I am running the Ubuntu 20.04 LTS I need certain packages as dependencies for an opensource project I want to contribute to, however the required package versions are only available for 20.10 normal release. I realize that this isn't recommended but is there way to make apt remove that restriction and take them from the universe package registry into my ubuntu LTS?

I need these packages with the latest upstream version backported for ubuntu/natty   libccid_1.4.5-0ubuntu1_amd64.deb libpcsclite1_1.8.1-0ubuntu1_amd64.deb libpcsclite-dev_1.8.1-0ubuntu1_amd64.deb libusb-1.0-0_1.0.9-0ubuntu1_amd64.deb libusb-1.0-0-dev_1.0.9-0ubuntu1_amd64.deb opensc_0.12.2-1ubuntu1ppa1~natty1_amd64.deb pcscd_1.8.1-0ubuntu1_amd64.deb pcsc-tools_1.4.18-0ubuntu1_amd64.deb   I tried to build them from source with update but it failed. I am not an expert at packaging and there are so many tutorials and recipes out there.  Do you know a good and up to date tutorial for backporting Ubuntu packages?  How do I get packages from other releases without having to build them myself?


I'm an MS in CompSci grad who wants to do a PhD someday. The one thing I don't have from my time in undergrad and MS is significant research experience. Of course, I did undergrad research but was never published in any papers. I make a lot as a professional and want to volunteer(read, free) part-time doing research for a professor or lab post-graduation, but I have no idea how to approach this or even find interest amongst professors or labs. Any ideas?  Edit: Undiagnosed disability crippled my undergraduate performance. I was unmedicated, untreated, and had no idea on how to cope. I really managed to redeem myself through my graduate performance and am basically looking for a second chance. If anyone has disability-specific resources as well, that would be great.

I am planning to take a break from industry (software) and want to work under a professor/lab on a research project for 3-6 months, computer science/computing related. I was wondering if people could give me some advice on how to go about achieving this arrangement - success tips, what not to do and the feasibility of this whole endeavour.  I'm in my late 20s. Went to a good UK school and got a decent GPA. I got what is known as an undergraduate masters (MEng), which for all intents and purposes is a BSc + MSc. I regret never undertaking a summer UROP placement while doing my undergrad. I've often wondered about doing a PhD (I kinda always thought I would) and this would be one way to get some kind of feel of what it might be like. Who knows maybe I will change my career and move into research.  I have some potential projects (though still a little vague) that I would like to work on, but I am also looking for existing projects that sound interesting to contribute to. My current plan is to reach out to professors that seem like a good fit with my research interests (by scouring their academic pages and published work). I'm yet to reach out to anyone. Actually that's a good question - would I have more luck joining an existing research project or proposing my own?  This potential opportunity is unlikely to happen again - I currently do not have too many responsibilities e.g. kids, a mortgage, etc. That and the window for me doing something like this is shrinking all the time. I want to make the most of it by going to go to what is considered a competitive school (not that I'm applying for a programme per se).   I also want to sample US university life (I have a degree from the UK), go to a new city and meet some new people.   What I hope works in my favour is I have the money to entirely fund myself - I've been working in the tech indusry for the last half decade. Hopefully this means I don't have to work within the confines of the academic calendar nor compete for funding. I am concerned about the legality of working for free - I have seen .  I understand what I am trying to do may be a little unorthodox, but if I was a professor, and there was an enthusiastic individual who has a decent academics and willing to give up 6 figures for a chance to work on something interesting to us both, then I'd like to meet them. Of course I'm nothing special and I could be a hindrance, but hopefully my work experience, previous academics and genuine interest abate these concerns. To academics reading this, imagine if it was you I contacted asking for this opportunity, what would make you consider me?  Anyway, if people could give me some kind of assurance if what I want to do is not out of the question (or let me know it is), along with some pointers on how to be successful in finding a position.  Really appreciate it, Thomas


I had tried flagging a comment in Stack Overflow, which was the last one before the answer input form area and I noticed a strange z-index issue:    This thing happens even in Meta. I just checked it now. The reason being there are a few inline styles, which make it display that way. It was hard to replicate, but it was possible:    Is this a known bug, or?

The flag window on (a comment to) the last question is hidden beneath the answer box, as shown in the following screenshot:    Linked: , which is currently  - this is not fixed for flags on comments!


I think I overwrote my Windows 10 by Ubuntu. I still can see my installed software on Data C: and also on D:. But I can't open it. How can I solve it?

Can .exe and .msi files (Windows software) be installed in Ubuntu?


It has been repeatedly explained to me that from the perspective of an outside observer a particle takes "infinite time" to cross the event horizon of a black hole. Also, according to these explanations there is no information inside the black hole because nothing gets inside. Then I read answers to the contrary. Whether or not a particle can cross a horizon does not seem to be answerable when an "infinity" is used to describe events in time. I am not trying to make any statements by this question. I am asking for knowledge that is not conflicting because I also see many questions on this website (with answers) that deal with particles hitting a singularity, inner horizons and how an observer would feel when crossing the horizon for different size black holes (for examples) I hope no-one minds me splitting this question into two parts because I need to do so...  1) Does space-time curvature actually reach infinite curvature at the event horizon boundary?  and therefore...  2) Does anything cross the event horizon?

The event horizon of a black hole is where gravity is such that not even light can escape. This is also the point I understand that according to Einstein time dilation will be infinite for a far-away-observer.  If this is the case how can anything ever fall into a black hole.  In my thought experiment I am in a spaceship with a powerful telescope that can detect light at a wide range of wavelengths.  I have it focused on the black hole and watch as a large rock approaches the event horizon.  Am I correct in saying that from my far-away-position the rock would freeze outside the event horizon and would never pass it? If this is the case how can a black hole ever consume any material, let alone grow to millions of solar masses.  If I was able to train the telescope onto the black hole for millions of years would I still see the rock at the edge of the event horizon?  I am getting ready for the response of the object would slowly fade.  Why would it slowly fade and if it would how long would this fading take?  If it is going to red shift at some point would the red shifting not slow down to a standstill? This question has been bugging me for years!  OK - just an edit based on responses so far.  Again, please keep thinking from an observers point of view.  If observers see objects slowly fade and slowly disappear as they approach the event horizon would that mean that over time the event horizon would be "lumpy" with objects invisible, but not passed through?  We should be able to detect the "lumpiness" should we not through?


The title says it all. This is a question that has been nagging at me for some time. Mathematically, the first derivative is not really any different from the second derivative, or the $k$-th. So I ask, what is so special about the second derivative?

What is the reason for the observation that across the board fields in physics are generally governed by second order (partial) differential equations?    If someone on the street would flat out ask me that question, then I'd probably mumble something about physicists wanting to be able to use the Lagrangian approach. And to allow a positive rotation and translation invariant energy term, which allows for local propagation, you need something like $-\phi\Delta\phi$.  I assume the answer goes in this direction, but I can't really justify why more complex terms in the Lagrangian are not allowed or why higher orders are a physical problem. Even if these require more initial data, I don't see the a priori problem.  Furthermore you could come up with quantities in the spirit of $F\wedge F$ and $F \wedge *F$ and okay yes... maybe any made up scalar just doesn't describe physics or misses valuable symmetries. On there other hand in the whole renormalization business, they seem to be allowed to use lots and lots of terms in their Lagrangians. And if I understand correctly, supersymmetry theory is basically a method of introducing new Lagrangian densities too.   Do we know the limit for making up these objects? What is the fundamental justification for order two?


I've been searching everywhere for a cheat to get infinite candies, I find that candy box kind of rips me off!  So is it possible to get infinite candies?

In Candy Box 2, the candies are being produced at a rate of 1 candy per second. Is there any way to increase the potential amount of candy made at a faster rate? (notice that I am only up to the part where the person with the cellar in their house gives me a map.


After I grapple a foe can I drag him off a cliff or do I have to push/shove him at the end?

The situation is like this. PCs having a fight on a battlefield with several very deep chasms. One of the PCs attempt to grapple an enemy, then moves with him into one of the chasms (bringing himself and his target down and potentially very much dead). Looking through the rules, I have found only the following info about grapple and movement:     When you move, you   can drag or carry the grappled creature with you, but   your speed is halved, unless the creature is two or more   sizes smaller than you.   No other rules are preventing the PC from just moving into the chasm and dropping his enemy in it. Or at least I have found none. If I remember correctly, in previous editions there were some rules pointing out, that the victim in this situation is subject to some save or an ability check. That was my ruling during the game.  My question then is basically this:  Is there any rules about what options the grappled creature has in case the enemy tries to push it into dangerous terrain, such as a long fall from a high height?  I am looking for RAW answers, because I want to balance my judgments on at least some rule base (or certainty that there is none). My players are OK with my rulings, but I feel uncomfortable nerfing their strategies just because I feel it is wrong.


This is my first post so apologies for any incorrect formatting or whether this has been answered elsewhere but I seem to be going around in circles.   Basically, I have 12 survey plots and have recorded 17 variables for each; # of tree species, # of dead trees, % grass cover etc. I have 2 years worth of this data (2016, 2017) so would be running each separately. The plan is to use PCA in R to reduce the number of variables by using the component scores from the top principle components instead. I ran PCA using PRCOMP as follows:  dframe1 <- read.csv('g:/veg.csv', header=TRUE) PCA.results <- prcomp(dframe1, center = TRUE, scale. = TRUE)   The first 5 PC's have eignenvalues >1 so I obtained the component scores for these (abbreviated results shown):  PCA.results$x             PC1         PC2       PC3          PC4         PC5  [1,]    -2.7329607  -0.3238917  -1.2887333   0.15997834  1.0115736 [2,]    -0.4176688  -2.6465327  -2.4567818   1.17885072  0.130746 [3,]    -0.2304915  -1.8657283  -0.4056321  -0.12534494 -1.6435601 [4,]    -4.2221891   1.860162    0.5397799  -0.19361945 -1.2656926 [5,]    -3.0834      1.7658483  -0.1064903  -1.02139467  0.9627706   I have read about using rotations such a varimax or oblimin to better separate your components. To check which one to use, I have run an oblimin rotation to see if the any factors are above 0.32 in the correlation matrix.  library(psych) library(GPArotation) my.oblimin <- fa(PCA.results$rotation, nfactors=5, rotate = "oblimin")   None of them were, so it looks as if orthogonal (varimax) rotation should be okay to use although I did get an error message for one year, the other didn't have any errors, that said  "The estimated weights for the factor scores are probably incorrect.  Try a different factor extraction method."  If I do decide to run a varimax rotation on my PCA results, how do I then get the new component scores? It doesn't seem possible to specify a rotation type in PRCOMP so you have to run the rotation afterwards. This will only give you the rotated loadings, i.e. variables against PCs but no component scores, whether I use prcomp or fa to perform the rotation:  r.varimax <- varimax(PCA.results$rotation[,1:5])   or  fa.varimax <- fa(PCA.results$rotation, nfactors=5, rotate = "varimax")   So, my questions are:   Does any/none/all of this seem reasonable? Is it possible to obtain new component scores for my 12 sites using varimax rotated PC values and would you want to? What does error message about estimated weights refer to?   If the answer to 1 or 2 is No, and I shouldn't be running varimax after PCA if I'm interested in component scores, then question 3 is moot really.   Sorry if any of this isn't clear or I'm totally off target. Any help with this would be appreciated. Thanks, Rich

