I have a shapefile containing civic numbers. For each number there are string values of street name and civic number. During the editing it happens that I make typing mistakes and at the end of the work I find some duplicate points, i.e. two or more civic numbers on the same street.  How can I easily find these duplicates in order to export them to another shape using QGIS?

I have a lot of coordinates in attribute table like this one:    I'm looking the way how to find and select on active layer duplicated points using Python in QGIS ? I needn't delete them but only find and show (or select).


The joint distribution of $(X,Y)$ is given:  $f_{(X,Y)}(x,y)=e^{-(\theta x +\frac{y}{\theta})}$, $0<x,y<\infty$  Find the distribution of $U=XY$ and $V=\frac{X}{Y}$. Also find the conditional pdf of $V$ given $U=u$.  I have transformed $(X,Y)\rightarrow (U,V)$, and found the joint distribution of $(U,V)$ as the following:  $f_{(U,V)}(u,v)=\frac{1}{2v}e^{-(\theta \sqrt {uv}+\frac{1}{\theta}\sqrt {\frac{u}{v}})}$, $0<u,v<\infty$  But I cannot find the marginal pdf of $U$ and $V$ and the conditional pdf of $V$ given $U=u$.  Please anyone help me solve it. Thanks in advance.

Suppose that $(U,V)$ has the following joint pdf: $$f_{U,V}(u,v)=\exp(-\theta u-\theta^{-1}v)$$ , where $u\geq0$, $v\geq0$, $\theta>0$. Define $X=UV$ and $Y=U/V$. Find the marginal pdf of $X$ and $Y$.  With transformation, I got $U=\sqrt{XY}$ and $V=\sqrt{X/Y}$ and the absolute value of Jacob is $1/2Y$. Then, the joint pdf of $(X,Y)$ is  $$f_{X,Y}(x,y)=\exp(-\theta \sqrt{XY}-\theta^{-1}\sqrt{X/Y})1/2Y, X,Y>0.$$  But I am not sure how to get the marginal pdf?  Thank you!


$v=\omega * r$, so with $\omega = 1 rad/s$ and $r=3*10^8 m$ the v would be c. I know that the information of the rotation travels with the speed of sound in the rod.

Imagine a bar   spinning like a helicopter propeller,  At $\omega$ rad/s because the extremes of the bar goes at speed  $$V = \omega * r$$  then we can reach near $c$ (speed of light) applying some finite amount of energy just doing   $$\omega = V / r$$  The bar should be long, low density, strong to minimize the amount of energy needed  For example a $2000\,\mathrm{m}$ bar  $$\omega = 300 000 \frac{\mathrm{rad}}{\mathrm{s}} = 2864789\,\mathrm{rpm}$$  (a dental drill can commonly rotate at $400000\,\mathrm{rpm}$)  $V$ (with dental drill) = 14% of speed of light.  Then I say this experiment can be really made and bar extremes could approach $c$.  What do you say?   EDIT:  Our planet is orbiting at sun and it's orbiting milky way, and who knows what else, then any Earth point have a speed of 500 km/s or more agains CMB.  I wonder if we are orbiting something at that speed then there would be detectable relativist effect in different direction of measurements, simply extending a long bar or any directional mass in different galactic directions we should measure mass change due to relativity, simply because $V = \omega * r$  What do you think?


If Rey's staff (and others like it, such as the scavenger that tries to kidnap BB8) is just an ordinary staff, then why is it all techy looking?  What exactly is this staff, just techy looking sections or something more?

Looking at Rey's staff, it sure looks like it is made of lightsabers as parts.   Are they actually lightsabers? Did she get them (or the whole weapon) from scavenging?


In the sentence below, is it better to use per or by?  When you create a new software component, the database is used per/by default.  I've taken a look at the "By" vs "Per" question suggested below. This is close but not exactly what I was looking for. In software engineering, we tend to "enable software components per or by default". The example you state has a different context, if I understand correctly.

In the finance field, it is quite common to express some measures in relation to some grouping criteria. Some groupings can be temporal (year, month, etc.) and others like greography, asset class (e.g. a financial product), strategy (used in trading), and others.   Which one is the most appropriate preposition to apply in this kind of expression ?    "VaR per asset" or "VaR by asset" "P&L per strategy" or "P&L by strategy".   Is there any well defined rule behind the most appropriate use ?


I want to extract every single MODIS 16 Day NDVI and EVI Data image on a particular area from 2000 to 2016. I was able to filter image collection but I do not know how to export every single image on the collection.  Here is my code:    // Area of interest  var AOI = ee.Geometry.Rectangle([93.8, -8.8, 109.9, 6.84]);  // Go to the center of the map  Map.centerObject(AOI, 4 )  // Find MOD13Q1.005 Vegetation Indices 16 Day Global 250 m  var modis = ee.ImageCollection('MODIS/MOD13Q1')  // Filter the collection  var image = ee.ImageCollection((modis).filterDate(ee.Date('2000-01-01'),ee.Date('2017-12-31')).filterBounds(AOI));  // NDVI dan EVI  var NDVI = image.select(['NDVI'])  var EVI = image.select(['EVI'])   //Print the image list on console  print(NDVI) print(EVI)  //Load it into map  Map.addLayer(NDVI);   I know that my code is too long and not efficient, but it helps me to read and understand it.  Can you help me to write code to export every single NDVI and EVI image on my image collection?

I am trying to export each image in a filtered stack of Sentinel-1 images and cannot seem to get it right.   suggests using imageCollection.map() and a custom function (such as a geometric clip).  // Create a geometry representing an export region. var roi = ee.Geometry.Rectangle([-63.0, 9.2, -63.1, 9.3]);   // Load the Sentinel-1 ImageCollection. var sentinel1 = ee.ImageCollection('COPERNICUS/S1_GRD');   // Filter by metadata properties. var IW_H = sentinel1   // Filter to get images with VV and VH dual polarization.   .filter(ee.Filter.listContains('transmitterReceiverPolarisation', 'VV'))   .filter(ee.Filter.listContains('transmitterReceiverPolarisation', 'VH'))   // Filter to get images collected in interferometric wide swath mode.   .filter(ee.Filter.eq('instrumentMode', 'IW'))   // Filter IWs to get High res.   .filter(ee.Filter.eq('resolution', 'H'))   // Filter IW-Highs to get 10m res   .filter(ee.Filter.eq('resolution_meters', 10));   // Filter to get images from different look angles  var DescCollection = IW_H.filter(ee.Filter.eq('orbitProperties_pass', 'DESCENDING'));   var ClipFunc = function(iImage, geom) {   var iClip = clip(iImage, geom);   return(iClip); };   imageCollection.map(ClipFunc(DescCollection, roi));


Can we recover the data which has been truncated by >hello.log.

I accidentally deleted a file from my laptop. I'm using Fedora. Is it possible to recover the file?


Currently I am finishing a master's degree in linguistics. I was accepted for a Ph.D at my university, but I decided not to do it in the end. I love my research and my field, but I don't see myself as a professor and I'm not sure a purely academic career is for me. Furthermore, my husband and I would suffer from the 'two body problem' if I got my Ph.D since he already graduated from his Ph.D program, and that is a situation I want to avoid. I am considering doing a clinical master's in SLP to apply my background in linguistics and biology in a clinical rather than purely academic setting. For the time being I will be taking a year off, but I am wondering about the idea of 'independent researchers'. If I continued with my research (which I can do from my computer using open access corpora and other corpora I have access to) could I publish/present my findings? If I became an SLP could I continue to publish even though I wouldn't have a Ph.D? Thank you in advance.

Assume you have already completed your undergrad and have been working for a number of years. Does one need to be part of a university or a learning institution to publish papers?


I've started with the base case first by letting $n=3$, which yields $$LHS = 1^{3}+2^{3}+3^{3} = 36 = \frac{3^{2}\left ( 3+1 \right )^{2}}{4} = RHS.$$  Assume $n=k$ holds: $1^{3}+2^{3}+...+k^{3}=\frac{k^{2}\left ( k+1 \right )^{2}}{4}$ by Induction Hypothesis.   We want to show that $1^{3}+2^{3}+...+\left ( k+1 \right )^{3}=\frac{\left ( k+1 \right )^{2}\left ( k+2 \right )^{2}}{4}.$  I have started from $$1^{3}+2^{3}+...+\left ( k+1 \right )^{3}$$ $$\Rightarrow 1^{3}+2^{3}+...+ k^{3} + 3k^{2} + 3k + 1$$ $$\Rightarrow 1^{3}+2^{3}+...+  + \frac{k^{2}\left ( k+1 \right )^{2}}{4}+3k^{2} + 3k + 1 \text{ (By Induction Hypothesis)}.$$   I am pretty much stuck here so any help would be appreciated.

How can I prove that     $$1^3+ 2^3 + \cdots + n^3 = \left(\frac{n(n+1)}{2}\right)^2$$    for all $n \in \mathbb{N}$? I am looking for a proof using mathematical induction.  Thanks


When I enter  find . -iname "[0-9]*.nii"   on my OSX machine it returns:  ./03_Rest_fcMRI/9793_01_03_1.nii ./04_VEMP/9793_01_04_1.nii ./04_VEMP/9793_01_04_2.nii ./05_Tapping/9793_01_05_1.nii ./05_Tapping/9793_01_05_2.nii ./06_Adaptation/9793_01_06_1.nii ./06_Adaptation/9793_01_06_2.nii ./06_Adaptation/9793_01_06_3.nii ./06_Adaptation/9793_01_06_4.nii ./07_SWM/9793_01_07_1.nii ./07_SWM/9793_01_07_2.nii ./07_SWM/9793_01_07_3.nii ./08_Foot_Tapping/9793_01_08_1.nii   When I enter the same line of code on RHEL, I get:  ./06_Adaptation/9793_01_06_3.nii ./06_Adaptation/9793_01_06_4.nii ./06_Adaptation/9793_01_06_2.nii ./06_Adaptation/9793_01_06_1.nii ./03_Rest_fcMRI/9793_01_03_1.nii ./08_Foot_Tapping/9793_01_08_1.nii ./04_VEMP/9793_01_04_2.nii ./04_VEMP/9793_01_04_1.nii ./07_SWM/9793_01_07_3.nii ./07_SWM/9793_01_07_2.nii ./07_SWM/9793_01_07_1.nii ./05_Tapping/9793_01_05_2.nii ./05_Tapping/9793_01_05_1.nii   The file order on OSX seems logical to me. The one on RHEL does not. I know I can get the same order on RHEL by piping to sort, but this is not my issue.  I am trying to understand why find on RHEL outputs this non-alphanumeric order.

What order does the find command use to print out a list of files? Is this order different across different Linux distributions or versions?


I have my own library with some basic functions inside which I compile using ar rcs *a few .o files* Now I'm in a project where I have to use this library the code is basic : #include "libft.h"  int main() {     ft_putstr_fd("test", 1);     return (0); }  I create the binary file using this command clang -fsanitize=address -ILIBFT/includes/ -c test.c -o test.o And when trying to make the final executable file I get this and I don't understand why... Does it have something to do with the fact that I'm using Ubuntu 20.04 ? Here's the command when I create the executable file clang -fsanitize=address -ILIBFT/includes/ -L LIBFT -lft -o test test.o  And here's the output : /usr/bin/ld: test.o: in function `main': test.c:(.text+0x1f): undefined reference to `ft_putstr_fd' clang: error: linker command failed with exit code 1 (use -v to see invocation)  The function does is defined in libft.h as it works on my school's iMac. Thanks for your help.

