I am in the process of building this High Rise, and have come across this problem. This first screenshot is just after finishing making the exterior of the building, and before I click 0 to jump into Camera View. The selected object is my camera. No problems yet!   This next screenshot is after pressing 0 and panning out of somehow being zoomed into the interior (clearly the camera is outside and is not even facing the interior...) and now one of the sides of my building is missing?! I also tried messing with the camera's Focal Length which didn't work, and the outsides of the camera view aren't blacked out like they're supposed to be.   And third, the missing wall mesh somehow ended up floating in space all the way over there...  Any idea what the problem here is? Thanks so much!

I have a problem with rendering in cycles. In blender render my object is rendering fine, but in cycles when I pushed F12 I got only this:    One more thing: when I click 0 on keyboard I'm not in camera persp, but in object as camera, it looks like invisible layer, I don't know how to undo this, and be in camera persp again.  Does anybody have any idea how to fix this?


I expect this is from an anthology from about 1950.  It is set on Earth, in the U.S., I believe.  The key part of plot is by walking with his eyes closed down a college path and visualizing very hard that the slope is the reverse of what it "really" is (slightly up instead of slightly down, or vice versa, I don't recall), the protagonist is instantaneously shifted into a parallel world which is technologically very similar but much more restrictive of thought.  The happy ending is an escape via desperately reversing the visualization.  This may well have been in an anthology including a story about a man trapped in a large Möbius strip.  I haven't read this in a lifetime, so I recall no more details.  It may or may not have been a reaction against McCarthyism.

It's been about 25 years since I read a story in an anthology.  The only details I remember from it are that a guy is told that if, while walking down a road (or something similar), he mentally forces himself to think of dimensions opposite of what they are (down is up, left is right, etc.), he will be able to move into another dimension.  He succeeds, but that's all I remember of the story.


There are similar questions but i didn't find a clean answer for what i think is simple.  I want to get once the first 1000 elements of a list, then the first 2000 ecc...  for i in range(1000, len(l1), 1000):      a = l1[:i]   but obviously won't work if len(l1) % 1000 != 0 or if len(l1) < 1000. What is an easy solution for this?  Thanks.

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


Because our client base is largely government agencies, we have been way behind on mobile support for our site. Now with google making mobile readiness a core part of their search rankings, it is suddenly a priority.  A truly responsive design would require a complete redesign, which in all honestly is desirable anyway, but it is proving to be a tough sell, and management wants to leave the existing desktop-oriented site as-is and use redirects to host completely separate versions of our pages for mobile users.  Before I dig my heels in and fight for the more time consuming responsive redesign, is there a concrete SEO advantage to either approach?

Given a site which is not optimized for mobile (and not responsive), Google's new ranking algorithm, which is set to go into effect April 21, 2015, will result in a lower ranking.  If the site does not currently have an "m dot" site (m.example.com), would introducing a new site at the new domain solve the SEO problem? Or would it cause another one? Wouldn't that the pages to be indexed twice?  Responsive design is clearly the best solution for maintainability and certainly solves the "mobile-friendliness" problem, but I'm curious if introducing a mobile-only site would also solve the problem.


I have the following:  @Book{Faber, ALTauthor = {•}, ALTeditor = {•}, title = {Fluid Dynamics for Physicists}, publisher = {Cambridge University Press}, year = {1995}, OPTkey = {•}, OPTvolume = {•}, OPTnumber = {•}, OPTseries = {•}, OPTaddress = {•}, OPTedition = {1}, OPTmonth = {•}, OPTnote = {•}, OPTannote = {•} }  @Book{Goff,   ALTauthor = {•},   ALTeditor = {•},   title = {Gold Medal Physics: The Science of Sport},   publisher = {Johns Hopkins University Press},   year = {2010},   OPTkey = {•},   OPTvolume = {•},   OPTnumber = {•},   OPTseries = {•},   OPTaddress = {•},   OPTedition = {•},   OPTmonth = {•},   OPTnote = {•},   OPTannote = {•}   }   This is all saved as mybib.bib.  Then I use    \bibliography{mybib.bib}   \bibliographystyle{plain}   Then there is no bibliography :(

I've browsed the forums and found a number of posts that have addressed this issue, but none of the solutions seem to work for me. I have the following script that I just copied from the bibtex home page to get familiar with it. Instead of the citation number I get a question mark. I compile using Latex+Bibtex+Latex+Latex+PDFLatex+ViewPDF just as has been previously suggested and the problem persists.   \documentclass[11pt]{article} \usepackage{cite}  \begin{document}  \title{My Article} \author{Nobody Jr.} \date{Today} \maketitle  Blablabla said Nobody ~\cite{Nobody06}.  \bibliography{mybib} \bibliographystyle{plain} \end{document}   My bibliography (Bib.bbl)  @misc{ Nobody06, author = "Nobody Jr", title = "My Article", year = "2006" }    Looking at previous posts one thing that is concerning is that my .bbl looks empty as shown below. Further, I don't have a .blg  \begin{thebibliography}{}  \end{thebibliography}


We have tried punishing and then rewarding the child for pooping their pants.  He has been to the doctors and was suggested to try a laxative for this problem.   We also tried setting certain times to have the child sit on the toilet.  Nothing seems to be working.  Would hypnotizing work?

My 12 year old daughter has been dealing with retentive encopresis since age 6. She avoids going to the toilet at all. This results in soiling and the production of an amazing huge toilet-clogging log-like object every week. We have been trying for years to get her to talk about this, but when we do talk about this, the response is ALWAYS "I don't know" despite what her pedi, GI doc and psychologist tried to do or suggested we do to get her to talk about it. We switched psychologists last year after a year of not talking about this, no luck.  We have tried so many treatment plans since diagnosis, specifically tailored to her, such as enemas, scheduled toilet sittings, rewards, consequences, psychologist, etc. she just keeps holding it in. Right before summer, her pedi and the GI doc laid out a clear treatment plan of laxatives, regular bathroom visits, and a rewards program. She did take the Miralax (2 table spoons) but she just kept holding it in and soiling her pants. She avoided going to the toilet. I made her stay at the toilet and told her "if you poop, I will buy you XYZ" (something she REALLY wants)" you can do XYZ only after you poop" and not letting her do things "you can't do XYZ until you poop" and XYZ would be something she LOVES to do. I wouldn't let her leave the toilet until she pooped, so she sat there for hours, no luck. When school started, she refuses to take the Miralax.  Now we laid out a new treatment plan. We TRIED to involve her, the response is again "I don't know." She is supposed to take an enema every morning and sit on the toilet, but she fights daily about taking it. When she does take it, she holds it in and won't sit on the toilet. There is also a diet plan she refuses to follow. She is not supposed to drink dairy, but drinks milk at school. Now the past 2 weeks she refused all treatment which we fight daily about. She refuses to sit on the toilet, no matter what we try. 2 years ago we tried ucanpooptoo, didn't help.  We asked her why she holds it in. Does pooping hurt? Does it scare you to poop? Does it feel good to hold it in? The answer is always "I don't know" and you can question her for hours and hear "I don't know". We explained to her digestion and she knows why she needs to poop. We ruled out any physiological reasons for retention. Luckily her friends don't notice, but one day her friends might smell her soiling, and I talked to her about this, how it would affect, boys , high school, etc. Her response was "I don't know" and she would not talk about this.  Does anybody have suggestions how to get her to start pooping in the toilet regularly?


I often write my notes as logical statements and constantly wonder why people use only the "if" direction in the definitions instead of the "if and only if". Consider:  "A homomorphism $\phi$ is said to be an isomorphism if it is an injection  and a surjection." would translate to:  $homomorphism(\phi) \wedge injection(\phi) \wedge surjection(\phi) \implies isomorphism(\phi)$  By adding the following statement consistent with the previous one:  $homomorphism(\phi) \wedge \neg injection(\phi) \wedge surjection(\phi) \implies isomorphism(\phi)$  we could deduce  $homomorphism(\phi) \wedge surjection(\phi) \implies isomorphism(\phi)$  which is obviously not what we intended to express in the definition, however the intention does not imply the deed.  From the strict logical perspective do you agree that all definitions of this form are "flawed" owing to the lack of the attention to details? Or is there some reason which I have not managed to observe that explains why "if" is used in lieu of "if and only if"? Would you accept if I write in papers definitions in the iff version? I.e. "A homomorphism $\phi$ is an isomorphism if and only if it is an injection and a surjection."

In some books the word "if" is used in definitions and it is not clear if they actually mean "iff" (i.e "if and only if"). I'd like to know if in mathematical literature in general "if" in definitions means "iff".  For example I am reading "Essential topology" and the following definition is written:     In a topological space $T$, a collection $B$ of open subsets of $T$ is said   to form a basis for the topology on $T$ if every open subset of $T$ can be written as a union of sets in $B$.   Should I assume the converse in such a case? Should I assume that given a basis $B$ for a topological space, every open set can be written as a union of sets in $B$?  This is just an example, I am not asking specifically about this sentence.


I have a directory called music who have many albums and separate tracks. Some of them are in subdirectories. What I want is remove this folders and mix all tracks in the music directory without separations.  Will be hard do this manually, so I am looking for some  command.

I have 50 folders with some subfolders too, with more than 1000 audio files total. I need to remove all subfolders and put all files in present level. Tried mv */* ./ but it complaints: argument list too long


I have trouble in understanding the last part of the sufficiency proof of Pépin´s Test ().  "In particular, there are at least least F_{n}-1 numbers below F_{n} coprime to F_{n}, and this can happen only if F_{n} is prime".   Can anybody explain me that? Is it true that if the order of a number (mod n) equals n-1 then n is prime?

Problem:   If $x^{n-1} \equiv 1 \pmod{n}$, and for all divisors $q$ of $n - 1$, $a^{q} \not\equiv 1 \pmod{n}$, then $n$ is prime. $(n > 1)$   I read the proof in the book and it was very straightforward; however, I wonder is there a way to prove it by just using congruence property?    And another related question about power residue: If we have $a^{n - 1} \equiv 1 \pmod{n}$. Is there any relation between $n - 1$ and $\phi(n)$?  Because I thought of $a^{\phi(n)} \equiv 1 \pmod{n}$, when $(a, n) = 1$. I try to think of away to connect these two ideas, but I still cannot see it. Any idea?    Thanks,


It seems that when exporting a model, the output .mtl file does not include reflectance coefficient, which in blender is set using under "Mirror" in "Material".    The .mtl file is as follow:  # Blender MTL File: 'None' # Material Count: 1  newmtl Material Ns 96.078431 Ka 0.000000 0.000000 0.000000 Kd 0.640000 0.640000 0.640000 Ks 0.500000 0.500000 0.500000 Ni 1.000000 d 1.000000 illum 2   Is there a way to include reflectance in this file?  Thanks in advance!


