2 then there are 4 possible multisets   [2, 3, 2] [-2, -3, 2] [-2, 3, -2] [2, -3, -2].   Any help would be appreciated.


We are looking to build a new website which would make use of 2 web applications: Drupal and Magento. Drupal will be used for corporate website while Magento will serve as a web shop. One of the challenges that I'm facing is the single-sign-on (SSO) part. I have done quite a lot of reading about this subject and haven't come across the "best way" to do this.  Do we keep a separate user database on both Magento and Drupal? (Taking into consideration that not every Drupal user will have access to the web shop.)  Should we use a central authentication server (CAS) instead?  Currently I'm testing the following method:   Installed the  Configured that the user is redirected to a file sso.php after he/she logs in on Drupal The sso.php file reads the information of the currently logged in user and optionally creates the Magento session for this user (if an account with a matching username/e-mail) exists   Does anyone have any previous experience in getting the SSO feature between Magento-Drupal? Any input would be appreciated!  Some more info:   The website and web shop will run on the same domain. The web shop is located in a subfolder Preferably the SSO has to be done programatically without using the slow Magento API


I wrote a bash script that executes a Java jar for a n number of times.  In practice, I defined e foo() function, containing the invocation of the jar, and then I run this script:  for RUN in $(seq 1 $RUNS)  do      foo &  done   Now, I would like to not execute runs times in parallel the jar. There is a wait to limit the number of parallel execution (like a wait every 10 process for instance)?


I am playing about with 'John the ripper' to see how easily my password can be cracked. The only issue i I cannot seem to fin the hashed password.  Things I've tried.   Reading hash from /etc/passwd - Result: No user found sudo dscl . -read /Users/<user>/ | grep GeneratedUID | cut -c15- cat /var/db/shadow/hash/<Result From First Command> | cut -c169-216 - Result: directory 'shadow' does not exist Some others (forgotten what they were. Had similar issues.    also didn't work for me.  Would like to know where the password hash is for my user so I can test out JTR. Thanks in advanced.  Edit: When I do sudo defaults read /var/db/dslocal/nodes/Default/users/Test.plist ShadowHashData|tr -dc 0-9a-f|xxd -r -p|plutil -convert xml1 - -o - I get 2 hashes'zcvUSru/AH3YNusqitC14z8dm8iX9dZTRzKKkv+oMODQQ9CG79yGmsjo8s13UCSIZ6TmE/U2krMC7KzxgafDwVkOq0eJ1F6aYFUBex649rUnj/58jhCp7Lgt5vWYN95SrDQwMKEYkFXkHM/Ieg0GsnCJnZwem4ugfSnU2fKCquE= and weXOBzKgCTzoeamwRXZ8vLNQNrHyCyFk/ZD2Bc/Vb6c= However when I put 'Test:' in a text file and do ./john <file> It gives me 'No password hashes loaded'.  Is this an issue with how I'm using John The Ripper or am I getting the wrong hashes?  Note: This was a test user and this is not my real password hashed. The encrypted password is 'password'


Independence relation between observation and error

Having a simple model like: Y = a + bX + u where u represent the error term, if I know that the observation of X and Y are i.i.d, also the error term is i.i.d?


Ubuntu 18.04 - Lenovo Thinkpad Carbon sound card not recognized since firmware update

I recently updated firmware on my Thinkpad Carbon X1 (last gen, 7th I guess) and since (I'm not sure it is the cause of my problem, but it happens simultaneously), I only have a "dummy device" in sound configuration panel on Ubuntu 18.04. I tried a lot of stuff suggested around the web and still, the result of aplay -l is always no sound card detected. The output of lspci -nnk | grep -A2 Audio is :  Audio device [0403]: Intel Corporation Device [8086:9dc8] (rev 11)     Subsystem: Lenovo Device [17aa:2292]     Kernel driver in use: snd_soc_skl   Any suggestion how to fix this ?


Not getting any items (pokeballs or anything else) at poke stops

Today, i stopped at 4 different pokestops multiple times but couldnt get any pokeballs.  My bag is not full but it just spins but not give anything.  I am using pokemon trainer club account.  We do use the same account on 2 iphones (and both have the same problem).


Are 15A receptacles safe on 20A circuits?

I recently got a circuit added to my spare room to grow some tomatos, the lighting I am going to be using is 8amp on each plug, I noticed the electrician didnt install a 20A rated receptacle with the side blade but installed a 15amp instead. I am wondering if this is safe, it is the only receptacle on the line. Pretty simple fix to swap it out if need be


Maximum number of bits in one single qubit?

How many bits can a qubit hold? I know there are probabilities involved in a qubit, but there must be some limit to how many bits a qubit can take. If different qubits can have different amounts of information then we can think of these as different sizes of processor-registers: $8$-bit, $16$-bit, $32$-bit or $64$-bit, can't we?  But my question is really, is there a limit to how much information content (discreete-wise) a qubit can store?


How to reduce blur or haze when shooting long distances?

I am new to photography any i am not sure what is the correct settings when shooting long distance landscapes.  The photo that I took is pretty blurry/hazy. Is there any specific settings or equipment to reduce this blur/haze when shooting long-distance landscapes?  Here is an example of a photo that I took.


Mathematical Induction, show that $n!>n^3$ for all $n \ge 6$

I have a math question where I am to show, using induction, that $n!> n^{3}$, $n\geq 6$ i) I have shown that $LHS > RHS$ for $n=6$ $$720 > 216$$ ii) Set $n=p$ and assume that $p!> p^{3}$ iii) set $n=p+1$ $$(p+1)!>(p+1)^{3}$$ by the assumption we know that $$(p+1)p! > (p+1)p^{3}$$ this is where I am stuck and would appreciate some help.


Finding rank of a matrix depending on parameter a

We have the matrix  $$A = \begin{bmatrix}1 & a & 1\\-4 & 2 & a \\ a & -1 & -2 \\ 4 & 6 & 1\end{bmatrix}$$  and we want to find the rank of this matrix as a function of parameter $a$.


"Title cannot be longer than 150 characters" - why doesn't the field have an input limit or a character count then?

This is really frustrating. Having to edit a title because it was "too long" despite the title field not having a hard limit or a character count.


Extrude edges (or a curve) using an offset/inset to create a mitred patch of faces?

I'm trying to find a way to quickly use a curve or series of edges as an outline for creating a mitred patch of coplanar faces. I guess what I'm actually asking is whether there's a way to draw a series of edges and then extrude them into faces, but... rather than extrude all of the new edges in the same direction, can they be extruded so that they each remain perpendicular to their respective original edges, creating a mitre where they meet, like what an offset or inset does? Here's what I mean:   (A) I start with a series of edges; then I want to... (B) offset those, like an extrusion inwards or outwards but specifically inwards in this case, so as to create new faces; and (C) Adjust the thickness later.  I will explain how I've already accomplished this, but I'm hoping someone can help me find a quicker way to do this. Here's what I already did:  Start with a single vertex, and extrude it to create the edges I want => this gives me (A). Take that mesh and convert it to a curve (while using Keep Original, and setting the new curve to 2D) Use Object Data > Geometry > Offset set to a negative value -- this creates the main effect of what I mean by offset/inset, because unlike (say) doing a scale, this method does what I'd call "a perpendicular projection" of each edge. Convert that offset curve to a mesh again. Join (CTRL+J) the two meshes, hence giving me now an outline for the outside and inside edges of the faces. Connect the open ends of those two outlines and fill to create one big polygonal face. Use the knife tool to cut the mitred corners between each pair of vertices. Now I have (B). Finally, I get to step (C) by selecting the inside edges and doing an Edge Slide (with Clamping disabled) to adjust the thickness both in and out as I need.  So, can anyone suggest how I might do this more quickly and easily?


Hiding some slides in student handouts in Beamer

I am preparing lecture slides for a class. I would like to hide some of the slides from the students. As an example, I would like to be able to compile students.pdf which has only student slides 1 and 2 (i.e., "teacher slide" is hidden); but teacher.pdf which has all three slides.  \documentclass{beamer}  \begin{document}  \begin{frame}{Student slide 1} blah blah blah \end{frame}  \begin{frame}{Teacher slide} secret stuff not to be shared with students \end{frame}  \begin{frame}{Student slide 2} blah blah blah \end{frame}  \end{document}   How would I do this in beamer? In a regular document, e.g., article, I would use the comment environment.  I feel that the approach in  is overkill for my needs.


Why did Dumbledore allow The Forbidden Forest for Detention?

“First years should note that the forest on the grounds is forbidden to all pupils. And a few of our older students would do well to remember that as well.”      -Harry Potter and the Sorcerer's Stone, Chapter 7-The Sorting Hat   Why did Dumbledore allow detentions to be in forbidden forest even though it is Forbidden for all the students.     “At this, Neville let out a little moan, and Malfoy stopped dead in his tracks.              “The forest?” he repeated, and he didn’t sound quite as cool as usual.      “We can’t go in there at night — there’s all sorts of things in there — werewolves, I heard.”      -Harry Potter and the Sorcerer's Stone, Chapter 15-The Forbidden Forest


Nested/embedded quotations (quoting quotes)

Possible Duplicate:          I'm having some trouble with this.  Usually, I would quote with doubles, and then singles within.  But this is becoming a bit confusing and ugly too, when working with some translated literature in which it is very, very common for someone to quote someone, who then quotes another, and the chain goes on.  Would I retain the principle of using double quotes initially when I quote the passage, and then keep using singles in the embeds/nests?  Edit:  Thought I'd add, it looks fine and dandy until the initial quoter ends his discourse on the clause of the one he is quoting!  I end up with ' ' " and all sorts at the end!


What is difference between the different 'flavours' of neutrinos?

Moreover, how-come scientist know that muon-neutrino are different from electron-neutrino when they didn't even know what the difference was? Did they interact differently with other particles?


Should I put myself last? "me and my friends" vs. "my friends and me" or "my friends and I"

I've always been taught to put myself last when referring to myself in the same sentence as others but the usage of "me and..." seems to be everywhere these days. The misuse of the word "me" instead of "I" aside, is there some new rule I haven't heard of? Shouldn't we put ourselves last regardless of the "me"/"I" usage?  Examples of "correct" usage:      My friends and I went for some ice   cream. Did you see my friends and me   at the ice cream stand?   Examples of "incorrect" usage:     Me and my friends went for some ice   cream. Did you see me and my friends   at the ice cream stand?   Note: I was also taught that the only person who could put themselves first was the queen.


