The title pretty much covers it all, but I want to create a USB drive with Ubuntu on it to boot a Macbook Air. My computer has Ubuntu 14.04 on it, and that's it. How do I do it ?
How do I make an Bootable Ubuntu USB containing the the latest version of Ubuntu?  For completeness, how would I be able to do this on Ubuntu, Windows, OS X or another Linux distro?
How should I submit bug reports and feature requests? Inspired by  I became curious about what is the current preferred mechanism for submitting bug reports and feature requests to Apple. I'm aware that they have the internal RDAR bug tracking system, and that there is an  project to crowdsource the tracking of issues, but I'm at a loss as to the preferred channel to submit something.    Is there a public-facing portal for submitting issues? What is the distinction between a professional and amateur photographer? What tool do I need to install to make my terminal show the autocompletion of the command that I'm writing? A question about causality and Quantum Field Theory from improper Lorentz transformation Related post   In Peskin and Schroeder's QFT p28, the authors tried to show causality is preserved in scalar field theory.  Consider commutator $$ [ \phi(x), \phi(y) ] = D(x-y) - D(y-x) \tag{2.53} $$ where $D(x-y)$ is the two-point correlation function,  $$D(x-y):= \langle 0 | \phi(x) \phi(y) | 0 \rangle  = \int \frac{d^3 p}{ (2\pi)^3} \frac{1}{ 2E_{\mathbf{p}}} e^{-ip(x-y)}\tag{2.50}$$  P&amp;S argued that each term in the right-hand-side of (2.53) is Lorentz invariant, since $$\int \frac{d^3p }{ (2\pi)^3} \frac{1}{2E_{\mathbf{p}}} = \int \frac{ d^4 p }{ (2\pi)^4} (2\pi) \delta(p^2-m^2)|_{p^0&gt;0} \tag{2.40}$$ is Lorentz invariant.  Since there exists a continuous Lorentz transformation in the spacelike interval $(x-y)^2&lt;0 $ such that $(x-y) \rightarrow - (x-y) $ and $D(y-x)=D(x-y)$, (2.53) equals zero in the spacelike interval. In timelike interval, since such continuous Lorentz transformation does not exist, (2.53) is non-zero in general.  My question is, consider a non-continuous Lorentz transmation in the timelike interval, $PT$, namely time reversal times parity transformation. I can also let  $(x-y) \rightarrow - (x-y) $. Why (2.53) in the timelike interval is non-zero?  I guess $PT$ will let (2.40) go to $p^0&lt;0$ branch. But I am not sure if it breaks the Lorentz invariant of (2.40) and (2.50). A typical $L^p$ function does not have a well-defined trace on the boundary My try, using $x = \sec(u)$ substitution:  $$ \begin{eqnarray} \int \frac{\sqrt{x^2-1}}{x} \mathrm{d}x &amp;=&amp; \int \frac{\sqrt{\sec^2(u) - 1}}{\sec(u)}\tan(u)\sec(u) \mathrm{d}u \\ &amp;=&amp; \int \tan^2(u) \mathrm{d}u \\ &amp;=&amp; \tan(u) - u + C \\ &amp;=&amp; \tan(arcsec(x)) - arcsec(x) + C \end{eqnarray} $$  However, according to , the answer should be: $$ \int \frac{\sqrt{x^2-1}}{x} \mathrm{d}x = \sqrt{x^2-1}+\arctan \left( \frac{1}{\sqrt{x^2-1}} \right)+C $$ When I derive this last answer I don't get back the integrand, but rather: $$ \frac{\mathrm d}{\mathrm d x}\left(\sqrt{x^2-1}+\arctan \left( \frac{1}{\sqrt{x^2-1}} \right)+C\right) = \frac{x}{\sqrt{x^2-1}}- \frac{x}{(x^2-1)^{3/2}\left(1+\frac{1}{x^2-1}\right)} $$  I don't know how to simplify this expression more. Also, I am unable to check whether my answer is correct because I don't know how to find the derivative of $arcsec(x)$.  Can someone check my calculations and tell me where I've done something wrong and how one can simplify the last expression to get back the integrand? New post formatting Update 3 It took me longer than I wanted, but I’ve got some updates for you on our s-prose component. You can see the  with my thinking over at our design system’s repo. It does the following:  Spreads s-prose headers out from paragraphs for better grouping. Tightens up s-prose paragraphs a bit, and made sure spacing under headings are more consistent. Replaces all s-prose margins internal to the component with a CSS variable var(--s-prose-spacing) so our users can more easily tinker with it in their browsers and user scripts. Kills trailing margins in s-prose  You can see  of content at our Stacks documentation.  