The command has to be  ls -ld   Just from viewing the output of this, how can I determine how many files are in this directory?

How can number of subdirectories and files be determined from the output of using ls -ld command?  I realize that this command only lists the directories.


How to prove $(\mathbb{R}\backslash \mathbb{Q})\cap (x,y)\neq \emptyset$ for $x,y\in \mathbb{R}$ and $x<y$?  Sorry, but I don't even know how to start. Any ideas and impulses?

I'm being asked to prove that the set of irrational number is dense in the real numbers.  While I do understand the general idea of the proof:   Given an interval $(x,y)$, choose a positive rational number (say) $z=\sqrt{2}$.  By density of rationals, there exists a rational number $p$ in the interval $(x/z, y/z)$, which essentially means that $$\frac{x}{\sqrt{2}} < p < \frac{y}{\sqrt{2}}.$$  I find that $pz$ is irrational, since it is the product of a rational and irrational number. However, my instructions besides writing that proof down is to specifically verify that $y=xz$ is irrational.  What does this have to do with anything and how does it prove denseness of irrationals?  Regardless, assume that $x$ is a nonzero rational number and that $z$ is irrational. For the sake of contradiction, assume that $y=xz$ is rational. This should mean that $y/x$ rational as well, and therefore that $z$ is rational, a contradiction.


I'm trying to have dynamically generated elements call functions, or be selected by jquery to do another action. Not having much luck so far.  html  <button id="staticButton">static button</button> <button id="onClickButton" onclick="onClickFunction()">onClick button</button>

buttons created using static button

buttons created using dynamic buttons

   js  element_number = 1;  $('#staticButton').on('click', function(){     $('#from-static').append(         '<button id=' + element_number + ' >' + 'Dynamic Button #' + element_number + ' generated by static button</button>
'     );     element_number = element_number + 1; });   how would I select the newly generated buttons?  $('?').on('click', function(){     var currentId = $(this).attr('id');      $('#from-dynamic').append(         '<button id=' + element_number + ' >' + 'Dynamic Button #' + element_number + ' generated by Button #: ' + currentId + '</button>
'     );     element_number = element_number + 1; });   another approach perhaps: add an onclick event to generated buttons that call a function  function onClickFunction(){     alert("should this work?");   }   but clicking on the button I get: ReferenceError: onClickFunction is not defined

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'm facing this problem with my laptop. Ubuntu is installed alongside Windows 10 and when I press "Enter" at startup it's not showing the Ubuntu Grub menu! I'm new to this OS and noob!  Can anyone help me? Also, I tried to add a new entry with EasyBcd, and not working! Please help! Edit: Well i found a solution for this problem! So • first open your BIOS and Go to System Configuration > BOOT Options > Os Boot Manager • Then select ubuntu by pressing arrow keys • Then press F5 or F6 (Just look for bottom of your pc screen and look for "Change Value" ) • Now save & exit 🙂

Ok, so I'm such a newbie to Ubuntu and I bought a Windows 8 pre-installed laptop last month.  I updated to Windows 8.1 and then I thought about installing Ubuntu as a dual boot so I could mess around and learn more about it.   So I followed a Youtube tutorial (  ) and I got my stuff working fine.   The first few times I booted I got the GRUB menu instead of my default HP Boot OS Manager, and I was able to select my OS.   So I went to sleep and the next day I turned on my computer and the GRUB menu did not show up. I tried several times and it didn't automatically show up.  In order for me to see the GRUB menu I had to turn on my PC and on start had to press ESC to pause startup and press F9 to get boot options. Then from there I had to pick from OS Boot, Ubuntu, Ubuntu (Yes there were two Ubuntus available) and a default EFI file thingy.   When I click the first Ubuntu I get the GRUB Menu (I was too scared to try the second in case I screwed my laptop up) and I can safely load Ubuntu from there and use it (although I do have to increase my brightness every time I load Ubuntu because it somehow reduces my brightness to complete darkness on boot)  So my problem here is why isn't my GRUB showing on boot, after it worked on the first day?   My laptop is a HP TouchSmart j-078CA.  EDIT 1: FYI I just switched to Ubuntu LiveCD to check my Installation and found out that one of my partition is flagged as msftres. Here is a screenshot of my GParted on a LiveCD:


I have 14.04 LTS and when it was installed there were three partitions it looks like from Gparted.   Is /dev/sda1 which is the /root Is /dev/sda2 which is Extended and does not show anything for mount. (the size is the total drive size which is 1.8Tb) Is /dev/sda5 which is lvm2/pv and mounted as ubuntu-vg (this also shows as 1.82Tb but also shows 1.82Tib used.    When I look at the graphical display it shows the root as 256 mb over all three partitions. I think I need to expand that but how?   Thanks

My first issue was when I tried to apt-get update or apt-get upgrade. On upgrade I get the following error:  You might want to run 'apt-get -f install' to correct these. The following packages have unmet dependencies: linux-image-server : Depends: linux-image-3.2.0-27-generic but it is not installed E: Unmet dependencies. Try using -f.   I tried running apt-get install -f and this was the output(after saying yes on prompt)  (Reading database ... 186183 files and directories currently installed.) Unpacking linux-image-3.2.0-27-generic (from .../linux-image-3.2.0-27-generic_3.2.0-27.43_amd64.deb) ... Done. dpkg: error processing /var/cache/apt/archives/linux-image-3.2.0-27-generic_3.2.0-27.43_amd64.deb (--unpack):  failed in write on buffer copy for backend dpkg-deb during `./boot/System.map-3.2.0-27-generic': No space left on device  No apport report written because the error message indicates a disk full error                                                                           dpkg-deb:    error: subprocess paste was killed by signal (Broken pipe) Examining /etc/kernel/postrm.d . run-parts: executing /etc/kernel/postrm.d/initramfs-tools 3.2.0-27-generic   /boot/vmlinuz-3.2.0-27-generic run-parts: executing /etc/kernel/postrm.d/zz-update-grub 3.2.0-27-generic /boot/vmlinuz-3.2.0-27-generic Errors were encountered while processing: /var/cache/apt/archives/linux-image-3.2.0-27-generic_3.2.0-27.43_amd64.deb E: Sub-process /usr/bin/dpkg returned an error code (1)   I tried running apt-get autoremove and it gives me the same error as apt-get upgrade.  When I run df, I get this for /boot:  /dev/sda1                    233191     230297         0 100% /boot   So, I read elsewhere that I should try to purge old kernels. I checked for what kernels I had with:  $ dpkg -l linux-image-\* | grep ^ii ii  linux-image-2.6.38-13-server  2.6.38-13.52  Linux kernel image for version 2.6.38 on x86_64 ii  linux-image-3.0.0-13-server   3.0.0-13.22   Linux kernel image for version 3.0.0  on x86_64 ii  linux-image-3.0.0-14-server   3.0.0-14.23   Linux kernel image for version 3.0.0  on x86_64 ii  linux-image-3.0.0-15-server   3.0.0-15.26   Linux kernel image for version 3.0.0  on x86_64 ii  linux-image-3.0.0-16-server   3.0.0-16.29   Linux kernel image for version 3.0.0  on x86_64 ii  linux-image-3.0.0-17-server   3.0.0-17.30   Linux kernel image for version 3.0.0  on x86_64 ii  linux-image-3.2.0-24-generic  3.2.0-24.39   Linux kernel image for version 3.2.0  on 64 bit x86 SMP ii  linux-image-3.2.0-25-generic  3.2.0-25.40   Linux kernel image for version 3.2.0  on 64 bit x86 SMP ii  linux-image-3.2.0-26-generic  3.2.0-26.41   Linux kernel image for version 3.2.0  on 64 bit x86 SMP   When I try to remove the oldest with this:  $ sudo apt-get purge linux-image-2.6.38-13-server Reading package lists... Done Building dependency tree Reading state information... Done You might want to run 'apt-get -f install' to correct these: The following packages have unmet dependencies: linux-image-server : Depends: linux-image-3.2.0-27-generic but it is not going to be     installed E: Unmet dependencies. Try 'apt-get -f install' with no packages (or specify a solution).   How can I free up or extend boot without messing up my installation?


Prove that for all integers $r, s$ and $t$, that $\gcd(\gcd(r, s), t) = \gcd(r, \gcd(s, t))$.   I am stuck in this proof. I have tried using Bézout's Lemma but I have no idea how to proceed further.   Any help would be appreciated.

I am trying to demonstrate that  $$((a,b),c)=(a,(b,c))\qquad\text{ (Associativity of GCD)}.$$   My proof is the following:  Since $((a,b),c)|(a,b)$, $(a,b)|b$, $(a,b)|a$ and by transitivity we have $$((a,b),c)|b, ((a,b),c)|a.\tag{1}$$ We also have $((a,b),c)|c$.   By linearity we have $\forall x,y\in \mathbb{N}$ $$((a,b),c)|bx+cy.\tag{2}$$  We can choose $x$ and $y$ so that $$bx+cy=(b,c).\tag{3}$$   Therefore $((a,b),c)|(b,c)$ and $((a,b),c)|a$.   Again by linearity $$((a,b),c)|xa+y(b,c)\tag{4}$$ and we can choose $x$ and $y$ so that $$xa+y(b,c)=(a,(b,c)).\tag{5}$$   This mean $((a,b),c)|(a,(b,c))$.   Using an analogous argument we can show that $$(a,(b,c))|((a,b),c)$$ and by the reflexivity the thesis follows.      Is this correct?


I know that 0/any number=0 and any number/0=no answer, (negative) infinity, undefined.  So, what happens if we divide zero by itself?  Is it zero?  Is it infinity?  Well, infinity isn't a real number, but let's cut to the real chase.  Let's say there are two points on a coordinate plane put together.  How will we know what line to draw?  What slope does it have?  We know that the x- and y-intercepts are the same.  What happens when we divide zero by zero?