I ran PCA on 25 variables and selected the top 7 PCs using prcomp.   prc <- prcomp(pollutions, center=T, scale=T, retx=T)   I have then done varimax rotation on those components.  varimax7 <- varimax(prc$rotation[,1:7])   And now I wish to varimax rotate the PCA-rotated data (as it is not part of the varimax object - only the loadings matrix and the rotation matrix). I read that to do this you multiply the transpose of the rotation matrix by the transpose of the data so I would have done this:  newData <- t(varimax7$rotmat) %*% t(prc$x[,1:7])   But that doesn't make sense as the dimensions of the matrix transposes above are $7\times 7$ and $7 \times 16933$ respectively and so I will be left with a matrix of only $7$ rows, rather than $16933$ rows... does anyone know what I am doing wrong here or what my final line should be? Do I just need to transpose back afterwards?


I'm using graduated symbology on a vector layer in QGIS and i do not want lines between polygons of the same color. I tried making the border outline transparent, and also setting the border outline to match the fill color and set the border width to 1. I can still see a thin grey border regardless of the settings.   I should add, i'm trying to do this in python. This worked in QGIS but not python:   for actmin, actmax, myLabel, myColor in ranges:     mySymbol = QgsSymbolV2.defaultSymbol(maplayer.geometryType())     mySymbol.setColor(myColor)     mySymbol.setAlpha(myOpacity) mySymbol.symbolLayer(0).setDataDefinedProperty('color_border','color_rgba'+str(rgbacolors[i]))           myRange = QgsRendererRangeV2(actmin, actmax, mySymbol, myLabel)         myRangeList.append(myRange)         i+=1  myRenderer = QgsGraduatedSymbolRendererV2('', myRangeList) myRenderer.setMode(QgsGraduatedSymbolRendererV2.Quantile) myRenderer.setClassAttribute(mappingcol) maplayer.setRendererV2(myRenderer)

In the past I have just manually matched the color of the border to the color of the fill, but this can be time consuming.   I am wondering, is there any way to have the program automatically match the border color to that of the fill?   The fill color is being assigned through the styling tab in layer properties.  Using QGIS 2.8.6


Let $S$ be a set and $P(S)$ the power set of $S$. For sets $A,B⊆P(S)$, we say that $A \sim  B$ if there exists a bijective function $f: A \rightarrow B$. Show that $\sim $ is an equivalence relation.

Let $\mathcal{A}$ be the class of all sets and define the relation $R$ on $\mathcal{A}$ as: $A\space R\space B$ iff there is a bijective function $f:A \to B$. Prove that $R$ is an equivalence relation on $\mathcal{A}$.  I know I need to prove bijection by proving injection and surjection, but I don't even know where to start. Any help would be greatly appreciated.


How can I convert an input if 16 characters to a byte array with the following format. E.g. From textBox.Text = 4a4de6878247d37b    to      byte[] esk_bytearr = { 0x4a, 0x4d, 0xe6, 0x87, 0x82, 0x47, 0xd3, 0x7b };   The method I'm using is not working and is the below.  static byte[] GetBytes(string str) {     byte[] bytes = new byte[str.Length * sizeof(char)];     System.Buffer.BlockCopy(str.ToCharArray(), 0, bytes, 0, bytes.Length);     return bytes; }   The byte array is an input to an decryption method using DES. The method is working but the decrypted message is different from when I use directly the esk_bytearr directly as parameter to decryption method. Thanks

How can you convert a byte array to a hexadecimal string, and vice versa?


I've got an error "The repository ' artful-updates Release' no longer has a Release file" while running Update Manager.  Thanks.

There are now errors when updating and I cannot install most software due to a corrupted  /etc/apt/sources.list   file. Is there a copy I can download to replace it?  The file would be for Ubuntu 12.04 (Final Beta) in the United States.


I'm using a raspberry pi. I didn't think mounting a samba share to a folder full of files would do anything - I thought it would copy the files to the samba share. Now the files are gone from this folder, but the pi's drive is still full. Where did the files go when I mounted the samba share to the folder?

On my headless NAS I have sdf1 (a flash-card) mounted as / while /home is mounted from lv00 (an LVM volume backed by a software RAID). To be able to access the machine when the RAID fails, I have a copy of my ssh public key, etc. in /home/foo/.ssh on the file-system from sdf1. To update the files that are hidden by the mounted /home I normally remount lv00 in /mnt/home, do what I have to do, and then move lv00 back in place. Is there a way to achieve this without unmounting /home?


I want to use Ubuntu on my external hard drive by shrinking into a partition. I use both SSD and external hard drive on my PC and both are installed Windows 10. My external hard drive has 931 GB available capacity and I shrink its volume as 150 GB unallocated and 781 GB NTFS formatted partitions.  Does that mean this unallocated part also have NTFS format or not?  Also, When I configure boot options from BIOS. I see a Partition 1 when I use my Ubuntu installed USB stick.  If I choose Partition 1, would it also install Ubuntu on my 781 GB NTFS formatted partition? To make it clear I am sharing my disk management page for my PC.    Any help would be appreciated.

It looks like  isn't possible with UEFI, where as with MBR there wasn't a big difference between external and internal. Is that true or is it still possible?  Is it even possible to combine both boot methods?


I haven't RPed much, only 2-3 games; most of them are never completed due to events happening and the RP can't be continued.  In the current game I have made a Chaotic Neutral character, whose main goal is to search for treasure and likes to plan his steps. My DM is currently expecting all characters to go along with the quest for the fact that is the right thing to do, or heroic act. My character does not see a reason to follow with the quest, making the DM provide exp to the members following this quest while I'm left with nothing. I am not sure what the best choice to make with this. Should I break out of character and just follow with the story or make a new character that aligns with the DM's purpose?

I've been reading forum posts and blogs who mention "my guy" syndrome as a specific type of difficult player, but I can't seem to find a solid definition for the term. Can someone explain this particular kind of problem player to me? How do you deal with this kind of problem?


Currently, an author of a question can delete his own question or "vote" for closing. Sometimes it happens to me that I ask a question and then I realise I was doing some silly mistake. When this happens, I normally then edit the question and explain the error. For example,  I explain that the hitcount parameter in iptable counts the number of connection attempts, not the individual password attempts. Still I don't want to delete the question. This error can happens to other people, so while I don't need any more answers to the question, also I don't want to close it. Currently I am forced to "vote" to close it, and give some nonsense reason for closing it. I propose that for question authors there could be a more direct "close" action that closes the question directly, or at least that this is implemented for recent or no answers own questions.

A couple of days ago  for a problem I had.  I got no answers, but almost by chance I solved my problem.  I am not quite sure if the question and answer are really relevant given that the solution was so simple.  So I have a question on the question:   Should I answer it (moving current Update 2 as an answer) and in a couple of days accept my own answer, so that question and answer are part of the archive? Should I ask for an administrative closing of the question, so the question reminds in the archive but not as an answered question? Should I ask for deletion of the question, so the question is removed for the archive?


I am looking for a noun to describe a person who embodies  and . This would be someone whose public image does not reflect their core beliefs and values, for the reasons of opportunism or because they have none.  In my native language (Serbo-Croatian-Bosnian), the word is poltron and the English cognate thereof seems to be "" but the broad meaning (coward) seems to lack the specificity it has in my language, i.e. the connotation of inauthenticity, value betrayal, and opportunism. Another word that comes to mind is "conformist" but that also doesn't seem specific enough.

I'm looking for a precise word to describe someone who is hypocritical on moral issues, for example:   a cult guru who claims to be holy while doing something evil. or a company which partakes in some kind of sordid business practice while pretending to be holier-than-thou.


Supposing I have a square real matrix M. If $MM^{T}$ is positive definite,  is $M$ invertible?  I came up with the proof $MM^{T}=M\times I \times M^{T}$, that is equal to say $MM^{T}$ is congruent to an identity matrix, where $M$ is the transformation matrix. However, I couldn't prove why $M$ should be non-degenerating.  Can anyone gives me a hint on this?  Thanks a lot.

Say if $A$ is an $n \times  n$ matrix, why is it that if $A^{T}A$ is positive definite, the matrix $A$ is then invertible? All I know is $A^{T}A$ gives a symmetric matrix but what does $A^{T}A$ is positive definite tell or imply or hint about the matrix $A$ itself that leads to the fact that it will be invertible?


I recently converted a PDF to Microsoft Word, and I'm facing a problem after changing the margin and paper size of the converted file. There is a paragraph mark in the middle of the dialogue. Here is the example:     "When Fillmore was dying, he was super hungry. But his doctor was trying to starve his fever or whatever.   Fillmore wouldn't shut up about wanting to eat, though, so finally the doctor gave him a tiny teaspoon of soup.   And all sarcastic, Fillmore said, 'The nourishment is palatable,' and then died. No truce."   This dialogue was suppose to be in the same paragraph, and there are many same problems in the converted article. How do I fix it? (I hope I could fix it all at once, which is a time saving.)

When I copy text out of a PDF file and into a text editor, it ends up mangled in a variety of ways. Formatting like bold and italics are lost; soft line breaks within a paragraph of text are converted to hard line breaks; dashes to break a word over two lines are preserved even when they shouldn't be; and single and double quotes are replaced with ? signs.  Ideally, I'd like to be able to copy text from a PDF and have formatting converted to HTML codes, "smart quotes" converted to " and ', and line breaks done properly. Is there any way to do this?