Why does the order in which libraries are linked sometimes cause errors in GCC?


What is the name of the book/story where a boy goes to a planet and is offered the choice of  many weapons but chooses a knife.  I read it when I was in secondary school in the seventies.

I would love to identify a sci-fi novel I read in the late 60s or 70s.  It followed a group of young space cadets through their training in the Space Academy.  The training culminated in small groups of cadets being sent through a gateway in the space station, into different worlds where they had to survive whatever conditions they met beyond the gateway, as part of their training.  One such trip went wrong and the group ended up stranded in a hostile world for days, hoping to be rescued by their trainers.  I can't remember much about the story or protagonists so this may be too vague, but I remember descriptions of a vast space station hall and these young cadets bringing whatever kit they hoped they might need - some brought breathing apparatus and full survival gear, but others came with very little as they believed they would not be sent into conditions where they could die without the right equipment.  They hadn't bargained for the power surge or whatever it was that misdirected them as they passed through the gateway!  I also remember rivalry between the cadets - I think the hero was male and quietly heading for top cadet of the year award... and I think at least one of the group died in the unknown planet before they were rescued.  Does this ring a bell with anyone?  I remember the mood and tension more than the details but it was a long time ago!  I have a 10-year old son who I think would love this kind of story.  If anyone can help you have my thanks!


What is the difference between logical and physical cores in a multicore processor? And is execution core another name for a physical core?

I wonder what's the difference between a dual core computer and a computer with 2 processors on the mother board.. I think it's something related with the threads but a I don't understand it very well..


Why is this substitution acceptable?  $\sqrt{i}=\frac{1+i}{\sqrt{2}}$

If $i=\sqrt{-1}$, is $\large\sqrt{i}$ imaginary?     Is it used or considered often in mathematics? How is it notated?


I'm having a hard time proving that $R^2$ is equal to the square of the sample correlation between $Y$ and $\hat{Y}$. Every book I search tells me that's very easy, like verbeek. They just state that from the definition of $R^2$ and knowing that $SST=SSR+SSE$, it's very easy to prove the claim. However, I've spent a lot of time thinking about it, with no sucess.  Any help would be appreciated.  EDIT (My try): $R^2=\frac{SSE}{SST}=1-\frac{SSR}{SST}$  Sample correlation$^2=\frac{\left(\sum(\hat{y_i}-\bar{y})(y_i-\bar{y})\right)^2}{ SST\cdot SSE }$  From then on, I have no idea...

As the title to my question says, I am confused as to when the $R^2$ of a model fit does not equal the slope of the regression between observed and predicted values.   I am trying to present model prediction statistics in a similar way to those presented in the summary figures of the Globcolor validation report () - (e.g. figure from page 53 of the .pdf):    Here we see that they present the plot of observed versus predicted Chlorophyll concentrations, as well as statistics relating to its regression (e.g. the dashed line: $R^2$, $RMS$, $\alpha$ - intercept, and $\beta$ - slope).   My issue is that in my comparisons, I always get exactly the same value for the overall model fit $R^2$ and $\beta$-slope of the observed versus predicted regression.  Basic question: When (if ever) can these be different?  I have included a basic example of my problem in the following R script:  set.seed(1) n <- 100 x <- runif(n) e <- rnorm(n) a <- 3 b <- 5 y <- a + x*b + e  #fit model fit <- lm( y ~ x )  #plot regression plot(x,y) abline(fit)  #plot predicted versus observed png("plot.png", units="in", width=5, height=5, res=400) par(mar=c(5,5,1,1)) pred <- predict(fit) plot(y, pred, xlim=range(c(y,pred)), ylim=range(c(y,pred)), xlab="observed", ylab="predicted") abline(0,1, lwd=2, col=8)  #add regression fit2 <- lm(pred ~ y) lgd <- c(     paste("R^2 =", round(summary(fit2)$r.squared,3)),     paste("Offset =", round(coef(fit2)[1],3)),     paste("Slope =", round(coef(fit2)[2],3)) ) legend("topleft", legend=lgd) abline(fit2, lwd=2) legend("bottomright", legend=c("predicted ~ observed", "1:1"), col=c(1,8), lty=1, lwd=2)  dev.off()  cor(pred, y)^2 # also the same


I am trying to understand this paper better , but I start having difficulty at around Equation (6) and (7).    What does a gradient w.s.t. to an equation mean ($\partial F(x)$), could anyone provide a concrete example showing how it could be calculated?

For a function $$ y =f(x), x=\left(x_1, x_2, ..., x_N\right)$$ the law of propagation of uncertainty, see $^{[1]}$ (pdf), is generally given as $$ u_y^2 = \sum_{i=1}^N \left(\frac{\partial f}{\partial x_i}\right)^2 u_{x_i}^2 $$ where $u_{x_i}$ is the uncertainty associated with each $x_i$.  How do we derive this propagation law? I understand that it can be achieved by Taylor expanding the function, but I don't see why this is a sensible thing to do, or what is the physical meaning of it.  (I've asked basically the same question at Signal Processing  but haven't got any useful answers. Hopefully you guys are more suited to this question).  [1] Evaluation of measurement data – Guide to the expression of uncertainty in measurement  (html) [Sec 5 ]


My goal is to use reboot as myusername without entering a password. How can I achieve this?  I have read  and followed the suggestions but it still doesn't work for me. Here is my /etc/sudoers but it still asks for a password:  # # This file MUST be edited with the 'visudo' command as root. # # Please consider adding local content in /etc/sudoers.d/ instead of # directly modifying this file. # # See the man page for details on how to write a sudoers file. # Defaults        env_reset Defaults        mail_badpass Defaults        secure_path="/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin"  # Host alias specification  # User alias specification  # Cmnd alias specification  # User privilege specification root    ALL=(ALL:ALL) ALL myusername  ALL=NOPASSWD:/sbin/reboot  # Allow members of group sudo to execute any command %sudo   ALL=(ALL:ALL) ALL  # See sudoers(5) for more information on "#include" directives:  #includedir /etc/sudoers.d   I then run  sudo reboot   and am asked for a password. How can I run reboot as a normal user without being asked for a password?  Here is sudo -l output :  Matching Defaults entries for myusername on this host:     env_reset, mail_badpass,     secure_path=/usr/local/sbin\:/usr/local/bin\:/usr/sbin\:/usr/bin\:/sbin\:/bin  User myusername may run the following commands on this host:     (root) NOPASSWD: /sbin/reboot     (ALL : ALL) ALL   I also tried with   myusername  ALL=NOPASSWD:/bin/ls   but sudo ls still asked for a password so this seems to be a general problem, not specific to reboot.

On a sandbox VM environment, I have a setup of Ubuntu Linux which is firewalled and cannot be accessed from outside the local system.  Therefore, on that VM, I'd like to give the administrative user (which I set up) the ability to run anything with sudo and not need a password.  While I know this is not secure, this VM is not on all the time, and requires my personal passcode to run.  So even though this is not "secure", is there a way to get the desired functionality?


Any idea about this inequality:  $$\large \pi^4+\pi^5<e^6$$  Any hints would be appreciated.

A proof of the inequality using properties of $\pi$ and $e$, for example, is what I'm looking for. Not calculator approximations showing the inequality holds.


How do I change the font in beamer to be as the standard font in a normal LaTeX document?  As far as I have found, the standard font in LaTeX is computer modern roman, but I don't know how to set the font to this.

The default beamer font seems to be Computer Modern sans serif. How do I change this to serif?    Note: \setbeamerfont{<element>}{family=\rm} seems to work for specific elements such as title, but I want this to be a global change.


I have a new Lenovo computer and windows explorer stops working from time to time, I have windows 10.  This is the XML log of the error:  - <Event xmlns="http://schemas.microsoft.com/win/2004/08/events/event"> - <System>   <Provider Name="Application Error" />    <EventID Qualifiers="0">1000</EventID>    <Level>2</Level>    <Task>100</Task>    <Keywords>0x80000000000000</Keywords>    <TimeCreated SystemTime="2017-11-07T13:02:52.128724600Z" />    <EventRecordID>3226</EventRecordID>    <Channel>Application</Channel>    <Computer>DEVELOPER.w2d.sub.de</Computer>    <Security />    </System> - <EventData>   <Data>explorer.exe</Data>    <Data>10.0.15063.674</Data>    <Data>d8364343</Data>    <Data>unknown</Data>    <Data>0.0.0.0</Data>    <Data>00000000</Data>    <Data>c0000005</Data>    <Data>00000000073c0fd8</Data>    <Data>b48</Data>    <Data>01d357c64cfa379f</Data>    <Data>C:\WINDOWS\explorer.exe</Data>    <Data>unknown</Data>    <Data>354346ba-4d07-4316-8f12-eda67d12a656</Data>    <Data />    <Data />    </EventData>   </Event>   Hope you can help me. Thanks in advance

I see you have succussfully answered this question previously but it is not specific to my system.  I have downloaded your file and created the relevant dump file but I don't know how to analyse it. Can I upload it to you for some advice please?


I got into a discussion regarding the light from the Sun that reaches the Earth and whether it maintains the same path from the moment it was emitted to the point it is processed by our eyes. My thoughts were that each photon reaching the surface of the Earth must have undergone some refraction/reflection while passing through the Earths atmosphere, so while the apparent path of any individual photon can be traced on a straight line directly back to the Sun, the chances of this occurring are slim and from  and one of the answers from , it would appear some bending does occur, so it is near impossible to have a photon reach our eyes that has maintained a straight path from the Sun since being emitted.   The question here is: if light travels in a parallel path, what then explains the phenomenon where a break in cloud cover produces two rays of light that seemingly converge at a point (Sun).    My thoughts were that the sheer size of the Sun and the amount of light being emitted would create such an illusion of the divergence in light beams, but then I am unable to reconcile that with the beams not maintaining their actual path. Any explanation or pointers would be appreciated.

Consider this picture of sun beams streaming onto the valley through the clouds.    Given that the valley is only (at a guess) 3km wide, with simple trigonometry and the angles of the beams, this gives the result that the position of the light source is being a few tens of km away at most.   What is wrong with the analysis?


I am travelling from Chennai to Portland, USA via San Francisco International Airport (SFO). Do I need to collect my baggage at SFO and re-check it before boarding the flight to Portland?

I'll be traveling to Memphis, Tennessee form New Delhi, India via Qatar Airways.  The itinerary would be: New Delhi <--> Doha || Doha <--> Chicago || Chicago <--> Memphis  Would I be required to claim and re-check my baggage at Chicago even though all the flights were booked with Qatar Airways or can I check it in all the way from New Delhi to Memphis without re-checking in the baggage again?