How many sets of positive integers $(a,b,c,d)$ for $a^3+b^3 = c^3+d^3$?

Four distinct positive integers  $a, b, c, d$ satisfy the equation $a^3+b^3 = c^3+d^3$ . An example for $(a,b,c,d)$ is $(9,10,1,12)$ as $9^3+10^3 = 1^3+12^3$. Is there an infinite number of such examples for $(a,b,c,d)$? If there is no an infinite number of examples for $(a,b,c,d)$ then how many?


I am given the series $\Sigma_{n=1}^{\infty} \frac{\sqrt{a_n}}{n}$, where $a_n \geq 0 \forall n$ , and $\Sigma_1^{\infty} a_n  $ converges.   I was advised to expand $|\sqrt{a_n} - \frac{1}{n}|^2 $ . Doing this gives me expressions like $-\frac{2 \sqrt{a}}{n}+a+\frac{1}{n^2}$ , but I don't see how this is useful.


I am trying to match a search term up to a first period using grep  So for example, grep-ing through  foobar searchterm. hello world.   should print foobar search term blah. I save the above to a plain text file called search. But when I try  grep -i 'searchterm.*\.'search   it prints out  foobar searchterm blah. hello world.   instead of stopping after blah. What am I getting wrong here? The period star .* should match anything up to the first occurrence of a literal period \. right?


click handler for button that was created using JavaScript

I'm trying to add a click function to a button that was created in JS, i already tried   $(Selector).click(function(){}); <button type=button id=edit>&#9998;</button>	;


Best way to flatten a curled photographed book photograph?

I have photographed some pages of a book for reading. This is much faster than scanning and you don't have to carry the heavy books. However, the photographed books are not as nice: curved, skewed, and shadowed, as opposed to the much flatter, cleaner scanned books. Especially when you're trying to print them out.  Google's used some specific technique of converting books to e-books with a camera and a laser overlay.  But is there any home user software that can flatten a curled photographed book photograph?  Or maybe there is some technique which you can use in Photoshop?  What is the best way to achieve that?  Example:


Is it possible to grant rename permissions, but not delete, in NTFS?

We have a folder for employees to scan contracts to. After scanning, they're supposed to rename them according to our conventions so they can be processed further. In response to a recent incident, these folders have had their security locked down (they're granted write, but not modify, permission) and now they are unable to rename the files.  Is there a technical way to accomplish what I'm trying to do? From what I've read, I don't think this is possible.  If not, can you suggest any workarounds? One possibility is to set the name of the file as it's being scanned in. Another is to have a trusted person in management be given sufficient permissions to rename.


I am very new to Ubuntu, so should I try Xubuntu and Lubuntu first?

I am very new to Ubuntu. The reason I came here and asked the question is that I lost my windows XP CD for my old laptop. My laptop has a P4 CPU, 1GB RAM and 50GB HDD (7200 rpm). I googled for the alternative OS to XP, and there were at least thousands of results returned. Yet, some of the experts in forum (MakeUseOf) recommended Xubuntu and Lubuntu. :  But I am lost. What are Xubuntu and Lubuntu? Are they better than Ubuntu alone? I am just looking for a free OS with rich UI and easy to use for my old laptop.


Mahalanobis distance: What if S is not invertible?

The Mahalanobis distance is a distance metric used to measure the distance between two points in some feature space. Unlike the Euclidean distance, it uses the covariance matrix to "adjust" for covariance among the various features.  The Mahalanobis distance formula uses the inverse of the covariance matrix. What if the covariance matrix is not invertible?


How can I get more citizens to educate themselves?

I noticed that I have too many uneducated citizens. While a small minority of them go to high school and college to get educated on their own, is there a way to attract more students? I pay a fortune to get foreign educated workers, while my island's population is too lazy to study!


Can a charged particle interact with its its own electromagnetic field?

Say an electron begin moving with velocity V back and forth very quick or at the speed of light, could it interact with its own previous pre existing electromagnetic field?


Can I draw a box which (dynamically) fills to the bottom of the page?

Is there a way to draw a simple box with width \textwidth and height so that it fills from wherever it is placed to the bottom margin of the page?


Why isn't $1^{\infty}$ considered as equal to $1$ but is said to be an indeterminate form in limits?


Let assume $f(z)$ is defined and analytic at $|z|>1$ and such that $\lim_{z\to \infty}f(z)=L$ when $L<\infty$ Prove: $\lim_{z\to \infty}f'(z)=0$  $f(z)$ is defined and analytic at $|z|>1$ so it can be expanded to a power series $f(z)=\sum_{n=0}^{\infty}\frac{a_n}{z^n}$ at $|z|>1$ now we know that $lim_{z\to \infty}f(z)=\lim_{z\to \infty}\sum_{n=0}^{\infty}\frac{a_n}{z^n}=L$ Taking the derivative we get: $\lim_{z\to \infty}f'(z)=\lim_{z\to \infty}\sum_{n=1}^{\infty}-n*\frac{a_n}{z^{n-1}}=0$ Or am I missing something?


I've a question that many of yours could consider stupid: if i sum a matrix with its transpose, I obtain a particular result? E.g. $A + A^T = B$, $B$ has some particular properties?


I've been using the iOS application for 2 days now and still no hat.  Is it some sort of bug?  As a matter of fact, I'm writing this question on my phone.  Oh... Well, the text use the iOS application isn't very descriptive :|


Splitting feature class by unique values for an attribute/field in ArcGIS for Desktop?

I would like to split a single shapefile into multiple shapefiles by using unique values for one attribute/field to select features for each value out into a new feature class.   I found ET Geowizard to do this but it's not free.   In  I found a tool named "SplitLayerByAttributes" but it does not work in ArcMap . (see comments below, this was an old version which has been updated.  The new version can be found at    )  Do you know of any tools or solution to split by attribute in the way described above?


What should I look for in lenses for long range and close up animal and natural shots?

I am looking at trying to buy a long range lens for shooting animals and nature. I'm kinda new to photography and am not sure which brand or size I should be looking for. What features are important and what will I get from different price points? I also would like to get a macro lens for really close shots — is that possible with the same lens?  I have a nikon d3000.


How do I contact the UFW developers to make a feature request?

I have some ideas for improving the package, but have been unable to locate any valid contact information.  The content information I did find bounced.


When I compile my PDF from LaTeX source, do I have to care about all the messages (currently 28) about 'bad boxes'?  The PDF seems fine to me.


Problem: I have a single list of data that is updated with a new value every few seconds. I simply want to check whether the data points in that list are decreasing, increasing or staying steady over time. It would also be helpful to quantify that the strength of the trend.   So far, I have looked at the Pearson correlation and differences in values, but neither has helped (or I am not using them correctly). I also looked at other answers here, but I couldn't find anything that worked for me.  Question: Are there any other tests or calculations that I can do to determine the direction of the data? Would the moving average give any information?  This might be a relatively trivial question, but I would appreciate some help or pointers to the right resources.


ArrayList list=new ArrayList(); List list=new ArrayList(); What's the difference between the two?

I'm a beginner.i can't understand the difference between "ArrayList list=new ArrayList();" and "  List list=new ArrayList();".please help me.Thank you very much!


Migrate Oracle BLOB to Postgres BYTEA or OID

After the BLOB columns of Oracle (11g r2) tables are migrated into a Postgres (9.4.5) table such as using Ora2Pg, I have two questions:  1) Which data type will the new column assume, is it BYTEA or OID?  2) Will the (BLOB) data be copied over correspondingly?  Or I need to do a separate migration of the data?


I have a script, which creates multiple objects through a loop. However, the script freezes the viewport until it is done. Instead, I would like every object to be seen in the viewport one by one as it is created.   In its simplest terms:  import bpy import random for i in range(1000):     XYZcoord = (random.random()*100, random.random()*100, random.random()*100)     bpy.ops.mesh.primitive_uv_sphere_add(location=XYZcoord)     # Update the viewport here.   Is there a way to update the viewport after every iteration of the loop to see every newly added object as they are created? Or do I need to use a different method?


Java: Check if current date is in range of specific days

I am struggling with following problem:  In my app I want to check whether a current datetime from LocalDateTime.now() is in range of some specific days of week, let's say between Friday and Sunday.   Example:  Datetime window is from Friday 20:00 to Sunday 20:00. When I check current date on Thursday at 22:00*, answer should be false but when I check it on **Saturday at 8:00, answer should be true.  I can sort of achieve this with DayOfWeek class in java.time API using compareTo() method and comparing hours and minutes separately but I would like to know if there is any better way to do it  and especially when the range of days spans over two weeks (e.g. Friday to Monday of the next week)?  Thanks in advance for any advice or help.


Article Class: How to remove the self-reference of the ToC from the ToC?

I have a very basic question:      In the article class how can I take the hyperlink "Contents" out of the table of contents without deleting the header "Content" which is above the whole table of contents?   [Notice that most – if not all – of the other questions on the topic are for the memoir class]  The question comes because, , I found an answer (the one made by user Ashley) whhere it was suggested to use the following code:  \makeatletter \@starttoc{toc} \makeatother   However, as pointed out below the answer in a comment by user Werner, the result is that you take out the selfreferential hyperlink, but also the header with the title "Content".     Is it possible to avoid this?  Thank you for your time.


take numeric value without label in line, regex

Input:  df=pd.DataFrame({'text':['value 123* 333','122* 666','722 888*']}) print(df)              text 0  value 123* 333 1        122* 666 2        722 888*   I need to extract from df['text'] only numeric values, but withou *label my code:  df.text.str.extract(r'([0-9]+|[0-9]+\.[0-9]+)')   But with this code, values with the * char on the right are returned.  Expected output:  text 333 666 722


if $\sum_{i=1}^n a_i$ converges but $\sum_{i=1}^n (a_i)^2$ diverges, does that mean that $\sum_{i=1}^n a_i$ is conditionally

I don't think this is true, but cannot find an example to disproof it. Either that or i need to prove that $\sum_{i=1}^n |a_i|$ diverges, which I am unclear how to approach the proof.


