Everyone knows that 1+1=2, but how would one mathematically prove that this equation is true? Or can you?
Is it possible to prove that $1+1 = 2$? Or rather, how would one prove this algebraically or mathematically?
Today a couple of buffer overflows in NTP were announced , . It looks like updating my system to fix these issues is in order.   How can I find out if they have been fixed in the Ubuntu repositories, such that if I were to run:   sudo apt-get update sudo apt-get upgrade   then the fix would get installed and the vulnerability closed?   Edit: The selected answer specifically addresses the question of how to identify if a given CVE has been fixed or not, "Does Ubuntu generally post timely security updates?"  is certainly related but not identical Find the maximum likelihood estimator for $\theta$ when $f(x)=2\theta^{-2}x, 0\leq x \leq \theta$ Find the maximum likelihood estimator for $\theta$ when $f(x)=\frac{2x}{\theta^2}, 0\leq x \leq \theta$.  This should be a really easy question but I somehow cannot seem to get the right answer. My likelihood function is $\prod\limits_{i=1}^n \frac{2x_i}{\theta^2}$ which gives me after some simplification $n\ln(2\theta^{-2}) + \sum\limits_{i=1}^n ln(x_i)$ as my log-likelihood function. Then the derivative becomes $\frac{-2n}{\theta}$. If I equate this to $0$ to obtain the maximum I obtain $\hat{\theta}\rightarrow\infty$. However, this answer does not seem plausible. What did I do wrong? I had recently faced a problem:     Solve the Diophantine Equation $x^2 - y! = 2001$.   Solving it was quite easy. You show how $\forall y \ge 6$, $9|y!$ and since $3$ divides the RHS, it must divide the LHS and if $3|x^2 \implies 9|x^2$ and so the LHS is divisible by $9$ and the RHS is not. Contradiction. Hence, the only solution is $(45, 4)$.  That made me wonder, how we can solve the Diophantine Equation $x^2 - y! = 2016$. We cannot apply the same logic here. $2016$ is a multiple of $9$ and it is clear that $3|x$ and $9 \nmid x$. How do I proceed from here? Why isn't Higgs coupling considered a fifth fundamental force? Forbid links to open new tabs in Google Chrome Edit Mail rules manually James Paterson in his novel writes, “she was shrink by trade, a forensic profiler, and Jack Morgan’s number two at Private “.   What does whole sentence mean? Is there a GUI IDE for programming python just like java has netbeans?  I wanted one where we could drag &amp; drop test boxes &amp; labels just as we do in swing components using netbeans or eclipse.  Or is there an add-on present in either netbeans or eclipse itself? Drag and drop not working inside Nautilus on Ubuntu 17.10 I'm having a strange problem on Ubuntu 17.10: when I try to drag and drop something inside Nautilus it simply doesn't work, it doesn't even select the item, it seems like it's ignoring the action... Also, I cannot select things inside nautilus by drawing rectangles with the mouse.  All of these actions work only on the Desktop. Here is a demo:    I'm using the Xorg session with nVidia proprietary drivers. I also noticed that Nautilus seems to hang when I try to copy, paste or cut a file...  EDIT 1: I solved the problem for the slow copy/paste by disabling the clipboard sync plugin of KDEConnect. I also discovered that if I open Nautilus as root, I can drag and drop or select whatever I want... In SQL Server, how do I generate a CREATE TABLE statement for a given table? I've spent a good amount of time coming up with solution to this problem, so in the spirit of , I'm posting it here, since I think it might be useful to others.   If anyone has a better script, or anything to add, please post it.  Edit: Yes guys, I know how to do it in Management Studio - but I needed to be able to do it from within another application. Find all continuous functions satisfying $\int_0^xf=(f(x))^2+C$ for some constant $C \neq 0$. Find all continuous functions $f$ satisfying   $$\int_0^xf=(f(x))^2+C$$ for some constant $C \neq 0$, assuming that $f$ has at most one $0$.  I have a question about the solution to this problem. It says that   Clearly $f^2$ is differentiable everywhere, its derivative at $x$ is $f(x)$ (I'm assuming that this is because the left hand side is differentiable, the right hand side must be differentiable as well). So $f$ is differentiable at $x$ whenever $f(x) \neq 0$, and  $$f(x)=2f(x)f'(x),$$ so $f'(x) = \frac{1}{2}$ at such points. Thus, $f= \frac{1}{2}x+b$ for some $b$ on any interval where it is non-zero; if $f$ has a zero, this gives two possible solutions, with two possible values of $b$, but since $f$ is assumed continuous, they must be the same. So we need $$\int_0^x(\frac{1}{2}t+b)dt=(\frac{1}{2}x+b)^2+C$$  so we must have $b=\sqrt{-C}$ or $-\sqrt{-C}$, leading to two solutions for $C \lt 0$.  I don't understand the bolded statements. First, how does the differentiability of $f^2$ guarantee that $f$ is differentiable, and why only at $x$ where $f(x) \neq 0$?  Next, why are there two possible solutions if $f$ has a zero, but since $f$ is continuous they must be the same?  Finally, does the last statement mean that if $C \gt 0$, then there is no solution, since we're restricted to real numbers here?  I would appreciate it if anyone answers my questions. I'm looking for a specific scifi book that I read years ago, I only partially remember the story, and I don't remember the author or the title.  What I remember of the story is:   An alien race picks up a signal from humans that includes instructions on how to make their own humans (genetic instructions). The humans grow up knowing they are created and are taught by the alien race. They are eventually given resources to build a ship, and go looking for their origins. They eventually find the solar system, but nobody answers. They find some stations orbiting earth and find that the station is very old, so old in fact that humans have long been extinct and other creatures have reached local space, and have been looking around the station as an archeological dig. I think they refer to two developed races from earth, but one developed from rats.   