I found some sentences that in which  by is not used. Such as:        I did it myself .   I will kill you myself .   he cooks food himself.          Why by isn't used with these sentences like: by myself, by himself?

Could you please explain me which option should I use?     I would like to have a green house with rare plants from all over the world. I could take care of them (myself / by myself)?   And why?


Problem  I'm looking for a way to open multiple instances of an application in Windows 8.1, such as , which does not seem to have an option to enable multiple instances.  My goal in this particular instance is to be able to use FastStone Image Viewer to open as many instances as I need. So if I need a side-by-side comparison of two images, I could just open two images and view them side-by-side. A lightweight application that's always-on could work, but I'd like to see what else is available.  Workarounds  The only way around this I personally know of is using  to sandbox the app and have multiple instances of it open thinking it's running by itself.  Question  Are there any other mechanisms for enabling this without installing a wrapper app?  Similar Questions

Suppose some author has enforced his Windows application to be single instance. Is there any way to make multiple instance of this application (aside from running inside a virtual machine or requesting the author to rewrite the app)?  If there is a readymade tool, I would like to know it. (I have tried sandboxie and Altiris SVS without luck).  If there is nothing out there, I want to program a tool/hack that will let me do this.  I am looking for pointers where to start - what will be involved, what skills would be needed. I have moderate programming skills in C and Java.  If this cannot be done, please explain why.  EDIT: I know its a bad idea but I still need to do it (for various reasons). I want a generic way that works for any application and does not introduce errors.


I am completely new to Minecraft. Where can I learn more about how Minecraft's so-called "seeds" work?   (I imagine the Minecraft "world" as a , and the "seed" as an somehow encoded initial configuration from which by certain rules an initial scenery is calculated. But this is most probably not the (whole) truth.)

I see minecraft seeds listed, and I started trying some of my own.  I have noticed using the same seed produces very similar styles of maps, i.e. start in a specific biome, very high mountains etc, but do they reproduce the maps exactly and you just spawn in the same place, or are they just a very specific set of rules for the area you first spawn?   If I have two maps of the same seed, and I walk 1000 blocks north, will the maps be identical/similar or totally random after the first spawn area?


I'm working on a model at the moment and I've spent hours texturing the torso of my character. The node setup is okay (I think), the paint worked perfectly, it was all fine and dandy until I stopped to texture a 2nd object. As soon as I had done this, the texture on the first object disappeared entirely, to be replaced with solid black. I suspect it might be something simple, but I honestly can't for the life of me figure it out & would really appreciate some help.  P.S I did UV unwrap, did create an image texture, and the image texture is still saved in the blend file. Did I need to save the UVs somehow perhaps?

I was following a  on how to use the Texture Paint feature on blender so I could paint on a terrain I am modeling. I was successful to paint the whole terrain with beautiful, exuberant vegetation, and crystalline water running through the valley.  So I saved my file, and I went to sleep. But now I've reopened the file and everything seems like I left it yesterday, except that I can see no texture in the terrain... The weird thing is that the textures i used are still there... I don't understand, I barely understand the interface, please help. I'm not even sure if the texture is there or if it was never "saved" or something...     I am now going through the second part of the tutorial for possible answers but I (and hopefully many more) will be grateful for your help.


If the accretion disk is on the (x,y) plane of an orthogonal reference frame what happens to objects outside the (x,y) plane (e.g. objects on the z-axis) ? In other words why is the accretion disk a disk and not a sphere (as space in 3D). Thank you. Twelvetones

Why does matter in orbital motion around a central body tend to form an , as opposed to some other configuration like a sphere? I know this has something to do with angular momentum making a disk the most stable configuration.


I have gone through several threads here but haven't found an answer to my question.  In my paper, there are two theorists and each has a theory. Theorist A has theory 1 and theorist B has theory 2.  Can I use both example 1 and example 2 and express this fact?     1) A's and B's theory are worthwhile considering.   2) A's and B's theories are worthwhile considering.   I reckon that 1) is a form of ellipsis standing for A's (theory) and B's theory... Does 2) imply that both A and B have EACH devised more than one theory or that I include A's theory and B's theory to form the plural "theories"?  And on a similar note, Bohr has written one book on a subject and Gitman has written one book:     3) The Bohr and the Gitman volume are worthwhile considering.   4) The Bohr and the Gitman volumes are worthwhile considering.   Which one is correct?

Which option is grammatical?        There will be readings from Nikki Giovanni’s and Alice Walker’s writings.   There will be readings from Nikki Giovanni and Alice Walker's writings.      Saying it out loud the latter sounds right, but looking at it the former looks better.


$1+x+x^2+\dots=\frac{1}{1-x}$, where $-1<x<1$  But I saw in one video this expression is true for $x=-1$ too. So can I write $1+x+x^2+\dots=\frac{1}{1-x}$, where $-1\le x<1$?

Grandi's series,  $$1+1-1+1-1+1-1+...$$  can be expressed as the below:  $$\sum_{n=0}^\infty(-1)^n$$  Two valid sums that make sense to me are $1$, and $0$, depending on how you approach the series. $(1+1)-(1+1)-(1+1)-...=0$, and $1+(1-1)+(1-1)+(1-1)+...=1$.  There is consensus, however, that the actual sum is $\frac{1}{2}$. Why? I understand the approach of finding partial means of the series, and they do indeed tend to $\frac{1}{2}$, but it seems unintuitive to assert that the sum is neither $1$ or $0$.  A more convincing method I found was assuming the series is $S$, then shifting it such that $S-1 = S$, then through algebra finding $S = \frac{1}{2}$, but again, it seems more intuitive answer is either $0$ or $1$. I say this strictly because adding and subtracting integers should equal an integer, never a fraction.  Is this a characteristic of infinite series, which is not specific to Grandi's series?


How would one write down this equation in Latex? What kind of font is used for l and nu?

I know what my symbol or character looks like, but I don't know what the command is or which math alphabet it came from. How do I go about finding this out?


Is there a keyboard shortcut to switch tabs on Safari?

I'm used to switching tabs with cmd+x where x is a number and takes me to tab x in firefox and pretty much every other browser I've ever used. I like safari's speed and would like to try it a bit, but the cmd+x shortcut is burned in my brain and every time I use safari I end up screwing up. I'd like to know if its possible to change this behavior, because this simple thing is a stopper for me.


In The Rise of Skywalker, there's a point where Resistance fighters are performing an assault along the surface of a Star Destroyer, and Admiral Pryde reacts by telling a crew member to "jam the speeders". The crew member states that the Resistance members aren't using speeders, and it's revealed that they're riding horse-like animals for their assault.  Is there any explanation of what "jam the speeders" actually means, or what it would achieve, in any other Star Wars media (Legends or canon)?  Particularly, is there any example of it being used successfully at any point?

During the speeder bike chase in Return of the Jedi, Luke Skywaker instructs Leia to jam the communications of the Imperial Scout Troopers they are chasing/being chased by.   The jammer seems to be activated by a simple switch, which strikes as odd. Is communications jamming such a common function of a speeder bike such that it needs a prominent, easy to reach control?   The explanation I've come up with is that the Empire enforces control by preventing the general populace from spreading information quickly. Comms jammers are routinely installed in all Imperial vehicles and equipment, much like cameras and RFID technology come in a lot of electronic devices in our world.  So, does communication jamming technology appear a lot in Star Wars – both movies and extended universe? Does the theory hold up?


My C:\Windows\Installer folder is huge: 14 GB. My understanding is that this is where failed updates go to die, and it should not be this big. What is the correct way to clean it on Windows 10?

On my SSD machine, the C:\Windows\Installer folder is massive and takes up about 15% of my total disk space.   Is there a way to clean up that folder without killing Windows 8.1/10? Tucking away the installers on the OS partition seems wasteful.


What is the difference between a function and a sequence? I have googled it but I have not found any solid answer anywhere.

Online resources describe a function as a correlation between domain and range values,  while a sequence is just a bunch of numbers correlated with the term.  Isn't this the same thing if you consider the term to be the domain and the sequence value at that term to be the range? What's the difference between a sequence and function?


I'm not sure which of these is more correct.      Your 1 hour is up.   This is easy. Singular.      Your 5 minutes are up   Again, simple enough. Plural.      Your 1 hour and 6 minutes is up.   Your 3 hours and 1 minute are up.   Should the plural be based on the hours or minutes?

When writing about specific quantities, should the verb reflect a singular or a plural value?  Do abbreviations vs. spelled-out words make any difference?  I took 2 ml of water, which was/were then added... Six microliters of protein solution was/were placed in a centrifuge...


I'm a national of country XYZ who wants to visit the state ABC for the purpose of tourism. How can I find out if I will need a visa?     NB: this is intended as a canonical/wiki question

When thinking about travelling, I often have to think about a place to visit, and then look up visa rules for that particular country. This can be a fairly painful process because official government sites can often be hard to find, and advice on (say) guidebooks or Wikitravel tends to be generic.  Is there any resource where I can enter my nationality/residency, and then look up a list of visa rules for various countries?


I have a website that has been online for about 4 months. Out of a sudden, it stopped working. I get this error:  This is my URL:  Any advice? Thanks,

This is a  about Connection Refused    We see a lot of questions to the effect      When I try to connect to a system I get a message      Connection refused      Why is this ?


It is known that $S^6$ admits an almost complex structure which is not integrable, recently Michael Atiyah posted a proof of non-existent of a complex structure on this sphere.  I am curious now about the other spheres i.e what about $S^{4}$ and $S^{2n}$ for $n\geq4$?  Is there any good introduction reference where one at the undergraduate level can read about that?

We know that there is an almost complex structure on $S^6$ which is not integrable. Is it always possible to find almost complex structures on $S^{2n}$? In particular does $S^4$ admit one?


Is there are way to create a material that will colour according to the thickness of the mesh it covers, based, perhaps, on length of edges at right angles to the mesh surface?  For example, white for a zero thickness plane, through a spectrum, to black at an arbitrary thickness beneath, that will change automatically if the mesh is manipulated.

I would like to create a material that has a volumetric component whose local Density depends on the depth of each volume point below the surface.   Can the information "how deep below the surface is a given point" (i.e. the intensity of red color in the figure below) be obtained directly from the material nodes, without adding extra geometry or modifiers?    I've tried using the Z component of the UV Texture Coordinate (after having assigned an UV map), and other kinds of node setups, but I couldn't find a way to obtain that quantity.    Another way of looking at it: consider that SSS can be seen as a Volume Scatter with a Density decreasing smoothly from the surface to one skin-thickness below, while an abrupt fall-off (density goes suddenly from one to zero) corresponds to a Volume Scatter applied on a mesh with a Solidify modifier.   I would like to be able to create any generic falloff profile, including these two.