I came up some definitions I have sort of difficulty to distinguish. In parentheses are my questions.   $\dfrac {x}{0}$ is Impossible (  If it's impossible it can't have neither infinite solutions or even one. Nevertheless, both $1.$ and $2.$ are divided by zero, but only $2. $ has infinite solutions so as $1.$ has none solution, how and why ?) $\dfrac {0}{0}$ is Undefined and has infinite solutions. (How come one be Undefined and yet has infinite solutions ?) $\dfrac {0}{x}$ and $x \ne 0$, it's okay for me, no problem, but if someone else wants to add something about it, feel free to do it.


I understand that aspirin prevents blood clots from forming by interfering with the clotting action. I want to know at which stage aspirin interferes with clot forming and what really happens in the process. I've used google to understand this but did not find a satisfactory answer. For example,  I found:  How can aspirin prevent a heart attack? Aspirin interferes with your blood's clotting action. When you bleed, your blood's clotting cells, called platelets, build up at the site of your wound. The platelets help form a plug that seals the opening in your blood vessel to stop bleeding.   But this clotting can also happen within the vessels that supply your heart with blood. If your blood vessels are already narrowed from atherosclerosis — the buildup of fatty deposits in your arteries — a fatty deposit in your vessel lining can burst.   Then, a blood clot can quickly form and block the artery. This prevents blood flow to the heart and causes a heart attack. Aspirin therapy reduces the clumping action of platelets — possibly preventing a heart attack.  Every site I visited had descriptions like this (mostly concentrated on the medicinal side). I want to know what aspirin does that prevents blood clotting at the chemical level, which I haven't been able to find.

As we all know, aspirin doesn't actually thin the blood, as it has been explained to me, it makes it "slippery". Slippery blood doesn't stick to itself hence this helps prevent internal blood clots (or allows blood to pass more easily around an existing clot). I also understand that having your blood too "slippery" can lead to the body attempting to counteract that and making it too "sticky".   Anyhow, my question regarding that is this, how does aspirin work? How does it make the blood "slippery"? (If there is a more medically correct term for "slippery" and "sticky", I'm all ears).  P.S. I paid the Mayo Clinic's website a visit before coming here, the information about aspirin's mechanism wasn't particularly helpful to me.


I want to send email from my application. How can i send it?

I want to send an email from my iPhone application. I have heard that the iOS SDK doesn't have an email API. I don't want to use the following code because it will exit my application:  NSString *url = [NSString stringWithString: @"mailto:foo@example.com?cc=bar@example.com&subject=Greetings%20from%20Cupertino!&body=Wish%20you%20were%20here!"]; [[UIApplication sharedApplication] openURL: [NSURL URLWithString: url]];   So how can I send an email from my app?


Do you know any software for Ubuntu, that I could upload a large quantity of GB...I need to make a backup of 500 GB with some files with more than 10 GB....  I only find Windows software and I've to pay for most of them...  Thanks in advance

I'd like to install a  client for Xubuntu (12.04).  I'm getting non-English Google results, and I didn't find  in the Xubuntu repositories.   Does anyone know of a client that works well for Ubuntu or it's supported derivates (or installation instructions for grive?)


I have a algorithm and from the post its time complexity is:  $$\sum_{k=1}^{n}k\binom nk= n  2^{n-1}$$  My question is, how to get the result $n2^{n-1}$ need some help . thanks

I am trying to prove this binomial identity $\sum_{r=0}^n {r {n \choose r}} = n2^{n-1}$ but am not able to think something except induction,which is of-course not necessary (I think) here, so I am inquisitive to prove this in a more general way.  The left side of an identity occurs while solving another problem (concerning binomial theorem) so I am more interested in deriving the right side from the left side, else I have to remember it now onward.  EDIT: I am more interested in an algebraic proof rather than combinatorial argument or something involving calculus (however I liked  and  solution), hence I am removing the combinatorics tag.


I'm trying to solve a recursion/DFS/backtracking problem, which is return all possible subsets for a num; for example: Input: nums = [1,2,3] Output: [[],[1],[2],[1,2],[3],[1,3],[2,3],[1,2,3]] So I wrote the following code: class Solution { public List<List<Integer>> subsets(int[] nums) {          if (nums == null) return new ArrayList<>();          List<List<Integer>> result = new ArrayList<>();     List<Integer> numlist = new ArrayList<>();          dfs(nums, 0, numlist, result);          return result;           } private void dfs(int[] nums, int index, List<Integer> numlist, List<List<Integer>> set) {     if (index == nums.length) {         // set.add(numlist);     // ->>>>>>>>>> WRONG          set.add(new ArrayList<>(numlist)); // ->>>>>>>>> RIGHT          return;     }          // left:     numlist.add(nums[index]);     dfs(nums, index + 1, numlist, set);     // backtrack:     numlist.remove(numlist.size() - 1);  // delete the last char in the sb and backtrack     dfs(nums, index + 1, numlist, set); }  } I am very confused that, in the line I marked as WRONG and RIGHT, why is that when I use "set.add(numlist)" the result will be all empty which is [[],[],[],[],[],[]], but when I changed it to "set.add(new ArrayList<>(numlist))", the result is correct. Why do I have to create a new value copy of the numlist to be added to the result? I thought JAVA is always pass-by-reference, so everytime it should be the value of numlist to be added to the result, and then remain unchanged, but why the the result arraylist changed if I didn't create a copy of the value? I am very confused and thought it should be something related to reference/value.

I always thought Java uses pass-by-reference. However, I've seen a couple of blog posts (for example, ) that claim that it isn't (the blog post says that Java uses pass-by-value). I don't think I understand the distinction they're making. What is the explanation?


Hi I have the following code:  public class Dog {     private String name;     private int size;     public Dog(String name, int size){         this.name = name;         this.size = size;     }     public void changeSize(int newSize){         size = newSize;     }     public String toString(){         return ("My name "+name+" my size "+ size);     } }  public class PlayWithDog {     public PlayWithDog(Dog dog){         dog = new Dog("Max", 12);     }      public void changeDogSize(int newSize, Dog dog){         dog.changeSize(newSize);     }       public static void main(String[] args){         Dog dog1 = new Dog("Charlie", 5);         PlayWithDog letsPlay = new PlayWithDog(dog1);          System.out.println(dog1.toString()); // does not print Max.. Prints Charlie... .. Does not change... WHYYY???         letsPlay.changeDogSize(8, dog1);         System.out.println(dog1.toString()); // passing by value.. Expected Result... changes the size         dog1 = new Dog("Max", 12);         System.out.println(dog1.toString()); // Expected result again.. prints Max     } }   I know Java always passes everything by value. Be it primitive types or objects. In objects however, the reference is passed that is why you can modify the object after its being passed through a method. I wanted to test whether the same thing applies when the object is passed through a constructor of a different class. I found out that the object does not get changed. This seemed weird to me because I am just passing a reference of the object in the constructor. It should change...?


I'm running Ubuntu on a virtual machine with Virtualbox. The host uses Windows 8. Right now, the guest has internet access, but it's some sort of virtual network because it thinks it's using a wired connection when I'm using wireless.  How do I get my Virtualbox guest to get direct access to the network the host is using?

I have virtualbox running on a Windows 2008 server, with a guest running ubuntu 10.04. The ubuntu guest is given a static IP of 192.168.1.4, which also has openssh installed. The guest has bridged network setup, I can ping 192.168.1.4 from any machine in the LAN, the ubuntu guest can also access the LAN. However, when I try to PuTTY into the ubuntu machine, I always get "connection refused". Below are some setup details:  ubuntu IP: 192.168.1.4  hosts.allow  sshd : 192.168.1.38   hosts.deny  ALL : ALL   when I the following command, I can see that sshd is listening on port 22:  lsof -i tcp:22   Any idea?  EDIT:  It turned out to be a wrong VirtualBox Bridged Network setup. I give the Ubuntu guest a static IP of 192.168.1.4 (assigned to eth0). Then in the Windows 7 host, in the Network and Sharing Center, there is a new connection named "VirtualBox Host-Only Network" after the bridge is setup, that connection is again given the same static IP of 192.168.1.4. Once I change the "VirtualBox Host-Only Network" to automatically obtain an IP address, it's getting a different IP address of 169.254.249.70(Tentative). And now I can SSH into 192.168.1.4 with no problem, even without touching hosts.allow and hosts.deny.  I've also noticed that in the properties windows (see screenshot below) of the "VirtualBox Host-Only Network", the second checkbox, "VirtualBox Bridged Networking Driver" is unchecked. While the same checkbox of the physical NIC (that is bridged to) is checked. So my further question is: is this how VBox bridged networking supposed to be setup? Any rationale behind this? I'd appreciate if someone could provide some explaination on VBox bridged networking setup on Windows host and I'll accept it as an answer.


Can anyone please help me in this?     Prove that every well ordered set is a totally ordered set.   To start this proof will this be sufficient:  Let $x_1, x_2 \in X.$  Let $A=\{ x_1, x_2 \}$.  If $x_1$ is the least element, then $x_1\le x2$. If $x_2$ is the least element, then $x_1\ge x_2$.  How do I end the proof?

Can anyone please help me in this question:     $(X,\leq )$ is a well-ordered set. $\forall x\in X$, either $x$ is the largest element of $X$ or there exists $y\in X$ such that   (i) $x<y$ and   (ii) if $x_0\in X$ such that  $x\leq x_0\leq y$, then either $x = x_0$ or $x_0 = y$.   Will this be sufficient to start the proof:  If $x$ is the largest element then there is nothing to prove. Suppose $x$ is not the largest element. $$A=\{ z\in X \mid x<z\}\neq \emptyset$$ How do I proceed?


So I created a set of text boxes, that I styled with different colors, but the same paragraph style and area type options. I want to put these in a library so I can grab them and type identifications so I can use them as tab style labels on various projects. When I try and add them to the library I get a notification about advanced type styles not being added and only adding the simple styles. What's the best way to proceed? Is there a way I can make like a link to the master file to grab elements as I need them (I thought that was the purpose of the libraries)? Is there a workaround like making them symbols and then adding it? Any help would be appreciated.

I frequently create labels that follow the same format: white text on a 75% opaque black background, with 10px of margin around the text. Currently, I have to manually build these labels, which takes a lot of work.  In one method, I write the text, figure out its height and width, then create a separate rectangle and place it behind it. This takes a lot of clicking around for every label.  In the other method, I draw out a text box, select it directly, give it the correct background and margins, and then insert the text. However, I must then resize the box manually, meaning more clicking around and greater imprecision. There doesn't seem to be a way to directly select a text box once it has text inside it.  I tried using the script contained in  to resize the text box to the content, but it only resizes the box vertically, and removes my color and margins.  Does anyone have suggestions on how to resolve these problems, or for a better method? I'm using CS3.