As title goes, one knows that for a holomorphism $f(z)$, zeros of $f(z)$ cannot have limit point unless $f(z)$ vanishes everywhere. But I am confused at the behaviors of holomorphism at boundary. My question is      Let $\mathbb{D}=\{z\in \mathbb{C}: |z|<1\}$ to be the unit disc. If $f: \mathbb{D}\to \mathbb{C}$ is continuous in $\overline{\mathbb{D}}$ and holomorphic inside $\mathbb{D}$. Can the zeros of $f$ in $\partial \mathbb{Z}$, $Z_0=\{z\in \partial\mathbb{D}: f(z)=0\}$, have limit point for nonzero $f$?    Here are some remark on it.    Firstly, if $Z_0$ is the complete unit circle, then by maximal module principle, $f$ equals to zero inside $\mathbb{D}$.  And, if $Z_0$ consists a piece of arc of unit circle, then $f$ vanishes everywhere. Since one can take $F=\prod_n f(\mathrm{e}^{i\theta_n}z)$ for some suitable $\theta_n$ such that $F$ vanishes all over the unit circle.  Note that given a boundary value of $f(z)$, then by Cauchy's formula, $f(z)$ is given by  $$f(z)=\frac{1}{2\pi i}\int_{C} \frac{f(\zeta)\textrm{d}\zeta}{\zeta-z}$$ Naive thought is to give a continuous function at boundary whose zeros have limit point. But there are two problems, firstly, the integral may fails to be continuous at boundary; secondly, the function should at least satisfy $\int_C f(\zeta)\textrm{d}\zeta=0$, so not all continuous functions can derive a holomorphism from this method.  Poisson's integral determines $f(z)$ by the real part of boundary value of $f(z)$, which may not help in this problem.    Even more, I am confused that      What is the condition of a function on unit circle being the boundary value of some holomorphism?    Of course, it is essentially a PDE problem.

Suppose $f$ is continuous on the closed unit disc $\overline{\mathbb{D}}$ and is holomorphic on the open unit disc $\mathbb{D}$. Must $f$ have finitely many zeros in $\mathbb{D}$? I know that this is true if $f$ is holomorphic in $\overline{\mathbb{D}}$ (by compactness of the closed unit disc), but I'm not sure of what happens when I just consider $\mathbb{D}$.


Is it okay to say 'historic events'?  It feels kind of double, because both meanings have something to do with the word 'important'   historic means: famous or important in history, or potentially so.   And event means: a thing that happens or takes place, especially one of importance.

can you call a meeting of world leaders that took place in 1947 a historical event?  Thanks


Evaluate $\lim _{n\to \infty }\int _{0}^{1}nx^ne^{x^2}dx.$  I applied the  to $\int _{0}^{1}nx^ne^{x^2}dx.$ We get $c\in (0,1):$ $$\int _{0}^{1}nx^ne^{x^2}dx=(1-0)nc^ne^{c^2}.$$ Taking limit ($\lim_{n\to \infty}$)on the both side, We get, $$\lim_{n\to \infty}\int _{0}^{1}nx^ne^{x^2}dx=\lim_{n\to \infty} nc^ne^{c^2}=0.$$ My answer in the examination was wrong. I don't know the correct answer. Where is my mistake?

The value of $$\lim_{n\to \infty} \int_0^1 nx^n e^{x^2} dx$$ is ____________(round off to three decimal places) I tried integrating by parts and bring out some recurrence relation , but it was of no use. However, I can show the limit to be greater than or equal to 1. $\int_0^1 nx^n e^{x^2} dx \gt \int_0^1 nx^{n+2} dx$ (using  $e^x\gt x $ for $x\gt 0$) $=\frac n{n+3}=1-\frac 3{n+3}$ Taking limit as $n\to \infty$ , proves my assertion. Please help me find the actual limit.Thanks in advance.


Is there anything like NeoDownloader for Ubuntu that I can use to download all the images from a link? Or is it somehow possible to download the directory from a web server containing photos?

Is it possible to download all .jpg and .png files linked in a web? I want to download the images from each post of each thread of [this forum][1] containing a link. For example [this post][2] contains a link to [this file][3].  I've tried with wget:    wget -r -np http://www.mtgsalvation.com/forums/creativity/artwork/340782-official-digital-rendering-thread?    and it copied all the html files of that thread. Although I don't know why it jumps from ...thread?comment=336 to ...thread?comment=3232, when it was going one by one until comment 336.


It is clear that when Voldemort attempts to kill Harry Potter in the Deathly Hallows he instead ends up killing the part of his own soul hidden within Harry Potter. Why did this happen? Was an in-universe answer ever given?

‘So the boy ... the boy must die?’ asked Snape, quite calmly.   ‘And Voldemort himself must do it, Severus. That is essential.’   Deathly Hallows - page 551 - UK Hardcover - chapter 33, The Prince's Tale   Dumbledore tells Snape it is 'essential' that Voldemort be the one to kill Harry, I'm assuming in order for the piece of Voldemort's soul in Harry to be properly killed as well.  But why?   Hermione destroyed the Hufflepuff cup; Ron destroyed the Slytherin locket; Neville killed Nagini; Harry destroyed the diadem and Tom Riddle's diary. So the Horcruxes were not immune to destruction at the hand of someone other than Voldemort. And as it ended up, Harry himself wasn't even a Horcrux, but rather just an unknowing host to a parasitic bit of Voldemort's soul.   Why was it 'essential' that Voldemort be the one to kill Harry in order for the piece of Voldemort's soul to die?


As a part of my class project I need to implement UI testing and QA testing on my sample android app which I have developed in Eclipse a while ago.  I am thinking to run the Robotium as part of UI automation test. And I am implementing the JUnit for unit test cases.  I am stuck up with tools for QA testing. Can some one suggest me the tools for QA testing in Android.  Thanks.

Please suggest me some tools for Android and iPhone app automation testing. I have searched some, like - Appium, Calabash, MonkeyTalk, Selendroid, Robotium, etc.  I am confused to choose any one from above. Please assist me in choosing best automation testing tool so that I can start with better tool which should have following features:   Support for Android and iPhone as well (Android is highly needed, iPhone is optional) Support for Continuous Integration Tool should be Open Source and Free Supported scripting language should have Java Community should be active   Suggest some Android and iPhone mobile app automation tools.


Each site used to have its own chat room(s), even beta sites. Now on  and  when I open the upper left menu and click "chat", I am sent to:  Is it a new policy, or a bug, or my fault? See the URL in the lower left when I hover my mouse on "chat":  When I click on it, it sends me to a page where 27 pages of chatrooms appear, with entertaining names such as "Maid Café" or "The Frying Pan", and finding which ones are about information security is a big challenge.

Since the redesign of the top bar, it appears the chat room link next to a site no longer goes to that site's chats.  For instance, this link:  should go to something like , but it just goes to  instead.


I have an array, like so:   const myArray = [{key1: "value1", key2: "value2"}, {key1: "value4", key2: "value8"},   {key1: "value1", key2: "value3"}, {key1: "value1", key2: "value32"}]   I need to loop through the array, and see if ANY item in the array has a certain value. I have looked through other questions and most loop through and create variables, however I am not allowed to use var (ES6 something, I'm a js noob  and am not sure, just was told to never use var, always const). Basically I need something like this:  if (myArray.contains(object where key1=="value2")) {   // do something }   I would like for the function to return true/false as well, not the object itself.  thanks

What is the most concise and efficient way to find out if a JavaScript array contains a value? This is the only way I know to do it: function contains(a, obj) {     for (var i = 0; i < a.length; i++) {         if (a[i] === obj) {             return true;         }     }     return false; }  Is there a better and more concise way to accomplish this?


Let's say we "seed" a xof function (eg. SHAKE256) with x cryptographically random bytes (enough so that they can't be bruteforced), could said function be used as a cryptographically secure random generator? If so, when should the function be reseeded and start the process over?

CSPRNGs have 2 design requirements:   output unpredictability,  back-tracing resistance.    In addition to which,  added other features such as a) instance customization/personalization, b) operation administration (reseeding counter, etc.).   Of the three functions listed on , key and salt generation can be accomplished with any KDF (even ones based on plain hash functions), and nonce can be accomplished with a simple counter.   And with the introduction of dedicated-purpose XOFs in the SHA3 standard, the problem of producing arbitrary-length string from a finite-length one becomes solved along the way.   Both XOFs and KDFs are much easier to implement and use practically, so what's the point of designing DRBGs in the "NIST-SP-800-90A" way?


As I understand it, single-celled organisms that reproduce via mitosis essentially live forever. When a cell divides, one cannot say that either one of the new cells "is" the parent and the other the child, neither is older than the other, and we might say that the original cell is still alive as long as either of the cells resulting from the division is. With humans the pictures is very different, of course: we have no trouble telling parents and children apart and no one lives longer than about 120-something years.  When in evolutionary history did organisms stop living forever? Was it with the advent of multicellular life with differentiated cells? Sexual reproduction?

Are the two cells that are derived from one cell, ‘twin sisters’ or a ‘mother and a daughter’?  In other words, can a cell really be divided to live an "immortal" life or is cell reproduction the reality of cell life that accounts cell age difference between two successive generations, cell aging-associated senescence in cell reproduction, and cell line survival after the death of old cells.


I am Palestinian with a Lebanese travel document, travelling from India to Bulgaria. I have a visit visa for Bulgaria and the layover in Amsterdam is 5 hours.  Do I need a transit visa?

I found many related questions on this site but I am still not sure about the rules. How can I decide if I need a visa to transit? Schengen members as of May 2021 are as follows:  Austria Belgium Czech Republic Denmark (excluding Greenland and the Faroe Islands - but an open border with the Schengen Area is maintained) Estonia Finland France (excluding overseas departments and collectivities) Germany Greece Hungary Iceland Italy Latvia Liechtenstein Lithuania Luxembourg Malta Netherlands (excluding Aruba, Curaçao, Sint Maarten and the Caribbean Netherlands) Norway (excluding Svalbard) Poland Portugal Slovakia Slovenia Spain (except Ceuta and Melilla) Sweden Switzerland


When people explain why light changes direction when it goes into other medium with different refraction index, they usually say because light changes its speed when it goes to a different medium. But why does light changes direction when it changes speed? It could change its speed while maintaining the same direction! Why is that responce is so common while (at least for me) I think it doesn't answer the question at all! What I'm missing?   How is that answer answers my question?

When a light wave enters a medium with a higher refractive index (e.g. from air to standard glass) and its speed decreases, why does that make it refract/bend?  I understand that wavelength decreases and frequency stays the same and therefore its speed decreases, but I can't find anywhere whatsoever why the speed decrease cause the wave to refract. So could someone please explain this?


I'm working on "Scorched earth"-like game just for learning purpose. I can't figure out how to launch the projectile from my tank's position, with a power of X ([0,100]),at an angle of Y ([-180,180]).

How can I calculate the position of an object after "firing" it from a fixed point?  I am to create a small game - most likely with canvas (pure HTML, JS based) or Adobe Flash - in which the player fires objects at other obstacles in order to clear them.