Windows installer for Ubuntu 14.04 LTS onwards

Is there any Windows installer (wubi) for Ubuntu 14.04 LTS?  When I mount the .iso file with Daemon Tools and run wubi.exe, it just asks me if I want to reboot (I think that's useful only when the .iso  is burned on CD), so is there no "real" installation?


When I boot up 32-bit Ubuntu 18.04.5 on my i686 32-bit machine, why am I prompted to upgrade to Ubuntu 20.04.1 LTS...which, as I understand it, is a 64-bit OS?  Surely the code is smart enough to tell that my machine will not run a 64-bit OS.


I want to show that $f(x)=x.f(1)$ where $f:R\to R$ is additive.

Possible Duplicate:             I know that if $f$ is continuous at one point then it is continuous at every point.  From this i want to show that $f(x)=xf(1).$ Can anybody help me to proving this?


UAE visit visa with expired passport number

I need a visa to travel to UAE. My passport will expire soon (June), so today I applied for a new passport and it will be delivered to me on March 17. I need to travel to Dubai on March 18. clearly not enough time to get a visa for the new passport.  Can I send a scan of my old passport to the agency who's getting the visa for me, get a visa with the old passport number on it and then travel with both passports to Dubai? My new passport to satisfy their 6 months validity requirement and the old passport to match the passport number?


Component events vs Application events (component.getEvent vs $A.get)

I am new to lightning experience and components. I have been through some blogs and code that guide through the basics, but other than that I haven't had much hands-on experience.  My question is:  When to use component events vs application events? If I have nested components (parent & child) and if the events are of type Component, will the parent be able to handle events fired from child, and vice versa?  Also, I've noticed there are two ways to get an instance of an event (say TestEvent) -      component.getEvent("TestEvent");   and      $A.get("e.c:TestEvent");   Is there any difference between the both? What do "$A" & "e" in the second form, represent?  Thanks in advance for your reply!


Can a subset of $N−1$ rectifiable set be partitioned into countably many connected pieces?

This is a follow up question regarding to the problem discussed . Thanks so much to @Silvia Ghinassi's nice and simple explanation there!  Ok, here is the updated question:    Let $\Gamma\subset \mathbb R^N$ be a $N-1$ rectifiable set such that $\mathcal H^{N-1}(\Gamma)<\infty$. I remove a small part of it, say I define $\Gamma' := \Gamma\setminus N$ where $N$ is a random set and $\mathcal H^{N-1}(N)<\delta$, where $\delta$ is arbitrarily small.   Same question but now with respect to $\Gamma'$: would it be possible to partition $\Gamma'$ into countably many connection pieces, up to $\epsilon>0$ error? (where $\epsilon>0$ is given). Also, you could redefined $\Gamma'$ on a set of $\mathcal H^{N-1}$ measure $0$ set.  That is, would it be possible to find a set $\{\Gamma_n\}_{n=1}^\infty$ such that each $\Gamma_n\subset \Gamma'$ is connected, and  $$ \mathcal H^{N-1}\left(\Gamma'\setminus \bigcup_{n=1}\Gamma_n\right)<\epsilon. $$


Number of bit strings with 3 consecutive zeros or 4 consecutive 1s

I am trying to count the number of bit-strings of length 8 with 3 consecutive zeros or 4 consecutive ones. I was able to calculate it, but I am overcounting. The correct answer is $147$, I got $148$.  I calculated it as follows:  Number of strings with 3 consecutive zeros = $2^5+5\times2^4 = 112$, because the 3 zeros can start at bit number 1, 2, 3, .., 6  Number of strings with 4 consecutive ones = $2^4+4\times2^3 = 48$, I used the same reasoning.  Now I am trying to count the number of bit-strings that contain both 3 consecutive zeros and 4 consecutive 1s. I reasoned as follows:   the strings can be of the following forms: 0001111x, 000x1111, x0001111..thus there are $2+2+2 = 6$ possibilities for bit-strings where the 3 consecutive zeros come first. Symmetrically there are $6$ bit-strings where the 4 consecutive ones come first.  Thus the answer should be = $112+48-12 = 148$.  clearly there's something wrong with my reasoning, if someone could point it out, that would be awesome. Thanks


How can lab equipment be transfered when the PI changes universities?

I've seen these answers:    However, I want a little more detail on a legend that I've heard that if the new university is offering you start-up funds, then you can buy back your old stuff using the start-up funds at fair prices for used equipment. How does this get negotiated? Does this ever actually happen in practice, or is it a myth?  My lab has a lot off stuff that I've acquired over several years. Some of it I bought with start-up, some I bought with external grant funds, and some I bought with (eek!) my personal money. There are numerous things that I scavenged from other labs. Some of the stuff in my lab is old and somewhat broken (a laptop with a glitchy screen). If I were to get a position at another university, how does this stuff get sorted out?   I'm working at a US university and the new university would be in the US or Canada.


Why does not equal length of line in DIRECTION/LENGTH with length of line in MEASURING in OpenLayers 2.13?

My map projection is: "EPSG:900913", display projection is "EPSG:4326" and units is "m", however does not equal the length in Direction/length with the length is calculated in measuring in OpenLayers, in fact OpenLayers show the length more than the actual length when I use measure control. I've set the option geodesic: true to my measure control.  For example:  the enter length is: 100m     the length after measuring is: 85.29m     Define measure control:   measureLine = new OpenLayers.Control.DynamicMeasure(OpenLayers.Handler.Path); measureLine.geodesic = true;  function insertDirectionLength(drawType) {     var values = parseInput(     window.prompt(             "Enter direction and length offset values for new point (e.g. '-45, 10')", "direction, length"     )      );      if (values != null) {          var controlKey,key;          for (key in controls) {              controlKey = controls[key];              if (drawType == key) {                   controlKey.insertDirectionLength(values[0], values[1]);              }           }      }  }   How to resolve this problem?


The Schwarz Reflection Principle for a circle

I'm working on the following exercise (not homework) from Ahlfors' text:  " If $f(z)$ is analytic in $|z| \leq 1$ and satisfies $|f| = 1$ on $|z| = 1$, show that $f(z)$ is rational."  I already know about the reflection principle for the case of a half plane, so I tried using the "Cayley transform" $$T (\zeta)=\frac{\zeta-i}{\zeta+i}$$ Which maps the closed upper half plane onto the closed unit disk with $1$ removed.  I defined $$g(\zeta)=(T^{-1} \circ f \circ T)(\zeta)=i\frac{1+f \left( \frac{\zeta-i}{\zeta+i} \right)}{1-f \left( \frac{\zeta-i}{\zeta+i} \right)},$$ And tried to apply the reflection principle in the book. $g$ is indeed analytic in the upper half plane, but for $\zeta \in \mathbb R$, I'm afraid that $g$ might get infinite (because on the boundary, $f$ takes values on the unit circle). If so, it will not be continuous and not even real, and the reflection principle is not applicable.  Am I missing something here? After all Ahlfors does mention in the text a generalized reflection principle for arbitrary circles $C,C'$.  Thanks


Sum of binomial $\sum_{k=0}^{n+1} \sum_{r=0}^{k-1}\binom{ n+1}{k}\binom{n}{r}$

I want to find(?) derive(?) obtain(?) closed formula for  $$\sum_{k=0}^{n+1} \sum_{r=0}^{k-1}\binom{ n+1}{k}\binom{n}{r}$$  Actually for some integers I found this as $2^{2n}$ ....   My first trial is using double sum technique in   and then via mathematica by some $n$,   \begin{align} \sum_{k=0}^{n+1} \sum_{r=0}^{k-1}  \begin{pmatrix} n+1 \\ k \end{pmatrix}\begin{pmatrix} n  \\ r \end{pmatrix} =  \sum_{r=0}^{n+1} \sum_{k=r+1}^{n+1} \begin{pmatrix} n+1 \\ k \end{pmatrix} \begin{pmatrix} n\\ r \end{pmatrix} \end{align} But still does not have explicit form...


Where can I ask questions that I don't know how to frame well enough for Stack Exchange?

I am what I would call an "advanced hobby programmer". So I have limited in-depth technical training. I'm also the "virtual CTO" for my SaaS application. Which means I have ultimate technical  responsibility for the entire scope of a complex multi-technology application. For budgetary reasons, my development team does not include senior people with broad and in-depth technical knowledge. As a result of these constraints, I occasionally need to do problem solving on issues that I barely know the key words for in order start researching. In the process, I sometimes ask questions on Stack Exchange for which I get negative feedback in one form or another. Question:  Is there a site in the Stack Exchange network where I can answer "less informed" questions (possibly considered "dumb") in order, for example, to just get started on what to specifically research? Or if not in this network, what would you recommend?


What causes this exception Caused by: java.lang.NullPointerException: Cannot invoke "java.net.URL.toExternalForm()"

I have developed a modular javafx application using eclipse, jdk14 and javafx14. However, when i try to run the application from the IDE i am getting an exception stated below. This started happening after i made attempts to modularize fontawesome-8.2 jar so that i can use it in my modular application. The modularization seem to have worked except for the exception i am getting when i try to run the application. I have googled but i don't seem to find a working solution to this problem. Your assistance and guidance will be appreciated. Below is an excerpt from the stacktrace: Caused by: java.lang.NullPointerException: Cannot invoke "java.net.URL.toExternalForm()" because the return value of "java.lang.Class.getResource(String)" is null at fontawesomefx/de.jensd.fx.glyphs.fontawesome.FontAwesomeIcon.(FontAwesomeIcon.java:31) ... 23 more


Trouble copying file while SSH'd into another computer to my local computer?

I am ssh'd into a computer.  There is a file on the home directory I would like to copy to my local computer.  I tried running scp readme brian@HomeLenovo:/home/Documents/cp_readme  where brian@HomeLenovo is my peronsal laptop, but I keep getting the error ssh: Could not resolve hostname homelenovo: No address associated with hostname lost connection  I assume this is because the computer I am ssh'd into doesn't "know" about my computer or what that hostname references - how can I resolve this without installing anything or making changes to the computer I am ssh'd into?


Does antimatter curve spacetime in the opposite direction as matter?

