This error comes up everytime   failed to load image grub error efi failed to start image   Then I get redirected to boot menu and every option has the same effect i.e the same error. I even tried inserting a recovery drive through usb and it resulted in the same error.
I have absolutely no experience with Linux, and I desperately need to get my computer back up and running again with Windows.  How do I remove Ubuntu and reinstall Windows?    Editor's note: many of the answers are about removing Ubuntu from dual-boot but keeping Windows (which is a bit complicated), while other answers are about removing Ubuntu from single-boot (which is easy: basically just format the disk while installing Windows). The question as written is ambiguous between dual-boot or single-boot.
How to self study Linear Algebra I have no idea if this question is appropriate for this forum, but I hope you guys can overlook the fact that I asked it on a wrong forum (if I did) and still help me answer it (of course, if this is indeed the wrong forum for the type of question I'm about to ask, do please say so).  I am a 16 year old guy who is passionate about physics and as a result wants to increase his knowledge in mathematics, the language of physics. I've read and heard a lot about Linear Algebra and how crucial it is to physics and I am deeply motivated to self study this intriguing part of mathematics. However, I have limited knowledge of maths. I (for example) know basic algebra, trig, diff/int calc and some analytical geometry, but I wouldn't say I master these subjects past the high school curriculum. Now my question is: Would you kind people say I am able to self study Linear algebra or is it too tough and/or does it require too much of a math background? And are there any good books out there for BEGINNERS in LA? I found this (free) e-book called: Elementary Linear Algebra by Kenneth Kuttler and another one called 'Linear Algebra: Theory and its applications' also by Kuttler? Are these any good? Or would you recommend other books? If you guys have any tips regarding books for LA but also tips in general, please, I'd appreciate them! I have always believed that it was ok to replace a capacitor with a slightly higher voltage rated one. eg 16v with 25v.Going higher than this would risk the capacitance value being out at the working voltage. However I just read the following quote from this       Electrolytic capacitors are non-ferroelectric with a very low dielectric constant. Their capacitance is derived from a very high surface area and nanometer thick dielectric layers. Their capacitance is not a function of applied voltage.‐Design Solutions For DC Bias In Multilayer Ceramic Capacitors (August 2010 Electronic Engineering Times)   So does this rule not apply to aluminum electrolytics? Eg will I have no issues replacing an electrolytic 25v 100uf with a 50v 100uf assuming both are low esr, similar footprint and good quailty? Is there a way I can share the 3.42 GB download of Windows 8.1 from Windows Store? Windows 8.1 is out, and I would like to know if it is possible to share the Windows 8.1 download upgrade between different computers so that I don't have to download it over and over again?  This might be helpful for people who are on a metered connection. Store is downloading 3.42&nbsp;GB of data so it must be stored somewhere. Is there a way I can copy it to my other computers and start the setup so that I don't have to download it over and over again on each computer I own? I am taking a course in Mathematical Methods for physicsPhysics (Junior Level).   We are working from   > Mathematical Methods for physicists, George B.Arfken .    I just need online resources covering ( Matrices, Determinants, Vector Analysis, Tensors and differential forms and Vector spaces...etc) to study and understand from. Symbolic coordinates for a hyperbolic grid? Rephrasing     (one year later)    (original question is below)   Apparently the original question wasn't clear, or nobody knows an answer (or both).  So I will try to rephrase it.   Look at your favorite .  This question asks for a labeling system for the points.  Of course we could draw the grid on the Poincare disk, and use real numbers (the (x,y) coordinates of each point), but in practice that would raise all sorts of precision issues that could surely be avoided if one had a proper symbolic coordinate system.  You shouldn't need real numbers if you're staying on grid points!  Just like (2,3)+(0,1) is trivial to do by hand (or in your head) for the square grid, we'd like some form of symbolic coordinates (i.e. consisting of finite sequences of symbols) for a hyperbolic grid, in which simple operations on small grid vectors are similarly easy.  If you take some sequence of left and right turns in a hyperbolic grid city, what should you keep track of in your head so you can take the optimal route back to your starting point?  In a Euclidean square grid, it is {(int)X, (int)Y, (enum)direction you are facing}, and we all know how to use this.  Is there any hyperbolic grid where this question has a nice answer?    Original Question  If we consider the Euclidean plane, then a square grid works well with using two integers (the coordinates) as a representation for vectors that lie on the grid.  Does anybody know of a similarly nice representation for working in the hyperbolic plane?  