I have a list of arbitrary length, and I need to split it up into equal size chunks and operate on it. There are some obvious ways to do this, like keeping a counter and two lists, and when the second list fills up, add it to the first list and empty the second list for the next round of data, but this is potentially extremely expensive.  I was wondering if anyone had a good solution to this for lists of any length, e.g. using generators.  I was looking for something useful in itertools but I couldn't find anything obviously useful. Might've missed it, though.  Related question:


Problem solved: see "Update 2" section.  I have a MacBook Pro 15'', A1286, Early 2011 which was running OS X Lion and became extremely slow few weeks after an upgrade to El Capitan. The upgrade itself took very long. After the upgrade, the laptop was running smoothly during about 1 week.   Then, performance suddenly dropped and all menus now take a while to open. The mouse cursor is very jerky. The one of the touchpad is also jerky, altough to a slightly less extent. Practically, it is impossible to use the laptop.  The battery is no longer charging and the time (date/hour) is no longer remembered, so that I have to reset it after each start of the OS.  (skip) Specifications : Processor i7 @ 2,3 GHz with 4 GB RAM (skip)    Update 1   Upgraded to 8 GB RAM.  Shrinked OS partition.  Cloned to SSD.   Checked SMART values.   Checked file system.   Problem not solved.  (skip)     Update 2  Short version:  The culprit is the low battery After thorough tests, I came to the conclusion that the jerky cursor movements and the MacBook coming slower and slower was caused by the battery with "replace now" status.    Long version or how the problem has been identified.   I first followed this procedure in the comments of a video showing how to fix battery issue on a MacBook:    Power off computer Remove battery  Disconnect magsafe  Connect magsafe  Connect batte Power on   This had the positive effect that afterwards, the date/time were remembered, although the battery was in very poor ("replace now") condition.  Then, I reset SMC and NVRAM, following the procedures linked by users Nimesh Neema and Amey. The problem remained. The MacBook was fast during the first seconds and then went slower and slower. This happened even when using softwares from Apple only and not from third-parties.  Lastly, I tested the MacBook with the battery from a 13'' inch (A1278) MacBook Pro. Both batteries operates at the same voltage (although thus of the 15'' has higher capacity). The battery connector is not a the same location, but is same, so that I could insert it and hold the battery with my hand. This battery was in better condition (with "must be checked" status, but didn't had yet the "replace now" status. This totally solved the problem. The MacBook remained fast and the cursor movements, from the touchpad or mouse were still smooth after several minutes.    Conclusion: If the battery has the "replace now" status, some artifacts totally paralyze the MacBook Pro, although it appears working correctly during the first seconds. This is a purely hardware problem and system reinstall or upgrade is NOT necessary.

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


Ok, as far as I understand a field has to look like $\mathbb{F}_{p^n}$. But why? What is the explanation?

Let $F$ be a finite field. How do I prove that the order of $F$ is always of order $p^n$ where $p$ is prime?


I want to prove that the topological space $\mathbb{N}$, with an open set defined as a set with a finite complement, is not path connected.  In case it is relevant, I have already shown (at least I hope so) that this space is connected and compact.  My plan is to suppose that we have a continuous function $$f: [0,1] \to \mathbb{N}$$ such that $f(0)=n$ and $f(1)=m$, where $m,n\in\mathbb{N}$, and then produce a contradiction.  It seems to me that the definition of continuity I need is probably the one that says that the open sets in the range must come from open sets in the domain, or else the one that says that closed sets in the range must come from closed sets in the domain.  Other than that, I am a bit stuck.  Any tips would be greatly appreciated.  *BEGIN EDIT: Thanks to David Moews comments, I can see now how the problem reduces to showing that $[0,1]$ cannot be written as the union of countably many disjoint closed sets. On the MathOverflow post  referred to in the comments, I found this sketch of a proof:     "The proof I like uses the fact that a nested sequence of open intervals has non-empty intersection provided neither end point is eventually constant. Now one inductively constructs a sequence of such intervals as follows. Each interval is a component of the complement of the union of the first n closed sets, for some n. Then wait till the next closed set intersects that interval. (If it never does, then we're trivially done.) It cannot fill the whole interval, and indeed must miss out an interval at the left and an interval at the right. So pass to one of those subintervals in such a way that your left-right choices alternate. Done."   I am not sure if I understand this argument correctly. Here is my version of it:  We know that for $n=f(0)$ and $m=f(1)$ there are closed sets $[0,a]$ and $[b,1]$ in $[0,1]$, possibly singleton,  such that $f([0,a])=n$ and $f([b,1])=m$. The union of these two closed subsets $[0,a]\cup [b,1]$ is a closed subset of $[0,1]$, with the open subset $(a,b)$ as its complement. Suppose that $[0,1]$ can be written as a union of countably many closed and disjoint sets. Then there is a closed set $[c,d]$ that lies within $(a,b)$. Since there exists $x$ such that $a=Inf((a,b))<x<c$, etc, we now have $[0,1]=[0,a]\cup (a,c)\cup [c,d]\cup(d,b)\cup [b,1]$. Similarly, there must be a closed set $[e,f]$ that lies within $(a,c)$ so that $(a,c)=(a,e)\cup [e,f]\cup (f,c)$. Note that $(f,c)\subset (a,b)$. We can proceed inductively so that $(f_{n+1},c_{n+1})\subset (f_{n},c_{n})\subset ...\subset (a,b)$.  So there is always another open set, and if we can show that this set contains a point, then there is a point that is not in the union of countable closed and disjoint sets and we have a contradiction.  I'm not quite sure how to show this but perhaps I could argue:  Since $(a,...,f_n,f_{n+1},...)$ is strictly increasing and $(b,...,c_n, c_{n+1},...)$ is strictly decreasing and since $\forall n, f_n\leq c_n$, they are bounded monotone sequences of real numbers and must converge. Thus we have our point.  Is this line of thinking correct. Or have I misunderstood something?  I'm sorry if I am going over old territory, but I just want to make sure I am on the right track. Thanks in advance for any help. *END EDIT

I am trying to prove that in $\mathbb{Z}$ with co-finite topology the only path-connected components are the singletons.  (I reckon that) showing that      "if a function $\gamma : [0,1] \to \mathbb{Z}$, where $\mathbb{Z}$ has   co-finite topology, is continuous then it is constant"   should do the trick.  However I am not sure this is true, let alone if this is a good approach to the problem. Any thoughts about it?  Edit: I was thinking: suppose $x,y \in \mathbb{Z}$ and $\gamma : [0,1] \to \mathbb{Z}$, where $\mathbb{Z}$ has co-finite topology. Further suppose $x \neq y$, then $f^{1}(\mathbb{Z}\setminus \{x\})=(0,1]$ which is not open in $[0,1]$, contradicting continuity. Hence $x=y$. Does it seem right?  Edit 2:  Forget the (stupid) edit above!


Several of the common partial differential equations encountered in physics are mentioned as easy to solve using the variable separable method. However I do not understand how does one guarantee that the solutions generated using this method is the complete set of solutions. I am finding it quite hard to believe that such a method can produce the entire set of solutions.  Can anyone explain if it indeed does generate the complete set of solutions to a PDE. If not, a counterexample would work. Also, I would like to know if we use this because it is consistent and easy to work with?

When a partial differential equation is solved using the separation of variables method, is the produced solution the most general one that satisfies the equation or have we lost some forms of the solution because of the assumption that it is in the form of separated variables?


I'm using SageMath but the obtainment of the metric from the stress-energy tensor is not trivial, i.e., it is not implemented in a predefined function.  Do anyone know a good software that where I can easily find the metric from a given stress-energy tensor with constant entries?

I would like to use an open source computer algebra system (CAS) for research in general relativity. Kindly suggest a good choice between Ipython and Sage. I am more interested in the theoretical aspect rather than numerical computations.


Is there any formula to calculate $2^i$ for example? What about $x^z$? I was surfing through different pages and I couldn't seem to find a formula like de Moivre's with $z^x$.

Greetings!  I am trying to understand what it means to have an imaginary number in an exponent. What does $x^{i}$ where $x$ is real mean?  I've read a    on this issue, and they all seem to boil down to the same thing:   Any real number $x$ can be written as $e^{\ln{x}}$ (seems obvious enough.) Mumble mumble mumble This is equivalent to $e^{\cos{x} + i\sin{x}}$    Clearly I'm missing something in step 2. I understand (at least I think I do) how the complex number $\cos{x} + i\sin{x}$ maps to a point on the unit circle in a complex plane.  What I am missing, I suppose, is how this point is related to the natural log of $x$. Moreover, I don't understand what complex exponentiation is. I can understand integer exponentiation as simple repeated multiplication, and I can understand other things (like fractional or negative exponents) by analogy with the operations that undo them. But what does it mean to repeat something $i$ times?


Show that a connected simple graph for which every edge is in some perfect matching is a block.   It seems obvious to prove by contradiction. so Suppose such a graph $G$ has a cut-vertex $v$.  The direction from here seems to be taking two components $H_1, H_2$ of $G-v$, and let $e_1, e_2$ be the edges by which $v$ was connected to those respectively.$e_1$ and $e_2$ are both in some perfect matchings in $G$, but they must be different matchings since they share a vertex. Call them $M_1, M_2$. How to continue from here? I'm guessing I'm looking for some contradiction to arise when looking at $M_1\cap E(H_2)$ or vice versa, but I'm not sure exactly how.

Seems to be an easy question, but I can't find the right direction.  Let $G$ connected graph on at least 4 vertices, such that every edge in it, participates in a perfect matching. Prove that $G$ is 2-connected.  Any help will be appreciated.  Thanks in advance.


My question is - I know, $0\times anything=0$ and $anything \times \infty=\infty$.  So,what is $0 \times \infty$?  I suppose it's $0$ but why not $\infty$?  If I say that area of an indefinitely long line is $\infty*0=0$,where am I wrong?  I know upto limits and basic derivatives.  Thanks.

I did a bit of math at school and it seems like an easy one - what am I missing?  $$n\times m = \underbrace{n+n+\cdots +n}_{m\text{ times}}$$  $$\quad n\times 0 = \underbrace{0 + 0 + \cdots+ 0}_{n\text{ times}} = 0$$  (i.e add $0$ to $0$ as many times as you like, result is $0$)  So I thought an infinite number of $0$'s cannot be anything but $0$? But someone claims different but couldn't offer a reasonable explanation why. Google results seemed a bit iffy on the subject - hopefully this question will change that.


I have URL in Lightning Community page, I want to get value of parameter from this ULR in Lightning.     How can I get value of accountRef?  I have tried with:            accountRef: {!v.accountRef}   The result is null.  I tried with   Do we have any way if we don't want to use decodeURIComponent(window.location.search.substring(1)) on controller js?

I am new to communities in lightning and I am trying to figure out a way to directly fetch the URL parameters into the lightning component attributes using the  {! urlParamName} expressions.  for example :   https://www.someurl.com/page?name=somename&surname=somesurname   My lightning component will be :   <aura:component>      <!-- Parameters Available in URL-->     <aura:attribute name="name" type="String">     <aura:attribute name="surname" type="String">      <!--It will get name parameter from URL directly-->     Name is : {!v.name}       <!--It will get surname parameter from URL directly-->     SurName is : {!v.surname}  </aura:component>   I am trying to figure out a way which cannot includes JS. Currently I am using Lightning JS to get these parameters.


Suppose $a_k > 0$ for $k=1,...,n$ and $\sum_{k=1}^n \dfrac{1}{1+a_k} =  n-1 $. Prove that $$ \prod_{k=1}^n \dfrac{1}{a_k} \geq (n-1)^n $$  Proof: Taking $log$ in both sides we obtain that $$ \sum_{k=1}^n  \log(1/a_k) \geq n \log (n-1) $$ And by hypothesis, it be enough if we can prove $$ \sum_{k=1}^n \log \left( \dfrac{1}{a_k } \right) \geq n \log \left( \sum_{k=1}^n \dfrac{1}{1+a_k} \right) $$ I dont see how to prove this. But, we go back to the beginning and apply Harmonic-Geometric mean ineq to $( \prod 1/a_k )^{1/n} $, we obtain $$ \left( \prod_{k=1}^n \dfrac{1}{a_k} \right)^{1/n} \geq \dfrac{n}{\sum_{k=1}^n a_k } \geq \sum_{k=1}^n \dfrac{1}{1+a_k} = n -1 $$ and this would be the end but we still to prove that $$ n \geq (a_1+.... + a_n) \left( \dfrac{1}{1+a_1} + ... + \dfrac{1}{1+a_n} \right) $$ but I am unable to prove this. Any assistance would be greatly appreciated.