I am very new to react and material-IU. This is the structure that is passed to each selector to configure it and that shows the three default options export const questionOptions = {   defaultValue: undefined,   control: {     type: "select",     options: {             Accept: true,       Decline: false,       Unknown: undefined,     },   }, };  And this is how each component is configured for the title and its options export const types = {   startAdornment: {   title: "First Text",   ...questionOptions,   },   startAdornment: {   title: "Second Text",   ...questionOptions,   }, }   I have to create a third select and I want to show only the first two options so I clone the object and modify the properties I want export const questionOptionsTwo = Object.assign({}, questionOptions);  questionOptionsTwo.control.options = { Accept: true, Decline: false, }    And then use this new object for the third select startAdornment: {     title: "Third Text",     ...questionOptionsTwo,  },    the problem is that, although I am cloning the original object, when I modify the properties in the cloned object they are also modified in the original. What am I doing wrong? thank you all in advance

What is the most efficient way to clone a JavaScript object? I've seen obj = eval(uneval(o)); being used, but . I've done things like obj = JSON.parse(JSON.stringify(o)); but question the efficiency.  I've also seen recursive copying functions with various flaws.  I'm surprised no canonical solution exists.


Is the following sentence correct?       Don't be afraid to talk about a time when you or a relative were a patient.    Or should it be one of the following:      Don't be afraid to talk about a time you or a relative was a patient.     Don't be afraid to talk about a time when you were or a relative was a patient.

I wanted to know if it is grammatically correct to say:  Either the teacher or the students WAS enjoying the picnic.  I'm talking about a grammatical principle and not a proximity or attraction one.  Thank you so much..


Wikipedia article () states that "the information in a random sample of n independent and identically distributed observations is n times the information in a sample of size 1". I know that formally it's proven via linearity of expectation but I am looking for an intuitive explanation.  On the other hand, I found at  that in the case of iid random variables $I_X(\theta)=\sum^n_{i=1}I_{X_i}(\theta)$.  I am confused and it would much appreciated if someone could clarify this for me.

For a Fisher Information matrix $I(\theta)$ of multiple variables, is it true that $I(\theta) = nI_1(\theta)$? That is, if $\theta = (\theta_1, \ldots, \theta_k)$, will it be the case that the fisher information matrix of multiple parameters for an entire dataset will just be $n$ times the fisher information matrix for the first data point, assuming the data is iid?  Update: As a concrete example, consider a sequence of random variables $y_1, \ldots, y_n$ such that $y_i = \beta_0 + \beta_1 x_i + \epsilon_i$ where $\epsilon_i$ is assumed to be i.i.d. $N(0,\sigma^2)$, with $\sigma^2$ known. Additionally, assume that $n$ is even. I am trying to find the Fisher Information Matrix for $\beta = (\beta_1, \beta_2)$. I know that the log-likelihood for one observation is:  $$ l(\beta_0, \beta_1) \propto -\frac{1}{2\sigma^2}(y-\beta_0-\beta_1x)^2 $$  Hence, we have that the observed information matrix (before the expectation), is:  $\frac{\partial^2 l}{\partial \beta_0^2}= \frac{-1}{\sigma^2}$, $\frac{\partial^2 l}{\partial \beta_1^2}= \frac{-x^2}{\sigma^2}$, and $\frac{\partial^2 l}{\partial \beta_0 \partial \beta_1} = \frac{-x}{\sigma^2}$.   Thus the information matrix for a single observation is: $$ -E\left(\frac{\partial^2 l}{\partial \beta^2}\right) =\frac{1}{\sigma^2}\left( \begin{array}{ccc} 1 & x \\ x & x^2  \end{array}\right) $$  and the information matrix for n pairs of observations $(x_i, y_i)$ is given by:  $$ I(\beta_0, \beta_1) =\frac{1}{\sigma^2}\left( \begin{array}{ccc} n & \sum_{i=1}^{n}x_i \\ \sum_{i=1}^{n}x_i  & \sum_{i=1}^{n}x_i^2   \end{array}\right) $$  Above, because the fisher information is additive, all we did to move from the single observation to the multiple observation case was just to add entry by entry. HOWEVER, I know that in general if $Y_1, \ldots, Y_n$ are iid, then $I(\theta) = nI_1(\theta)$. My question is, why is it NOT the case above we could have just multiplied each entry by $n$, and instead had to add?


I am taking my first course in Real Analysis this fall. With my background in analysis limited, I knew it was going to be a difficult course, and I prepared all summer. However, with the online university situation, my real analysis professor has been insufferable and made the class so much harder. His lectures are 100% reading out loud his textbook, and he has banned all external conversation and materials. I have been doing well, but I am essentially just teaching myself analysis from a textbook I dislike and it is taking a  real mental toll to adhere to deadlines on homework that is extremely difficult and is focused on finding counterexamples, rather than understanding the material. My main and only goal is to pass a graduate real analysis qualifying exam. At this point, I think it would be easier to just teach myself everything, rather than stress and frustrate myself with this course in such an already stressful time. Does anyone have any book or material resources that would be best for teaching oneself real analysis? I have been reading Royden's Real Analysis, and I find it very readable and good for an introduction. I still need other materials to get a variety of problem sets and information. Books specifically from a perspective of set theory and algebra would feel most natural to me. Unfortunately, I cannot go to a library to seek other books before buying them, so your suggestions would be very helpful.

Does anyone have a recommendation for a book to use for the self study of real analysis? Several years ago when I completed about half a semester of Real Analysis I, the instructor used "Introduction to Analysis" by Gaughan.   While it's a good book, I'm not sure it's suited for self study by itself.  I know it's a rigorous subject, but I'd like to try and find something that "dumbs down" the material a bit, then between the two books I might be able to make some headway.


I'm running Ubuntu server 19.10 In order to do a few things I installe KDE-Plasma desktop.  But I still want to just boot into TTY command line without loading the GUI etc. I don't want to remove plasma, just not load any of it at boot. Ctrl-Alt-F3 works but still seems that it loads a lot of processes (sleeping but still).  Thank you for any help!

I want to know if there is a way to switch to console mode from the boot menu.  I have an NVIDIA 1070 and every time there is an update, the GUI stops working. All I need to do is re-install the drivers; however, to do that I need to be in console mode. EDIT: I should have added more information to this question but I'll comment on all answers. In short: I've tried text instead of quiet splash I do see booting activity in text mode; however, I don't get a login screen and ctrl + Alt + F1 doesn't help because GDM keeps trying to restart. Previously I managed to kill GDM through multiple tries but is not working since the latest update. EDIT: After searching for runlevel, I've found  but I think it required me to have a running system to make changes -- please correct me if I'm wrong.


Is there anyway to dodge a Tower shot after it has already been fired at you? I find myself Tower-Diving to chase an enemy down, only to get sniped at the last second by a heavy bullet that had been chasing me. Is there a way to dodge one after it has been fired after me?   I would prefer answers that can apply to many/all champions.

As the title says, is there any way to run faster than the turret attack (the missile like thing) so that you can arrive spawn before the attack reaches you, and therefore can't kill you? You know, when you have low health, and you are targeted by the turret? Is there any item sets or things like that?


lol is there anything more to ask about it?! when I try "sudo bla bla bla" it asks me who are you? :)) I wanted to do it IN a folder in root, but I did it in only ne upper level which is, GOD, the root folder!

I recursively deleted the contents of my root directory with sudo privileges. My display reset, and windowing stopped working. I could no longer run non-buitin commands. Most of my directories (including the home directory disappeared).  What I meant to run:  sudo rm ./* -rf   What I believe I ran:  sudo rm /* -rf   I understand how this command works (see ).  I'm trying to get a better sense of how much (and what parts) of the original files and directory-structure physically remains on the hard-drive.  How much of these "remains" are recoverable? E.g is it possible to use data recovery software like TestDisk/PhotoRec to recover the full home dir itself? What about config files?


I'm having some trouble identifying where specifically the following proof is incorrect:  Statement: Given any positive integer $n$, every n people have the same name.  "Proof:" We prove by induction. When $n = 1$, the statement is trivially true. Now, assume the statement is true when $n = m$. In other words, every $m$ people have the same name. We show the statement is true when $n=m+1$ in the following way. Consider the following list of people: $p_{1}, p_{2},..., p_{m+1}$. By the inductive hypothesis, the individuals $p_{1},..,p_{m}$ have the same name. But we also see that the list $p_{2},...,p_{m+1}$ consists of $m$ individuals, so they all have the same name as well. It follows that $p_{1}, p_{2},..., p_{m+1}$ all have the same name. Thus, since we have shown the statement holds when $n=m+1$, the statement holds for all positive integers.   I'm given the following options:   The basis step is incorrect The inductive step is wrong when $m = 1$ The inductive step is incorrect for every $m$ The inductive hypothesis is incorrect.   Any help would be greatly appreciated!

I'm bugged by the following that's summarized on p. 109 of .     False theorem: All horses are the same color.      Proof by induction:      $\fbox{$P(n)$ is the statement: In every set of horses of size $n$, all $n$ horses are the same color.}$   $\fbox{Base Case or $P(1)$:}$ One horse is the same color as itself. This is true by inspection.   $\fbox{Induction Step:}$ Assume $P(k)$ for some $k \geq 1$.   $\fbox{Proof of $P(k + 1) :$}$   Since $\{H_1, H_2, ... , H_n\}$ is a set of $n$ horses, the induction hypothesis applies to this set. Thus, all the horses in this set are the same color.   Since $\{H_2, H_3, ... , H_{n+1}\}$ is also a set of $n$ horses, the induction step likewise holds for this set. Thus, all the horses in this set are the same color too.         Therefore, all $n +1$ horses in $\{H_1, H_2, H_3, ... , H_n , H_{n+1}\}$ are the same color. QED.   The issue the instructor was trying to point out is clearly valid. For the case $n = 1$, there is only ${H_1}$. So this case says nothing about possible overlapping elements of each set of $(n + 1)$, for instance $H_2$ in the above proof.    But it was proposed in the class discussion that this was the only problem. Had you been able to prove $P(2)$ true, then a proof of the above format would have been fine.    My interpretation is that yes, you could prove all horses are the same color, if you can prove that any set of two horses will be the same color. But this format would not work.  Why not? The problem I see is that the above proof is for the existence of at least one particular pair of sets of horses of sizes $n$ and $n + 1$, such that in each set, all horses are the same color.  Particularly when the set of size $n$ is a subset of the set of size $n + 1$.  In order to prove the induction step, don't you need to prove that sets of sizes $n$ and $n + 1$, do not necessarily contain the same, overlapping elements?  You could prove that any horse can be added to a set of 2 horses.  Take the last two, and they must be the same color, and so on.  Wwhatever color the first two happen to be, all other horses must thus be the same color.    Am I misinterpreting the example, or am I making a logical error? Thanks in advance.