Update 2 I’ve split the difference between the original 1.3 line-height and the proposed 1.6 line-height. We’re now at 1.5, with additional refinements to spacing between elements. I’ve also reduced line height within code blocks back to near the original value.  Update 1 This is now live.  We’re doing a bit of refactoring on our post formatting. Currently, we apply a single class with both layout and styling called .post-text. Our first goal is to separate layout from our text styles. Simple enough! However, our current post styling has a few missing spots and areas for improvements. Using our  as a sandbox, we’ve beefed up our styling and created a new component called .s-prose. It’s designed to offer styling for everything the  spec allows. This should allow us to add Stack Overflow-flavored styling anywhere we need to consume Markdown—questions and answers, of course, but also things like user profiles. Our .s-prose component adds:  Proper formatting for   Further header support and better spacing there  Additional blockquote refinements.  Refinements for revealing spoilers. We now reveal this on click / tap for a more consistent experience across devices—fewer accidental reveals as well, since it’s no longer a :hover interaction. Clicking again does not hide the spoiler. We also now add a badge to the top right corner. You can see how these work on our . It looks something like this:   This is a spoiler  It has two lines   General refinements to spacing including nested lists, images within lists  Sizing variations for different contexts. We offer xs, sm, and md variations of the .s-prose component.   As with everything, our prose component is a work in progress. We think we’ve got a heck of a start to a reusable component. We plan on going live with the new component network wide on Thursday, August 27, 2020. We’ll edit this post if that changes. If you see something funky, let us know. Some things are intended but might feel like regressions—images have a slightly different baseline—but others may have slipped through the cracks. I'm trying to determine the best way to truncate or drop extra decimal places in SQL without rounding.  For example:  declare @value decimal(18,2)  set @value = 123.456   This will automatically round @value to be 123.46, which is good in most cases.  However, for this project, I don't need that.  Is there a simple way to truncate the decimals I don't need?  I know I can use the left() function and convert back to a decimal.  Are there any other ways? Writing string at the same position using Console.Write in C# 2.0 I have a console application project in C# 2.0 that needs to write something to the screen in a while loop. I do not want the screen to scroll because using Console.Write or Console.Writeline method will keep displaying text on console screen incremently and thus it starts scrolling.  I want to have the string written at the same position. How can i do this?  Thanks How does LSTM prevent the vanishing gradient problem? LSTM was invented specifically to avoid the vanishing gradient problem. It is supposed to do that with the Constant Error Carousel (CEC), which on the diagram below (from ) correspond to the loop around cell.  (source: ) And I understand that that part can be seen as a sort of identity function, so the derivative is one and the gradient stays constant. What I don't understand is how it does not vanish due to the other activation functions ? The input, output and forget gates use a sigmoid, which derivative is at most 0.25, and g and h were traditionally tanh. How does backpropagating through those not make the gradient vanish ? I'd really like your help proving:  $(A\rightarrow B),(A\rightarrow C)\rightarrow B,  \mapsto_{HPC} B $  Where $HPC$ is the Hilbert's system proof which contains the following relevant axioms:   $A\rightarrow(B \rightarrow A)$ $(A\rightarrow(B\rightarrow C)) \to ((A\rightarrow B)\rightarrow(A\rightarrow C))$ $(A\rightarrow B)\rightarrow ((A\rightarrow\bar{B})\rightarrow \bar{A})$ $\bar{\bar{A}} \rightarrow A$   In addition tried to use these following lemmas: $\bar{A} \rightarrow (A \rightarrow C) $ and $(A\rightarrow B)\rightarrow (\bar{B} \rightarrow \bar{A})$.  