How can I completely wipe a USB stick that seems to crash any program that tries to use it?
What can I do if my USB flash drive is write-protected or read-only?
How to clear the BIOS security password on this notebook? I recently got an Acer Aspire E11 (E3-112m) and in order to install another OS I had to set a Supervisor password, so I used a well known password to me, the problem is that such password contains a special character ! which the password prompt won't let me input, though it let me when I had to set the password (buggy prompt I believe). Now everytime I need to change something in the BIOS I have to fail 3 times and go to  to generate a master key.  I have already tried several different methods to clear it:   Removing the CMOS battery Looking for the reset jumper (which doesn't even exist).   I also noticed there were 2 weird buttons on the front and back sides of the motherboard, I don't know what they are for but I also pressed them (while both the CMOS and the regular battery were disconnected). All of this without luck, the password just won't reset (though the RTC did).  Are there other ways to reset the Supervisor/Admin password on this model? I got a visa with my mother when I was 17 years old. On it was stated "Not valid unless accompanied by my mother".    Can I travel to the UK alone now that I am 18? List all files in all subfolders How many research interests should be included in a statement of purpose/objective I am wondering how many research interest should be included in a statement of purpose. Is it better to include just one core interest or to include up to three as in my case? Render shadows over a transparent background in cycles I'm trying to make a logo that will be on the header of a website. What I'd like to achieve, and the reason I'm using Blender, is the projected shadows on the background looking perfectly real (as opposed to doing a drop-shadow in Photoshop).  The only thing is, the background has to be transparent because the website might use different background colors / gradients that make it impossible to match with the exported 3D background.  I made this dummy file (not the real logo... duh!):    If I use the file as is, the grey borders of the image will be impossible to match with the website's background color.  Here what I want:    So obviously, I tried masking the plane, which made the shadows disappear. I tried having a plane set to glass, which didn't work either.  And I looked around for a similar question, but didn't find one.   I am not trying to render , or a . I've seen  which has a very difficult solution to this problem, and  that is very similar but in Blender Internal.  is similar too but has never been solved. I'm only a beginner at Compositor, and I'm trying to learn more any chance I get, so any solution in Compositor is welcome if detailed enough. Although if there's a simpler or faster way, it's welcome too!  .blend file: Find $\lim_{n \to \infty} \left[\frac{(n+1)^{n + 1}}{n^n} - \frac{n^{n}}{(n-1)^{n-1}} \right]$ (a question asked at trivia) My friend's trivia league had this math question:  $$\lim_{n \to \infty} \left[\frac{(n+1)^{n + 1}}{n^n} - \frac{n^{n}}{(n-1)^{n-1}} \right]$$  After computing a few values, one could guess the answer is $e$ = 2.718...But how can we prove that is the limit?  Someone offered up a hand-wavy proof like this:  \begin{align} \lim_{n \to \infty} \left[\frac{(n+1)^{n + 1}}{n^n} - \frac{n^{n}}{(n-1)^{n-1}} \right] &amp; = \lim_{n \to \infty} \left[\frac{(n+1)(n+1)^{n}}{n^n} - \frac{n \cdot n^{n-1}}{(n-1)^{n-1}} \right] \\ &amp;= \lim_{n \to \infty} \left[(n+1)\frac{(n+1)^{n}}{n^n} - n\frac{n^{n-1}}{(n-1)^{n-1}} \right] \\ &amp;= \lim_{n \to \infty} \left[(n+1)\left(1 + \frac{1}{n} \right)^n - n\left(\frac{n - 1 + 1}{n-1} \right)^{{n-1}} \right] \\ &amp;= \lim_{n \to \infty} \left[(n+1)\left(1 + \frac{1}{n} \right)^n - n\left(1 + \frac{1}{n-1} \right)^{n-1} \right] \\ &amp;= \lim_{n \to \infty} \left[(n+1)e - n \cdot e \right] \\ &amp;= \lim_{n \to \infty} e \\ &amp;= e \end{align}  The part about substituting $e$ is hand-wavy since technically this is an indeterminate form of $\infty - \infty$. And using $e$ as as upper bound did not lead me to an easy proof either.  Is there a way to rigorously prove the limit? I tried a few approaches: (a) sandwiching the limit--I could prove $e$ was a lower bound, but I could not find a suitable upper bound converging to $e$, (b) using L'Hopital's rule with no luck, (c) using the mean value theorem--but that also got complicated.  