I find myself in a situation where I'm trying to buy a house, but don't have the money readily available. And my bank won't give me a loan, in spite of not having any problems with loans/money in the past, because I can only promise them that I will pay them the money I get when I sell the apartment we own, as well as our small monthly income, and then profits from my Bitcoin in the future. At the end of the day, I won't be able to start paying off the loan if they hand me the full amount to buy the house right now and expect the typical monthly "payback fee". It's a very specific house with sentimental ties to me, up for sale right now, which is why this is time-sensitive. But then I had this thought: Why would they not pay for the house right now, and then simply let me "rent it" from them until I've either paid it off, die, or go completely broke? Does the house lose any value while I live there and pay them back as much as I can? I'm guessing that I'm missing something painfully obvious, but it seems to me that the bank risks nothing by buying the house "for" me, then have me live there for any amount of time, and when I'm gone, they still have the house and it may even have appreciated in value at that point. Plus they got all that money I paid them while I was around/alive, so they didn't lose any money, but gained a bunch. In my mind, this seems like a win-win situation. I get to move in to the house and they get their money and then some no matter what. Why would they not want to do this, assuming that I'm not some kind of dangerous criminal who brings home a whole gang and have shootouts every other day, decreasing the value of the property?

There was asked a similar question   It was about buying fonds and shares. Those are derivatives.  Here is an example. 2019 year in central Europe. A flat costs 150 000 USD. If a person buys it, the person can rent it for 700 USD per month = 8 400 USD per year, which can be considered as 5.6 % per year (assuming that economical situation is more or less stable). Also down-payment can be 20 %. In 2019 interests rates are low - 3 % per year.  What does it mean? A person needs to have 30 000 USD, and take a loan 120 000 USD. The person will pay 3 % from 120 000 USD per year, and receive 5.6 % from 120 000 USD.  As we see, it is beneficial for a person (who has 30 000 USD) to make such investment.  The bank which gives the person 120 000 USD also feels good because it will get payments. Let's assume that the person is solvent and has his primary place of residence (another flat where he lives). Why not the bank buy a flat and rent it out to make 5.6 % per year instead of giving it out to people at the rate of 3 %.  Also I learned when a company buys another company, the bank can lend most of money to make the deal.


An \emph inside another cancels the emphasis.  But what if I want to make sure something is never emphasized, even if the surrounding emphasis is removed?  \textrm doesn't turn off ItalicFeatures defined for the font family.

It is well known that you can make the font italic or bold using \textit{} or \textbf{}. However, if I have an italic or bold font, what command can I use to make it nonitalic or nonbold?


I remember reading a short story with the following synopsis:  An Earth exploratory expedition arrives at a planet thinly populated by friendly humanoid folk at a very primitive technological level - no wheel, no sails, etc. Perhaps they lack some key concept, I don't recall the exact reason for the technological block. However they turn out to be all of them extremely highly intelligent. From clues innocently and accidentally dropped by members of the expedition, and by observing their technological artifacts, in mere days they invent the wheel complete with ball bearings (made with round hard nuts), and other things which make expedition members afraid. The commander considers exterminating the village they made contact with, but it turns out that messengers have already gone to other villages and one guy  has invented the sail and went overseas to transmit the new knowledge. The expedition decides to leave before any more knowledge leaks out, and takes with them a girl child who desires to see more marvels. The story ends with the commander musing that the girl won't ever come back to tell her people about what she has seen: Earthmen will have to "dissolve", by assimilation and intermarriage, the people of this planet, who are yet very few, within the huge mass of humanity, to prevent them from dominating the galaxy.

I'm looking for a story that was probably written somewhere from the 1940s to the 1960s. I think I read it in an anthology, possibly in the 1970s.  A group of human explorers landed on a planet with primitive aliens, living in hunter-gatherer villages. They hoped to make a profit from trading our goods for—well, I'm not clear on what they wanted from the aliens.  The native people learned the human language before the explorers could learn theirs. Then the natives suddenly started producing technological innovations far beyond what they originally used. I remember that wooden sailing ships suddenly replaced their canoes. All the natives had to do was hear a story once from the explorers before copying the technology in the story.  Finally, the explorers realized that the natives were much, much smarter than us and that Earth faced a serious problem.  I'm fairly certain that it wasn't a Heinlein story, but I remember that it had some qualities similar to his work.


Is there a native way provided by Unity to save an arbitrary desktop session, in order to restore it during next system start? By desktop session, I refer to all the applications currently running with their windows states regarding work spaces and such.  To make things clear, I do not want to just use any hibernate modes to switch off the computer. Nor do I want to add applications to the Autostart configuration, as this does not solve the issue of having your latest session restored.  While doing research, I found quite a few similiar questions, just like  . However, those threads are rather old or have no real solution provided. My concern is Ubuntu 14.04. default installation (thus, using Unity as a window manager). Your help is much appreciated.  Best regards Ron

Is there a way to save current session (the applications + the organization of windows in desktops) in Unity and load it when needed?


Since Google Calendar Sync , what are some options for syncing Outlook Calendar with Google Calendar?

How can I synchronise my desktop  calendar with my  (Outlook -> Google)?   I saw the question , but the solution that was suggested there is no longer available - .  There are tools that required a payment, like ,  and , but I am looking for a free / open source solution.   One can download Google sync, but when trying to use it there's an error:    For now, I use  to synchronise, but as a freeware it allows to synchronise manually only, not automatically, so I have to remember to synchronise after every change.  I checked , but I couldn't find any relative posts on how to synchronise Outlook -> Google using it.  Just to be clear: I'm not looking for software; I am looking for a solution. What can I do if sometimes software is a solution?


1) In fact, NO LESS THAN 20 percent of people are injured severely due to car accidents.      2) However, because people whose cars had collided and were severely wounded were occupying the intensive units in the hospital, it took NO FEWER THAN an hour for him to have surgery despite his life threatening condition.   These are two sentences that I wrote in a practice writing, but my teacher (Canadian) said the use of "no less than and no fewer than"  didn't make sense.  I thought those are used to describe emphasis of numbers.  Could you someone help me understand why it's wrong so that I can improve my English. Thank you

I've just received a memo which says (effectively)      As more people leave, there will be less people available.   I want that word to be fewer. Are there guidelines for which word ought to be used when?


I'm new to webpack and trying to set up a basic implementation. I have a file script.js with some functions in it scripts.js export foo = () => {    console.log('foo') }  export bar = () => {    console.log('bar') }  And I'm trying to add it to my webpack bundle.js such that I can use these functions in the markup. webpack.confi.js const path = require('path')  module.exports = {     entry: './index.js',     output: {         path: path.resolve(__dirname, 'dist'),         filename: 'bundle.js'     } }  My index.js looks like this: import * as scripts from './scripts.js';  This works in node because if I add console.log(scripts.foo()) to my index.js below the import line, I can observe the console log. But if I try to call foo() in my markup, I get an undefined error: Uncaught ReferenceError: foo is not defined index.html <script src="./dist/bundle.js"></script> <script>      scripts.foo(); // throws undefined error  </script>  What am I missing?

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?


A couple days ago, text and buttons in title bars, menu bars, context menus, and even file names in explorer (and on desktop) became about 40% larger than they were before.  I'm not sure what caused this, as I didn't change any settings. Just turned off my computer one day, turned it on the next, and it's been like this since.    My machine is a laptop with a touchscreen, screen resolution of 1366x768 px. It's really driving me crazy; how can I get this text back to its original size? (I can provide any additional screenshots/info as needed.)

A few days ago, my desktop icons and certain text in programs (eg the text in my Mozilla Firefox toolbars) suddenly enlarged, but I changed nothing. To confirm this uncontrolled suddenness, I  just checked that all inputs in the following have remained unchanged:  Control Panel\All Control Panel Items\Display\Screen Resolution Control Panel\All Control Panel Items\Display   How do I fix or revert this sudden enlargement? The screenshot below shows this problem: the red arrows pinpoint the wrongfully enlarged text, in the toolbars and Bookmarks tab. The green arrows pinpoint the original (and correct) smaller text, in the URL, Tab title, and Bookmarks toolbar.


Why does the following command: mkdir -p '~/something' creates a directory directory named as '~' in the current, instead of creating a directory named as something in the home directory? Is there any way to fix this? ps. I get the value ~/something as an environment variable wrapped in single quotation.

Writing my first script so I'm sure this is a basic question, but can someone please explain to me why I can:  cd ~ cd bin cd ~/bin cd 'bin'   But not  cd '~' cd '~/bin'   I need to cd to a directory path with a space in one of the directory names, so I need the quotes (it's Windows Program Files under wine). I can get around it with two cd commands, but why can't I put ~ in quotes?  If I type cd '~' (or cd "~") I get:  bash: cd: ~: No such file or directory


I have an existing script in my Linux host with these statements:  local variable=$1 if [ "z${variable}" != "zfalse" ]; then   local flag="--some_flag" fi   I haven't found an explanation of these "z${variable}" and "zfalse" notation or syntax in my Shell Scripting book. Hope someone can help explain what they mean. Thanks in advance.

I see this often in the build scripts of projects that use autotools (autoconf, automake).  When somebody wants to check the value of a shell variable, they frequently use this idiom:  if test "x$SHELL_VAR" = "xyes"; then ...   What is the advantage to this over simply checking the value like this:  if test $SHELL_VAR = "yes"; then ...   I figure there must be some reason that I see this so often, but I can't figure out what it is.