I have built a rotational Eddy brake in a small car, where I use gears to make the metal disc in the brake rotate faster or slower at will.  I know that the braking torque is dependant on the rate of change of the magnetic flux linkage and therefore the faster the disc spins the stronger the brake force.  But I am unable to calculate the braking torque. I can't find a formula that joins the Rotational speed of the disc with the torque produced. I think I would first need a relation between rotational speed and magnitude of the eddy current produced. An then work with that to calculate magnetic drag. From which to obtain braking torque  I am currently lost. I think I have over researched and am unable to find something useful.

I have a conductor with volume $V$, passing a magnetic field($B$) with velocity($v$):   I'm trying to calculate the Eddy currents to figure out the magnitude of the drag force($F_d$) generated the Eddy's, how can that be done?    I could not find a direct formula, I noticed from a lot of sources that it seems to be a difficult task.  The conductor is in an open circuit(I don't think it makes a difference if it was in a closed circuit). Please let me know of any additional information I'm missing(not sure of all the required variables). I'll add them as an edit.


I have a somewhat old pc on my hands and i wanted to install Ubuntu, the installing is not the problem but Ubuntu says (at boot) that i do not have enough ram memory. What are the requirements actually?

I'm thinking about installing Ubuntu Desktop, but I don't know what flavor is the best for my system. What are the minimum and recommended hardware requirements? What kind of CPU? How much memory? Should I have Hardware Acceleration? What flavor should I use?  This is an attempt of a canonical answer. My answers have the "official  requirements", the recommended are a mix of official sources and opinion based (along with the answer it's told the source). You can comment or edit if you feel that the information is obsolete or incomplete. It is a good rule of thumb that any system capable of running Windows Vista, 7, 8, x86 (Intel) OS X will almost always be a lot faster with any Ubuntu flavor even if they are lower-spec than described below.


Target:  I would like to use a table where each second row is colored slightly gray. but i also have a backgrund image on the page so just using \rowcolors with standart colors isnt working.  \documentclass{book} \usepackage[table]{xcolor} \usepackage{background} \usepackage{eso-pic,graphicx}      \backgroundsetup{ scale=1, opacity=1, angle=0, color=black, contents={%  \ifodd\value{page}    \AddToShipoutPictureBG*{\includegraphics[width=\paperwidth]{Images/Backgrounds/HeXXenBG_Left_LQ}}   \else    \AddToShipoutPictureBG*{\includegraphics[width=\paperwidth]{Images/Backgrounds/HeXXenBG_Right_LQ}}   \fi     } }  \begin{document} \rowcolors{2}{black!40}{} \begin{tabular}{l|l|l|l} {\scshape Spalte 1}&{\scshape Spalte 2}&{\scshape Spalte 3}&{\scshape Spalte 4}\\\hline\hline Beispiel 1 & Hier geht mehr rein. & A & Die Tabelle sollte sich an die Textspalten halten\\ Beispiel 2 & Genauso hier. & B & Das musst du manuell machen.leider\\ \end{tabular} \end{document}   Current:  is there some possibility for activate multiply blend mode, for table background color? or some other workaround?  Edit: i am compiling with xelatex, so the duplicate is not working

I'm using the colortbl package to color table cells.  I've combined this w/ the xcolor package to define my own colors.  However, it appears that xcolor does not support transparency.  I saw the package transparent, but it is oriented toward text and I wasn't able to set the transparency level of a defined color.  Are there any packages that support alpha color channels?


<html> <head> <title> Web Page </title> </head> <body> <form action="" method="POST"> <input type="text" name="name" /> <input type="submit" value="Submit" /> </form> </body> </html>   actually what i wanted once you fill the name and click submit and when you again open the page to enter the data, then if you double click in the input field then it display the previously enters data. i don't want that what should i do.

How do you disable autocomplete in the major browsers for a specific input (or form field)?


I have a Dell Inspiron 15 dual-booted with Windows 10 and Ubuntu 18.04...to be honest I don't know why you need to know this lol. Anyway, whenever I use other Operating Systems Right-clicking on the touch pad of my Dell Inspiron laptop works but whenever I use Ubuntu it doesn't work it registers pretty much as a left click, now I have another mouse for my laptop so it's not an issue because right clicking works on this. I'm just curious because Linux isn't the problem of my laptop on this issue, it's specifically Ubuntu. I could run Mint and everything would run properly unfortunately I don't like Mint as much as Ubuntu. I'm mostly curious as to why it doesn't work and I apologize for dragging on with this question

I have installed Ubuntu 18.04 LTS on my HP Pavilion series laptop. After installing this version of Ubuntu, right click is not working of my touchpad. How can I solve this?  BTW:  does not have any solution which which is working for me. PS:- Problem remains after selection area in gnome-tweak-tool


A non-English native friend has just said that an English speaker told him the question mark should NOT be used after a pair of sentences separated by a comma. Something like this: "Could someone else have done that, as she was on holidays" I am also a non-native speaker and am not a language expert but I find this construction quite strange. I would use the question mark here, even if the second sentence is not interrogative. From my point of view, the question is in the first sentence but the second does not act as a separate statement. Help? Many thanks for your thoughts.

I'm basically looking at sentences which start with a question, and end with an explanation to it. But there may be more instances of a similar structure. Sample sentence :      Can you book a room in advance, because otherwise we'd be in trouble   Should this sentence end with a period or a question mark?  PS: I read the apparently similar question  but the sentence structure there is different from what I'm looking for.  Edit: I just discovered that this question is a duplicate. A resolved question already  exists:   But i do like the explanations here better.


Find the number of solutions of $\dfrac{1}{x} + \dfrac{1}{y} = \dfrac{1}{1995}$ in $N \times N$.   My Attempt:  This can be simplified to $1995(x+y)=xy$ and then further to $$y={1995x\over x-1995}$$  Since $1995=3\cdot5\cdot7\cdot19$, it has $16$ divisors  Now since $x>0$, This yields total of $16$ solutions (the answer according to book). however, Mathematica found $81$ solution

I have a question about the following problem from a Putnam review:  Let $n\in \mathbb{N}$. Find how many pairs of natural numbers $(x, y)\in \mathbb{N}\times \mathbb{N}$ solve $$ \frac{xy}{x+y}=n. $$  I have found some solutions for all $n$, such as $(2n, 2n)$ and $(n+1, n(n+1))$, but I feel as though this is the wrong approach, as the question is only asking for the number of solutions to the equation.  I don't really want a complete solution, but any hints would be greatly appreciated.


I want to execute a script before starting a service every time the service is started. I know that I can use ExecStartPre inside the service definition file, but I wonder if it's possible to achieve without editing a file which comes from the service's package. The script is a simple command which exits when it's done, it creates files which are used by the main service (it fetches TLS certificates and keys from secure storage).

I have installed the pimd service by means of apt. This comes with an upstream systemd unit file (/lib/systemd/system/pimd.service).  I want the service to be restarted when for some reason it gets killed, hence I wish to add the line Restart = always in the unit file.   However, I don’t want to modify the upstream unit file.  Is there any workaround for this?


I used Python2.7 to do this but I always got the same error when I try to insert the '€' symbol in my code. My OS system is windows 10.  When I run this code:  dic = { '\\' : b'\xe2\x95\x9a', '-'  : b'\xe2\x95\x90', '/'  : b'\xe2\x95\x9d', '|'  : b'\xe2\x95\x91', '+'  : b'\xe2\x95\x94', '%'  : b'\xe2\x95\x97', '$'  : b'\xe2\x82\xac', } def decode(x):     return (''.join(dic.get(i, i.encode('utf-8')).decode('utf-8') for i in x)) print(decode('+------------------------------------%')) print(decode('|                                    |')) print(decode('|                                 |')) print(decode('\\------------------------------------/'))   I got this:  ╔════════════════════════════════════╗ ║                                    ║ ║                                    ║ ╚════════════════════════════════════╝   but when I add the $ symbol I got:  ╔════════════════════════════════════╗ ║                                    ║ Traceback (most recent call last):   File "test.py", line 14, in <module>     print(decode('|                $                    |'))   File "C:\Python27\lib\encodings\cp850.py", line 12, in encode     return codecs.charmap_encode(input,errors,encoding_map) UnicodeEncodeError: 'charmap' codec can't encode character u'\u20ac' in position 17: character maps to <undefined>   What I did wrong?

When I try to print a Unicode string in a Windows console, I get an error . UnicodeEncodeError: 'charmap' codec can't encode character .... I assume this is because the Windows console does not accept Unicode-only characters. What's the best way around this? Is there any way I can make Python automatically print a ? instead of failing in this situation? Edit:  I'm using Python 2.5.  Note: @LasseV.Karlsen answer with the checkmark is sort of outdated (from 2008). Please use the solutions/answers/suggestions below with care!!  is more relevant as of today (6 Jan 2016).


Natural selection makes perfect sense when describing the evolution of say camouflage. For example 2 bugs of the same species live on a tree. One is mutated to look slightly more like a tree, so the bird misses it and eats the one that sticks out more.   This logic seems to fail for poisonous animals though. For example, two bugs are equally visible but one has developed a mutation to be poisonous. Since they are both easy to spot they both get eaten. Now the poisonous mutation has died out. How does natural selection explain the poison mutation overcoming the initial hurdle?

The chapter by Douglas Futuyma in 'Evolution' (Losos et al 2013, Princeton) states that natural selection can occur at the species level. Futuyma states that if natural selection occurs at the species level it does not occur at the individual level:      Neither gene selection nor species selection has molded the advantageous characteristics of individual organisms; rather, they have affected properties at the gene level or at the species level.    But how does natural selection occuring at the species level not affect individuals? Surely any selective advantage of a particular species must occur among particular individuals of that species. For example, if Species A is selected because it is browner than Species B, this will be because individuals of Species A are browner than individuals of Species B.


Show that a group can not be expressed as union of two of its proper subgroups. I am not sure how to start.

"Let $G$ be a group, and suppose $G=H \cup K$, where $H$ and $K$ are subgroups.  Show that either $H=G$ or $K=G$."  Let $h \in H$ and $k \in K$.  Then $hk \in H$ or $hk \in K$ (since every element of $G$ is in either $H$ or $K$).  If $hk=h'$ for some $h' \in H$, then $k=h^{-1}h'$, so $k \in H$.  If $hk=k'$ for some $k' \in K$, then $h=k'k^{-1}$ so that $h \in K$.  If for all $h \in H$ we have $h \in K$, or if for all $k \in K$ we have $k \in H$, then $H \subseteq K$ or $K \subseteq H$.  Then since $G=H \cup K$, we must have either $H=G$ or $K=G$.  I'm not sure if the first paragraph of my 'proof' implies the second.  I've shown that for arbitrary $h \in H$, $h \in H$ and possibly $h \in K$, and similar for $k \in K$.  I don't know how to wrap it up (or perhaps this route won't lead anywhere at all).  If this way won't work, I'd just like a hint on a new direction to take.  Thanks.


What is the inverse of $y = x^x$? I know it won't be in terms of elementary functions, but I believe some function analogous to Lambert W function for $z = ye^y$ would be defined? I couldn't find it on google.