Hello I'm new to induction so please bare with me. For this problem I have to use induction to prove: For every integer $n\geq 1$, the number $n^5 − n$ is a multiple of $5$. Can someone please help me figure this out. I've tried to follow the examples in the book, but they were very confusing.

So I started with a base case $n = 1$. This yields $5|0$, which is true since zero is divisible by any non zero number. I let $n = k >= 1$ and let $5|A = (k^5-k)$. Now I want to show $5|B = [(k+1)^5-(k+1)]$ is true....  After that I get lost.   I was given a supplement that provides a similar example, but that confuses me as well.   Here it is if anyone wants to take a look at it:  Prove that for all n elements of N, $27|(10n + 18n - 1)$.  Proof:  We use the method of mathematical induction. For $n = 1$, $10^1+18*1-1 = 27$.  Since $27|27$, the statement is correct in this case.  Let $n = k = 1$ and let $27|A = 10k + 18k - 1$.  We wish to show that $27|B = 10k+1 + 18(k + 1) - 1 = 10k+1 + 18k + 17$.  Consider $C = B - 10A$ ***I don't understand why A is multiplied by 10. $= (10k+1 + 18k + 17) - (10k+1 + 180k - 10)$    $= -162k + 27 = 27(-6k + 1)$.  Then $27|C$, and $B = 10A+C$. Since $27|A$ (inductive hypothesis) and $27|C$, then $B$ is the sum of two addends each divisible by $27$. By Theorem 1 (iii), $27|B$, and the proof is complete.


Hello, I need help with this problem. When I render my image the background is transparent, but when I save it, it has a black background. How can I save it without the black background?

I would like to render an animation as a series of .png images with transparent backgrounds for use in a video. Is this possible?


I'm trying to set an Object property equal to the value of a clicked list item (0, 1, 2, 3).  I am able to console.log the correct value, but the object property is not being set.  Could someone please explain how to set my gameObject property to the correct list item value?    var gameObject = {   questions: [     {       title: "What color is the sky?",       answers: [         "blue",         "green",         "red",         "purple"       ],       correctAnswer: 0,       userSelection: ''     },     {       title: "What color is UNC blue?",       answers: [         "Duke blue",         "Sky blue",         "red",         "purple"       ],       correctAnswer: 1,       userSelection: ''     },     {       title: "What color is UNC blue?",       answers: [         "Duke blue",         "Sky blue",         "red",         "purple"       ],       correctAnswer: 1,       userSelection: ''     },   ],   currentQuestion: 0,   userCorrect: 0,   userIncorrect: 0,   userBlank: 0,   timer: 30,   timerRunning: false };  var triviaAnswerSection = $('#answers');  function renderGameAnswers() {   var html = '';   html += `<ul class='question'>`   html += `<li class='answer' value='0'><a href='#'>${gameObject.questions[gameObject.currentQuestion].answers[0]}</a></li>`   html += `<li class='answer' value='1'><a href='#'>${gameObject.questions[gameObject.currentQuestion].answers[1]}</a></li>`   html += `<li class='answer' value='2'><a href='#'>${gameObject.questions[gameObject.currentQuestion].answers[2]}</a></li>`   html += `<li class='answer' value='3'><a href='#'>${gameObject.questions[gameObject.currentQuestion].answers[3]}</a></li>`   html += `</ul>`   triviaAnswerSection.html(html);   $('.answer').on('click', function() {     var answer = $(this).attr('value');     gameObject.questions[gameObject.currentQuestion].userSelection = answer;   }); }  renderGameAnswers();

I have a bit of code where I am looping through all the select boxes on a page and binding a .hover event to them to do a bit of twiddling with their width on mouse on/off.  This happens on page ready and works just fine.  The problem I have is that any select boxes I add via Ajax or DOM after the initial loop won't have the event bound.  I have found this plugin (), but before I add another 5k to my pages with a plugin, I want to see if anyone knows a way to do this, either with jQuery directly or by another option.


i have been working on converting a python code to java related to my research work, i have a query in Python len() object. my problem is in [::-1] as the code provided.  i have tried to do it in java by simply an incremental loop but it does not work. it gives array out of bound exception at temp_line.split('$target/')[1].   for i in range(0, script_lines.__len__())[::-1]:    temp_line = script_lines[i]         if "$target/" in temp_line and "cp" in temp_line:            Case_num = 1 + int(temp_line.split('$target/')[1].split('.txt')[0])             return Case_num   i want to know what does [::-1] mean in the code so i can convert it to java.

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


I created a .txt file on Win 8 [using sublime] (with copied text for here) and moved it to my VM running Linux.  I used cat tmp.txt >> .bashrc to append those lines into .bashrc but mysterious ^M were added in the end of every line (I noticed after sourch .bashrc failed).  I removed those and now it's fine, but where did they come from?  Before and After image:

On Solaris, if you open a file in vi that has Windows line endings, this shows up as ^M at the end of every line.  On Linux, vi is cleverer and understands the Windows file format, and does not display ^M.  Is there a setting to make Linux vi behave the same as Solaris in this respect?  A common problem for us is copying a shell script off a (Windows) dev box and forgetting to dos2unix it, and then being confused when it doesn't work properly. On Solaris the problem is obvious as soon as you vi the file, but not on Linux.  Thanks.


As far as I understand,  is a separate game, not an expansion pack, that doesn't require the original Fluxx deck to play. But can it be used with the original deck  - can it be used to supplement the original cards, or does it not work like that?   (This related question  didn't quite answer my question.)

What should be taken into consideration when mixing fluxx sets?   I played a game of Stoner and Zombie fluxx mixed the other day, and I found it super fun. It add variance to the theming, and especially with the Stoner fluxx (if you're playing with the, ahem, special rules) and stretches it out.   What are the potential pitfalls of mixing sets, and what else should be taken into consideration?


Here's my problem:  I have a power supply rated at 5V, 2.1A  I need this to feed two devices, both running at 5V    Device one is a single-board computer that can consume anything between 0.5A and 1.5A depending on what it's doing. Device two is a battery charger, which is happy to take anything it can get up to (and quite possibly beyond) 2A, and equally happy to take no power at all.   I need a way to feed device one with as much current as it is demanding right now, and give whatever is left to device two.  In order to stay within the PSU limits, I'm going to be limiting the input current to 2A.  I'm a beginner, and from my limited understanding (so please correct me if I'm wrong) the chances are that device one could end up current-starved otherwise.  I'm not happy with simply making two fixed current-limited paths (1.5A to A, 0.5A to B) - I really do want any excess current delivered to device B, if there is any available for it.  The only thing I can think of is to dynamically monitor the amount of current currently going to devices A and B, and to throttle down device B by opening and closing current-limited gates with transistors (or using a variable current-limiting circuit controlled by a digital pot) with a microcontroller until the sum of the two is less than (2A minus a safety buffer), along with some caps in there to keep things running during switching.  However, that sounds a bit complex for something that I have a gut feeling ought to be much simpler, and possibly involves using some kind of specialized IC that I don't know the name of in order to search for it.  This is a problem I feel I'm going to run into with other things as well - not just charging a battery, so I'd like to know if there's any way (simpler than the complex microcontroller solution I imagined earlier) to manage the current distribution in a circuit when the supply doesn't meet the demand - some way to simply say "current goes here first, and what is left over goes there"

I am doing a project where my electronics runs on 5V which I wanted to power from a 7.2v lipo regulated down to that voltage. I'd really like to include the opportunity to charge the lipo without removing it from the project. What kind of circuit/components do I need to do it properly?  Say, would putting a battery charging ic at the battery's terminals in parallel to my system be enough to achieve what I need?


I have Ubuntu 18.04.5 LTS.  When I try to update with the Software Updater it returns this error:  I have tried everything that I found here and still no results, the above error is repeated every time. When I try to update from the terminal with this command: sudo apt update && sudo apt upgrade -y  it returns: dpkg: error processing package libpam0g:amd64 (--configure):  installed libpam0g:amd64 package post-installation script subprocess returned error exit status 1 Errors were encountered while processing:  libpam0g:amd64 E: Sub-process /usr/bin/dpkg returned an error code (1)  Here is a screenshot of the output:  I want to upgrade to Ubuntu 20.04, but without solving this, it seems that I can't. Is there something I can do?

I'm trying to install the flashybrid but when I enter the apt-get install flashybrid command, I get this error:  root@user-desktop:/home/user# apt-get install flashybrid Reading package lists... Done Building dependency tree Reading state information... Done flashybrid is already the newest version. 0 upgraded, 0 newly installed, 0 to remove and 0 not upgraded. 1 not fully installed or removed. After this operation, 0B of additional disk space will be used. debconf: DbDriver "config": /var/cache/debconf/config.dat is locked by another process: Resource temporarily unavailable Setting up flashybrid (0.15+nmu2) ... debconf: DbDriver "config": /var/cache/debconf/config.dat is locked by another process: Resource temporarily unavailable dpkg: error processing flashybrid (--configure): subprocess post-installation script returned error exit status 1 Errors were encountered while processing: flashybrid E: Sub-process /usr/bin/dpkg returned an error code (1)   I also tried this one to find what is already using that file:  root@user-desktop:/home/user# lsof | grep /var/cache/debconf/config.dat lsof: WARNING: can't stat() fuse.gvfs-fuse-daemon file system /home/user/.gvfs Output information may be incomplete. dpkg-prec 4672 root 4rW REG 8,6 39658 1697827 /var/cache/debconf/config.dat   But I don't know how to fix this.


Database table: Some people say that the database table name should be "plural" and some debate for "singular". Is there any standard for renaming the database tables?  Database table columns: Some argue that database column should start with table name as a prefix and some say that it is repeating the same thing twice.   Can anyone help me with what's right and why?  Thanks in advance

Whenever I design a database, I always wonder if there is a best way of naming an item in my database. Quite often I ask myself the following questions:   Should table names be plural? Should column names be singular? Should I prefix tables or columns? Should I use any case in naming items?   Are there any recommended guidelines out there for naming items in a database?