Any suggestions? In the 1997 film "", the antagonist is attempting to elude some assassins who are after him. When they are pursuing his van, he quickly      pulls the van into a parking garage and washes off the color-changing paint he had earlier painted the van with, thus changing the color of the van.    He then takes a small can and sprays it onto the door handle of the van before taking off. A few minutes later, the assassins      enter the parking garage and notice the dyed water running away from the van. When one of the men goes to open the van using the tainted door handle, he pulls his hand away like it hurt, then starts foaming at the mouth. He immediately has a seizure of some kind and falls down dead.   What was the substance sprayed on the handle, and how could it do this so quickly? How could I execute a script in Shell when a shortcut key is pressed.   Essentially what I need is when a shortcut key is pressed the script should read from a file and display that content in the terminal. I have a Toshiba satellite A-200 laptop with a Vista OS on it with 4 NTFS partitions  (C:) Vista  (D:) Entertainment  (E:) Work  (F:) Sources   and I wanted to start using Ubuntu instead. So I tried it first from the live CD and everything was OK and all the partitions were shown and working and so I decided to install Ubuntu to replace Vista on the (C:) drive. After I did that I can no longer find my folders and files on the (D:), (E:), (F:) partitions and the only file system that is shown is one 198 GB although my HDD is 320 GB.  I can't access the lost data on the remaining 120 GB which I hope is still there and not totally lost  I am now working from the live CD but I am unable to install testdisk. Can I recover the Vista partitions by the product recovery CD to get my laptop back to the factory settings? Can I recover the NTFS partitions using a recovery program for Windows or will that make the problem worse?   I need these data badly as I don't have a backup for them. Is a DNA molecule a single strand of polynucleotide or two of them linked together? What changes when an Alienist becomes an outsider? Are there massless bosons at scales above electroweak scale? Spontaneous electroweak symmetry breaking (i.e. $SU(2)\times U(1)\to U(1)_{em}$ ) is at scale about 100 Gev. So, for , gauge bosons $Z$ &amp; $W$ have masses about 100 GeV. But before this spontaneous symmetry breaking ( i.e. Energy > 100 GeV) the symmetry $SU(2)\times U(1)$ is not broken, and therefore gauge bosons are massless.  The same thing happens when we go around energy about $10^{16}$ GeV, where we have the Grand Unification between electroweak and strong interactions, in some bigger group ($SU(5)$, $SO(10)$ or others). So theoretically we should find gauge bosons $X$ and $Y$ with masses about $10^{16}$ GeV after GUT symmetry breaks into the Standard Model gauge group $SU(3)\times SU(2)\times U(1)$, and we should find massless X and Y bosons at bigger energies (where GUT isn't broken).  So this is what happened in the early universe: when temperature decreased, spontaneous symmetry breaking happened and firstly $X$ &amp; $Y$ gauge bosons obtained mass and finally $Z$ &amp; $W$ bosons obtained mass.   Now, I ask: have I understood this correctly? In other words, if we make experiments at energy above the electroweak scale (100 GeV) we are where $SU(2)\times U(1)$ isn't broken and then we should (experimentally) find $SU(2)$ and $U(1)$ massless gauge bosons, i.e. $W^1$, $W^2$, $W^3$ and $B$ with zero mass? But this is strange, because if I remember well in LHC we have just make experiments at energy about 1 TeV, but we haven't discovered any massless gauge bosons. Rendered image is just grey I am having some issues when rendering an image, my rendering screen is turning into grey even when making a full render. What am I doing wrong? Simplest or nicest proof that $1+x \le e^x$ How does Ubuntu partition the disk when we choose "Erase disk and install Ubuntu" during installation? How will Ubuntu automatically allocate the disk partition sizes when we select Erase disk and install Ubuntu during installation?    Can the settings for automatic space allocation be changed?