Desirable features of any such system:  $-$ It should be easy to add two vectors.  $-$ It should be easy to see if two vectors are the same.  $-$ It should be easy to see if two vectors are close.  $-$ It should be easy to rotate a vector by an angle that is a symmetry of the grid.  $-$ Every point in the plane should be near some vector. (The grid shouldn't have large empty regions.)   Note that "addition" using continuous coordinates would most naturally be defined in terms of parallel transport, and it is neither commutative nor associative.  On a grid, however, the issue of orientation needs to be addressed differently, since parallel transport along arbitrary grid vectors will introduce rotations that are not a symmetry of the grid, so to remain on the grid, addition will need to be defined using something other than parallel transport.  Since hyperbolic grids have an exponential number of points (as a function of distance from the origin), our symbolic coordinates will need to have a length proportional to the length of the vector.  Don Hatch has a web page which gives some .  ("Easy" means an efficient algorithm that is doable by hand, like how the algorithms for addition and subtraction using the standard digit-sequence representation of integers can be used for the Euclidean square grid. Using hyperbolic functions of real numbers, always keeping track of enough digits to identify the nearest grid point, does not count as easy!)    Addendum: Many readers seem to be disturbed by a little voice saying "But vectors don't make sense in the hyperbolic plane!": What that voice is really saying is that the hyperbolic plane doesn't give you all the nice properties you are used to in Euclidean space or in vector spaces.  So if you define vectors as objects having specific properties you are used to (such as having a direction that is unaffected by parallel transport), then that definition may not correspond to anything in the hyperbolic world.  You could use the term isometry, but that is typically a fixed mapping from the space to itself, and in the hyperbolic plane the isometry corresponding to a vector would depend on the starting point. (However, isometries will be central to any solution, I assume.) And a geodesic is a fixed path within the space, no different from a hyperbolic line or segment.  The paper  offers one solution.  offer another.  I deliberately leave them undefined in this question, as I am looking for any workable system. How do I disable client side decoration globally in GNOME? I'm using Ubuntu GNOME 17.04. One encounters client side decoration (CSD) as most of the official GNOME applications (Nautilus, gedit, Evince etc.) use  (a combined title bar and toolbar, see linked screenshots) whereas other applications don't. This feature is disabled in Unity, all the applications use traditional separate title bars.  Screenshots (from ):     Nautilus with GtkHeaderBar   Nautilus without GtkHeaderBar     For consistency I want to disable GtkHeaderBars globally (in all the applications using it) and use separate title bars. Is there a way to achieve that?  I have heard of gtk3-nocsd package, but couldn't make it work with GNOME for all the applications. Shouldn't the badge requirements scale? Many badges have fixed requirements, such as:   Answer score of 100 or more   However different websites means a different level of difficulty: the more active users a website has, the easier the badge is to get.  On a new and/or low-view website getting this badge may be impossible for several months; on a website like stack overflow now you can obtain it in a day, and it's relatively easy (compared to other SE sites).  Do you think it would be a good idea to implement a formula that allows the required score to scale? The more active users voting, the more votes are required to get it?  If yes how would you handle people who got it for a post that no longer meets the requirements? lsusb relevant output Bus 001 Device 006: ID 0bda:8812 Realtek Semiconductor Corp. RTL8812AU 802.11a/b/g/n/ac WLAN Adapter  Upon plugging the device it is recognized by lsusb, however when I go to wireless settings no adapter is recognized. The driver is installed (by going to software and updates -> addition drivers and selecting the open source driver). Strategies to Defeat Memory Editors for Cheating - Desktop Games Network account problems with mac server OSX 10.6 Snow Leopard Okay the situation is this.   Yesterday my company changed our dns server, because our former one, was too unstable to work with. anyway today i went to one of our mac server, because it needed to be configured because of the new dns server. So i tried logging in to the local admin, because it couldn't find the network account server, because of the domain shift, but it just froze when trying to log in.  Okay so I went down to our server room to get a look at it locally. I tried logging in to the local admin, but i froze again. So i tried pulled the network cable out, and suddenly i could login just fine.  I tried logging in via vnc once again and it just hanged. better than it freezing, but still a problem. so i logged in locally. went to system preferences to edit the path to the network account server, so the mac server could find it once more, but then it just froze the system preferences when i went to login options.   