I was looking into  and came across with this term:     # of Managed Operating System Environments (OSEs) per license   Do they mean regular Operating Systems? or adding "Environments" mean something else (platform, architecture, etc.)?  Thanks

This is a  about Licensing.    Questions on licensing are off-topic on Server Fault.  If your question has been closed as a duplicate of this question, then this is because we want to help you understand why licence questions are off topic rather than just telling you "it just is". In all likelihood, this question will not address your question directly, it was not meant to.    I have a question regarding software licensing. Can the Server Fault community please help with the following:   How many licenses do I need? Is this licensing configuration valid? What CALs do I need to be properly licensed? Can I run this product in a virtual environment? Can I downgrade this product to an earlier version? Am I entitled to feature X with license Y?


I can not get my DVDs to work in vlc or any other player. How do I fix this? I have tried to install vlc gremlin and other players.

My machine can't play encrypted DVDs on a fresh install.  How do I add this capability?  Another useful bit of information would be what programs are best for playing DVDs, once I'm able to do so.  See the .  Will I be able to play DVD movies from ?


I created a QGIS project containing several layers which are on my PC. I saved the project to my local drive and then I saved it to the network and copied all the relevent project layers into a folder except the osmap shp files which are on a separate network drive.  I then hunted for a way to remap the QGIS project layers so it points to the network copies and not my local drive.  In AutoCAD this is easy, but I can't find a way to do it in QGIS.  I then tried just deleting the layers from the project and then re-adding them from the new location, but I got a minidump crash every time.  I ended up saving the print composers as templates, exporting the layer styles. Then I created a new project, using the files on the network, and created new print composers from the saved templates.  Is there an easier way to make this project available to other users?  I've seen some info about mapping bad layers, but I couldn't find a dialogue box to do that.  If nothing else, everything on the network will eventually end up on the archive drive and we need to be able to keep projects together.  For example, in CAD if I open a project and someone has moved a file into a new folder, it will tell me that it can't find the external reference. I then open the x-refs window, scroll to the saved path, click browse, then find the file in its new folder and click on it. That saves the changed path.    Based on responses so far, I now know that I need to know how to set a path to relative AND how to remap a path to a different folder. One response gives a plugin for the latter, so I will try that. I am close to understanding the former.  The answer seems to be as follows -  Save project. Then use the save button again which creates a project home folder. Use Qpackage to copy the shp files to the new destination. Than open that new project and save to create a new project home folder. Then use change data source to remap all the layers to the project home folder (as QGIS does NOT save anything as relative at all. It saves all paths as absolute.)

In my project, I use a lot of geodata from different directories. Now I want to give the QGIS project to a colleague (eg on a CD).  Is it possible to copy the shapes from different directories automatically to one directory?


enter preformatted text here  find the recurrence relation.  a(n)=a(n−1)+n with a(0)=0  Do I have to make a replace? Can someone help with initial steps?  Thanks.  Do like this....

Apparently $1+2+3+4+\ldots+n = \dfrac{n\times(n+1)}2$.  How? What's the proof? Or maybe it is self apparent just looking at the above?   PS: This problem is known as "The sum of the first $n$ positive integers".


I installed windows on my SSD as the C:\ drive and it is 71.6gb used out of 111gb.  I should note that when I select all the folders in C:\ and right click and view properties of all the folders in the drive, they total 15gb.  What gives?  What is taking up a fake ~50gb?

How can I visualize which folders and files are taking up all of the space on my hard drive?  I'm getting some conflicting reports on the size of hard drive contents. Namely what is and isn't there and what folders are actually using the space.   I need to know which of the files or folders the culprits behind all this hidden bloat. Also there should be a print option to get it on paper.


I have a problem, caused by me. I just bought a NAND usb stick 2 TB which worked out of the box.  I tried to copy 36GB into it. That of course took too long so, I put my laptop on suspension to not interrupt the process, (that's what I thought). The process stopped of course, and I tried to delete half copied files. This also took too long so I closed the window and tried to delete the from command line which also took to long so I stopped the process and pulled out my usb stick.  Since then my stick is not recognized.  I can see these on journlactl  kernel: usb-storage 3-1:1.0: USB Mass Storage device detected Jan 24 06:40:36 192.168.2.7 kernel: scsi host6: usb-storage 3-1:1.0 Jan 24 06:40:36 192.168.2.7 mtp-probe[29780]: checking bus 3, device 6: "/sys/devices/pci0000:00/0000:00:14.0/usb3/3-1" Jan 24 06:40:36 192.168.2.7 mtp-probe[29780]: bus: 3, device: 6 was not an MTP device Jan 24 06:40:36 192.168.2.7 upowerd[3864]: unhandled action 'bind' on /sys/devices/pci0000:00/0000:00:14.0/usb3/3-1/3-1:1.0 Jan 24 06:40:36 192.168.2.7 upowerd[3864]: unhandled action 'bind' on /sys/devices/pci0000:00/0000:00:14.0/usb3/3-1 Jan 24 06:40:37 192.168.2.7 kernel: scsi 6:0:0:0: Direct-Access     NAND     USB2DISK         0.00 PQ: 0 ANSI: 4 Jan 24 06:40:37 192.168.2.7 kernel: sd 6:0:0:0: Attached scsi generic sg3 type 0 Jan 24 06:40:37 192.168.2.7 kernel: sd 6:0:0:0: [sdc] Attached SCSI removable disk Jan 24 06:41:07 192.168.2.7 kernel: nouveau 0000:01:00.0: Enabling HDA controller Jan 24 06:41:13 192.168.2.7 kernel: ACPI: \_SB_.PCI0.PEG0.VID_: failed to evaluate _DSM Jan 24 06:41:14 192.168.2.7 sudo[29855]:     User : TTY=pts/0 ; PWD=/home/User ; USER=root ; COMMAND=/bin/lsusb Jan 24 06:41:14 192.168.2.7 sudo[29855]: pam_unix(sudo:session): session opened for user root by User(uid=0) Jan 24 06:41:14 192.168.2.7 sudo[29855]: pam_unix(sudo:session): session closed for user root Jan 24 06:45:19 192.168.2.7 kernel: brcmsmac bcma0:1: wl0: brcms_c_d11hdrs_mac80211:  txop exceeded phylen 153/256 dur 1730/150 Jan 24 06:47:02 192.168.2.7 dbus[1784]: [system] Activating via systemd: service name='net.reactivated.Fprint' unit='fprintd.se Jan 24 06:47:02 192.168.2.7 systemd[1]: Starting Fingerprint Authentication Daemon...   With lsusb I have this  Bus 002 Device 003: ID 0a5c:5802 Broadcom Corp. BCM5880 Secure Applications Processor with fingerprint touch sensor Bus 002 Device 002: ID 8087:0024 Intel Corp. Integrated Rate Matching Hub Bus 002 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub Bus 001 Device 004: ID 1bcf:2895 Sunplus Innovation Technology Inc.  Bus 001 Device 003: ID 413c:8197 Dell Computer Corp.  Bus 001 Device 002: ID 8087:0024 Intel Corp. Integrated Rate Matching Hub Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub Bus 004 Device 001: ID 1d6b:0003 Linux Foundation 3.0 root hub Bus 003 Device 005: ID 045e:07fd Microsoft Corp. Nano Transceiver 1.1 Bus 003 Device 006: ID ffff:1201   Bus 003 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub   I think   Bus 003 Device 006: ID ffff:1201   is the records for my USB.  I have Centos 7 with kernel 5.4 and xforms as window manager.  I don't know what to do.

When I plug in my USB flash drive, it shows up on my computer as write-protected or read-only. I am unable to transfer data to it, nor can I modify or delete any files already stored on it. I also cannot repartition or reformat the drive using Windows Disk Management, DiskPart, GParted, or other tools. The drive does not have a write-protect switch.  Why did this happen and what can I do about it? Is there a way to remove the write protection?  (Note that this can happen with some memory cards, too, as they often use controllers similar to those used in flash drives. In some cases, the system may report that the drive or card was formatted successfully even though it was never actually formatted; the original data reappears when the device is reinserted.)     This question comes up often and the answers are usually the same. This post is meant to provide a definitive, canonical answer for this problem. Feel free to edit the answer to add additional details.


How many 4 digit numbers are there which contains not more than 2 different digits?  My attempt   total no. of digits -  the digits which have all different digits.  i.e (9.10.10.10)-(9.9.8.7)=4464  But the answer is 576..What am i missing..Is there any other way to solve this.?

How many 4 digit numbers are there which contain not more than two different digits?  As usual, I will highlight my attempt:   I can have 9 numbers using only 1 digit, e.g. $1111, 2222, \dots 9999$ = 9 digits Using two digits out of 9 (excluding 0) (selected in $\,^{8}C_{2}$ ways), I can arrange them in $4!$ ways. Furthermore, I can use one digit out of the selected 2 once or thrice (e.g. $2111$ or $2221$)  or simply both digits 2 times (e.g. $2288$, $6677$). Hence I get: $$\,^{8}C_{2} \times \left(\frac{4!}{2!\times2!} + \frac{4!}{3! \times 1!}\times 2\right) = 392$$ Finally, I consider numbers with zeroes. With zero selected as a digit, I have 9 options for other digits. And using the same logic as in 2) I can have either 1 zero ($8880$), 2 zeroes (e.g. $8800$) or 3 zeroes in a number ($7000$). This gives me $$9\times \left( \frac{4!}{2!\times2!} + \frac{4!}{3!\times1!} + 1\right) = 99$$   the above 3 steps yield a total number of $9+392+99=500$  However, the answer i have with me is $576$.


Mail : "Who will be doing the validation?" Reply : "Myself and Sarah will be doing validation"  I believe the usage of myself is incorrect here. It should be "Sarah and I will be doing validation". Correct me if I am wrong.

Possible Duplicate:              Does it make sense to say that?  For example: Jim and myself could not attend the party.  If not, how would I say it? Thanks.


They are both in the front. Looks like they're the exact same thing.  Is one part of the other?  What?  Why is it called prefrontral cortex? What does pre before frontal mean? Before front?

Pre means before. Frontal means front.  What does cortex means? Brain?  Is it the front most part of the brain? Is it located at the most frontal part of the brain and that's why it's called prefrontal cortex?  Is morality processed at ventro medial pre frontal cortex or at anterior singular cortex?  My background: I am a programmer. I just want to understand humans brain the way a programmer understand computer. It seems that we don't have CPU. We have huge analog based memory. And we got registers instead of tons of abstract variables. Understanding why certain part of the brain is named under certain things will help me a lot in remembering where exactly that thing is and why. It's something very useful in my ways of learning math and programming.  Basically there are 2 theories.   Prefrontal cortex is named as such because it's before (or in front of) prefrontal lobe. It's because it's behind prefrontal bone (the way other brain lobes are named)   Some people told me to just look that up on wikipedia. If you can show me something in wikipedia explaining the exact answer I am looking for I will be very happy.