If anyone know what story this is, and can point me at it, its been driving me crazy for at least 15 years, and I think it's actually been much longer, since I can't remember when I read it. Can two people with different one time pads securely exchange a message like this? Alice has a message, generates a one time pad, encrypts her message and sends it to Bob. Bob generates his own one time pad, encrypts the message again, and sends it back to Alice. Alice then decrypts this message using her one time pad, sends it back to Bob who then decrypts it the last time using his one time pad.  The only problems I see with this technique:   It is vulnerable to a man in the middle attack. It requires sending the message back and forth twice between sender and recipient. It doesn't scale well if you want to use it to communicate with multiple people. Requires a way of generating cryptographically secure random numbers.   Does this method of encryption have a name?  If we ignore the fact that it's vulnerable to a man in the middle attack, is this method of encryption information-theoretically secure?  Why isn't this method used widely, i.e. which of the above listed problems or other problems makes this method infeasible for production use? Flagging multiple comments versus flagging the whole post for moderator attention When multiple comments in a comment thread ought to be removed (especially if they're all for the same reason), should I flag each of them individually or flag the parent post for moderator attention?  I've usually adopted the former strategy - flagging each comment with the same flag reason, often a custom one copied and pasted. I had always assumed the following things that led me to follow this strategy:   Flagged comments were discretely marked as flagged in some way when the reviewer viewed the question (much like how I can see others' pending suggested edits now that I have editing privileges). By individually flagging all the comments that needed cleaning up, I was allowing the flag reviewer to see at a glance which comments needed removing, thereby providing them with useful additional information that wouldn't be available if I flagged the entire parent post. By flagging comments individually, rather than flagging the whole post, I was letting my flags be handled by anyone with 10k+ rep and access to the mod tools, rather than having to be handled by a diamond moderator.   However, I just read  (now deleted) by Shog9 that makes me suspect that approach is misguided, and question whether any of my assumptions about how comment flags work are actually true. Notably he says:     If you'd pinged me once for every comment in that thread you found noisy, I would probably be plotting my revenge instead - at very least, I would think you very rude for doing so. Yet, that's exactly what you're doing when you start flagging multiple comments in a single thread: instead of taking a few seconds to describe a problem, you're attempting to use a moderator as a tool to do your bidding, without any real effort to communicate.   He also said some more stuff on the topic - I think there was something about huge offensive boxes blotting out the UI when he views questions with multiple flags - but I now can't recover it any more because that question was deleted while I was in the process of writing this one, and it doesn't seem to be available in the Google cache.  Much of the flagging and review system is still a black box to me as a low/mid rep user, and it's difficult for me to figure out what flagging behaviors are appropriate and helpful when I have no idea what actually happens when I flag a comment. (The Privileges section doesn't mention comment flags anywhere that I can find. I don't even know who reviews them at the moment, and can't find a Meta question anywhere that addresses that.)  Could somebody provide some input on when (if ever) flagging lots of individual comments in a thread is appropriate, and when flagging the entire parent post is? A pretty screenshot of the UI of the relevant review/mod tools, demonstrating the effect of each approach, might also be helpful for understanding this, if that's not asking too much. I have a fraction with sums above and under the line. How can I convince LaTeX to write the indices of the sums under the sigma instead of next to it?  \begin{displaymath}   \frac{\sum_{s \in S} s^2}{\sum_{p \in P} p^2} \end{displaymath} Is there a single word with the same meaning as "good moments" or "pleasant memories"? I'm looking for a word which describes good thing(s) that happened to someone. The only word I can think of is "joy".  Some examples might be:   Wayne has many pleasant memories of the days spent with the family. She could remember many good moments from the last weekend. ASP.NET MVC controller actions that return JSON or partial html Looking for sci-fi novel I read about humanity finding alien station on orbit of Earth I am looking for a novel that I'd love to re-read it with my wife (my 13-year old self must be proud of me I guess). Key Plot points The plot was about humanity finding an alien station on an orbit of Earth. (I'm not sure if it wasn't Moon itself). On this station there were thousands of ships ready to travel so there rose a company that paid people to get on those ships and explore the galaxy. The problem was humans didn't understand how to steer those ships so they had to rely on preset targets. Of course there was no telling where particular ship was to go and fair amount of them never returned. Chronology and other relevant information I read it as an early teenager back in early 2000s. It was Polish translation of a foreign (possibly English) story. I think (not sure) that the book wasn't new at the time. It was just one of those books you dig out in a library and take to see if it's good. I don't recall cover either and even if I did it'd be of the Polish version. Additional information could be that the narration was led along the psychoanalytics of the main protagonists where he relives his memories from inside the station and his journeys. In 10.04, I had a lot of keyboard shortcuts defined using Super/Mod4 and one single other key,   Super+O ran Opera Super+W opened Nautilus pointing to my Work folder, etc.   In 11.04, these do not seem to work -- only Super+R works to run the terminal, and Super+Shift+W successfully runs Nautilus.  Is there some way I can get these to function again?  Adding them in Keyboard Shortcuts does not work, and neither does adding commands in CompizConfig Settings Manager. update line based on previous line