According to the Dirac equation, antimatter is the negative energy solution to the following relation:  $$E^2 = p^2 c^2 + m^2 c^4.$$  And according to general relativity, the Einstein tensor (which roughly represents the curvature of spacetime) is linearly dependent on (and I assume would then have the same mathematical sign as) the stress-energy tensor:  $$G_{\mu \nu} = \frac{8 \pi G}{c^4}T_{\mu \nu}.$$  For antimatter, the sign of the stress-energy tensor would change, as the sign of the energy changes.  Would this change the sign of the Einstein tensor, causing spacetime to be curved in the opposite direction as it would be curved if normal matter with positive energy were in its place?  Or does adding in the cosmological constant change things here?


Please do not include questions not in English in "Hot Network Questions"

Today, I got some Spanish "Hot Network Questions", having read  it looks like a filter was supposed to be in place. I'm sure it's interesting but to my shame I do not know Spanish.  That question contains no English, it does contain some shell commands that are in English but certainly not text.  Please fine tune the filter or make these questions opt-in.


Show: $X_n\xrightarrow{\mathcal{d}} X$, then $\mathbb{E}\lvert X\rvert\leqslant\liminf_{n\to\infty}\mathbb{E}\lvert X_n\rvert$

Let $X_n, X$ be random variables with $X_n\xrightarrow{d} X$. Show that then     $$ \mathbb{E}\lvert X\rvert\leqslant\liminf_n \mathbb{E}\lvert X_n\rvert. $$      So let $X_n\xrightarrow{d} X$; in our lecture this means that for all bounded continious functions $f$ it is $$ \lim_n\int f\circ X_n\, d\mathbb{P}=\int f\circ X\, d\mathbb{P}.~~~~~~~~~(*) $$    I do not know, how to make the proof. Nonetheless, my first idea was, to work with Fatou's lemma, i.e. $$ \liminf_n\mathbb{E}\lvert X_n\rvert\geqslant\mathbb{E}\liminf_n\lvert X_n\rvert=\int\liminf_n\lvert X_n\rvert\, d\mathbb{P}. $$  Now I do not know how to continue (in case that this is the right start).  Maybe you can help me.  With greetings  math12


What does "avoided poor Internet connection" mean?

The connection to my work wifi just failed and below the network my phone is saying "Avoided poor Internet connection". What does this mean exactly? Has the phone detected that it can't get out to the wider Internet or did the network fail to allocate an IP address or something else?  Not sure if it matters but this is on a Galaxy Nexus.


How do I solve "Incorrect permission on/usr/lib/policykit-1/polkit-agent-helper-1(need to setuid root)"?

I'm getting this error message:  "Incorrect permission on /usr/lib/policykit-1/polkit-agent-helper-1(need to setuid root)"   Due to this problem I can't download any app.


Has powered by ATI   CEFC and CT-ARP128B1-32M who makes it and amount of memory


Can a single sentence be used to distinguish between isomorphic classes of finite structures?

The answer seems to be yes, judging from the following exercise I found in the book Mathematical Logic by H.D. Ebbinghaus, J. Flum, and W. Thomas:     Let $S$ be a finite symbol set and let $\mathfrak{U}$ be a finite $S$-structure. Show that there is an $S$-sentence $\varphi _{\mathfrak{U}}$ the models of which are precisely the $S$-structures isomorphic to $\mathfrak{U}$.   I think I have an idea of how to solve this exercise, but I seem to be unable to materialize it. Thanks.


If my layover time at London is 14 hours, should I have a UK transit visa for the travel?

I am travelling from Mumbai to Houston via London and have a valid US visa. I have to wait in London for 14 hours for my connecting flight. Some of my friends were saying transit visa is not required if the layover time is less that 24 hours and others say you should have one if you stay more than 12 hours. Could you please help me with issue.


Is there any Mac OS X software I could use to learn keyboard shortcuts?

I saw a program on Windows that helped the user learn keyboard shortcuts in various applications by reminding there is a shortcut every time he used a mouse to particular task.   Is there some similar software available for Mac OS X?


How to force load desktop version of website (changing user-agent doesn't work)?

Some webpages forces mobile version even I change user-agent. I changed user-agent in built-in browser and "Dolphin Browser HD",  I am checking it on page www.user-agent-string.info  Main problem is engadget.com, always in mobile version. I tried to clean cookies, restart browsers etc.  This is my results:   in built-in browser, user-agent - "desktop"   () doesn't work, redirects to mobile version   in "Dolphin Browser HD", user-agent - "desktop"    (NSFW: redtube.com) doesn't work, redirects to mobile version  (allegro.pl) works fine  in "Dolphin Browser HD", user-agent - "IPad"   () doesn't work, redirects to mobile version  (allegro.pl) works fine (NSFW: redtube.com) works fine  in "Dolphin Browser HD", user-agent - "custom": Mozilla/5.0 (Windows NT 6.0; rv:7.0.1) Gecko/20100101 Firefox/7.0.1   (engadget.com]) doesn't work, redirects to mobile version  (NSFW: redtube.com) doesn't work, redirects to mobile version  (allegro.pl) works fine    Maybe this pages using "adobe flash" user-agent detection ?  (I'am using Asus Transformer TF101, Android 3.2.1, Adobe Flash Player 11)


Registering AppImage Files as a desktop app

How can I register an .appimage file (specifically, the tiled map editor found ) as a desktop app? (Like firefox -- I can launch it by typing 'Firefox' into search rather than opening up a console and typing /path/to/directory/firefox.ext)


$OMITS$ $2015$, $Indonesian$  If the complex numbers $a$, $b$, $c$, $d$ satisfy $a+b+c+d=3$ $a^2+b^2+c^2+d^2=5$ $a^3+b^3+c^3+d^3=3$ $a^4+b^4+c^4+d^4=9$ Find the value of $a^{2015}+b^{2015}+c^{2015}+d^{2015}$  I think i can find the value $a$, $b$, $c,$ and $d$ and subtitute it to the question, but i think too difficult and complicated this is the related question, but i need more coherent, clear, and complete solution  I Just Junior High School Student


I use this word in my daily language even without knowing what it actually means.     Technically speaking, there is no big difference between […] and […].   So what does this word imply, not in the literal sense but when we combine it with a sentence? Is there a specific context to which we are supposed to limit the usage of this word? Because I hear it almost everyday.   Can we substitute the above sentence with "literally speaking, there is no big difference between […] and […]"?  Is the word technically supposed to bring out the meaning as in "literally" does? Are they synonymous? Can we use them interchangeably? If not, then what does the word "technically" actually refer to w.r.t daily English usage?


Does friction always act opposite to the motion of the body?

For context, please consider the following problem from an older AP Physics C: Mechanics practice exam:  Since the ball is rolling without slipping, there is static friction between it and the ground such that torque is exterted on it, making it rotate. If I understood correctly, the frictional force f, in this scenario, opposes the movement of the object, and it is zero if it stops rolling and starts slipping, or ceases contact with the surface. Therefore, at point A on the loop f would point downward, and in point B, since it is still rolling, it would point to the right like so:   However, the CollegeBoard answer sheet shows otherwise. It indicates that at point A f points upwards and at point B it does not act on the ball at all:   Does friction still act on the ball at point B? Is the friction on a rotating body opposite to its movement? If so, did CollegeBoard perhaps get the answer sheet wrong?


What changes can I make to enable programs to run under Process.Start()?

Our ASP.NET MVC application is used to coordinate parallel execution of a 3rd executable that loads records into an ERP system. With some sets of data everything works perfectly. When the set of data gets bigger the 3rd party program gets hung up and never exits even when it is done sending the data.  I ran a test using a batch file with the same level of parallel processing and data and the program works as expected.  It appears that there is something about running in the context of IIS that is causing this. We launch the application from our code using Process.Start().  I have ruled out permissions as the cause already. I also tried checking a box in the IIS Admin Service to allow the service to interact with the desktop but that made no difference.  Are there any other changes to the IIS configuration that are likely to be affecting the way the application runs?  UPDATE I am changing this question because I have now learned that my problem had nothing to do with IIS. It was a deadlock condition caused by the way I was configuring Process.Start(). This problem and it's solution duplicate:  Tim's comment gave the clue needed to ask the right question.


I'm trying to prove that $\limsup \sin(n) = 1$. This fact sounds obvious to me, but I don't know how to use the given hint that any numbers of the form $n + 2m\pi$, $m,n \in \mathbb{Z}$, are dense in the real numbers. (I also can't figure out how to prove this, aside from taking $a < b$, defining the positive difference $b - a$, and using density of the irrationals.) Any hints or help would be appreciated.


I have always been told and understood that rainbows occur from water droplets and the light gets dispersed into its colors. I also understand that light travels in straight lines. This might sound like a stupid question but it most likely has a simple answer: Even though light travels in straight lines, why do rainbows appear to be bending?


Is there a quick way to get to the Control Panel in Windows 8?

Obviously in all previous versions of Windows you could simply click START and then select "Control Panel" to get to it, but on Windows 8 there is no such option.  Is there an easy way to quickly get to it without having to press WIN, type "Control Panel", and then press Enter?


What will happen first: the rod's front end will hit the back wall of the cave or the left end of the rod will enter the cave?

A rod flies into a cave at the speed of 0,8c relative to the cave. In the reference frame of a stationary observer, the cave is 30 meters deep. According to the observer, who "sits" on the rod, the rod is 30 meters long.  Thus,  in the frame of the stationary observer, the rod will be 18 meters long and in the frame of the moving observer, the cave will have the depth of 18 meters (since the cave moves towards the rod at the speed 0,8c).


Calculating gravity when taking into account the change of gravitational force

This is a problem that has bothered me for a couple of weeks now, and I can't seem to wrap my head around it and understand it.  Let's say we have a planet with a mass of m. We also have an object of relatively small mass (so small that its gravitational field would not affect the planet), and we know that at time 0 it is at position h.  If we know the acceleration due to gravity (g), we can calculate the position y  at time t:  $y = h - { g \; t^2 \over 2 } $  And we know that the acceleration due to gravity could be calculated:  $g = G { m \over y^2 }$  But since the acceleration depends on the position of the object relative to the planet, and the position of the object is dependent on the acceleration, this would obviously mean that the first formula won't work when we are working with displacement so large that it would change the acceleration significantly.  So, in essence, my question is, what formula can we use to calculate the position of an object, taking into consideration the change in acceleration due to gravity?