Imagine a solid sphere of radius $R$. From the inside of this sphere we remove a smaller sphere of radius $r$. The sphere can be situated anywhere inside the massive sphere. How does the gravitational field in this hollow sphere look like?   I don´t mean how the field inside a hollow sphere looks like (which is obvious zero everywhere).  I thought it would look like this:  g=-4/3(pi)G(ro)r1-(-4/3(pi)G(ro)r2)=-4/3(pi)G(ro)(r1-r2)=-4/3(pi)G(ro)c  g is the acceleration ro is the (uniform) mass density r1 and r2 are the vectors from the centre of thebig sphere to a random point in the cavity and the vector from the centre of the cavity to the random point. c is the vector from the centre of the big sphere to the centre of the cavity (a constant).  So g is constant, and thus the force.

It is quite easy to derive the gravitational field intensity at a point within a hollow sphere. However, the result is quite surprising. The field intensity at any point within a hollow sphere is zero.   What exactly is the reason behind this? Except for, of course, the mathematics behind it. Is there any logic why the field intensity should be zero within a sphere? For example, it is logical to say that the field intensity would be zero at the center, as all the intensities cancel out. However, this cannot be the case for any point within the sphere.


Imagine an individual touched a high voltage line (like a bird) without touching any ground. For sake of illustration, imagine that this high voltage line was at a 100 Exavolt potential.   Would the bird or person notice anything when they touched the line, since they were not also touching ground?  Now, imagine that the bird flies away from the line and lands on a ground line, after having touched the hot line (i.e. the bird is no longer touching the hot line and is far from it). Would the bird notice anything in this case?  Obviously, if the bird touched both at the same time it would be electrocuted.

At the voltage levels of typical overhead transmission lines in the US, a bird can land on one and be just fine (as long as it doesn't do something like spread its wings and touch a tree or something else at lower electric potential).  However, what about a hypothetical powerline at much higher voltage (as in tens of megavolts). Could landing on such a powerline fatally-shock the bird even though it does not complete a circuit for sustained current? (Assume that the distance is long enough that electrical arc'ing is impossible.)  NOTE: My understanding of what happens when a bird flies from an earth object to a powerline (please correct me if I'm wrong) is that - upon contacting the wire - its electric potential changes from earth-potential to the powerline's potential. In order for this to happen, there is an initial transfer of electrical energy (i.e. flow of charge i.e. current) from the powerline to the bird which "equalizes" their electric potential, which happens nearly instantaneously. If this is correct, then my question can be restated more generally as "Can an 'equalization charge' such as this result in a fatal shock, if the potential difference that it's equalizing is high enough?"


Here is the question:  Given function $f$ is bounded on a measurable set $E$. Show that if $f \in L^{p_1}(E)$ then $f \in L^{p_2}(E)$ whenever $p_1<p_2$ .   I know that I need to show $|f|_{p_1}\geq c |f|_{p_2}$ for a constant c   I tried to let $p=\frac{p_1}{p_2}$ and then try to use Holder inequality but it did not get anywhere.  I also try to let $g=f^{p_1}$ and try to look at $g^p$  but it did not work .

Suppose $1<p_1<p_2<\infty$, then show $L^{p_1}[a,b] \supset L^{p_2}[a,b]$.  I was able to show $\|f\|_{p_1} \le \|f\|_{p_2} (b-a)^{1/p_1 - 1/p_2}$ but I'm not sure how to proceed from here.


I created a class which basically serves as a public structure in this example, and let's say the class name is X. I want to declare a local object in main function. The short version of my question is: I know we can do X foo;, but I think X foo(); (attach a pair of parenthesis) should work, and I thought the first usage is actually a shorthand of the second usage. The entire code is provided below:  #include <iostream>  using namespace std;  class X {     public:         int val1;         int val2; };  int main() {     X a;     X b();    // A warning here     X *c = new X;     X *d = new X();      cout << "val of a: " << a.val1 << " " << a.val2 << endl;     cout << "val of b: " << b.val1 << " " << b.val2 << endl;    // Compile error     cout << "val of c: " << c->val1 << " " << c->val2 << endl;     cout << "val of d: " << d->val1 << " " << d->val2 << endl;      return 0; }   And the compiler complains:  11_stack.cpp:16:6: warning: empty parentheses interpreted as a function declaration [-Wvexing-parse]         X ab();             ^~ 11_stack.cpp:16:6: note: replace parentheses with an initializer to declare a variable         X ab();             ^~             {} 11_stack.cpp:22:26: error: use of undeclared identifier 'b'         cout << "val of b: " << b.val1 << " " << b.val2 << endl;                                 ^ 11_stack.cpp:22:43: error: use of undeclared identifier 'b'         cout << "val of b: " << b.val1 << " " << b.val2 << endl;                                                  ^ 1 warning and 2 errors generated.   My initial guesses are the following:   In any case, we shouldn't put an empty parenthesis after a declared variable. It triggers operator().   But later on I disproved both hypotheses. We can see the first disproof in the code: both X *c = new X; and X *d = new X(); work. For the second one, I put additional code like this:  a();   Then I got compilation error messages:  11_stack.cpp:26:2: error: type 'X' does not provide a call operator         a();         ^   So what exactly cause the error?  Working environment:   Mac OS 10.11.3 g++ with flag c++11 Xcode Version 7.2 (7C68)   P.S. Please also help me think a better and descriptive post title if it's too ambiguous...

Is there any good reason that an empty set of round brackets (parentheses) isn't valid for calling the default constructor in C++?  MyObject  object;  // ok - default ctor MyObject  object(blah); // ok  MyObject  object();  // error   I seem to type "()" automatically everytime. Is there a good reason this isn't allowed?


I'm at a loss for why Google is indexing my site incorrectly. I just uploaded a new version of the site last night and "fetched as google" last night as well. Also uploaded sitemap.   www.lemonsevens.com Search Term: lemon sevens  Still, though, for some reason google isn't displaying my title correctly and it is saying that it can't display the meta-description due to a blocked robot.txt (which isn't true). Help!?

My website changed significantly this month.  Amongst the changes was the website's title.  Two weeks ago, I finally used Webmaster Tools and submitted the page.  So far, Yahoo and Bing have updated the title in the search results, but not Google.  I've resubmitted via Webmaster Tools the website, and the bots have crawled the page, and have added "content keywords".  But the title still doesn't match.  The "content keywords" lists many of the words in the new title (but contains keywords of the existing title also).  Must say that 4 of the top 5 key words in the "significance" list are the new title's.  Still, no change.  Any remedies for this problem?  Is adding the "alt" tag for the logo significant enough to trigger the change?  There isn't an appropriate place to put the company name between  tags on the front page.  Any suggestions?  Thanks.


I have a MicroMax Canvas Doodle 4 Smart Phone with Android 5.0, purchased in November 2015. It came with a lot of bloatware, probably including some app named "9Apps", which keeps suggesting apps for me to try out. I always cancel it. While watching YouTube videos, I get some advertisements for some app or the other. Again I never click or install those.  Unfortunately, in touch-phones, it is possible to accidentally tap the wrong button and install malware unintentionally. Also, a friend installed CleanMaster to "help" me, but it looks suspicious to me.    After about 6 months of usage, some malware got installed and it used to show random advertisements at odd times. It was tolerable for some time, but the frequency of advertisements increased, and there was a possibility that I might have unknowingly installed some more apps "suggested" by the malware.    About 6 months back, anytime I would connect to wifi, "SystemUI" would automatically download a whole lot of apps : BatterySaver, Duplicate WhatsApp, web browsers, games, Pro*n downloaders, . . . Also, Phone would become hot and battery would drain-out quickly. Crashes & Reboots were common.    I tried to uninstall all unknown apps, but either system would say that it could not disable system apps, or it would reinstall these apps at next wifi connect.  I tried a factory reset last week, but it was hanging on the next reboot. After repeating the factory reset, I got to the main screen, where I could see the Default Apps, but I got some popups like "WhatApps has stopped running" and "System update in Progress". Moreover, most of the unwanted apps are now shown as Default System Apps. Clearly, malware is still in control.    How can I get rid of this malware ? How can I reset the system to the real factory settings ?  I went to recovery mode and selected "root integrity check" : It shows 66 new files, 2 modified files, and 2 lost files. It does not provide a way to resolve these issues.

My Samsung Note 8 has gotten very weird lately. I get programs I never have installed, and when I try to reboot/reset my device with no backup they still come up after I'm finished with the reboot.  I also have in my "SIM" 2 cards, but I only have 1? And I can't access number. It also shows 2 different IMEIs.  The programs with weird names have all the permissions in my device. Some of them I can't delete, and some can't force stop, and they start running after some time.  Facebook was already installed when I did a reboot and the programs started coming in. I have a secure file on my phone. But this program has permission to everything.  How do I get rid of this problem? Do I root my phone? Can some of you guys please help me with this? This is making me a little paranoid.   Some of the programs:   Dagger Customrabsclient flexbox istrumentzip OpenCenus rxandroid2 agera customclient   I have used many anti-viruses like McAfee, Bitdefender, etc. I have factory reset my computer 2 times, but nothing changes. I have now downloaded AFWall+ to try to stop all these files, but I want to delete them all.  And when I check root manager it says that my phone is not rooted in the proper way. I never ever have rooted this phone.