How can I find the inverse function of $f(x) = x^x$? I cannot seem to find the inverse of this function, or any function in which there is both an $x$ in the exponent as well as the base. I have tried using logs, differentiating, etc, etc, but to no avail.


I have plotted several graphs using "gnuplot" and post-processed the graphs in "GIMP". I decided to remove the legend within the graph and place the legend separately below my set of graphs. I have used the script of "Christian Feuersänger" mentioned in .  In general I would like to use the "sharp plot" functionality for my legend but the thickness of the lines shown is very small. I tried to use the scaling factor but it scales along the x-axis whereas I would like to scale it along the y-axis. Any hints on how this could be done?  Thanks; Saideep

I'm creating a custom legend for some pgfplots graph by drawing a node containing a shortstack. Inside the node I'm using \ref{} to insert correct line-styles in front of my text labels.  The problem is that while the lines in the graph are printed with line width=1pt, the lines from \ref are the standard thin size of pgfplots.  This does not happen when using the normal pgfplots legend setup (\addlegendentry), but this is not possible in this graph since the legend either needs to contain extra information or is a common legend for 2 different axis.   So how can I control the line width when using \ref?


I entered Hungary earlier this year (mid April), and spent my 90 days there. Just before my time was up, I applied and was approved for a temp. residence permit - which would allow me to stay (not work) until mid November.   My question: To return to Hungary, do I need to wait a full 90 days from when my RP expired, 90 days from the day I actually exited Hungary, or 90 days from the date my initial 90 days (on the schengen stamp) would expire?  Feel free to ask me to clarify anything. To note, it is important I do go back to Hungary, because my partner is there and he's recovering from an injury. We're unmarried. We obviously will need to sort out a better system.   Additional info: I'm a Canadian citizen, and I have an active working holiday visa for Ireland. We lived there and in the UK together. We're still confused whether Hungary recognizes us as common-law, therefore myself as a family member. The immigration there were not very helpful.

I have a 1-year residence permit from one Schengen country that is now expiring. Upon its expiration, I would like to get my 90/180 days validity as a tourist to stay, or return here as soon as possible.  I understand that the tourist short-stay scheme is based on the 90/180 days "counter". But what happens if my previous stay was not tourism but residence (as searching year). Wouldn't that mean that I can quickly exit and re-enter the Schengen area to activate my tourist stay?   Also, is there a way to change this purpose of stay without exiting the Schengen area?


Someone had spawned a while true loop in bash (logged in as root) on a server. It kept spawning processes, which fortunately exited but I needed to kill the parent. I came to know it was spawned directly from command line and not from a script, so I grepped for '-bash' and killed those processes owned by root. It worked fine.   When you do ps aux, In the command column different variants of bash show up.  /bin/bash -bash -bash -bash /bin/bash bash /bin/bash /bin/bash bash   etc..  What are the differences?

I understand the basic difference between an interactive shell and a non-interactive shell.  But what exactly differentiates a login shell from a non-login shell?  Can you give examples for uses of a non-login interactive shell?


This sub-question is part of a larger question:     If $S_n = \left(3 + \sqrt{5}\right)^n + \left(3 - \sqrt{5}\right)^n$, show that $S_n$ is an integer. Also prove that the next integer greater than $\left(3 + \sqrt{5}\right)^n$ is divisible by $2^n$.   I was able to prove the first part easily using induction, but for the second part, I have no clue. If I use induction, I get stuck with the ceil function, which, for me, is difficult to manipulate.  How do I prove the second part?

If $S_n=(3+\sqrt{5})^n+(3-\sqrt{5})^n$ show that $S_n$ is integer and that $S_{n+1}=6S_n-4S_{n-1}$. Further deduce that the next integer greater than $(3+\sqrt{5})^n$ is divisible by $2^n$.  My work so far:  I have done part 1 using mathematical induction but it is part 2 of divisibility where I am stuck


I got Minecraft on July 2, 2019. I put in the code, entered the username and password, and logged into minecraft.net.  Once I put in my email and password, it says "Invalid username or password." I tried waiting for a while but the output remains. I tried my HP laptop and it worked somehow, but on the Mac it doesn't work.   I know that my username should be my email, but it still doesn't work. I've waited for 1-2 days now, but it still doesn't work.

We just got a new laptop (ASUS) though we did have a mac.  We are trying to log onto Mojang to download Minecraft and it keeps saying, "The username and password are not recognized."   We have done all the usual procedures; we have reset the password, we are using the email, not the username to sign in, and it looks like the minecraft login servers are working etc. etc.  We quit Minecraft on the old computer and shut off that computer thinking that was the issue.   Still, we can't get onto Mojang.  We are accessing mincraft through firefox and trying to download it to the new computer but we can't get into the account to do that!  What in the world could be the issue?


When using the package lettrine.sty, I have noticed an annoying interference between drop caps and floats.  \documentclass[10pt,a4paper]{article} \begin{document} \usepackage{lettrine} \usepackage{wrapfig} \title{My title} \maketitle \begin{wrapfigure}{r}{0.5\textwidth}     \vspace{-20pt}     \begin{center}     \includegraphics[width=0.4\textwidth]{image.jpg}         \end{center}         \vspace{-20pt}         \caption{\textit{My caption}         \vspace{-10pt} \end{wrapfigure} \section{My text} Lorem ipsum dolor sit amet, consectetur adipisicing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. %\lettrine[lines=3,slope=0pt,nindent=1pt]{L}{orem} ipsum dolor sit... \end{document}   This LaTex seems to compile fine, however as soon as I add a drop cap to the first word, the LaTex starts behaving weirdly and I get the body overlapping with the image. Here's how it looks:

How can I use lettrine at the start of a paragraph used in the wrapfigure environment.  Consider the following code:  \documentclass{article}  \RequirePackage[demo]{graphicx} \usepackage{lettrine} \usepackage{wrapfig} \newcounter{cnt}\setcounter{cnt}{0} \def\t{\stepcounter{cnt}\thecnt. cat sat on the mat. }    \begin{document}     \begin{wrapfigure}{r}{0.3\textwidth}         \vspace{1ex}         \includegraphics[width=\linewidth,height=1in]{image}     \end{wrapfigure}     \lettrine{T}{he cat sat} \t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t \end{document}   Which yields the following result, I have shifted the image down so that the problem is made more apparent, ie, wrapfig is ignored.    NOTE: David Carlisle has provided a pretty good answer so far, however, the following anomalies occur with the output, specifically, an update was made to David's original code to allow the modified lettrine (wflettrine{...}) to take the optional arguments in order to control the letter height etc, however, by default, the following output is returned if the optional argument lines=5 is now parsed.    The above was achieved with the code command:  \wflettrine[lines=5]{T}{he cat sat}   And it is clear to see under the red-highlighted region, that the drop-cap letter is not taking up the whole space, strangely enough, the same behavior was observed on my machine with the default computer-modern font, under a normal use of lettrine.  By changing the font to Helvetica, via the use of the following in the preamble:  \usepackage{helvet} \renewcommand{\familydefault}{\sfdefault}   And executing the same command, yields the following output.    And it is clear that the previous problem is resolved (by the correct drop-cap usage under the green highlighted section), however, this has pushed the wrapfig component to the right, as can be seen under the red-highlighted section.  It appears as though the wrapfig has been pushed to the right by what appears to be the same amount as the width of the dropcap letter 'T'.


I want to use some arcpy function outside arc map  i used following code but it ends up with error no module named arcpy can anyone help  import sys sys.path.append("D:\Installed Softares\ArcGIS\Desktop10.1\arcpy"); import sys.arcpy Radiancetemp = "C:\\Model_Uz\\radianMap" # Process: Raster Calculator arcpy.gp.RasterCalculator_sa("Float(\"%LE71970282002228EDC00_B6_clip.TIF %\" * 0.03705882) + 3.2", Radiancetemp)

I have written a script and am trying to run it in Python IDLE 2.7.6. I first try to import arcpy, but I get an error message saying:  ImportError: No module named arcpy  Why does it not work? I am using ArcGIS Desktop 10.2.


I can not remember the name of this logical fallacy. The fallacy suggests that when there is a lack of knowledge on a subject it is because, either: a rational answer does not exist, or a answer without any need for proof exists.  Example:   "We can't explain why the lamp just moved, therefore it must be supernatural." In the History Chanel TV programme "Ancient Aliens", the logic "no one can explain it, therefore it must be aliens"   Examples 1 and 2 have subtle differences and might have different names.

A person dismisses an otherwise valid argument, because some of its proponents support it for the wrong reason.  How is this fallacy called?  EDIT: Here is an example. A person defends the idea that the earth is flat. In an interview he asks several skeptics and each one of them responds "The earth is round because if you dig deep enough you'll reach the other side". The person then shows that this is a circular argument and then concludes that the earth is flat.


I often see sentences like     We are interested in predicting whether an individual will default on his or her credit        card   or      Activate only when your opponent adds a card to his or her hand   Why are people using "his or her"? Would it be correct to replace "his or her" with "their"? For example     We are interested in predicting whether an individual will default on their credit card   This seems like it says the same as the first sentence, but I never see it used.

Is this sentence grammatically correct?  Anyone who loves the English language should have a copy of this book in their bookcase.  or should it be:  Anyone who loves the English language should have a copy of this book in his or her bookcase.


I have defined a few custom commands using \newcommand in order to standardize figure sizes in a paper I am writing. For instance:  \newcommand{\bigfigure}[1]{\includegraphics[width=0.8\linewidth]{#1}}   However when using this command I don't get the handy autocomplete of the path to the image as I would when just using \includegraphics[]{...}. Is there anyway I can enable this feature for my custom commands?   I am using Overleaf as my editor.

For example, when I use the command (in Overleaf/ShareLaTex):  \begin{figure}[H]     \centering     \includegraphics{some_graphic}     \caption{some_caption}     \label{fig:some_label} \end{figure}   the \includegraphics{} comes without the [] parameter to change the size of the image, and \begin{figure} without the [H] option by default.   Is it possible to renew the command to make it default? By that I mean that when I type the \begin{figure} command it adds the [H] and [h] as well as [width=\textwidth] in the \includegraphics command, rather than making a global change in the preamble e.g.


I have a web-server, (complete with user account and payment system), that was vulnerable to the Heartbleed attack.  What I'm wondering is:   How can I detect if my server has been compromised? How do I recover from a heartbleed attack? How do I ensure the safety of my users data?

This is a  about understanding and remediating the Heartbleed security issue.   What exactly is CVE-2014-0160 AKA "Heartbleed"? What is the cause, what OSs and versions of OpenSSL are vulnerable, what are the symptoms, are there any methods to detect a successful exploit?   How can I check to see if my system is affected? How can this vulnerability be mitigated? Should I be concerned that my keys or other private data have been compromised? What other side effects should I be concerned about?


Just installed Ubuntu on a new laptop I bought (came with Win 10).  Three days later, in my installed programs in the Ubuntu Software, I see:  core - The core runtime enviornment for snapd  I didn't install this (that I can remember).  What is it? What does it do? Do I need it?