Magical enhancements that work by taking attributes from other people

I recall reading a book a long time ago which had an interesting concept of magic. Essentially, magic created superhumans by taking the attributes of one person and giving them to another. So, for example, the king had three or four people bound to him magically, each of whom had no physical strength whatsoever because they were giving it to the king. I specifically remember a moment where the newly-coronated king meets the people who had given their mental capacity to his father - the "King's Wits" they were called.  But I can't for the life of me remember what the book(s) were called. I only read the second or third one in a series, and it was ten or fifteen years ago. I recall the cover art included some big non-human creatures with oversized noses. I thought the magic system was interesting, and figured I might like to re-read the book(s). Anybody know what I'm talking about?


Cumming (2008) claims that distribution of p-values obtained in replications depends only on the original p-value. How can it be true?

I have been reading Geoff Cumming's 2008 paper  [~200 citations in Google Scholar] -- and  am confused by one of its central claims. This is one in the series of papers where Cumming argues against $p$-values and in favour of confidence intervals; my question, however, is not about this debate and only concerns one specific claim about $p$-values.   Let me quote from the abstract:     This article shows that, if an initial   experiment results in two-tailed $p= .05$, there is an $80\%$   chance the one-tailed $p$-value from a replication will fall in   the interval $(.00008, .44)$, a $10\%$ chance that $p < .00008$,   and fully a $10\%$ chance that $p > .44$. Remarkably, the   interval—termed a $p$ interval—is this wide however large   the sample size.   Cumming claims that this "$p$ interval", and in fact the whole distribution of $p$-values that one would obtain when replicating the original experiment (with the same fixed sample size), depend only on the original $p$-value $p_\mathrm{obt}$ and do not depend on the true effect size, power, sample size, or anything else:     [...] the probability distribution of $p$ can be derived without   knowing or assuming a value for $\delta$ (or power). [...] We do not assume any prior knowledge   about $\delta$, and we use only the information $M_\mathrm{diff}$ [observed between-group difference] gives about $\delta$ as   the basis for the calculation for a given $p_\mathrm{obt}$ of the distribution of   $p$ and of $p$ intervals.      $\quad\quad\quad$    I am confused by this because to me it seems that the distribution of $p$-values strongly depends on power, whereas the original $p_\mathrm{obt}$ on its own does not give any information about it. It might be that the true effect size is $\delta=0$ and then the distribution is uniform; or maybe the true effect size is huge and then we should expect mostly very small $p$-values. Of course one can start with assuming some prior over possible effect sizes and integrate over it, but Cumming seems to claim that this is not what he is doing.  Question: What exactly is going on here?    Note that this topic is related to this question:  with an excellent answer by @whuber. Cumming has a paper on this topic to:  -- but that one is clear and unproblematic.  I also note that Cumming's claim is repeated several times in the 2015 Nature Methods paper  that some of you might have come across (it already has ~100 citations in Google Scholar):     [...] there will be substantial variation in the $P$ value of repeated experiments. In reality, experiments are rarely repeated; we do not know how different the next $P$ might be. But it is likely that it could be very different. For example, regardless of the statistical power of an experiment, if a single replicate returns a $P$ value of $0.05$, there is an $80\%$ chance that a repeat experiment would return a $P$ value between $0$ and $0.44$ (and a $20\%$ change [sic] that $P$ would be even larger).   (Note, by the way, how, irrespective of whether Cumming's statement is correct or not, Nature Methods paper quotes it inaccurately: according to Cumming, it's only $10\%$ probability above $0.44$. And yes, the paper does say "20% change". Pfff.)


There is a tiny window that I am unable to identify or close. It is big enough for me to move but I can't seem to stretch it to make it bigger, I can't close it. It does not appear to be any of the items listed as Applications in the Task Manager.  Is there any sort of program that allows me to identify a process by clicking on the window of the application?  I really want to know what this is. If I log out it goes away but something I am doing is causing it to re-appear.  Any ideas how best to troubleshoot it?


Does $x^{x^{x^{x^{x^{\,\,\style{display: inline-block; transform: rotate(60deg)}{\vdots}}}}}} =y$ imply $2=4$?

Edit:  My question has been requested to close due to its apparent lack of clarity. My question is below under "Problem". If the information above it is redundant, please let me know in a comment. I will try my best to make my question as clear as possible.    I was looking at the equation $x^y=y$. If I want to isolate $x$, we would have $$x=y^{1/y}\stackrel{\small\rm{or}}{=}\sqrt[y]{y}.$$  Now let's consider $x^{x^y}=y$. I did not know how to do this, but I noticed something at first. If we let $x^y=y$, then this means $x^{x^y}=y\implies x^y=y$ by order of substitution. Notice that the same equation we substituted is in fact yielded; and, as mentioned previously, this equation would arrive at the fact that $x=y^{1/y}$. If we substitute this equation in, we obtain:  $$({y^{1/y}})^{(y^{1/y})^{y}}=y$$ which is clearly true.  But that means...  $$x^y=y\implies x^{x^y}=y\implies x^{x^{x^y}}=y\implies x^{x^{x^{x^y}}}=y\implies \cdots\tag1$$  It is now clear that we can look at this from a different perspective: if $x^y=y$ then similarly, $y=x^y$. We can substitute this on the LHS of the former equation, therefore resulting in that $x^{x^y}=y$. Clearly, this can be done ad infinitum, and this angle of looking at it is much easier to mentally grasp.  However.... if $x^y=y$ and $x^{x^y}=y$ then this means $x^y=x^{x^y}$ which doesn't make sense. Perhaps I am missing the part that $$x^y=x^{x^y}\color{red}{\iff x^y=y}$$ for otherwise we could let $x$ and $y$ be equal to anything, even each other, in the equation $x^y=x^{x^y}$ and quickly arrive at some problems.    Problem:  Now I have a problem when it comes to a certain substitution. If we can carry out the implications as shown in $(1)$ forever and ever, we will get the following equation:     $$x^{x^{x^{x^{x^{\,\,\style{display: inline-block; transform: rotate(60deg)}{\vdots}}}}}} =y.\tag2$$   Considering that $\sqrt[4]{4}=\sqrt{\sqrt{4}}=\sqrt{2}$ then one can quickly deduce from Eq. $(2)$ that $2=4$ which is clearly wrong. Let $y=2$ then $x=\sqrt{2}$. Let $y=4$ then $x=\sqrt [4]{4}=\sqrt{2}$. Thus $2=4$.  But since we just discussed the entire concept of this equation and there doesn't seem to be any flaws with it, why am I getting the absurd flaw now that $2=4$? Clearly I did something wrong with the substitution, but that's the easy part, so I believe I am overlooking something, something likely obvious $-$ but I don't understand!  May someone please correct me on this? Any help would be much appreciated (particularly hints).  Thank you in advance.


The cartesian graphing system is based on using three mutually perpendicular lines to plot a point in $3D$ space. But that is for real numbers and no graphs for complex numbers exist. For eg. If I Have a function $y=x^2-i,$where $i=\sqrt{-1}$ And i want to find its root graphically then how can i plot a graph which will help me? $\because$ real numbers require only one number to specify them while complex numbers need two it won't be very easy, Please help...


Get User's Date & Time in User' TimeZone

I need the current Date Time from where the user of my website filling a <form/>. The Date-Time should be user's Time Zone I need to get the DateTime without setting the TimeZone    When I use  date("Y-m-d H:i:s")   It only returns DateTime in IST. whether user is from India,USA or UK.  I need the current Date-Time from the User's TimeZone.  I need to insert the value to datetime field in MySql  I didn't ask for user timezone , rather I need the date and time from user's time zone


Automatically replace original uploaded image with large image size

As our users regularly upload ~6MB images to use on the website (and aren't too familiar with how to resize them first), WordPress stores the originals as well as resizing them to several different sizes.  I'd like a function or plugin that takes the uploaded image, resizes it down to something more manageable and then replaces the original.  I've seen some functions that delete the original but do not replace it, meaning it is impossible to regenerate the thumbnails at a later date. I need this to be replaced so the user can upload a large image and it is automatically resized down and stored for future resizing if needed.


Some background & context  When including third party logos, we often get given low quality files. Mostly these are low resolution JPGs, but I have seen badly hand drawn scans (expected to be used as is) or even photos of old stationary.  Recently we were given a folder with all the variations of a logo in a number of formats and sizes. Great! But. There are a lot of variation, some of which have only very slight differences, a lot of file types, a lot of sizes and no usage guidelines. So it's not always obvious which to use. I don't have the files to hand to count but there was probably at least 40 different files.  Another example: I worked on a project for a company who wanted a main logo with a variation for each department, then for each of these a horizontal version with the full company name, website and tagline, a square version with just the logo and website and just the logo.. Then for all of these a PDF, an EPS, a low res JPG, a high res JPG, a low res transparent PNG and a high res transparent PNG. All the variations were sufficiently different and they did (in their opinion) have justification for wanting all the different file types so this isn't as bad as the first example, but I did think this was too much.    My question - How many variations is too many? (or too few)  Note: By variations, I mean all the final files you deliver, so all actual design variation (e.g. horizontal / vertical / square variations, 4 color & monochrome variations, size variations etc) as well as all file types (e.g. EPS, JPG, PDF) and sizes (e.g. low and high res JPGs)  I always at a minimum supply vector and bitmap versions of the logo in full color and monochrome. Assuming no specific requests, is this enough? Should low-res versions be supplied, or is relying on the client to downsample the high-res version ok?  Size variations are also needed (sometimes?), for example, simplifying complicated shapes for showing the logo at smaller sizes. Should this always be done, or only when absolutely needed?  I understand this depends on a lot of factors and varies for each project, but should I try to keep the number of files to the minimum essentials or supply as much (as is appropriate and within reason as I can?    Edit: This question -  - is about initial ideas and concepts, I am asking specifically about finished work and the final delivered files.  This question -  - is very similar, but more general. I believe the reasoning behind the question is different.