Let $x_n $ be positive, $s_n = \sum_{i=1}^{n} x_i $         and  the series $\sum x_n$ diverges.  I'm trying to see how we can prove the following two propositions withouth using anything related to Cauchy ( Cauchy criteria for series and notion of cauchy sequences ) or too advanced but i can't seem to suceed in finding a way.     The propositions are :         a) $\sum_{i=1}^{k} \frac{x_{n+i}}{s_{n +i}}   \geq  1 -  \frac{s_n}{s_{n+k}}$   b) The series $\sum_{n=1}^{\infty} \frac{x_n}{s_n} $ diverges   Thanks in advance

I am working on the following problems and I have a couple of questions.     Suppose $a_n>0, s_n = \sum_{i = 1}^{n}$ and $\Sigma a_n$ diverges.      RTP      (a)  $\Sigma \frac{a_n}{1+a_n}$ diverges.      (b) By showing $$\sum_{i=1}^{k} \left[ \frac{a_{N+i}}{s_{N+i}} \right] \ge 1 - \frac{s_N}{s_{N+k}}$$      prove that $\sum \frac{a_n}{s_n}$ diverges.      (c) By showing  $$\frac{a_n}{s_n^2} \le \frac{1}{s_{n-1}}-\frac{1}{s_n}$$      and deduce that $\sum \frac{a_n}{s_n^2}$ converges.      (d) What can be said about       $$\Sigma \frac{a_n}{n a_n +1} \text{ and } \Sigma \frac{a_n}{a+n^2a_n}$$   I understand (a).  But I am generally very iffy with proving these kind of problems because I usually get stuck with showing some inequalities being true.  1), How are the rest of the problem solved ?  2), Is there a general way to solve most of these inequalities ? Especially with those that have summations ?  3), Are these problem considered easy ? I am teaching myself analysis and it's such a struggle for me.


If one copies a file from one directory into the same one, Windows will append a - Copy to the file (well, technically - Kopie, since I have a German install, but you get it).  Is there a way to change that behaviour, as in change the suffix of the new file (perhaps even to the current date)?  (Note that I would like a way to do it directly [via Ctrl+C / Ctrl+V ] instead of having to right click on the file to copy the way it is shown in the similar question.)

Is there an option or tool that will allow me to change the default naming convention for files copied into the same directory in Windows (XP) and above.  e.g. from: Copy of {name}.{ext} to: {name}.{ext}.copy  Currently:  original_file.php Copy of original_file.php   Desired:  original_file.php original_file.php.copy   This would make finding/working with duplicated files much easier (they auto-sort together) and the filetype (by extension) changes thus it can't accidentally "break" something (e.g. if it were a *.java file, upon compiling I would get errors)


The soil cover percentages of some plant species have been measured in a number of plots between control and treatment. In the same plots also some environmental variables have been measured. I am brand new of statistics but I need to run a PCA with these vegetation soil cover data for some plant species (ranging from 0 to 100) and other environmental variables that are expressed at different scales and with different units. In order to standardize data, I started calculating z score but I noticed that it seems to be not satisfying since for a species that has high values of soil cover in many plots z score seem to flatten the differences among plots. Differently, with species that are observed in few plots the z score values are very high in the few cases in which the species is present even if with low soil cover values. I am afraid that this would make poorly represented species weight more than other species that are more represented in the plots when running the PCA. I would like to know if there is a way to analyze the relation between the aforementioned variables through a PCA. Sorry if the issue is not clear. In the case I can provide a more precise explanation. Thanks in advance

What are the main differences between performing principal component analysis (PCA) on the correlation matrix and on the covariance matrix? Do they give the same results?


I use xmbc to view my tv shows. Before I began using xmbc, I batch downloaded the first few seasons of "Bleach". What can I say, I'm an anime fan ;-). These are named: "bleachxx.mp4" where xx is the episode number in respect to the whole series, not to the season. so "bleach21.mp4" is the 1st episode of the second season and 21st overall. The files themselves are, however, divided into their own season folders.   I know you can use the "rename" command to batch rename files. After much tinkering with it using this guide:  I got this command:  rename -n 's/.*(\d{2}).*$/Bleach S0XE$1/' *   The problem is that the command will rename all the files into "Bleach S0XExx" but because the files have the overall file numbers, bleach52.mp4 --> 'Bleach S03E52.mp4' when there obviously aren't 52 episodes in season 3.  I would like to know, then, if there is any way to apply mathematical operations to the file renaming. This would solve the problem as I could subtract The number of episodes in the previous seasons by the overall number and essentially get the season number.  Example: If there are 20 episodes in season 1, then 25-20=5 so the 25th episode is the 5th of season 2 and renaming would carry out as normal.  So, is there anyway to change the values of renaming by applying math operations?  P.S. I'm sorry for the long explanation but I wasn't sure how to or if my question would be clear without it.


Stark's Hulkbuster armor manages to knock a tooth out of Hulk's mouth in Age of Ultron. Did this tooth simply regenerate, or is Banner missing it as well? It's clearly not a front tooth, because we see Banner apparently none the worse for wear in that regard afterwards.  Is there anything in the comics supporting this, or anything else that mentions it? If the question were broadly "what happens to banner when Hulk loses a tooth", the answer is clearly 'nothing', but the cinematic representation of Hulk's abilities is significantly different than what is portrayed in the comics and elsewhere. This question refers specifically to the Hulk in Age of Ultron and not elsewhere.

In Age Of Ultron we witnessed Hulk lose a tooth.   My question is: Has Bruce Banner lost a tooth as well?


While compiling my document i have several problems with itemizes in tabular environments, so I tried it with a simple test build and it didn't really work out.   This is the scipt:  \documentclass{article} \usepackage{tabularx} \begin{document}  \begin{tabular}{l l} Test &  \begin{itemize} \item Test \end{itemize}\\ \end{tabular} \end{document}   And the error says for line 8 and 9:  ! LaTeX Error: Something's wrong--perhaps a missing \item.   I'm trying to find a simple solution for my problem that I can adapt into my other documents. That's why I'm using an example.  The error is the same as in my project so I think it has the same reason.  Thanks for help

I want to create a table like the picture below, and i wish to itemize the lamba_1 > lamba_2 > 0 using 'item style', which is the cell of each categories. Can someone help me?


What are the text and math fonts (most likely) used in ? At first I thought \usepackage{mathpazo}, but the greek letter \Omega seems different.  Using pdffonts I get for page 2  pdffonts -f 2 -l 2 bcov.pdf  name                                 type              emb sub uni object ID ------------------------------------ ----------------- --- --- --- --------- UGOVRZ+URWPalladioL-Roma             Type 1            yes yes no       6  0 ZMKAUH+URWPalladioL-Ital             Type 1            yes yes no       5  0 OZNADR+URWPalladioL-Bold             Type 1            yes yes no       4  0 SOSTRQ+CMR10                         Type 1            yes yes no      12  0 CBYRKR+EURM10                        Type 1            yes yes no      13  0 CGVYUP+CMSY10                        Type 1            yes yes no       7  0   Is it then possible to trace the precise packages used? it seems like a combination of amsmath mathpazo and euler, but not the obvious one.  My QUESTION amounts to: is it possible to use mathpazo for everything, except for greek math fonts in euler?

Is it possible to identify the font used in a specific document/picture?  Answers to this question should identify:   Possible methods to do this (perhaps one answer per method) and adequately describe how to use it (as opposed to merely stating it); Ways of finding the identified fonts, if possible (free or not); and Any prerequisites associated with the method used, if required (for example, "In order to use method X, your document has to be in format Y").   This question is meant as an FAQ, based on an . Its aim is to facilitate the community with the general procedures involved in font identification. Similar cases are solved on a per-usage basis on 's  tag.


I have a script file called "go" of which content reads these lines #!/bin/bash  for i in $1 $2 .. $N do nohup /usr/bin/time     $HOME/bin/antoine.out <$i  >> $i.res 2>> $i.res done  To sort .res files I run ./go file1  My intention is to give this bash script multiple files at once, but the above "for" loop doesn't work for more than two files, that is to say, N is unreadable as the number of inputs. ./go file1 file2 file3 ... filen  It outputs only the files "file1" and "file2". How to correctly make this script runs through all inputs I give, such that the number and names of inputs are not constant?

I have the following code snippet  for num do    echo $num done   But I don't understand why it works! How come does Bash know to loop through my params $1, $2, $3, $... using my personal taste of "num" variable???


I am writing a lexer in which I want to remove comments such as:  /* this is a block comment that can    span across multiple lines */ // this a line comment that can only span one line   I have attempted this already with /\*.*\*/ which matches block comments. The problem with this is that RegEx's first match always seems to be the longest. If I have multiple block comments in the same code, it will match the substring from the start of the first block comment to the end of the last block comment. This is an issue I would like to fix. I assume I can (after the .*) add in something that checks that there isn't a */ in the comment itself. However, I do not know how to tell RegEx (Java) to not match a specific word in the substring.  How can I edit /\*.*\*/ to stop String.replaceAll() matching across several comments? (I can use the same solution for the line comments for // and \n)

I have this gigantic ugly string: J0000000: Transaction A0001401 started on 8/22/2008 9:49:29 AM J0000010: Project name: E:\foo.pf J0000011: Job name: MBiek Direct Mail Test J0000020: Document 1 - Completed successfully  I'm trying to extract pieces from it using regex. In this case, I want to grab everything after Project Name up to the part where it says J0000011: (the 11 is going to be a different number every time). Here's the regex I've been playing with: Project name:\s+(.*)\s+J[0-9]{7}:  The problem is that it doesn't stop until it hits the J0000020: at the end. How do I make the regex stop at the first occurrence of J[0-9]{7}?


How can this be possible in Python 3? k1 and k2's a attributes refer to the same memory location in IPython console  class K():      def __init__(self, a):         self.a = a   k1 = K(4) k2 = K(4)  hex(id(k1)) # 0x10d77b668 hex(id(k2)) # 0x10d77b6a0  hex(id(k1.a)) # 0x10d41caa0 hex(id(k2.a)) # 0x10d41cac0  id(k1.a) == id(k2.a) # True   I am mostly concerned about the object reference issue going on here rather than the 'is' operator test, which I believe is not the problem I am trying to solve. Because, both k1.a and k2.a would pass the is test because the two references refer to the same object. But what I would like to know is, why that happens.

Why does the following behave unexpectedly in Python?  >>> a = 256 >>> b = 256 >>> a is b True           # This is an expected result >>> a = 257 >>> b = 257 >>> a is b False          # What happened here? Why is this False? >>> 257 is 257 True           # Yet the literal numbers compare properly   I am using Python 2.5.2. Trying some different versions of Python, it appears that Python 2.3.3 shows the above behaviour between 99 and 100.  Based on the above, I can hypothesize that Python is internally implemented such that "small" integers are stored in a different way than larger integers and the is operator can tell the difference. Why the leaky abstraction? What is a better way of comparing two arbitrary objects to see whether they are the same when I don't know in advance whether they are numbers or not?