I was wondering if it was possible to have a question template for new users.  I was thinking of something simple, where, for example, in the first 2 sentences they have to enunciate what their issue is, and then have a full description of the problem, and possibly, at the end, have a 2 lines section with some "final remarks"?  I have seen many questions that are very long and it is hard to know what the issue the OP has.  I think it is something you learn with experience, I have done it myself, and sometimes still struggle with, but at least I am aware of.   For new users it could be useful to have a reminder of a good way to structure a question.  Do you think this would be useful? Or even possible to implement?

suggested to have templates for tags. Their example was with the  tag on Stack Overflow.  I'm suggesting a more general approach:  Templates, Mark II  I suggest that each site will have a template. That template will prefill the  textbox when a new question is asked. However, it will be completely optional.  Something like (for Stack Overflow):  ## The Problem ## { Please tell us what the problem is with as many details as possible.   Include language, operating system, and any other relevant information.   Remember to add the relevant tags below, too. } ## Attempted Solutions ## { Please tell us what you've tried so far. Have you tried searching Google?    What queries? } ## Existing Code ## { Do you have any existing code to show? Please keep it short and simple.    We should be able to detect the problem right away. }   Why am I suggesting this?  Well, it seems as though most users will stick with the default. They don't bother to read, and so prefilling the question form for them with information that we know might be relevant, will forceWe'll get to that in a second them to actually stop and read.  Scenarios:   Best case: User arrives to ask a question, actually reads the template, fills the correct information in the placeholders. (Yeah, because that'll happen a lot) Neutral: User simply removes all of the template text and rewrites their own question. Result is exact same as we have currently. Worst case: User will ignore or misunderstand the template, will use it wrong or not at all and we'll get something like  <template text here, still unfilled> <(crappy) question>   This can be solved in a couple different ways. We could detect the template tags (i.e. { }, subject to discussion), and throw an error when a user attempts to post with them still available. We could also act more autonomously and remove placeholders which still exist.    Some more points:   Templates should be per-site, not per-tag. Sure, there are differences between the tags, but all questions are expected to have the same general information, and this isn't meant to be a rule, but a guideline to help write better questions. Site templates should be editable by that site's mods, like close reasons. We could autofocus on the first placeholder, and perhaps implement TAB to jump from one placeholder to the other, similar to mixins in IDEs. This doesn't have to be implemented everywhere. This suggestion makes sense to Stack Overflow or Superuser, but not to Anime & Manga or Gaming All of the details are subject to discussion, and all discussion is welcomed.


I have a .ai file that I've opened in Illustrator. All of the fonts are listed as paths. This is the original file. Any idea how I can update the text?

I'm trying to edit my designer's artwork by changing the "5" into a "4". I have the font installed already.  When I try to open the design file in AI and highlight the "5", to my surprise it isn't a text object. It looks like it's something called a compound path. How would I update it's type so I can type "4" in it?


I'm looking for a book (well, an audiobook) that I listened to maybe 7, 8 years ago in English (I live in the U.S.), and for young children, or maybe for teens. My memory is very shaky but here goes:  I remember a boy and his friends entering a competition. I don't remember what the competition was for, but I remember the first stage being some sort of space game or something with each team having a certain target (so sort of like the Assassin game), and the main character eliminated his friends. One of the spaceships had an ability to become invisible, if I remember correctly.  I remember the boy was (intentionally, I think) harpooned by another person competing with him relatively late-stage. The kids/teens were divided into 2 groups and were competing for something, and all had harpoons.  I remember the boy and another boy having to compete by rolling a marble/ball through a maze telekinetically, and the main character barely won by choosing a faster path, despite not being able to roll the marble as fast.  I remember the boy and a girl going into another part of the world that was previously unknown to them (and was sectioned off or something).

Sci-fi book in the future about a city that had 2 levels.    The top level was for the rich people. A game center with a space flight game is added. The main character (male) plays with friends and wins a competition. He ends up in huge competition and does well. He finds his sister (twin I believe) and joins the military as the competition was just a recruitment game. He flies into "destroyed land" and finds out that rich barons are living on private islands.  The destroyed lands were caused by some plague.  I read this book in 2010.


I want to use the Internet Connection of my Windows 10 PC with my Android-Device through USB-Cable.  How can I reverse tether through windows 10 using my usb-cable?  I have found some , but the question and its answers are telling me how to use the Android SDK to do USB-Tethering. I don't want to install additional software like the Android SDK.  It sounds, like there was an built in solution in windows, but the necessary sharing tab is missing:   Is there really no way to do usb-tethering using Windows 10 without installing external software like the Android SDK?

I'm using Android 4.4.2 (on ). I've a Windows PC at home which has highspeed broadband internet connection. I don't have wireless router or access point. I just want to use PC's internet connection on my phone. I've tried multiple methods but none seems to work.  Method 1: Using native Android 4.4.2 option  In my phone when I connect my phone, in Settings > Wireless & networks > USB Internet (sharing Windows PC internet via USB cable) checkbox, which I checked then it asked me to choose my Windows version (which is Windows 8.1 but since it didn't show that option) I chose Windows 8.  It gives me further instructions as showing in the following picture:    Here is the problem, there is no sharing tab (see the following screen shot)   Method 2: As described in   I learned on this site that it is called Reverse tethering. I read and followed the procedure mentioned in    I followed all the steps described in that answer, until executing the command.   Install USB drivers from Android SDK [DONE] Connect USB cable and activate USB Tethering (You should see on a new network interface.) [DONE] Bridge the 2 network interfaces [DONE] On your computer execute adb shell netcfg usb0 dhcp [PROBLEM]   When I execute adb shell netcfg usb0 dhcp it says: error: device not found. I tried the same thing with USB Debugging in Developer settings, ON & OFF. The error remains the same.  Method 3: Rooting the device and using an app  I read here and there that there is another method, in which we can directly use an app but it requires rooting the device. My phone is a new phone and warranty becomes void if I root it.   EDIT: I've tried the method suggested in answer, at the 4th step of method 2, I'm facing this problem:


It is my first question. In advance please sorry for my bad English!  I need to calculate this integral with help the Euler's integrals: $$ \int_0^{+\infty} \frac{1}{1+x^5}  $$  I have tried decompose integrand in Taylor Series but I did not get anything. Also I tried use partial fractions and I got crazy expression.  I'm here to get an elegant solution of this question. Thank you for help in advance.

$\int_0^\infty \frac{1}{1+x^9} \, dx$  I tried taking the integral of $\Gamma_R = [0,R] \cup \gamma_R \cup I_R$, where we see that \gamma_R is the circle parametrized by $z = Re^{it}$ with $t\in[0,\frac{\pi}{2}]$. And $I_R$ is the line form $iR$ to $0$  one can note the following three things:  1) $\int_0^\infty \frac{1}{1+x^ 9}\,dz$ = $\int_0^\infty \frac{1}{1+z^ 9}\,dz$. (Note that $z$ is on the $x$-axis)  2) $\int_{\gamma_R}\frac{1}{1+z^ 9} = 0$. (By the ML inequality)  the main problem is when i parametrize $I^{-}_{R}$ with $z(x) = xi$ and $x \in [0,R]$. The main problem is that i get that:  3) $\int_{I_R}\frac{1}{1+z^9} = -\int_{I_R^-}\frac{1}{1+z^9} = -\int_{0}^{R} \frac{i}{ix^9 + 1}$.   note that i want to work towards taking $R$ to infinity eventually and then equal the sum of the integrals to the sum of the residuals of $\Gamma_R$ times $2\pi i$. The main problem here is that my term in 3), does not look like the form $c \cdot \int_{0}^{\infty}\frac{1}{1+x^ 9}$ with c a constant value. If i can get this done i think i'm finished.  PS: The singular points i got where $e^{\frac{\pi i}{9}},e^{\frac{3 \pi i}{9}}$.


Given we have two Guassian wave pulses in the same medium (string) but in opposite directions. The principle of superposition states that they should pass through each other without being disturbed, and that the net displacement is the vector sum of the individual displacements.   Like this:    My question is, how does the string have 'memory' of the information on the shape and velocity of both pulses separately? For instance, consider if the interference were destructive. Then when the string is perfectly flat, it cannot have memory of what brought it to this state; similar to how a particle does not continue to accelerate after a force has stopped acting: it has no memory. I understand that although the displacement is zero, the velocity is non zero and at this point the string has kinetic energy. How can the string know from the velocities of various points which waves will emerge?  How do both the waves emerge unchanged?  I think my confusion stems from a lack of conceptual clarity on the principle of superposition, I may not completely understand it. Any help is appreciated.   Note to moderators: I request that this question not be treated as a duplicate. While there are similar questions  and , none of the answers are able to justify how this happens in terms that make sense to me.

My professor asked an interesting question at the end of the last class, but I can't figure out the answer. The question is this (recalled from memory):  There are two travelling wave pulses moving in opposite directions along a rope with equal and opposite amplitudes.  Then when the two wave pulses meet they destructively interfere and for that instant the rope is flat.  Why do the waves continue after that point?  Here's a picture I found that illustrates the scenario    I know it's got to have something to do with the conservation laws, but I haven't been able to reason it out.  So from what I understand waves propogate because the front of the wave is pulling the part of the rope in front of it upward and the back of the wave is pulling downward and the net effect is a pulse that propogates forward in the rope (is that right?).  But then, to me, that means that if the rope is ever flat then nothing is pulling on anything else so the wave shouldn't start up again.  From a conservation perspective, I guess there's excess energy in the system and that's what keeps the waves moving, but then where's that extra energy when the waves cancel out?  Is it just converted to some sort of potential energy?  This question is really vexing! :\


Anyone know how to resolve this?  I have a Thinkpad W520 running 17.04 upgraded not fresh install     I have two disks on my laptop /dev/sda (which is original Windows not my Ubuntu) and /dev/sdb which is my mPCIe that has Ubuntu.  Can anyone confirm whether I need to grub-install /dev/sdb to resolve this error?  Please note I can safely boot when I hit enter as it shows GRUB with list of selections to select Ubuntu and boot.  This has been the case without error since Ubuntu 14 or 15 and I've been upgrading all the way, and when I upgraded to 17.04 this started to show.

Whenever I boot Ubuntu 16.10, just before the Plymouth screen, I'm seeing this message:  No symbol table found.  Press any key to continue...   and it remains there for a minute or so before showing me the log in screen. If I press any key it will be stuck for ever and I'll have to restart the computer.  Any help is appreciated..


I have a JSON file on my website, and I want to access it from client-side vanilla javascript. How do I do that? I don't want any HTML involved, like linking to the JSON file in the HTML and then accessing it via JavaScript. I need it to be in JavaScript and JSON, nothing else.