I have Ubuntu 12.04 installed on my HP G62-453 TU Laptop. I cannot access the contents of my hard disk partition E.


I have an old schengen visa that expires on the 11th and a new one that starts on the 12th and is valid for three months. Is it possible to arrive on 9th?


I have started to learn how to write statements in Java. I have seen on Stack Overflow prepared statements that have values, but I was wondering how I could write something like my statement to become a prepared statement.  This is my code:  public void put(MySQLDatabase mysqlDB) {     if (mysqlDB != null) {       boolean bool = mysqlDB.setMySqLData("UPDATE Person SET personName = '" +         personName +         "', personDescr = '" + personDescr + "', personAge = " + personAge + "         WHERE personId = " + personId);     } }  public void post(MySQLDatabase mysqlDB) {   if (mysqlDB != null) {     boolean bool = mysqlDB.setMySqLData("INSERT INTO person VALUES(" + personId +       ", '" +       personName + "', '" + personDescr + "', " + personAge +       ")");   } }  public void delete(MySQLDatabase mysqlDB) {   if (mysqlDB != null) {     boolean bool = mysqlDB.setMySqLData("DELETE FROM person WHERE personId=" +       personId);   } }   I don't know if it is possible to do it like this and I would like to know if I would have any benefits doing a prepared statement for these queries.


Is it possible to list all instances of a class? I don't mean definitions, I mean allocated declarations of a class. Reflection is typically used to get a list of classes defined but that is not what I am asking for.  This is for educational purposes. I want to list all instances of a specific class (such as the string class) to learn about that class. Actually, I want to list all instances of the WPF Binding class since that will help me understand how bindings work in WPF. This however is not a WPF question.  Update: I don't think that  answers the question. It says that walking the heap or stack might be possible but there are no details of how to do that. I don't need detailed code but I am asking for more guidance than saying to walk the heap or stack.  I have found the following suggestions:        I am not familiar with any of those but I can learn if it will help here. I will however appreciate reasonable assurance that it is worth the time to pursue something.  Also, I know C++ and I am familiar with Detours (as in my ). If Detours can be used then a hint about what to detour would help.


I have looked at other similar questions on this site but couldn't answer my question. I have a model made of cubes the edges look very sharp (I would put a picture here but I don't have the required rep) is there a simple way to make the edges round?


In previous versions of Ubuntu I could get the computer to boot into console mode by setting the variable GRUB_CMDLINE_LINUX_DEFAULT to "text" in the file /etc/default/grub and run sudo update-grub. In Ubuntu 11.10, however, it has no effect - I am still presented with the LightDM login screen. Any clues?


I get this error message, during compiling my .tex-document.  line 234 - ! Package inputenc Error: Unicode char ́ (U+301)(inputenc) not set up for use with LaTeX.See the inputenc package documentation for explanation.Type H <return> for immediate help.... \cleardoublepage   I am writing my thesis right now and I am very confused about this error message, since it seems to be connected to a special character, which I do not use in my manuscript. The solution up to now was the reloading of an older version of my manuscript...after some hours of work and after several times of successful compiling this error suddenly occurs again. I don't get it why, since I just write some text, add some figures and nothing more...  any suggestions, how I can solve that issue? I have no idea, what kind of MWE I should post here :( where does this comment "line234" refer to. Line 234 is normal text in my manuscript...


SciFi novel about a vault on the Ocean floor

The main character (male) is called to a lab built on the ocean floor that is atop some sort of vault that is in need of the main character's expertise in figuring out the password to unlock it.  The calculations always come up with impossible numbers like 0/0.  Does this ring any bells?  I believe the main character appears in other novels by the same author.  Published within the last 10-15 years.


what does void main return to os when finished executing?

We know int main() returns 0 to OS when it terminates  without error  and non-zero in case of failure. But how will the OS identify normal(without error) or abnormal(error) termination in case of void main().


How do I get money back for my foreign coins?

Tonight I just cleaned my room and while doing this I found some money. I counted it and I found out that there are a lot of coins from 25 different countries.  I know that normally banks don't exchange foreign currencies in coins, but is there a way so that I can still get some money for my foreign coins?


If V=IR Why are voltage and current interchangeable through a constant resistance

I hear people say things like "I only put 5 amps through the circuit but I put a bunch of volts".  I don't understand how this is possible if V=IR.  Lets say you have a circuit with 5 ohms of resistance so V=I(5).  The amount of voltage and current I am allowed to put through it has to be proportional.  Can anyone can give a good intuitive answer (don't go too in depth with math) that is understandable?


how do you calculate CI in R and explain the method?

I am trying to perform prediction using R with confidence interval:  mod <- glm(y ~ x, data = foo, family = binomial) preddata <- with(foo, data.frame(x = seq(min(x), max(x), length = 100)) preds <- predict(mod, newdata = preddata, type = "link", se.fit = TRUE)  critval <- 1.96  upr <- preds$fit + (critval * preds$se.fit) lwr <- preds$fit - (critval * preds$se.fit) fit <- preds$fit   I am trying to understand why are we multiplying preds$sef.fit by 1.96? Can somebody explain to me the importance of 1.96, please?


Interesting application of mean value theorem

Suppose $f$ is continuous on $[a, b]$, differentiable on $(a, b)$ and satisfies$$ f^2(a)−f^2(b)= a^2−b^2$$Then show that the equation $f′(x)f(x) = x$ has at least one root in $(a, b)$.


I just created a USB bootable for ubuntu (but also tried other distributions) but it did not succeed as GRUB displays this error:  error: unknown filesystem Entering rescue mode... grub rescue> ls (hd0)(hd1)   I have a XPS 13 (9360) and I don't know how to fix this problem. I tried some solutions proposed over the web, but it did not work for me.  PS: I switch the SATA mode from RAID to AHCI but I don't think it's related


Closed form for infinite series $\sum_{n=1}^\infty \frac{1}{n(n+1)(n+2)\ldots(n+m)}$

Let $m$ be a positive integer. Is there a closed form for the infinite series $\displaystyle\sum_{n=1}^\infty \frac{1}{n(n+1)(n+2)\ldots(n+m)}$?  In the cases $m=1, 2$, one can use a partial fraction decomposition to make the sum telescope. However this seems to become much more difficult for larger $m$ (and I'm not sure whether it continues to telescope). I suspect there is a closed form, but I don't know how one would obtain it.


I tried to create some udev rules to mount and unmount my USB flash drives; the rules for the moment are very simple:  ACTION=="add",KERNEL=="sd[b-z]",RUN+="/root/scripts/plug_flash_drive.sh %k" ACTION=="remove",KERNEL=="sd[b-z]",RUN+="/root/scripts/unplug_flash_drive.sh %k"   plug_flash_drive.sh is also very simple:  device_name=$1 mount_options="umask=000,utf8" if [ ! -e "/media/$device_name" ]; then     mkdir "/media/$device_name" fi sleep 1 /usr/bin/mount "/dev/$device_name" "/media/$device_name" -o "$mount_options"   unplug_flash_drive.sh:  device_name=$1  umount "/dev/$device_name" rmdir "/media/$device_name"   I have done some tests so I can ascertain that:   When plugged in, my flash drive is detected; a file is created in /dev plug_flash_drive.sh is called by udev the mkdir part of the script works however, it seems that the "mount" part of the script is not executed, so my drive is not mounted when I call my scripts on the command line, they perfectly work   Does anybody know why mount is not executed when called by udev?  EDIT 28/08/14: I added "grep -q /proc/mounts && echo success || echo failure" at the end of my script to check in my debug log if the device is actually mounted before the script ends. It appears that the device is mounted at that point even when the script is called by udev. So the real problem is now "my block device is seemingly unmounted after the mount script end when called through udev" :s


Is it possible to test default / private class?

I know that method with the private access can be tested using 1. reflection or 2. powermockito but how do you test default class with private methods and the parent class is abstract?  class AirSpaceBuilder extends SynchronizedSpace {      private Request request;     private Status status;  public AirSpaceBuilder (Log log, SpaceTable st, Collection locks, SpaceRequest request) {         super(log, st, locks, request.getAirSpace());         this.request = request; }     private Status recursiveSignal() { ... }  abstract class SynchronizedSpace {      private Collection sync;     private String requester;     private SpaceTable st;     private Log log; ... }   My first thought was to call it from the higher level but then it becomes integrated test and defeated the purpose of unit testing.  Edit:  Correct me if I am wrong but is this how you invoke the method?  Object airSpaceBuilder=Class.forName("com.airport.resource.AirSpaceBuilder").newInstance(); Method m = airSpaceBuilder.getClass().getDeclaredMethod("recursiveSignal"); m.setAccessible(true); m.invoke(allocationFunction);


Ubuntu won't boot from my Sony vaio SSD laptop

I have tried booting ubuntu 14.04 with DVD, but screen just goes black and stuck on vaio icon, nothing happens.  Is there a problem with my SSD (is sony ultra book)? Wasn't sure if I had windows virus as windows behaving funny and lost internet connection. Could virus stop ubuntu from booting?  Thanks


Do I need a Transit visa if I'm Colombian and going to transfer in Toronto, Canada?

I'm Colombian and need to know, if I'm going to travel from Colombia to Switzerland and transfer in Toronto, do I need a Canadian visa?


How do I properly change the debian default python 2.7.9 to python3 or another version?

what is best-practice for changing the default global python interpreter on my fresh debian-based linux node to python3.x?  When I create a fresh Debian or Ubuntu VM, one of the first things I do is use apt to install python3-dev & python3-pip, and sometimes either echo "alias python=python3" >> ~/.bashrc so I don't need to do it again, or even sudo su && echo "alias python=python3" >> /etc/profile.d/00-aliases.sh && exit when I need to make a daemon user like /home/SQLserviceacct/ or /home/Neo4jworker/.   The result is often havoc for potential programs or humans who make shell calls to python and then use any other default python-related environment variables. When things like $PYTHONPATH get assigned out of context, problems arise. I think virtualenvis probably involved somehow.


I am using web to lead form to enter data on a form externally. Whenever the form i submitted, leads are created in salesforce.  Now, i want to have a check for duplicates based on some fields, say first name and last name.  When the form is submitted with duplicate first name and last name, i want to show error message on the form saying that the lead exists in system.  Can you please guide me on how we can achieve this? Can we show real time error messages on web to lead form?  Thank you.