The snap packaging format finally frees us from dependency hell by allowing each package to have its own copy of dependencies. I'm interested in the technical details in how it does this. How does it handle:   snaps depending on the version of a library already installed via deb packages for the current release? Does it ignore the installed library? different snaps specifying the same version of the same library? Does it do deduplication somehow? updates to core libraries that are likely to be used by a lot of snaps? OpenSSL comes to mind as a huge pain point.   xdg-app has something called :     A fundamental concept in xdg-app is the runtime/application split.   Every app depends on a runtime, which supplies the core libraries that   the app relies on. Runtimes are typically shared by many applications,   but a user can have multiple runtimes installed at the same time.   It seems that in the case of OpenSSL, it would be part of the runtime in xdg-apps, so an update to OpenSSL should transparently affect all xdg-apps using the same runtime.


Not sure if this is the appropriate place to ask this question, but my IP has me listed in Nebraska, and I'm in Atlanta, GA. It's becoming a nuisance because every search engine shows me Nebraska results and gives the wrong times for things (because I'm EST, and the city in Nebraska it has me listed in is CDT). Any idea on how to change this? Thanks!

Numerous services and  do GeoIP lookups.  They get the country correct, but often the city is wrong.  Are there places where I can go and correct this, letting people know the actual location of my IP address.  I have a static IP, so it's not going to go to another user in a different location.


I am new to Blender and I have attached the photo of the render and the photo of the scene I'm working on. If anyone knows what I'm doing wrong please let me know, thank you!

A scene I made is not rendering, at all. This grey screen stays the same and nothing changes.  Here are my settings:  [


I have found a third-party CKEditor plugin I want to add to the editor provided by Drupal core in Drupal 8. What do I need to do to be able to make it possible to add this new option to the editor?  The plugin I would like to add is the image2 plugin (called enhanced images) found on the CKEDITOR site. Based on my research, it appears I'd need to add a YAML and a module file to what CKEDITOR provides.

I need to add the Templates plugin into Drupal8 CKeditor. So far it is available on the editor configuration page, but not on a node edit page. The code:  namespace Drupal\module_name\Plugin\CKEditorPlugin;  use Drupal\ckeditor\CKEditorPluginInterface; use Drupal\ckeditor\CKEditorPluginButtonsInterface; use Drupal\Component\Plugin\PluginBase; use Drupal\editor\Entity\Editor;  class ContentTemplates extends PluginBase implements CKEditorPluginInterface, CKEditorPluginButtonsInterface {    public function getButtons() {     return array(       'ContentTemplates' => array(         'label' => t('Content templates'),         'image' => drupal_get_path('module', 'module_name') . '/js/CKeditor/Plugin/templates/icons/templates.png',         'image_rtl' => drupal_get_path('module', 'module_name') . '/js/CKeditor/Plugin/templates/icons/templates-rtl.png',       ),     );   }    public function isInternal() {     return FALSE;   }    public function getDependencies(Editor $editor) {     return array('dialog', 'dialogui');   }        public function getLibraries(Editor $editor) {     return array();   }    public function getFile() {     return drupal_get_path('module', 'module_name') . '/js/CKeditor/Plugin/templates/plugin.js';   }    public function getConfig(Editor $editor) {     return array();   }    // TODO: to be sure, should be removed and served by config   function isEnabled(Editor $editor) {     return TRUE;   } }   I also could see the methods injected by templates/dialogs/templates.js while inspecting the CKEditor object, but the file is not listed in the Chrome's resources inspector. I also don't see any code changes in this file takes effect (browser and drupal cache disabled, aggregation disabled).


Prove: For a function $f$, if $f^2$ and $f^3$ are analytic in G (a set in C), then $f$ is analytic in C.  I don't get the question. Why would I need to know that $f^3$ is analytic if I already know that $f^2$ is. Can't I just derive the Taylor series expansion? Any help with this would be appriciated!

Let $f: \mathbb{C} \to  \mathbb{C}$ be a continuous function such that $f^2$ and $f^3$ are both analytic. Prove that $f$ is also analytic.   Some ideas: At $z_0$ where $f^2$ is not $0$ , then $f^3$ and $f^2$ are analytic so $f = \frac{f^3}{f^2}$ is analytic at $z_0$ but at $z_0$ where $f^2$ is $0$, I'm not able to show that $f$ is analytic.


I follow  docs on how to build MariaDB on my Ubuntu. It says run On a Debian based distribution: apt-get build-dep mariadb-server-10.X where X is the suffix of the major version.  So I run sudo apt-get build-dep mariadb-server-10.5  and get this error: Reading package lists... Done E: You must put some 'deb-src' URIs in your sources.list  This error hint message is meaningless to me.  Even tried sudo apt-get build-dep mariadb-server-10.5 sudo apt build-dep mariadb-server-10.5 sudo apt build-dep mariadb-server-10.4 sudo apt build-dep mariadb-server-10.3  Also, used a simpler command and yet I get the same problem: $ sudo apt-get build-dep build-essential Reading package lists... Done E: You must put some 'deb-src' URIs in your sources.list  How to fix this error? My Ubuntu is a server with a gui desktop installed on top of it $ uname -a Linux myserver 5.4.0-42-generic #46-Ubuntu SMP Fri Jul 10 00:24:02 UTC 2020 x86_64 x86_64 x86_64 GNU/Linux  PS. While I probably can use apt install, I do not really want to install anything more than it is mandated.

I'm trying to install PIL a python module on ubuntu   I first need to install a package called python-imaging using the following command    sudo apt-get build-dep python-imaging   When I try and do this I get the error   E: You must put some 'source' URIs in your sources.list   I saw  question whihc shows how to fix via the GUI but I'm using the command line. Does anyone know how I can fix this error..?    UPDATE: Based on the below answers I've updated my package list but I now get this error. Not sure if it is related, if not I'll start a new question as I can't find reference to the error anywhere.   E: Build-Depends dependency for python-imaging cannot be satisfied because candidate version of package python-all-dev can't satisfy version requirements


I've got two c++ templates. I want to have h and cpp files. It works with only one template but it doesn't work with two different templates. I receive this error from gcc:  ../Temp1.cpp:16:17: error: definition of ‘Name::Temp1<T>::Temp1()’ is not in namespace enclosing ‘Name::Temp1<T>’ [-fpermissive] ../Temp1.cpp:22:18: error: definition of ‘Name::Temp1<T>::~Temp1()’ is not in namespace enclosing ‘Name::Temp1<T>’ [-fpermissive] make: *** [Temp2.o] Error 1   Here the code for Temp1 header:  #ifndef TEMP1_H_ #define TEMP1_H_  namespace Name {  template<class T> class Temp1 { public:     Temp1();     virtual ~Temp1(); };  #include "Temp1.cpp"  } /* namespace Name */  #endif /* TEMP1_H_ */   Temp1 cpp:  #ifndef TEMP1_CPP_ #define TEMP1_CPP_  #include "Temp1.h"  namespace Name {  template<class T> Temp1<T>::Temp1() {     // TODO Auto-generated constructor stub  }  template<class T> Temp1<T>::~Temp1() {     // TODO Auto-generated destructor stub }  } /* namespace Name */  #endif   Temp2 header:  #ifndef TEMP2_H_ #define TEMP2_H_  #include "Temp1.h"  namespace Name {  template<class T> class Temp2: public Temp1<T> { public:     Temp2();     virtual ~Temp2(); };  #include "Temp2.cpp"  } /* namespace Name */  #endif /* TEMP2_H_ */   Temp2 cpp:  #ifndef TEMP2_CPP_ #define TEMP2_CPP_  #include "Temp2.h"  namespace Name {  template<class T> Temp2<T>::Temp2() {     // TODO Auto-generated constructor stub  }  template<class T> Temp2<T>::~Temp2() {     // TODO Auto-generated destructor stub }  } /* namespace Name */  #endif

Quote from :     The only portable way of using templates at the moment is to implement them in header files by using inline functions.   Why is this?  (Clarification: header files are not the only portable solution. But they are the most convenient portable solution.)


CloudFlare help needed  Recently I was looking for a free CDN service. I was looking for free subscription. Someone suggested me cloudflare for this. I registered here but it seems to be complex for me to understand the matter. Please help me by telling me that how this is beneficial for me.  Sorry if any typos mistake.

What exactly is a Content Delivery Network (CDN), how does it work, and why would I want to use one for my web site?  Which are the well-known CDNs out there?


When I boot up I get the message that the /boot is low on space.  I have been reading various responses but when I type the command 'dpkg -l | grep linux-image-' it tells me that the "-1" is not recognised.  Is there an updated version of Ubuntu Tweak? I have Ubuntu 15.04.  I could resize the /boot partition with Gparted but I am new to ubuntu and uncertain about doing that.  sudo dpkg -1 linux-image-* | grep ^ii  [sudo] password for david:  dpkg: error: unknown option -1  Type dpkg --help for help about installing and uninstalling packages [*]; Use 'apt' or 'aptitude' for user-friendly package management;  Type dpkg -Dhelp for a list of dpkg debug flag values;  Type dpkg --force-help for a list of forcing options;  Type dpkg-deb --help for help about manipulating *.deb files;

My /boot partition is nearly full and I get a warning every time I reboot my system. I already deleted old kernel packages (linux-headers...), actually I did that to install a newer kernel version that came with the automatic updates.  After installing that new version, the partition is nearly full again. So what else can I delete? Are there some other files associated to the old kernel images?  Here is a list of files that are on my /boot partition:  :~$ ls /boot/ abi-2.6.31-21-generic         lost+found abi-2.6.32-25-generic         memtest86+.bin abi-2.6.38-10-generic         memtest86+_multiboot.bin abi-2.6.38-11-generic         System.map-2.6.31-21-generic abi-2.6.38-12-generic         System.map-2.6.32-25-generic abi-2.6.38-8-generic          System.map-2.6.38-10-generic abi-3.0.0-12-generic          System.map-2.6.38-11-generic abi-3.0.0-13-generic          System.map-2.6.38-12-generic abi-3.0.0-14-generic          System.map-2.6.38-8-generic boot                          System.map-3.0.0-12-generic config-2.6.31-21-generic      System.map-3.0.0-13-generic config-2.6.32-25-generic      System.map-3.0.0-14-generic config-2.6.38-10-generic      vmcoreinfo-2.6.31-21-generic config-2.6.38-11-generic      vmcoreinfo-2.6.32-25-generic config-2.6.38-12-generic      vmcoreinfo-2.6.38-10-generic config-2.6.38-8-generic       vmcoreinfo-2.6.38-11-generic config-3.0.0-12-generic       vmcoreinfo-2.6.38-12-generic config-3.0.0-13-generic       vmcoreinfo-2.6.38-8-generic config-3.0.0-14-generic       vmcoreinfo-3.0.0-12-generic extlinux                      vmcoreinfo-3.0.0-13-generic grub                          vmcoreinfo-3.0.0-14-generic initrd.img-2.6.31-21-generic  vmlinuz-2.6.31-21-generic initrd.img-2.6.32-25-generic  vmlinuz-2.6.32-25-generic initrd.img-2.6.38-10-generic  vmlinuz-2.6.38-10-generic initrd.img-2.6.38-11-generic  vmlinuz-2.6.38-11-generic initrd.img-2.6.38-12-generic  vmlinuz-2.6.38-12-generic initrd.img-2.6.38-8-generic   vmlinuz-2.6.38-8-generic initrd.img-3.0.0-12-generic   vmlinuz-3.0.0-12-generic initrd.img-3.0.0-13-generic   vmlinuz-3.0.0-13-generic initrd.img-3.0.0-14-generic   vmlinuz-3.0.0-14-generic   Currently, I'm using the 3.0.0-14-generic kernel.