So this is a pretty tough problem to ask at trivia! Is there a way to prove this limit formally?  Sources  Trivia question:   Thread on trivia:   Hand-wavy proof:   Idea for mean value theorem: Failed to save undefined: No COMPONENT named markup://svg found : Short story (maybe two in the same collection) about Alien education versus Earth I read this somewhere in the 1990s, but it was probably older. I vaguely remember it as being two stories in sequence in an anthology. One was a story involving an Earth administrator comparing Earth curriculum to Mars curriculum and the second was just a class listing for Martian curriculum.  In the first story, what sticks out in my head was the Earth administrator proudly claiming some high value of WPM for reading for his students and the Martian admitting that their rate was lower, and then added a comment along the lines of that the Martian students, when reading at the rate attained at Earth, could not recall every word of the book and recite them back verbatim. In the curriculum listing, I remember that the physical education classes included Tightrope Walking and Advanced Tightrope Walking. In short, the implication was that Mars held its children, and therefore its citizens, to much higher standards, at the cost of sacrificing actual childhood. The children never played, just studied and drilled.  In retrospect, it might not have been Mars... I know one side was Earth and the other was a planet in the Solar System, and Mars sounds about right, but so does Venus. Either way, it was the casual arrogance of the extra-terrestrial society and the blustering attempts of the Earth administrator that stuck out for me. C++ cout hex values? I want to do:  int a = 255;  cout &lt;&lt; a;   and have it show FF in the output, how would I do this? How fast would the Earth need to spin for us to feel weightless? It's a classic question with many answers all over the Internet, but none here so I figured I'd ask it:  How fast would the Earth need to spin for a person (or anything for that matter) to feel weightless while on the surface at the equator?    In this situation everything on the Earth's surface would essentially be in orbit around the Earth at the radius of the Earth's surface (let us assume the atmosphere was also spun up to this angular velocity so there would be no air drag slowing things down).  Let us also say by "surface of the Earth" we mean mean sea level.  You can decide for yourself if/how to factor in the bulge of the Earth.  You can assume that the Earth somehow is able to maintain its present shape while spinning up.  Any comments on whether an Earth spinning slightly faster than this speed will cause it to break apart or not will also be appreciated. After updating to 2.81, my previous works (done in 2.80) doesn't show colors I'm exploring the effects of removing the intercept in a logistic regression model.  Assume a model:  $$logit(Y = 1) = \beta_1 x + \beta_2z + 0$$  with $x$ and $z$ being categorical variables with 2 levels each and no intercept.  I understood that having no intercept with categorical predictors produce coefficients that compare the $P(Y = 1)$ in each level of the two predictor against a null case where $P(Y=1) = 0.5$ or $logit(Y=1) = 0$.  I noticed a phenomenon that can understand. Using glm() function in R if you change the order of the variable in the right hand part of the formula, the coefficients change too. But even more oddly, the coefficient of the first variable is always the same.  Here's an R demo:  y &lt;- as.factor(sample(rep(1:2), 30, T)) x &lt;- as.factor(sample(rep(1:2), 30, T)) z &lt;- as.factor(sample(rep(1:2), 30, T))  coef(glm(y ~ x + z - 1, binomial) #        x1         x2         z2  #-0.1764783  0.3260739 -0.1335192  coef(glm(y ~ z + x - 1, binomial)) #        z1         z2         x2  #-0.1764783 -0.3099976  0.5025523    As you can see the first predictors have the same coefficient while the other are different in the two models.  Here is what I expected and instead behave differently than what I though:   Since every level of the two predictors is compared to the same null case, I expected to have the same coefficients in the two models, independently from the order in which I use them. I expected to see the coefficients of every level of every predictor, instead the coefficient for the 1 level of the second predictor is not shown. I therefore assume that only the first variable is compared against the null case, while the second is compared against a reference level; but what is this level? Is it $P(Y = 1 | X = 1 \cap Z = 1)$? Reproducing one of the models WITH the intercept we get:  coef(glm(y ~ x + z - 1, binomial) #        x1         x2         z2  #-0.1764783  0.3260739 -0.1335192  coef(glm(y ~ x + z, binomial)) #(Intercept)         x2          z2  #-0.1764783   0.5025523  -0.1335192    As expected x1 become the intercept, and x2 is likely relative to x1. z1 is missing also in this case and z2 is the same as in the model without intercept.  