I need to do an  request in JavaScript. What's the best way to do that?  I need to do this in a Mac OS X dashcode widget.


I want to know the correct use of apostrophe s? Is the 's' used either in small or capital letter. Which is right format either Ram's or Ram'S? Please answer me soon.

For example, if I wanted to write the equivalent of  There are many automated teller machines in this city.  Would it be  There are many ATMs in this city.  or  There are many ATM's in this city. (could get confused with possessive form or contraction).  or just  There are many ATM in this city. (assuming the final s is included in Machines represented by M).  Maybe something else?


I have a blog which can be accessed at  http://mysite.com/blog/   I would like to access it like this because I think it looks cleaner  http://blog.mysite.com   I did some reading on domains, subdomains, and redirects and have created a subdomain with the desired URL and re-directed it to the blog path.  Is this a common set up? Is there a better way to accomplish what I want to do?

We have more than one content management system (eCommerce) running on our site and we want to know would it be wise to separate these systems and run on their own server for better performance, easier to manage and better for security, but our concern is the SEO impact.  Is it better to run site.com/this-is-our-other-platform/ or this-is-our-other-platform.site.com?


the program says "TypeError: 'int' object is not iterable"     list=[3,3,2]    print(list)    k=0    for i in list:        for l in list:            if(l>i):         k=l        for j in k:            if(i==j):                del list[i]    print(list)

Is there a built-in that removes duplicates from list in Python, whilst preserving order? I know that I can use a set to remove duplicates, but that destroys the original order. I also know that I can roll my own like this:  def uniq(input):   output = []   for x in input:     if x not in output:       output.append(x)   return output   (Thanks to  for that .)  But I'd like to avail myself of a built-in or a more Pythonic idiom if possible.  Related question:


Why do we need to resample from an initial set of samples when using bootstrapping? Why don't we just take fresh sets of samples from the original distribution? What is the justification behind resampling? Or is it just a computational trick?  EDIT: I understand that it is usually very expensive to get fresh samples, but assuming we have access to a generator of the original distribution, does it still make sense to resample due to some theoretical reasons?

I recently used bootstrapping to estimate confidence intervals for a project. Someone who doesn't know much about statistics recently asked me to explain why bootstrapping works, i.e., why is it that resampling the same sample over and over gives good results. I realized that although I'd spent a lot of time understanding how to use it, I don't really understand why bootstrapping works.  Specifically: if we are resampling from our sample, how is it that we are learning something about the population rather than only about the sample? There seems to be a leap there which is somewhat counter-intuitive.  I have found a few answers to this question here which I half-understand. Particularly . I am a "consumer" of statistics, not a statistician, and I work with people who know much less about statistics than I do. So, can someone explain, with a minimum of references to theorems, etc., the basic reasoning behind the bootstrap? That is, if you had to explain it to your neighbor, what would you say?


My granddaughter received 2 w-2’s for money she was never paid.  She goes to college and thought she was volunteering to help with a cross country event at another university.  All the students that participated received w-2’s.  She said they were all taken into a room and told to complete paperwork.  She didn’t know what it was but I’m guessing it was a W-4.  Is this legal?

I just now received a W-2 from a company that I worked for 3 days as a contractor. I had to leave country for 2 months due to a family emergency. Since the employment duration was very short, I was not paid. I was told that they don't want to charge the client because 3 days is not enough contribution.  Since I had to leave country the same day, I did not argue with them and told it's okay if they feel right.  Now I have a W-2 from them saying they have paid me about $1500. I contacted them but I have not received any reply yet.  I just want to be prepared. What can I do here?


I am thinking of a nice and simple analytic method to solve the following equations simultaneously:  $$\sqrt x+y=7;\\x+\sqrt y=11.$$  To my suprise I can't. But, I solve the system numerically using Newton's method and the solution is $4$ and $9$.  Is there any simple way of solving the above system analytically?

I want to solve this system of equations, I have been out of Maths for a long!!  $$\sqrt{x}+y=7$$  $$\sqrt{y}+x=11$$  Just wondering easiest step to find values for $x$ and $y$ from the above equations?


I am using SASS/Compass to create a breadcrumb with the Compass mixin "@include delimited-list();"  I have a variable called $breadcrumb-separator: " > "; so that I can change the character out in different situations.  My css is: ul.nav {@include delimited-list($breadcrumb-separator);}  How can I change the use of the character ">", to use the en dash(&#8211; or &ndash;) entity?

How do you use the CSS content property to add HTML entities?  Using something like this just prints &nbsp; to the screen instead of the non-breaking space:  .breadcrumbs a:before {     content: '&nbsp;'; }


it is not differentiable but it should have a tangent line, x=0 as in the y-axis, still, no?  how is the notion of the derivative and the existence of a tangent line reconciled here?  (yes, I know there are repeated versions of this question but I haven't seen one talk about the tangent line perspective)

Plotting the function $f(x)=x^{1/3}$ defined for any real number $x$ gives us:   Since $f$ is a function, for any given $x$ value it maps to a single y value (and not more than one $y$ value, because that would mean it's not a function as it fails the vertical line test). This function also has a vertical tangent at $x=0$.   My question is: how can we have a function that also has a vertical tangent? To get a vertical tangent we need 2 vertical points, which means that we are not working with a "proper" function as it has multiple y values mapping to a single $x$. How is it possible for a "proper" function to have a vertical tangent?  As I understand, in the graph I pasted we cannot take the derivative of x=0 because the slope is vertical, hence we cannot see the instantaneous rate of change of x to y as the y value is not a value (or many values, which ever way you want to look at it). How is it possible to have a perfectly vertical slope on a function? In this case I can imagine a very steep curve at 0.... but vertical?!? I can't wrap my mind around it. How can we get a vertical slope on a non vertical function?


Please notice that this , but it seems that it doesn't interest MO community. So, I have got a comment to post in this community in the hope that I may get some attention to this question.  Background:  For Kernel ridge regression, I have normally come across the data-set given in vector and scalar form, i.e., $\overline{S}:= \{x_i, \overline{y}_i \}$, where $x_i \in M_{n,1}(\mathbb{R})$ and $\overline{y}_i \in \mathbb{R}$. Then, for example, I could do the ridge-regression as given here .    My question:   Can we do the same Kernel ridge regression but with a data set in matrix-vector form, i.e., $S := \{ X_i, y_i \}_{i=1}^{N}$, where $X_i \in M_{n,p}(\mathbb{R})$ and $y_i \in M_{n,1}(\mathbb{R})$? If yes, can you prove it or give me a reference/paper?  Thank you so much in advance for your help.


I'm reading through the not-so-short guide to Latex, and I've just got up to the tabular environment. If I want to create a table with two columns, one  left-aligned and one right-aligned, I write this:    \begin{tabular}{lr} text & more text \\ \end{tabular}   Meanwhile, if I wanted the second column to instead have width 1cm and to wrap text, I would write   \begin{tabular}{l p{1cm}} text & more text \\ \end{tabular}   My question is this: what if I wanted the second column to be right-aligned and to have the behaviour of p{1cm}? I see no reason that these commands should be in conflict - the behaviours they cause are completely independent. But I can't see a way of giving both arguments to one column simultaneously.

I would like to create a table with some columns' width specified, while the text in those columns should be centered both horizontally and vertically. I found out that  \usepackage{array} \begin{tabular}{| c | c | m{5cm} |}   vertically centers the text in the last column, but justifies it horizontally (like text in normal paragraphs).  Update: With Jake's method, it seems both \\ and \hline cause an error. How to fix it?


I've tried to look this up a few days now but came out empty handed I have a little website I'm working on and I've created a context menu (right click on a table row to get the context menu) and I wish to create a copy to clipboard method, I've a the data I wish to copy on a variable named $text This is the JS code:    copy: {     name: "Copy",     callback: function (key, option) {     var $row = $(this).closest("tr");     var $text = $row.find(".md").text();          //the $text is what I'm trying to copy     }     I've tried many method to do so, using JS only and when I didn't find any method to do so I've tried to find a way to send this variable to my init.py code which runs the server but without success.  I would very apprachet if anyone will be able to help me understand what am I looking for to make this work and how to implement it.  Thank you very much

What is the best way to copy text to the clipboard (multi-browser)? I have tried: function copyToClipboard(text) {     if (window.clipboardData) { // Internet Explorer         window.clipboardData.setData("Text", text);     } else {         unsafeWindow.netscape.security.PrivilegeManager.enablePrivilege("UniversalXPConnect");         const clipboardHelper = Components.classes["@mozilla.org/widget/clipboardhelper;1"].getService(Components.interfaces.nsIClipboardHelper);         clipboardHelper.copyString(text);     } }  But in Internet Explorer it gives a syntax error. In Firefox, it says unsafeWindow is not defined. A nice trick without using :


I try to change folder permission. But it went wrong and mess up with all permission like this    I tried   sudo chown -R root:root /var/www/html/   but nothing changed.  How can I revert back the permission or change owner ?  Note: I cannot add image direct to here due to insufficient reputation.

I would like the user to have full rights on this folder (as well as all sub-directories and files in it):  ~/.blabla   currently owned by root.  I have found numerous posts (in this forum and elsewhere) on how to do this for files but I can't find a way to do it for whole folders.


I was wondering if you could have a penguin as a pet and, if so, what are the stats and where do you put it in the character sheet? I'm not taking about an animal companion and I'm not a ranger; I am playing a fighter wizard snow elf.

I'm fairly new to DMing and so is my group, so we are all on a learning curve together. We're playing D&D 5e.  Last week a fighter in our group tamed a wolf with Animal Handling and then requested that he keep the wolf. I allowed this, but now I'm not sure about how to play the wolf.  Specifically, how can he train the wolf to perform certain actions such as attacking?  What other things might I need to be aware of with a PC owning a "pet"?


In English possessive adjectives and reflexive pronouns are   I - My - Myself You - Your - Yourself He - His - Himself * She - Her - Herself * It - Its - Itself * They (sing.) - Their - Themself * We - Our - Ourselves You (pl.) - Your - Yourselves They - Their - Themselves *   Except for the starred ones, all reflexive pronouns are formed by combining possessive adjectives and the word "self". But starred ones are formed differently. They use objective pronouns. Why are the formations of these reflexive pronouns different?

