Collisions with other objects in Java
What is a NullPointerException, and how do I fix it?
We were given the following problem as an assignment, we proved the converse in class for prime numbers; however, we can't use the assumption that $\operatorname{gcd}(a,b) = 1$.  So I am struggling to think of my first possible move.  We are given $ar + bs = 1$, the only think I can think of is let $d$ be a common divisor or $ar + bs$ and then show that the $d = 1$.  However, I am not really sure how to do that.  If anyone could just give me a hint or two to nudge me in the right direction I would be appreciative. What software can join videos? What's the best &amp; easiest GUI software that can join a video that I have downloaded in several parts? $f$ strictly increasing does not imply $f'>0$ We know that a function $f: [a,b] \to \mathbb{R}$ continuous on $[a,b]$ and differentiable on $(a,b)$, and if $f'&gt;0 \mbox{ on} (a,b)$ , f is strictly increasing on $[a,b]$. Is there any counterexample that shows the converse fails?   I have been trying to come up with simple examples but they all involve functions that are discontinuous or has derivative $f'=0$ which does not agree with the hypothesis hmmm A few weeks back I was using std::ifstream to read in some files and it was failing immediately on open because the file was larger than 4GB. At the time I couldnt find a decent answer as to why it was limited to 32 bit files sizes, so I wrote my own using native OS API.  So, my question then: Is there a way to handle files greater than 4GB in size using std::ifstream/std::ostream (IE: standard c++)  EDIT: Using the STL implementation from the VC 9 compiler (Visual Studio 2008).  EDIT2: Surely there has to be standard way to support file sizes larger than 4GB. Before upgrading to macOS Sierra, I really liked the Character Accent Menu by doing a long press on a key (for example, the character e) and being able to add an accent on it.   However, this functionality seems to not work anymore, and so far, I can't find out why?   Also, before, doing a long press on the delete button, would repeatly delete characters. Now, it is doing only one character deletion disregarding how long I'm pressing the key. So if I want to erase 10 characters, I need to press the delete button 10 times...  Also, I am not able to log off or shut down. When doing it, all applications are closed, status bar disappears but nothing happens. The dock remains here. I have no way to shut down or log out without doing a long press on the power button.  Is someone facing the same issue?  EDIT : Logging with a new user account or guest account fix all the problems. But I still would like to know what, in my user account, became corrupted during the upgrade. How can I add metadata to NTFS files/folders? I want to tag different file types (i.e. .pdf, .epub, .iso, .bin, folders,..) using the same descriptive fields. For example i would like a metadata field "type" which would be "eBook" on pdf- and epub-files, "CD-Image" on iso- and bin-files.  I read about Alternate Data Streams (ADS) to make this possible. Does anyone know a good program for Windows 7 to tag different files and search for them? It is important for me, that the metadata is NOT stored in a separate database. I move the files a lot and need to stay flexible (ADSs 'stick' to the files).  Any ideas? When articles are placed after adjectives? I couldn't afford that big a car. It was so warm a day that I could hardly work.   The sentences stated above have been taken from Practical English Usage by Michael Swan. If I write-   I couldn't afford that big car. It was so warm day that I could hardly work.   These make sense. But placement of article a makes these sentences awkward to me. Please say why and when articles are placed after adjectives. And what are the differences among 1, 2 and 3, 4. I've just received my new SSD since the old one died. This Intel 320 SSD supports TRIM. For testing purposes, my dealer put Windows on it, but I want to get rid of this and install Kubuntu on it.  It does not have to be a "secure wipe", I just need the empty the disk in the most healthy way. I believe that dd if=/dev/zero of=/dev/sda just fills the blocks with zeroes and thereby taking another write (correct me if I'm wrong).  I've seen the answer , but it looks like it's suited for clearing empty blocks, not wiping the disk.  hdparm seems to be the program to do it, but I'm not sure if it clears the disk OR cleans empty blocks. From its manual page:     --trim-sector-ranges           For  Solid State Drives (SSDs).  EXCEPTIONALLY DANGEROUS. DO NOT           USE THIS OPTION!!  Tells the drive firmware to discard  unneeded           data  sectors,  destroying  any  data that may have been present           within them.  This makes those sectors available  for  immediate           use  by  the firmware's garbage collection mechanism, to improve           scheduling for wear-leveling of the flash  media.   This  option           expects  one  or  more  sector range pairs immediately after the           option: an LBA starting address, a colon, and  a  sector  count,           with no intervening spaces.  