How can I find the possible values that $\gcd(a+b,a^2+b^2)$ can take, if $\gcd(a,b)=1$

If $\gcd(a,b)=1$, how can I find the values that $\gcd(a+b,a^2+b^2)$ can possibly take? I can't find a way to use any of the elemental divisibility and gcd theorems to find them.


Quand je compile mon document tex, il m'affiche cet avertissement [When I compile my tex document, it shows me this warning]

Package hyperref Warning : Token allowed in a PDF string (PDFDocEncoding):  (hyperref) removing 'math shift' on input line 26.


I am running into this issue when running this query: SELECT Info__c, Account__c, Date__c, Month__c, SUM(TotalA__c), SUM(TotalB__c) FROM Total__c WHERE IsDeleted=False AND Date__c >= 2019-01-01 GROUP BY Info__c, Account__c, Date__c, Month__c But I receive this error: EXCEEDED_ID_LIMIT: Aggregate query does not support queryMore(), use LIMIT to restrict the results to a single batch I realize the fix is to use the LIMIT function, but I would like to query all the records and not limit it. Any help is much appreciated!


how to display post content without post image?

i've implemented a jQuery gallery for displaying several images within a post. the problem is that the_content(); also displays the post image. any ideas how to filter it? thanks


Is there any application like amazing slow downer for window or Mac?  Some of the features:    Change the speed of the music - from 20% (one fifth speed) to 200% (double speed) without changing the pitch. Wrong key? Change the pitch in semi-tones - at full or changed speed. Out of tune? Adjust the pitch in cents (100ths of a semi-tone) to suit your instrument. Real-time processing - all described above is done in real-time - just insert the CD and press the play button! Also slows down MP3, Wave, Windows Media Audio, Ogg, FLAC and AAC/M4A files on your computer in real-time. Note: M4P files from the iTunes store is now supported.


Is "bullet" from "bite the bullet" an exaggerated metaphor?

I've learnt about this idiom and its meaning , but i don't know about its common use since i think the word "bullet" is used as an exageration for a painful task or or an unpleasant situation. What is the appropiate way to use it?


How do install a Adobe flash player in Ubuntu 13.10 for Chromium

I have just downloaded install_flash_player_linux.11_x86_tar.gz from the Adobe website. How do I install this package or any other package not found in the Ubuntu Software Center. I have used sudo apt-get install ubuntu-restricted-extras. Rebooted and flash is not working.


In my code there is a 'Null Pointer Exception' but  I can't seem to understand why. I've added the objects into the ArrayList in the constructor. When I try run the method, I get a Null Pointer Exception. Any help would be greatly appreciated.  private ArrayList products;  //PRODUCTS CLASS CONSTRUCTOR  Products(){        ArrayList<ProductsClass> products = new ArrayList<ProductsClass>(); //Declaration and instantiation of ArrayList      products.add(new ProductsClass("Bread", 0.65));     products.add(new ProductsClass("Milk", 2.00));     products.add(new ProductsClass("Pasta", 3.35));     products.add(new ProductsClass("Milk chocolate bar", 0.75));     products.add(new ProductsClass("Dark Rum", 25.00));      ProductsClass p = products.get(3);     System.out.print(p.getItemName() + ""); //Testing to see if works#     System.out.print("");     System.out.print(" " + p.getItemPrice());  }  public void findMatchingItem() {      for (ProductsClass product : products) {      System.out.print(product);      } }


Using correct coordinate system in ArcMap?

Im doing fyp on sabah & saraawak map. it came without prj file. i manage projected it and its allign to each other. but now i think the map is too small. as in the whole continent is within few hundred meters.    What is wrong here?


"Provide you with something" vs "Provide you something"?

I have a sentence that reads: "To provide you the best possible service..."   I'm being asked to add the word with so that it reads "To provide you with the best possible service..."  Is there a rule for whether or not I add the word with or is it a preference and the sentence works either way?


If $\gcd(a,n) = 1$ and $\gcd(b,n) = 1$, then $\gcd(ab,n) = 1$. Also... $a,b$ and $n$ are natural numbers.  I feel I should begin with EEA to multiply out the gcd's, but I don't know where to go from there...


Windows 10 still downloading updates over metered connection

I have a desktop PC with Windows 10 Pro and connect to The Internet via a cable to my router. I have set my connection to "metered" and told Windows Update to NOT download over metered connections. That did nothing as some time ago some update(s) were forced on me postfactum. Meaning Windows had silently and sneakily downloaded them and just told me I need to restart to install them. Again with no option not to do so, I could postpone it, at best but when Windows' patience runs out it would force my computer to restart. So I changed some Group Policies. Policy                                                                                Setting         Winning GPO -------------------------------------------------------------------------------------------------------------------------------------------------- Allow updates to be downloaded automatically over metered connections                                           Disabled        Local Group Policy Always automatically restart at the scheduled time                                                              Disabled        Local Group Policy Configure Automatic Updates                                                                                Disabled        Local Group Policy Do not adjust default option to 'Install Updates and Shut Down' in Shut Down Windows dialog box                 Enabled         Local Group Policy Enabling Windows Update Power Management to automatically wake up the system to install scheduled updates       Disabled        Local Group Policy No auto-restart with logged on users for scheduled automatic updates installations                              Enabled         Local Group Policy Turn on recommended updates via Automatic Updates                                                               Disabled        Local Group Policy Turn on Software Notifications                                                                                Disabled        Local Group Policy  Now even that doesn't help. Again I have a notification a (useless) update was downloaded and I must restart my computer to install it. Is there a way to completely stop Windows 10 Pro from checking for updates?


Get proxy, username and password using python TK

I'm trying to get a user's proxy information using a simple TK GUI with the following code:  def getProxyCredentials(proxy, username, password):     root = Tk()      #define the entry boxes for username password and proxy     proxyBox = Entry(root)     proxyBox.insert(0, 'some.default.proxy:8080')     userBox = Entry(root)     pwdbox = Entry(root, show = '*')     Label(root, text = 'Proxy Server').pack(side = 'top')     proxyBox.pack(side = 'top')     Label(root, text = 'Username').pack(side = 'top')     userBox.pack(side = 'top')     Label(root, text = 'Password').pack(side = 'top')     pwdbox.pack(side = 'top')      def onokclick():         proxy = proxyBox.get()         username = userBox.get()         password = pwdbox.get()         root.destroy()         return None      Button(root, command=onokclick, text = 'OK').pack(side = 'top')     root.mainloop()     return True   When I call the function outside, all the string fields do not change.  proxy = '' username = '' password = ''  getProxyCredentials(proxy, username, password)   The passed in variables are still blank even though they are assigned within the function. Strings are passed by reference, so they should no longer be blank. What am I missing/not doing correctly?


Is there a way to advocate for the removal of a "duplicate question" declaration?

I made my way to this question:    and there is a box purporting that it is a duplicate if this question:    Question A is arguably a special case of Question B, but not really – because Question B is arguably just a special case of a different kind of question about the same underlying system.  Is (or should there be?) a way for to advocate for the removal of the "duplicate question" declaration?


Any tips or tricks for getting arrows (besides cheating)? Or tricks for finding a skeleton spawn?  I've tried farming chickens and gravel for feathers and flint, but it takes a ridiculously long time. How do people get enough arrows to make using a bow actually feasible?


I have a 6yr granddaughter that has encopresis. It's very hard to watch her mom ( a single, working mom) deal with this every day. The little one tries but it is a constant struggle. With doctor visits and different medications it still goes on. It is good to know that there is a diagnosis but with everyday life it is an on going battle. After reading many of the comments on line ,I do feel we are "Blessed" to have a little one that really tries. The problem that I see is the different schedule of each day. My daughters job (different hours) and a busy life in general are very frustrating. I am very Greatfull that "this" is the only health problem that this little one has... however I wish there was a magic pill.I would appreciate any support or suggestions.


I am trying to un-tar into a different directory using this  tar xvf BACKUP.tar -C test   But I am getting the following errors  File -C not present in the archive. File test not present in the archive.   Using   tar xv -C test -f BACKUP.tar   I get the following error  tar: /dev/rmt0: A file or directory in the path name does not exist.   I do have a test directory and the file BACKUP.tar in the pwd that I am running the tar command in  Still the same error  tar -xvf BACKUP.tar -C test File -C not present in the archive. File test not present in the archive.   And   tar --version   gives this error  tar: Not a recognized flag: - Usage: tar -{c|r|t|u|x} [ -BdDEFhilmopRUsvwZ ] [ -Number ] [ -f TarFil e ]            [ -b Blocks ] [ -S [ Feet ] | [ Feet@Density ] | [ Blocksb ] ]            [ -L InputList ] [-X ExcludeFile] [ -N Blocks ] [ -C Directory ] File ... Usage: tar {c|r|t|u|x} [ bBdDEfFhilLXmNopRsSUvwZ[0-9] ] ]            [ Blocks ] [ TarFile ] [ InputList ] [ ExcludeFile ]            [ [ Feet ] | [ Feet@Density ] | [ Blocksb ] ] [-C Directory ] File ...


How to add keys and values from two dictionaries to third without mixing between them?

I have two dictionaries and I want to add their content to third dictionary naturally without mixing their between them.  a = {'life':'1','arts':'2'} b = {'technology':'3', 'culture':'4'} c = {} # here must be keys and values of the `a` and `b` dicts


Adding derived objects into an array of (abstract) base pointers

I ran into a problem when adding derived objects into an array of (abstract) base pointers. To simplify what I'm trying to do, here is an example:   Base** baseArray = new Base*[3]; baseArray[0] = new derived1(param,param); baseArray[1] = new derived2(param,param); baseArray[2] = new derived3(param,param);   Now, I have yet to get my virtual Print() working to print out the baseArray elements but using the vs2012 debugger I can only see baseArray[0] in baseArray. The other two are just gone.  But I guess my main question is that, should the example above work. If yes, would it be too much to ask of what could have happened. If not, is there a (better) way?  Edit: Thank you all!