In the earliest grades of elementary schools, students learn that "hisself" and "theirselves" are not words. I do not understand why this is.  If you wanted to refer to 'his' sock, you would say "his sock," not "him sock." Similarly, you would say "their socks," not "them socks."   Why do you not call 'his' self hisself and 'their' selves as theirselves?


What mechanism is used that allows the built-in function list.remove but not simply list.find?  If I have a list l = [a,b,c...] and want to remove an element, I don't need to know its index, I simply input l.remove(element).  Why is it then that I can't use a similar command to find an element's index or to simply check if it's in the list?

Given a list ["foo", "bar", "baz"] and an item in the list "bar", how do I get its index (1) in Python?


This particular question was asked in my  complex analysis assignment which couldn't be discussed due to pandemic.  prove that $\int_{0}^{2\pi} \log|1-e^{i\theta}|d{\theta} = 0$ .  Unfortunately, I have no idea on which theorem should be used to prove this result and I cannot ask anyone in my class as none of my friends did the assignment . Kindly help me!

Here is exercise 11, chapter 3 from Stein & Shakarchi's Complex Analysis II:  Show that if $|a|<1$, then:  $$\int_{0}^{2\pi}\log|1-ae^{i\theta}|\,d\theta = 0$$  Then, prove that the above result remains true if we assume only that $|a|\leq 1.$ ($a\in \mathbb{C}$)  I've already proved it for $|a|<1$, but couldn't make it for $|a|=1$, which I thought would be the easy part. But the only thing I could come up with was that, WLOG, it is enough to prove that:  $$\int_{0}^{2\pi}\log|1-e^{i\theta}|\,d\theta = 0$$  Tried to look for some kind of symmetry, but could't find it. Any ideas? Thanks!


Prove $(n!) ^2 > n^n$ for all $n > 3$ by induction. I know that we will have to use Binomial theorem somehow but I can't figure out how? Please provide some hint.

Show that if $n>2$, then $(n!)^2>n^n$.     My work: I tried to apply induction. So, at the induction step, I need to prove, $n^n>(n+1)^{n-1}$ Here, I tried to use induction again without any luck. I also took log of both sides, but I did not get anything. Please help!


I have a list, ls = [0 1 2 3 4] and I am running the following:  print(ls is ls[:])   I am getting the output as False. Why are they not the same list? When I print both versions I get the same list printed.

My  has failed me.  In Python, are the following two tests for equality equivalent?  n = 5 # Test one. if n == 5:     print 'Yay!'  # Test two. if n is 5:     print 'Yay!'   Does this hold true for objects where you would be comparing instances (a list say)?  Okay, so this kind of answers my question:  L = [] L.append(1) if L == [1]:     print 'Yay!' # Holds true, but...  if L is [1]:     print 'Yay!' # Doesn't.   So == tests value where is tests to see if they are the same object?


Can the square root of a real number be negative?  Dealing with the questions of functions in eleventh class my maths teacher says that square root of a real number is always positive. How is it possible?

It is perhaps a bit embarrassing that while doing higher-level math, I have forgot some more fundamental concepts. I would like to ask whether the square root of a number includes both the positive and the negative square roots.  I know that for an equation $x^2 = 9$, the solution is $x = \pm 3$. But if simply given $\sqrt{9}$, does one assume that to mean only the positive root? And when simply talking about the square root of a number in general, would one be referring to both roots or just the positive one, when neither is specified?


I am confused about the difference between the prior/posterior density and distribution. In my lecture notes the posterior density is:  $$ f(\theta | x_1, \ldots, x_n) = \frac{f(\theta) L(\theta)}{\int f(s)L(s)ds}, $$  where $L$ is the likelihood function and the prior density is $f(\theta)$.  But my notes also say that the posterior distribution is the same as above, with the prior distribution being $f(\theta)$.   So is the prior/posterior distribution and density calculated the same way? Are they the same thing? If not, can someone elaborate on this a bit?

I am confused about the following terminologies:   Distribution Function Cumulative Distribution Function (CDF) Probability Distribution Function Probability Density Function Probability Mass Function (PMF)  (1) Distribution Function == CDF. I.e. they are the same. Am I right?  (2) Which is called PDF: Probability Distribution Function or Probability Density Function?  (3) What is the difference between Probability Distribution Function and Probability Density Function?  (4) Which one is the continuous equivalent of PMF, Probability Distribution Function or Probability Density Function?    Die roll examples could be used for the discrete case and picking a number between 1.5 and 2.5 as an example for the continuous case.


My intuition tells me that the first case (tangent lines all passing through a fixed point) corresponds to a segment of a line, and the second one corresponds to a circle, but I'm having trouble actually proving it. I thought about assuming (without loss of generality) that the fixed point is the origin, but I didn't get anywhere. For the second one, it would be enough to prove that it has constant curvature... but I'm not seeing where to start.

Let $\alpha$ be a regular curve in $\mathbb{R}^2$ and let all of its tangent lines pass through the origin. Also, let $\beta$ be a regular curve in $\mathbb{R}^2$ and let all of its normal lines pass through the origin.   How can I show that $\alpha$ is contained in a straight line through the origin and that $\beta$ is contained in a circle around the origin?  I know that the tangent line $\alpha(t)$ is the line that points in the direction of the tangent vector $T(t)$ and that the normal line of $\beta(t)$ is the line that points in the direction of $N(t)$, but how can I put this all together to complete the proof?


I´m a recently graduated mechanical engineer, I  want to apply for a Masters degree but my average is quite low for a lot of universities requirements, what can I do in order to be more eligible?

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


A spokesman for the UK's Department of Food and Rural Affairs seems to be indicating that either DEFRA, the UK population or the whole of humanity are due to say goodbye to planet earth in 2043.     A Defra spokesman said: “We are committed through our 25-year environment plan to eliminating avoidable plastic altogether by the end of 2042 so we leave our planet in a better state than we found it.     Is there a word (or phrase) for using a familiar idiom (such as 'leave it as you find it') in such a way that it is ridiculous ?    Sample sentence :  _______ is the misuse of an idiom which leads to a ridiculous statement.

M-W has the following definition for mixed metaphor:     a figure of speech combining inconsistent or incongruous metaphors   Hence a requirement is that a 'mixed metaphor' contains more than one metaphor.  :      "mixed metaphor" is more commonly used to describe the result of   accidentally combining two metaphors in a way that does not make sense   as a whole. "For me it was stormy in the great sea of life, but then I   came to a crossroads."   He does not claim that this is a necessary condition, and I'd agree.  I've just written in another thread:  ' "John is a real tiger" works, but "That lion is a real tiger" is best avoided.' Each of these two statements contains a single metaphor.   Does any definition of 'mixed metaphor' apply to the inappropriate (incongruous juxtaposing of tenor and obviously related vehicle) metaphor in the second sentence?


I had a look at man locate but couldn't find an answer to this.  The updatedb command appears to index everything under /, but according to my experiment it didn't index a file at /media/mike/W10 D drive/nonsense_file.  Am I to suppose that it excludes mounted media volumes/locations? Is this documented somewhere? Is there some way of choosing to include some of these locations?

Does the locate database not save certain files? Like are there files that excluded from the database by default?


If I have a Pidgey, how can it I get the HM02 Fly in Pokemon X and Y. If Pidgey can't learn Fly, I also have a Hawlucha.

I have HM Strength and HM Cut.  I would love to fly around this new beautiful world but I'm curious when it will be possible.  Any help?


Snoke says to Kylo Ren:  There has been an awakening. Have you felt it? ... The dark side and the light...  It seems clear throughout Episode VII that Rey is waking up to her own potential, and that Kylo Ren takes definite steps to solidify his position with the Dark Side. Do these events represent the extent of Snoke's comments or is he hinting at broader events and possibilities? How should we understand this "awakening"? I'm hoping that the novelizations shed additional context.

I checked the Wikipedia article and some interviews, and haven't found any specific answer.  What specifically does the "awakening" of the Force in the title refer to?  Was the Force somehow asleep or dormant? (which would, since it Binds The Galaxy Together, explain the Inflationary cosmological models).  Or that there were no active Force users since Vader and Sidious offed every Jedi and then each other? We know Luke's still around.  Or something else?  Canon or word-of-god answers only, please.


I am using Ubuntu 14.04 in embedded  And I want to change Linux generic-kernel to Linux low-latency-kernel. But i think if i change the kernel, some programs already installed and devices(for example touch pad) may not work, and i have to build and re-install.  Current My Linux version is 3.10.17, So  How about changing to low-latency-kernel which is same version(3.10).  It could also have some side effect?    And additionally, is there any command to upgrade kernel to low-latency-kernel, like apt-get....  Actually i found 'deb' file to upgrade kernel to low-latency for version 3.16 but i couldn't find 3.10.

After installing Ubuntu Studio 12.04, I have found that it uses a low latency kernel.   I searched for an explanation and how to change back it to a real-time or generic one. However, it looks like this part of Linux hasn't been covered to explain the details.   Q: Why choose a low latency kernel over a generic or real-time one?  PS: I have already read the answers from  question and  post.


I've encountered an extremely hard problem. I have programmed a community on localhost with xampp on windows. When I exported it to my webserver (centos, apache2, php newest version, mysql newest) I can no longer add news with å ä ö. Everything else works, everything in language.php (translation file) with å ä ö and it appears as å ä ö on the website. But the editor in news/comments submits å ä ö as å, ä and ö. Then it would have been such as "Snö är fint" and on the website shown as "Snö är fint".  Now, it is added into the database as "SnÃ¶ Ã¤r fint" and appears as "SnÃ¶ Ã¤r fint" . I have not changed anything in the files, and have configured php and centos uses sv_SE.UTF-8.  What is the correct solution? One presumes you there's something wrong with encodings somewhere on the server, but I have configured it to use UTF-8 and mysql should use UTF-8 (although it does not say å ä ö in the database, but only ä or now in this case Ã¤), and I have the same settings I used on my own computer (the XAMPP server), where it works without problems. So that means that it's when i insert in to the database it turns to Ã¤ etc instead of ä  TLDR; After changing from my local XAMPP server to a centos server I got this problem: When I publish news or comments on the news with the letter "ä" (and å/ö) Ã¤ is shown instead of  ä as it should do and as it did on my XAMPP server. Everything on my centos server is utf-8 even the locales (sv_SE.utf8 / sv_SE.UTF-8).  Never encountered this problem during my 8 year I've coded php. And you'd think I should have enough knowledge to fix it...  Any help is appreciated, thanks in advance !

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