EXCEPTIONALLY DANGEROUS. DO NOT USE           THIS OPTION!!              E.g.  hdparm --trim-sector-ranges 1000:4 7894:16 /dev/sdz   How can I make all blocks appear as empty using TRIM? I am having problems starting my Apache server, because port 443 is already in use.  It turns out, the system process (PID 4) uses the port 443. I don't have IIS installed, the services.msc shows (predictably) no Exchange server running, nor WWW-Services, nor IIS. I have no idea how to find out what service uses that port, short of just disabling each service one after the other, and I am not even sure that would help.  I would be grateful if someone could point me towards how I can get my SSL port back, thank you :)  P.S.: Of course "just switch Apache to another port for SSL" would solve the problem of not being able to start Apache. But I'd still like to know what is so insistent about hogging port 443. :)    I by now took the 'hard route' and disabled services one after the other. It turned out that the "Routing and RAS" service was the culprit.  Thank you all for the valuable input and the new tools in the combat against "WTF does my system do now?". Searching for an equation to find the center of a sphere given 4 points, one finds that taking the determinant of the four (non-coplanar) points together with the variables $x$, $y$, and $z$ arranged like so:  $\left|\begin{array}{ccccc} x^2+y^2+z^2 &amp; x &amp; y&amp;z&amp;1\\ x_1^2 + y_1^2 + z_1^2 &amp; x_1 &amp; y_1 &amp; z_1 &amp; 1\\ x_2^2 + y_2^2 + z_2^2 &amp; x_2 &amp; y_2 &amp; z_2 &amp; 1\\ x_3^2 + y_3^2 + z_3^2 &amp; x_3 &amp; y_3 &amp; z_3 &amp; 1\\ x_4^2 + y_4^2 + z_4^2 &amp; x_4 &amp; y_4 &amp; z_4 &amp; 1\\ \end{array}\right| = 0$   yields the equation for the sphere.  Then one need only re-arrange terms into the more familiar form to find the center and radius.  This works fine.  My question is why.    This same approach also works for one or two dimensions.  I'm guessing it also works for finding hyperspheres in higher-dimensional spaces as long as you have a corresponding number of points.  But where did that determinant form come from?  Is there an intuitive meaning for what that relationship is saying? Is there a difference between Therefor and Therefore? Prove that , any primitive root $r$ of $p^n$ is also a primitive root of $p$ Expand the username auto-completion to everyone who can be notified Keyboard Shortcuts no longer working on GNOME 3.4.1 Is a +1/+1 counter I get from, say Unleash or Undying different than +1/+1 from something like  or ? Is there any truth to the idea that you shouldn't multiply seasonings when multiplying a recipe? I often hear cooks discuss that idea that if you are multiplying, say, a recipe for 4 to be a for 32, that you shouldn't multiply some herbs, spices, or salt. I've never understood any reason why this should be true. Maybe something to do with surface area to volume ratios, or cooking times? Does anyone have a real explanation, or is this nonsense? I want to know, if this bug is fixed, because all previous versions of Ubuntu didn't work for me. So I just want to know, should i leave Windows 10 and go for Ubuntu 17.10. Thanks! VS Code Salesforce plugin deploy does not provide an error message VS Code plugin for salesforce seems to be broken yesterday, It does not provide proper error message in case of failure.  Tried this in a developer org as well as scratch org. Neither deploy code or push gives an error message, and every time we need to go to Salesforce setup -> Deployment Status to view the details.  Is anyone aware of any workaround? What are the prerequisites for studying mathematical logic? I am looking to study mathematical logic, however, I find that introductory books are very daunting, which kind of disheartens me. You see, slowly but surely, I started to realize that the maths which I have learned did not just pop out of thin air, but is a collection of systems, which must of been developed via some other system, i.e, maths did not develop itself.  So I began to look into the origins of mathematics, and read that it was developed via a type of logic, which exists sort of by 'default', via a set of axioms, and then of course I looked up the definition of axioms.   So given that I'd be studying a type of logic whose origins are self evident axioms, naturally I believed there would be no prerequisites. However, in looking up mathematical logic, I have come across things such as Boolean algebra, sets, first order logic, some other type of logic, called 'traditional logic', as well as references to a sort of calculus, though not in a mathematical sense, I think.  So all in all, I am trying to develop a type of mental spider web, and I am trying to find out the strands which lye at the absolute bounds so that I may learn this mystique logic. Though I have no idea where to start.  Side note: This is the book I have started reading:   Credit goes to Wolfgang Rautenberg. How to avoid the wrinkle at the poles of the UV sphere?