Thus should I assume that the comparison against the null case $P(Y = 1) = 0.5$ is made only for the first variable in a formula, while the other are compared against the usual intercept? Is this behavior normal? What about the fact that the first coefficient has the same value whichever the order of the predictors in the formula? What if I want to compare all level of each predictor against the null case and have a coefficient for all levels? Or it's theoretically impossible for some reason I don't get? I am very new to the TikZ package, and I need to draw some flow chars by using the following shapes.   However I couldn't figure out how to draw the 4th and and 6th ones below. It would be very nice (for completeness) to help with all of the shapes in the list below.      Your help will be greatly appreciated.  Note: I have visited  but it contains some other shapes. I have found a strange behavior in TikZ. When using the \draw ... to ... syntax and trying to place nodes along the line with the node[...]{...} syntax, the nodes do not turn up at the expected location.  \documentclass{standalone} \usepackage{tikz} \begin{document} \begin{tikzpicture}   \draw(0,0) to[out=60,in=120] (1,0) node[midway]{x}; \end{tikzpicture} \end{document}     How is this done properly? Is there is any reason to make the permissions on an overridden C++ virtual function different from the base class?  Is there any danger in doing so?  For example:  class base {     public:         virtual int foo(double) = 0; }  class child : public base {     private:         virtual int foo(double); }   The  says that it is a bad idea, but doesn't say why.  I have seen this idiom in some code and I believe that the author was attempting to make the class final, based on an assumption that it is not possible to override a private member function.  However,  shows an example of overriding private functions.  Of course  recommends against doing so.  My concrete questions:   Is there any technical problem with using a different permission for virtual methods in derived classes vs base class? Is there any legitimate reason to do so? I am downloading macOS Sierra from Mac App Store. But I have electricity problem here. Due to which my iMac will lose power after 2 hours. Now I want to pause the downloading so that I can resume the download later on. How can I do that?  Here is a screenshot. How to jump to the region header from the endregion tag in c# visual studio 2012? I have currently a strange problem on debian (wheezy/amd64).  I have created a chroot to install a server (i can't give any more detail about it, sorry). Let's call its path /chr_path/. To make things easy, I have initialized this chroot with a debootstrap (also wheezy/amd64).  All seemed to work well inside the chroot but when I started the installer script of my server I got : zsh: Not found /some_path/perl (the installer includes a perl binary for some reasons)  Naturally, I checked the /some_path/ location and I found the "perl" binary. file in chroot environment returns :  /some_path/perl ELF 32-bit LSB executable, Intel 80386, version 1 (SYSV), dynamically linked (uses shared libs), for GNU/Linux 2.2.5, not stripped   The file exists, seems ok, has correct rights. I can use file, ls, vim on it but as soon as I try to execute it - ./perl for example - I get : zsh: Not found ./perl.  This situation is quite understandable for me. Moreover :   I can execute other basic binaries (/bin/ls,...) in the chroot without getting errors I have the same problems for other binaries that came with the project When I try to execute the binary from the main root (/chr_path/some_path/perl), it works. I have tried to put one of the binaries with a copy of my ls. I checked that the access rights were the same but this didn't change anything (one was working, and the other wasn't) Proving that $-a=(-1)\cdot a$ As the title reveals, I want to prove (based on the axioms of field) that $$-a=(-1)\cdot a$$ I've been trying for a while now, but couldn't think of a way to do it and it got me thinking that maybe its does not require a proof, but it doesn't feel right. Any ideas? Why wasn't Poe told about Holdo's plan?