I'm trying to compile a document with the LuaLaTeX engine, since LuaLaTeX is the only one that allows to use all fonts in my computer. But when I'm going to compile the document, I get this error message  This is LuaTeX, Version 1.0.0 (MiKTeX 2.9.6100)  restricted system commands enabled. (./formulario.tex LaTeX2e <2016/03/31> patch level 3 Babel <3.9r> and hyphenation patterns for 1 language(s) loaded. ("C:/Program Files/MiKTeX 2.9/tex/latex/base/article.cls" Document Class: article 2014/09/29 v1.4h Standard LaTeX document class ("C:/Program Files/MiKTeX 2.9/tex/latex/base/size10.clo")) ("C:/Users/Marco/AppData/Local/Programs/MiKTeX 2.9/tex/latex/microtype/microtyp e.sty" ("C:/Program Files/MiKTeX 2.9/tex/latex/graphics/keyval.sty") ("C:/Users/Marco/AppData/Local/Programs/MiKTeX 2.9/tex/latex/microtype/microtyp e-luatex.def" ("C:/Program Files/MiKTeX 2.9/tex/luatex/luatexbase/luatexbase.st y" ("C:/Users/Marco/AppData/Local/Programs/MiKTeX 2.9/tex/luatex/ctablestack/ctabl estack.sty")) ("C:/Program Files/MiKTeX 2.9/tex/luatex/luaotfload/luaotfload.st y"         FATAL ERROR         Luaotfload requires a Luatex version >= 0.95.0.         Please update your TeX distribution!  ...les/MiKTeX 2.9/tex/luatex/luaotfload/luaotfload-main.lua:36: version check f ailed stack traceback:         [C]: in function 'error'         ...les/MiKTeX 2.9/tex/luatex/luaotfload/luaotfload-main.lua:36: in main chunk         [C]: in function 'require'         [\directlua]:1: in main chunk. l.49 }  ?   Sounds like I should update the LuaTeX version: if so, how can I update this?  MiKTeX 2.9.6161 TeXWorks 0.61


All possible pairs of elements in a list

I have a list. For example: [1, 2, 3, 4] The result I would like to have is: [1, 2], [1, 3], [1, 4], [2, 3], [2, 4], [3, 4]. So I would calculate all the possible couple (the order isn't important) with no equal elements. I did this: result = []     for first_elem in my_list:         for second_elem in my_list:             if first_elem!=second_elem:                 c = [first_elem,second_elem]                 result.append(c)     return result  Is there a method to do this more efficient(here we have about n^2) without using libraries? Thanks  didn't answer my question.


Using two with statements with arcpy.da.SearchCursor()?

I often see code that is comparing 2 shapefiles where there needs to be 2 with statements in the same loop. In my head I always thought both with statements should be placed first before starting looping the rows in each cursor like:  with arcpy.da.SearchCursor(fc2, field4) as sCursor1:     with arcpy.da.SearchCursor(fc1, field5) as sCursor2:         for row1 in sCursor1:             for row2 in sCursor2:                 #do stuff   However I have seen code that looks like this:  with arcpy.da.SearchCursor(fc2, field4) as sCursor1:     for row1 in sCursor1:         with arcpy.da.SearchCursor(fc2, field5) as sCursor2:                         for row2 in sCursor2:                 #do stuff   Purely just looking at this I would assume that the second version reopens the cursor for every row in sCursor1, and therefore the first method would be better. I have read  and this suggests that :     The above with statement will automatically close the file after the nested block of code.   Therefore it looks like I might be correct, however is there a preferred method of the 2 or another way that would be better, such as creating the cursors first and the using the del statements at the end?  Some timings on small, med, large data would be good if possible.


Is $\exists x(x=a)$ a valid formula in first order logic with equality?

Under , is $\exists x(x=a)$ true in every interpretation in first order logic (FOL) with equality? If so, could $\exists x(x=a)$ be considered a tautology? This question was motivated by  which was closed for lacking clarity. Here I have attempted to add that clarity myself so that the same question can be useful to others who are wondering a similar thing. This is a self answer question.


Gold tag dupe-hammer posts a comment then removes it immediately

When a normal user votes to close as a duplicate, a comment is posted.  When the question is closed, the comment is removed.  The same happens with someone with a gold tag - a comment was posted then immediately deleted.  Is there any way that there could be a check - it's quite odd to see a comment message, then the comment goes, and the post is closed after a refresh.


When I send messages from my iPhone (A) to another iPhone (B), the responses from B keep coming to my Mac and do not appear on my phone (A), even when I have iMessages closed. This is maddening. How can I prevent this from happening?


How to calculate the velocity for such a situation

I am not sure whether this is the correct sub stackexchange to ask my question but I ll have a try.  I ve tried to solve this problem in so many ways but still didn't manage to do it...    What would be the correct way to solve it please?  This arm of this mechanism has a length of 0,2m. The piston has an angular velocity of 2000 tours/min. What would be the velocity of point D for an angle theta of 60 degrees?  I think that what I am missing is the angle formed by the arm and the line, which is 50mm long. Example like here (different  exercise):    I am trying to look for this angle beta which could help me solve the problem  expected answer:2,88m/s  EDIT: This is what I have so far: imgur.com/ADEp1bE


Why nothing appears in my storage space whenever dwellers collect something?

When i send to explore any Dwellers i can see the log working perfectly and also ai can see any item they collect, but when i recall them to the vault and hit the "collect" button those items just dissapear, they wont show up in my storage space, eqquiped or anything else, those items just dissapear and i´ve lose many outfits and weapons because i just noticed that; Someone have the same problem or know whats going on?


I've tried to install Anbox using , with a minimal distribution 18.04, without a desktop.   I had hoped that the required packages that are needed to create a window will be installed all along. I don't know how far off I am with that. When I try to open the anbox.appmgr the the following error comes up:  realpath: '': No such file or directory  realpath: '': No such file or directory  realpath: '': No such file or directory  realpath: '': No such file or directory  realpath: '': No such file or directory  realpath: '': No such file or directory  realpath: '': No such file or directory  realpath: '': No such file or directory  [2020-05-03 13:33:50] [daemon.cpp:61@Run] Failed to connect to DBus   Has anyone an idea what to do?  Thanks a lot


How to increase swap size when there is already a partition existing

~$ sudo swapon --show gives me this  NAME      TYPE      SIZE USED PRIO /dev/sda5 partition 976M   0B   -2   I want to increase my swap size. Is there a way to increase this or do I have to create a new partition or a file? I have gparted installed and I see that there are only 2 partitions as lsblk shows below -  NAME   MAJ:MIN RM   SIZE RO TYPE MOUNTPOINT sr0     11:0    1  1024M  0 rom   sda      8:0    0 238.5G  0 disk  ├─sda5   8:5    0   976M  0 part [SWAP] └─sda1   8:1    0 237.5G  0 part /   How do I go about increasing the size?


I was watching a Silverlight tutorial video, and I came across an unfamiliar expression in the example code.  what is => ? what is its name? could you please provide me a link? I couldn't search for it because they are special characters.  code:          var ctx = new EventManagerDomainContext();         ctx.Events.Add(newEvent);         ctx.SubmitChanges((op) =>         {             if (!op.HasError)             {                 NavigateToEditEvent(newEvent.EventID);             }         }, null);


Are back-ticks sufficient to escape user input for table columns?

For example:  $qry=  "SELECT * FROM `table` ORDER BY `$_GET[orderBy]` ASC ;" ;   Would that leave it open to any vulnerabilities?


I have installed numpy and pandas using pip. After executing my python code it shows the following error:  Traceback (most recent call last):   File "demo.py", line 1, in <module>     import numpy as np   File "/home/tauhid/.local/lib/python3.6/site-packages/numpy/__init__.py", line 142, in <module>     from . import core   File "/home/tauhid/.local/lib/python3.6/site-packages/numpy/core/__init__.py", line 59, in <module>     from . import numeric   File "/home/tauhid/.local/lib/python3.6/site-packages/numpy/core/numeric.py", line 3093, in <module>     from . import fromnumeric   File "/home/tauhid/.local/lib/python3.6/site-packages/numpy/core/fromnumeric.py", line 17, in <module>     from . import _methods   File "/home/tauhid/.local/lib/python3.6/site-packages/numpy/core/_methods.py", line 158, in <module>     _NDARRAY_ARRAY_FUNCTION = mu.ndarray.__array_function__ AttributeError: type object 'numpy.ndarray' has no attribute '__array_function__'   I have tried uninstalling and reinstalling the packages, but same error reoccurs.


I am visiting my sister in Switzerland, my visa type C, my duration of stay 32 days  for 30/Aug to 1/Oct. I want to extend my stay 10 days more, is it possible? And if I can, where should I go to? (it's still 7 days in my visa visit it end at 1/Oct i want to stay to 11/Oct ). What can I do? And what documents I need? Could anyone please suggest if I would need a formal approval process from local canton office?


Why is this array being passed by reference and not by value, and how can I change this?

I was working on a bug in some code that I wrote, and the culprit turned out to be this snippet (simplified for the sake of the question):  var a = [1, 2, 3, 5, 4]; // later... function f(arr) {     var sorted = arr.sort();     // other stuff } // later... console.log(a); // logs [1, 2, 3, 4, 5]!   My question is, why does a stay sorted after the function is done? Surely in JS all variables are passed by value as opposed to reference?


operator * cannot be applied to decimal and double c#

I am currently making a tax program (study project) that read in a CSV file and generates a list of people and account balances, i need to round down 2 decimal places from one text box and add them up in another text box. my code attached tell me i cannot use " * " how do i times a decimal with 0.1? and if i am doing this wrong let me know, cheers!  public partial class Form1 : Form {     //CSV ARRAY LISTS     List<string> fullName = new List<string>();     List<string> accBalance = new List<string>();      int currentItem;     int index;     int counter = 0;      decimal interestBalance = 0;     decimal result;      decimal interestRemainder = 0;     double round = 0.1;    private void interestBalanceBox_TextChanged(object sender, EventArgs e)     {         interestRemainder = decimal.Parse(interestBalanceBox.Text);         interestRemainder = Math.Truncate(0.1 * interestRemainder) / 100;         interestRemainderBox.Text = interestRemainder.ToString();      }   the program we are meant to represent is this one here! any help would be much appreciated.