So i restarted back and forth some time and finally got to edit the path to the network account server, but when i typed it in, the mac server just say that the network account server is not responding although all other computers, both linux and mac, are using it just fine. I tried updating, rebooting without the network. tried FQDN for the network account server, it's ip, it's hostname nothing work.  Does anyone have any clue to what is going on? cause I really have no idea what to do, other than maybe reinstall the system, which i would like to avoid if possible. Is it possible to load some package from a .sty file only if some option is selected?  (Naive approach \DeclareOption{something}{\RequirePackage{something}} doesn't work.) Is it possible to earn more than 100 lollipops per second? I have pumped my lollipop rate to 100/s, but it took a long time to go from 99 to 100. Is it even possible to get higher or should I stop? How to convert string to boolean php White cloudy areas on bottom of new stainless steel skillet I just bought my first few pot and pans "Calaphon" stainless steel trip-ply  I used my new 10" skillet tonight, and cooked pork chops. I heated the pan first, added olive oil, let it heat, then added chops. After I was done, cleaned it immediately under water, and noticed white cloud looking areas on the bottom of the skillet. They won’t wash or rub off  Do I need to return these? I did buy them for the look as well. I have several thousand nodes of a particular content type. Using the web interface (example.com/admin/content), I can only delete about 50 at a time. How can I quickly delete them? Can polymorphing monsters spam their ability to effectively give themselves a massive health pool? Some creatures have an ability that lets them polymorph, such as the Couatl's Change Shape action. I am wondering if this ability could be used again whenever the form is dropped to give the creature a massive effective health pool.  For example, if the Couatl used their action to Change Shape and become a Veteran, then was hit for enough damage to kill the polymorphed form, could it then re-use the Change Shape ability to transform into a fully healed Veteran once more? Drawing simple edge, no arrow I have  \begin{tikzpicture}[-&gt;,auto,node distance=3cm,   thick,main node/.style={draw,font=\bfseries}]   \node[main node] (111) at (0,1) {$X_{1,1}^{(1)}$};   \node[main node] (121) at (0,2) {$X_{1,2}^{(1)}$};   \node[main node] (1n1) at (0,4) {$X_{1,n}^{(1)}$};   \node[main node] (211) at (0,6) {$X_{2,1}^{(1)}$};   \node[main node] (221) at (0,7) {$X_{2,2}^{(1)}$};   \node[main node] (2n1) at (0,9) {$X_{2,n}^{(1)}$};   \node[main node] (n11) at (0,11) {$X_{n,1}^{(1)}$};   \node[main node] (n21) at (0,12) {$X_{n,2}^{(1)}$};   \node[main node] (nn1) at (0,14) {$X_{n,n}^{(1)}$};   \node[main node] (112) at (2.5,1) {$X_{1,1}^{(2)}$};   \node[main node] (122) at (2.5,2) {$X_{1,2}^{(2)}$};   \node[main node] (1n2) at (2.5,4) {$X_{1,n}^{(2)}$};   \node[main node] (212) at (2.5,6) {$X_{2,1}^{(2)}$};   \node[main node] (222) at (2.5,7) {$X_{2,2}^{(2)}$};   \node[main node] (2n2) at (2.5,9) {$X_{2,n}^{(2)}$};   \node[main node] (n12) at (2.5,11) {$X_{n,1}^{(2)}$};   \node[main node] (n22) at (2.5,12) {$X_{n,2}^{(2)}$};   \node[main node] (nn2) at (2.5,14) {$X_{n,n}^{(2)}$};   \node[main node] (11k) at (6,1) {$X_{1,1}^{(k)}$};   \node[main node] (12k) at (6,2) {$X_{1,2}^{(k)}$};   \node[main node] (1nk) at (6,4) {$X_{1,n}^{(k)}$};   \node[main node] (21k) at (6,6) {$X_{2,1}^{(k)}$};   \node[main node] (22k) at (6,7) {$X_{2,2}^{(k)}$};   \node[main node] (2nk) at (6,9) {$X_{2,n}^{(k)}$};   \node[main node] (n1k) at (6,11) {$X_{n,1}^{(k)}$};   \node[main node] (n2k) at (6,12) {$X_{n,2}^{(k)}$};   \node[main node] (nnk) at (6,14) {$X_{n,n}^{(k)}$};   \node[main node] (11n2) at (9.5,1) {$X_{1,1}^{(n-2)}$};   \node[main node] (12n2) at (9.5,2) {$X_{1,2}^{(n-2)}$};   \node[main node] (1nn2) at (9.5,4) {$X_{1,n}^{(n-2)}$};   \node[main node] (21n2) at (9.5,6) {$X_{2,1}^{(n-2)}$};   \node[main node] (22n2) at (9.5,7) {$X_{2,2}^{(n-2)}$};   \node[main node] (2nn2) at (9.5,9) {$X_{2,n}^{(n-2)}$};   \node[main node] (n1n2) at (9.5,11) {$X_{n,1}^{(n-2)}$};   \node[main node] (n2n2) at (9.5,12) {$X_{n,2}^{(n-2)}$};   \node[main node] (nnn2) at (9.5,14) {$X_{n,n}^{(n-2)}$};   \node[main node] (11n1) at (12,1) {$X_{1,1}^{(n-1)}$};   \node[main node] (12n1) at (12,2) {$X_{1,2}^{(n-1)}$};   \node[main node] (1nn1) at (12,4) {$X_{1,n}^{(n-1)}$};   \node[main node] (21n1) at (12,6) {$X_{2,1}^{(n-1)}$};   \node[main node] (22n1) at (12,7) {$X_{2,2}^{(n-1)}$};   \node[main node] (2nn1) at (12,9) {$X_{2,n}^{(n-1)}$};   \node[main node] (n1n1) at (12,11) {$X_{n,1}^{(n-1)}$};   \node[main node] (n2n1) at (12,12) {$X_{n,2}^{(n-1)}$};   \node[main node] (nnn1) at (12,14) {$X_{n,n}^{(n-1)}$};   \path     (111) edge (112)         edge (122)         edge (1n2)     (121) edge (112)         edge (122)         edge (1n2)     (1n1) edge (112)         edge (122)         edge (1n2)     (121) edge[--,dashed] (1n1); \end{tikzpicture}   I just want simple lines, no arrows. How to manage with edge to achieve that? Thanks Getting MTP enabled devices to work with Ubuntu? Can a plan "age" reach zero? How can you convert a byte array to a hexadecimal string, and vice versa?