I'm making a graph in tikzpicture using the code below.  \documentclass[11pt]{article} \usepackage[usenames,dvipsnames]{xcolor} %must come before tikz \usepackage{tikz} \usetikzlibrary{arrows} \usetikzlibrary{positioning} \usepackage{pgfplots} \pgfplotsset{compat=1.8} \usepackage{subcaption} \usepackage{caption}  \begin{document}  \begin{tikzpicture} \begin{axis}[width = \textwidth, height = 0.4\textheight, ylabel=\Large{$Y$}, xlabel=\Large{$X$}, xtick={0,2500,5000,7500,10000},  xticklabels={$a$,$b$,$c$,$d$,$e$}, name = border] \addplot[color=blue, smooth, ultra thick, domain=0:10000] {x}; \end{axis} \end{tikzpicture} \end{document}   Since a, b, c, d, and e are variable names, it doesn't make sense to have the "*10^4" appear below the x-axis, as it does in the image below.    How can I get rid of the multiplier?

When creating a plot like this one  \documentclass{article}  \usepackage{pgfplots}  \begin{document} \begin{tikzpicture}          \begin{axis}                  \addplot coordinates {                 (0.01,0.01)                 (0.09,0.09)                 };         \end{axis} \end{tikzpicture} \end{document}   pgfplot uses the following xticklabels:    Is there any way to make pgfplots create labels as 0.01,0.02,... without specifying them all manually using xticklabels and yticklabels?


Find $$\int_{0}^{\infty}{f(x)-f(2x)\over x}\, \mathrm{d}x$$ if $f\in C([0,\infty])$ and $\lim\limits_{x\to \infty}{f(x)=L}$.   I tried denoting $\displaystyle \int{f(x)\over x}dx=F(x)$, but I don't know what to do with $F(\infty)-F(0)$. I also tried somehow to use l'Hopital's rule but don't seem to come by a plausible justification for it, nor do I arrive at a clear expression. I would really appreciate your help in this.

How can I prove the Theorem of Frullani? I did not even know all the hypothesis that $f$ must satisfy, but I think that this are  Let $\,f:\left[ {0,\infty } \right) \to \mathbb R$ be a a continuously differentiable function such that $$ \mathop {\lim }\limits_{x \to \infty } f\left( x \right) = 0, $$ and let $ a,b \in \left( {0,\infty } \right)$. Prove that $$ \int\limits_0^{\infty}  {\frac{{f\left( {ax} \right) - f\left( {bx} \right)}} {x}}dx  = f\left( 0 \right)\left[ {\ln \frac{b} {a}} \right] $$  If you know a more general version please give it to me )= I can´t prove it.


I have recently been in terminal and somehow I lost my Mac name.  It's showing a strange IP followed by some numbers.  My computer's name is "my-xxx-macbook-pro."  When I type hostname I receive:  ip-10-xx-xx-xxx.us-west-2.compute.internal  I have been working in AWS a lot to try to develop some products.   How do I get back to my computer in terminal?

My computer name in System Preferences > Sharing is set to "archos", but is showing as "iphone" on Terminal. It just started doing this after I loaded Xcode for doing iPhone development: Last login: Mon Nov  7 14:46:55 on ttys001 iphone:~ travis$   Any ideas what could be causing this?


I have a South African passport (valid until 2021) and a Portuguese passport valid until 13 Feb 2018. I am flying to Cape Verde via Paris and Lisbon, with short layovers on both. Do I need to apply for visas if I am not leaving the airport and just walking to the connecting flight check-in areas?

I found many related questions on this site but I am still not sure about the rules. How can I decide if I need a visa to transit? Schengen members as of May 2021 are as follows:  Austria Belgium Czech Republic Denmark (excluding Greenland and the Faroe Islands - but an open border with the Schengen Area is maintained) Estonia Finland France (excluding overseas departments and collectivities) Germany Greece Hungary Iceland Italy Latvia Liechtenstein Lithuania Luxembourg Malta Netherlands (excluding Aruba, Curaçao, Sint Maarten and the Caribbean Netherlands) Norway (excluding Svalbard) Poland Portugal Slovakia Slovenia Spain (except Ceuta and Melilla) Sweden Switzerland


I am trying to understand why polynomial long division algorithm works. I have found an answer on Quora, please follow the link:   As you can see the explanation comes along with the example:    And the first step is calculation of the division of the leading terms of numerator and denominator and getting to know how much this differs from the original fraction. In this case:       What I can not understand is why we can perform this first step(why we can divide only leading terms of every polynomial). Could you please explain.  Thanks in advance.

I get normal long division but this doesn't make sense. How can doing it by only dividing by the leading term work? The problem is $$\dfrac{3x^3 - 2x^2 + 4x - 3 } {x^2 + 3x + 3},$$ not $$\dfrac{3x^3 - 2x^2 + 4x - 3} {x^2}.$$


my code is  import java.awt.EventQueue; import java.awt.Graphics; import javax.swing.JFrame; import javax.swing.JPanel; import javax.swing.border.EmptyBorder;  @SuppressWarnings("serial") public class point extends JFrame {  private JPanel contentPane;  /**  * Launch the application.  */ public static void main(String[] args) {     EventQueue.invokeLater(new Runnable() {         public void run() {             try {                 point frame = new point();                 frame.setVisible(true);             } catch (Exception e) {                 e.printStackTrace();             }         }     }); }  /**  * Create the frame.  */ public point() {     setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);     setType(Type.UTILITY);     getContentPane().setLayout(null);      JPanel panel = new JPanel();     panel.setBounds(0, 0, 300, 300);     getContentPane().add(panel);     setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);     setBounds(200, 200, 450, 300);     contentPane = new JPanel();      contentPane.setBorder(new EmptyBorder(5, 5, 5, 5));     setContentPane(contentPane);     contentPane.setLayout(null);      Graphics g = panel.getGraphics();      g.drawLine(10, 10, 20, 20);   } }   in g.drawLine or another draw I have error but eclipse note have error in code my error is :  > java.lang.NullPointerException     at org.eclipse.wb.swing.point.<init>(point.java:54)     at org.eclipse.wb.swing.point$1.run(point.java:20)     at java.awt.event.InvocationEvent.dispatch(Unknown Source)     at java.awt.EventQueue.dispatchEventImpl(Unknown Source)     at java.awt.EventQueue.access$500(Unknown Source)     at java.awt.EventQueue$3.run(Unknown Source)     at java.awt.EventQueue$3.run(Unknown Source)     at java.security.AccessController.doPrivileged(Native Method)     at java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(Unknown Source)     at java.awt.EventQueue.dispatchEvent(Unknown Source)     at java.awt.EventDispatchThread.pumpOneEventForFilters(Unknown Source)     at java.awt.EventDispatchThread.pumpEventsForFilter(Unknown Source)     at java.awt.EventDispatchThread.pumpEventsForHierarchy(Unknown Source)     at java.awt.EventDispatchThread.pumpEvents(Unknown Source)     at java.awt.EventDispatchThread.pumpEvents(Unknown Source)     at java.awt.EventDispatchThread.run(Unknown Source)   thanks for your help  I only need to draw any thing in to the panel My IDE is eclipse and using WindowsBuilder and My IDE not get error in code and I try to other Graphics Draw but have error too

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


I have 2 monitors connected to my Mac.  Each monitor has multiple spaces setup, for example - monitor 1 has Desktop 1, 2 & 3 and monitor 2 has Desktop 4 & 5.  ctrl+← and ctrl+→ only move between spaces on the currently focused monitor.  However, I can't find how to switch monitor focus using the keyboard.  If focus is on monitor 1, I need to point and click my mouse on monitor 2 and only then can I switch spaces on monitor 2.  Even if I switch to an application open on monitor 2 using ctrl+tab, the monitor focus and space switching still occurs on monitor 1.  Using Yosemite.

The fact that each monitor acts on its own in OS X Mavericks is pretty cool. However, I find that I have to use my mouse and click on the unfocused monitor before I can actually slide back and forth its screens (or spaces).  What's the keyboard shortcut to switch focus to another monitor?  update: follow up


I am having a hard time with the following exercise :  Let $w$ be a root of unity and $u \in \mathbb{R}^{\mathbb{N}}$ a decreasing sequence. The study the nature of : $\sum w^n u_n$  It seems to me like that there a lot of cases to handle. For exemple if $u_n \to 0$, $w = -1$ it converges by the alternated serie test. Yet if $u_n \to l \ne 0$ then it doesn't converge. So first we can say that we need $u_n \to 0$ for if we want the series to converge. Yet now I don't now where to go, since it's hard for me to see what is happening with complex numbers. Taking absolute value doesn't cut it since we only look absolute convergence in this case...

$\sum (-1)^n b_n$ is representative of an alternating series. We look at whether $\sum b_n$ converges and if $b_{n+1}<b_n$ $\forall n\in \mathbb{Z}$.  What if our alternating series is of the form $\sum z^n b_n$ where $z$ is any primitive root of unity.  Do the same tests still apply?  Another question: $\sum 1/n$ diverges but $\sum (-1)^n 1/n$ converges. Is there a $p \in \mathbb{Z}$ where $\sum z^n 1/n$ converges where $z$ is a primitive $p^{th}$ root of unity,  but diverges when $z$ is a primitive $(p+1)^{th}$ root of unity


in my super advanced code below I try subtract next values from a big num. I can't understand why this gives me wrong results. I am using cygwin gcc. $ gcc --version gives me gcc (GCC) 6.4.0     uint64_t val = 0xFFFFFFFFFFFFFFFFULL; // 0xFF FF FF FF FF FF FF FF ULL = 8 bytes     printf("[ 0]  %ju\n",  val);     printf("[ 1]  %ju\n",  val -= 1e19);     printf("[ 2]  %ju\n",  val -= 8e18);     printf("[ 3]  %ju\n",  val -= 4e17);     printf("[ 4]  %ju\n",  val -= 4e16);     printf("[ 5]  %ju\n",  val -= 6e15);     printf("[ 6]  %ju\n",  val -= 7e14);  gcc -Wall main.c -o main.exe && ./main.exe gives me results as below: [ 0]  18446744073709551615 [ 1]  8446744073709551616 <- here and below should be 5 [ 2]  446744073709551616 [ 3]  46744073709551616 [ 4]  6744073709551616 [ 5]  744073709551616 [ 6]  44073709551616  Did you notice last digit? Similar things happened for other numbers, but I don't know the reason...

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


I send invites through Outlook.  Some of the people do not use the Calendar feature and are not the most tech savvy.  When they accept the invite the email goes away.  Is there a way to set it on my end so the email doesn't go away.

I'm using Outlook Web Access to read my email. When I receive a meeting notice and acknowledge it, Outlook adds it to my calendar then deletes the email. Is there a way to disable Outlook automatically deleting the meeting email?  There doesn't seem to be any way to configure this in Options - Messaging and Options - Calendar. Note that I'm using Outlook Web Access and not the desktop client.  From the copyright date this appears to be Outlook 2007.  Follow-up: Based on edusysadmin's comment I logged-in using IE8, which exposed a setting not available in Firefox - "Move out-of-date meeting requests and responses to the Deleted Items folder". However unchecking this box doesn't seem to impact the auto-delete behavior.  Follow-up 2: Keep in mind I am using Outlook Web Access via a web browser. I do not have the thick client Outlook installed.