I want to use the elements of array comNumber, in ranNumber() method but when I using this in main() it only shows the address of array. How can I fix this problem?      public class BaseballGame {     public static void main(String[] args) {         BaseballGame bGame = new BaseballGame();         System.out.println(bGame.ranNumber());       }      public int[] ranNumber() {         Random rand = new Random();         int[] comNumber = new int[3];         for(int i=0; i<comNumber.length; i++) {             comNumber[i] = rand.nextInt(10);             for(int j=0; j<i; j++) {                 if (comNumber[i] == comNumber[j]) {                     i--;                     break;                 }             }         }         return comNumber;     } }

In Java, arrays don't override toString(), so if you try to print one directly, you get the className + '@' + the hex of the  of the array, as defined by Object.toString():  int[] intArray = new int[] {1, 2, 3, 4, 5}; System.out.println(intArray);     // prints something like '[I@3343c8b3'   But usually, we'd actually want something more like [1, 2, 3, 4, 5]. What's the simplest way of doing that? Here are some example inputs and outputs:  // Array of primitives: int[] intArray = new int[] {1, 2, 3, 4, 5}; //output: [1, 2, 3, 4, 5]  // Array of object references: String[] strArray = new String[] {"John", "Mary", "Bob"}; //output: [John, Mary, Bob]


I drew a popsicle and I want to animate it in After Effects but first I need to separate each object on my drawing into a new different layer   Is there a way to do that?

Lets suppose I have 10 objects in the root layer of my project named layer 1. Now lets suppose I quickly want to turn all those object as independent separate layers all at the root level. Is selecting individual object and pressing on collect in new layer the only way?  Is there a quick method of selecting all the objects and doing something to turn them all into layers at once?


On my MacBook I am connected to internet through WiFi but I also have a router for my lab connected to Ethernet port.  wifi(en1): 192.168.0.4/24 with 192.168.0.1 gateway.   ethernet(en0): 192.168.1.254/30 with no gateway.   When I try ping 192.168.1.254 or even ping 192.168.1.253 which is the other end of my Ethernet I do get a reply but when I run ping -S 192.168.1.254 192.168.0.4 or ping -S 192.168.1.254 192.168.0.1 ping an address on the internet I get this:  ~ ping -S 192.168.1.254 192.168.0.4  PING 192.168.0.4 (192.168.0.4) from 192.168.1.254: 56 data bytes ping: sendto: No route to host ping: sendto: No route to host Request timeout for icmp_seq 0 ping: sendto: No route to host Request timeout for icmp_seq 1   So while WiFi can ping Ethernet and further to it, Ethernet cannot ping WiFi or my ISP's router or go out to the internet.  My question is how I can make Ethernet reach my ISP's router and therefore internet as well as other devices on my WiFi network.  I tried static routes but it is not working. I was only able to ping WiFi (192.168.0.4) by sharing my WiFi connection to Ethernet from preferences, and then assigning  the IP address of eth to the bridge that was created with the following command sudo ifconfig bridge100 inet 192.168.1.254/30 but still I could not ping 192.168.0.1 or any other device on the WiFi network.

Okay, I'm struggling a bit here. I'm not all that good with Terminal and sorting out network issues using it but I've managed to scrape by so far.  Without using Internet Sharing (because controlling that via Terminal as per  doesn't actually seem to work in Yosemite) how can I share my internet connection from one interface (lets say en0) to another (again, lets say en1)?  I kind of understand that Internet Sharing creates a bridge (usually called bridge100) and then uses bootpd (I think) to establish a DHCP server and NAT to route all traffic from 192.168.2.xxx (which is the bridged network) through to your primary network.  How can I get the same result without using the Sharing pref pane?


I have the sum  $$\sum_{k=0}^{n} \binom{n}{k} k$$  I know the result is $n 2^{n-1}$ but I don't know how you get there. How does one even begin to simplify a sum like this that has binomial coefficients.

Proof that $\suṃ̣_{k=1}^{n}k {n \choose k}$ for $n \in \mathbb N$ is equal to $n2^{n-1}$.  As a hint I got that $k {n \choose k} = n {n-1\choose k-1} $.  I tried solving this by induction but, in the inductive step I'm not arriving to the correct result.


I've just created pants/trousers for a standard human model by selecting the legs area, creating a new object and scaling it up little, then adding cloth modifier (e.g. denim) When I animate, the pants just 'fall down' obviously - I think the answer is pinning - but not sure how to pin the pants to the original character's waistline (as if the pants had a belt keeping them up?)  And please don't point me to this question     Since it only links to a tutorial which shows how to create a top - not a skirt or pants hanging from a waist.  Thanks J

I made these pants with this tutorial another user directed me:   I followed the tutorial and got it to this:    I want to add an elastic waistband around the pant's waists and ankles so that the pants don't droop like that. How can I do this?


I'm trying to wrap my head around function templates. Specifically, why should function templates be declared and defined in their own header file? Suppose you've decided to write a function template that you expect to use in many different source files. Suppose, further, that you haven't followed the basic advice of writing C++ templates in header files, but have instead done the following: Written only a declaration of the function template in a header file x.hpp (i.e., all you wrote in the header file is template  and then the function's signature). Written the function template, including its body, in the corresponding source file x.cpp. Now suppose that you've written a separate source file, y.cpp, in which you've written #include "x.hpp" near the top and then instantiated the function template by calling it, and that your call to the function template is a legal instantiation (i.e., it has the right number of parameters and they're compatible with any constraints introduced within the template). Will it always be the case that this program can be built? If so, why do we have a rule about writing C++ templates in header files (i.e., If this isn't the problem that rule solves, what problem does it solve?)? If not, specifically why does the program not build? What steps will succeed? What steps will fail?

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.)


I was studying the concept of variable scope in JS, found this example on it:  (function() {     var foo = 1;     function bar() {         var foo = 2;     }     bar();     console.log(foo) //outputs 1     if(true) {         var foo = 3;     }     console.log(foo) //outputs 3 })();   output of this function is  1  3   Now I am confused how come foo gets gets value 3 in second log. even when foo is declared by using var in if statement. shouldn't the foo declared in if will have a new instance as it gets in bar()??

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


In the book Harry Potter and the The Chamber of Secrets, Percy (who is a prefect) is able to deduct house points from Gryffindor when Ron accuses with him about being more bothered about his chances of becoming a Head boy.  In a subsequent book, Harry Potter and The Order of Phoenix, in the context of the inquisitorial squad, it is mentioned that prefects cannot dock points from houses.  This seems to be contradictory to Percy's actions in second book. What accounts for this lack of consistency?

In Harry Potter and the Chamber of Secrets, Percy argues with Ron when he catches Ron and Harry in a corridor at night, and tells him, "Five points from Gryffindor." However, in Order of the Phoenix, it states that members of the Inquisitorial Squad, "unlike prefects," can take points from the houses.  Was Percy bluffing? Or is this just a small inconsistency in the books? I prefer to think that Percy just wanted to pretend, since he loved the feeling of power and authority, but I don't know of any other explanation.


When under the effects of true seeing, and you see past illusions and stuff, do you still see the other forms? So lets say people were using illusions as advertising banners, could you see the banners?

With the spell Shadow Conjuration you can essentially cast Summon Monster, however, the summoned creature is an Illusion (or at least from the Illusion school). How does True Seeing react to this?  True Seeing allows you to see through illusions, presumably like they aren't even there. So if you were to conjure up a Wolf with Shadow Conjuration, would the person using True Seeing even have the chance to disbelieve the Wolf for reduced damage? If so this seems like a great way to thwart those that use this spell, because the monsters you could summon would effectively be... well, "Invisible".


I have been trying to update ubuntu 12.04 but each time i am getting the following error..can anyone help me.  W: Failed to fetch cdrom://Ubuntu 12.04.4 LTS _Precise Pangolin_ - Release amd64 (20140204)/dists/precise/restricted/binary-i386/Packages  Please use apt-cdrom to make this CD-ROM recognized by APT. apt-get update cannot be used to add new CD-ROMs

When updating I got this error message:  W:Failed to fetch cdrom://Ubuntu 11.10 _Oneiric Ocelot_ - Release amd64 (20111012)/dists/oneiric/main/binary-i386/Packages  Please use apt-cdrom to make this CD-ROM recognized by APT. apt-get update cannot be used to add new CD-ROMs W:Failed to fetch http://ppa.launchpad.net/synce/ubuntu/dists/your_ubuntu_version/main/source/Sources  404  Not Found   What to do?


I am a beginner cyclist.So ,I want to know which things I have to do regularly.And what will be the time interval ?  Example :Pump,tuning etc.

It is forecast to rain this weekend so I was thinking I would drop a tarp down over my living room floor and give my bikes a bit of a tune up.    Question  What maintenance needs to be done on your bike?  How often?  Background  Generally speaking I am of the mind: "If it is not broken don't fix it".  However I recognize that there are preventative measures that I can take that will drastically improve the life of my bike and the expense of repairing it.    I am pretty good at noticing when something changes on my bike.  (For example: something is making a slightly different noise, something is not spinning well, etc).  One think that I am concerned about however is when something gradually gets worse in increments that are not noticeable.  For example you forget to oil part X and it gets increasingly noisier or harder to spin etc.  I am concerned that I would not notice it.    I like to do my own work when possible but I will bring the bike in for work when necessary.    Answer Structure  The best answer will have this format:   Daily   this thing this other thing   Weekly   Bla   Monthly   Something   Yearly   What else?   Ideally the bullets should be sorted by importance.  Importance is defined by expense.  If you don't do this thing then it will cost you $X.    It is not necessary to provide a description for each procedure as we can open additional questions for each of those procedures.    Similar Questions      Addresses how much maintenance a bike needs but does not lay out a clear schedule     What to do before putting your bike in storage for winter      Edit (To get the bounty)  What I am looking for is in terms of the Monthly/Yearly sections is what a bike shop would do during their yearly tune ups.  I do most of my own repairs/work and I want to make sure that I am not missing anything.


I'm trying to hide element inside Iframe from different website. This is the embed code for Iframe  <iframe width="853" height="480" src="https://my.matterport.com/show/?m=NtQzb5gDVTp" frameborder="0" allowfullscreen allow="vr"></iframe>   I want to hide the top bar at the top. I'm trying to use this css:  #model-title .title-row {     height: 50px; }   I tried from my browser developer mode and it works. My question is: How I can Include this css code in my page to hide this element and make it savable

I have a simple page that has some iframe sections (to display RSS links). How can I apply the same CSS format from the main page to the page displayed in the iframe?