Can we make a list of "favorite questions"? I found myself difficulty in searching for "favorite questions"; can we place the list in the profile view?
How do question bookmarks work? What does bookmarking a question mean? How do you bookmark a question? Do users get updates on their bookmarked questions? Are my bookmarks publicly visible? How do you see your own bookmarks? How do you see other users' bookmarks? How do you see which users have bookmarked a particular question? What impact does the bookmark system have on the voting system? Can I &quot;un-bookmark&quot; a question? Can I search within my bookmarks?
I read in  in this site that the KE a free-falling ball acquires is not originated by the attracting body but that energy was actually stored in the ball when it had been lifted to the height it dropped from.  In this way, it was said, gravity is subject to the conservation of energy principle and cannot change the total energy of an object.  Consider now the maneuver known as a  (also gravity assist) used by space probes such as the . A space probe approaches a planet with velocity $v$, slingshots around, and ends up with velocity $v+2U$, where $U$ is the velocity of the planet.  Consider the energy of the probe. Before, it was $E_i=\frac{1}{2} mv^2$ and after it is $E_f=\frac{1}{2} m(v+2U)^2$. It looks like $E_f$ is much bigger than $E_i$ - but where did the additional energy come from?   Is this not a violation of the conservation of energy principle? I installed Ubuntu on a Dell XPS 13 laptop that had Windows 10 preinstalled on it. I installed it from a USB flash drive on a partition. When I boot my computer I can only boot into Windows 10 and Ubuntu is nowhere to be seen.  If I boot into my USB then I can see that Ubuntu is installed, but I can't get to it from the BIOS boot menu. What's an intuitive way to think about the determinant? In my linear algebra class, we just talked about determinants. So far I’ve been understanding the material okay, but now I’m very confused. I get that when the determinant is zero, the matrix doesn’t have an inverse. I can find the determinant of a $2\times 2$ matrix by the formula. Our teacher showed us how to compute the determinant of an $n \times n$ matrix by breaking it up into the determinants of smaller matrices. Apparently there is a way by summing over a bunch of permutations. But the notation is really hard for me and I don’t really know what’s going on with them anymore. Can someone help me figure out what a determinant is, intuitively, and how all those definitions of it are related? Is there a Linux equivalent of Windows' "resource files"? Using conjugates to find a limit with a cubic root: $\lim_{h\to 0}\frac{\sqrt[3]{h+1}-1}{h}$ I currently have $$\lim_{h\to 0}\frac{\sqrt[3]{h+1}-1}{h}$$  Now, I know that when you have square root instead of a cubic root it's easy. You just multiply by the conjugate and simplify afterwards. If it were a sqrt I know that the limit is 1/2. I know that the result here is 1/3 but I can't seem to get there. I always end up with 1/4 due to getting something like: $$\frac{h+1-1}{h(\sqrt[3]{h+1}+1)(\sqrt[3]{h+1}+1)}$$  After simplifying and evaluating the limit you end up with $$\frac{1}{(\sqrt[3]{0+1}+1)(\sqrt[3]{0+1}+1)}$$  which turns out to be $1/4$.  What am I doing wrong? Add the ability to ignore users How to determine whether a unique factorization domain is a principal ideal domain? Could someone please provide an example of a unique factorization domain that is not a principal ideal domain?  Furthermore, is there some way to determine whether a UFD is a PID? Referencing equation counter value in custom float caption I have used the float package to create an equation float, eqfloat, so I can add captions to equations. Within the eqfloat I used the equation environment to typeset the math.  I want to keep the right hand arabic numbering within parentheses that is added by the equation environment but I also would like the eqfloat caption below the equation to use the same number as the equation environment.  The following code achieves this by making the eqfloat use the same counter as the equation environment and then manually adjusting the equation numbering within each eqfloat.   Is there a better way to make the eqfloat caption reference the current value of the equation environment counter?  Is it possible to prevent the custom float environment from increasing the counter and only to reference the current value of the equation counter?  \documentclass[a4paper]{article}  \usepackage[margin=25pt, labelfont=bf]{caption} \usepackage{amsmath, amsfonts, pifont, float, color, url} \usepackage[pdftex, plainpages=false, pdfpagelabels, bookmarks=true]{hyperref}  \newfloat{eqfloat}{h}{eqflts} \floatname{eqfloat}{Equation} \makeatletter \let\c@eqfloat\c@equation \makeatother  \begin{document}     ...     \begin{eqfloat}         \begin{equation}             E = mc^2         \end{equation}         \addtocounter{equation}{-1}         \caption{Equation caption here.}         \label{eq:example}     \end{eqfloat}  \end{document} Let $R$ be a UFD and $r\in R$ irreducible. If $S=R-(r)$, why is $S^{-1}R$ a PID?   I've finished proving the integral domain part, which was pretty easy.  How to prove it's principal? consider $R \subset S^{-1}R \subset F$, where $F$ is the field of fractions of $R$?  thank you! :p $$\lim _{x \rightarrow 0} \left(\frac{ \sin x}{x}\right)^{1/x}$$  I have spent an hour on the above limit and have no work to show. I tried using L'Hopital's Rule, but just kept going around in circles. Any help would be appreciated. Thank you. SSH and home directory permissions It took me hours to solve this SSH problem with one of my class accounts on my school's servers.    I couldn't ssh into one particular class account without entering my password, while passwordless authentication worked with my other class accounts. The .ssh/ directory and all of its contents had the same, correct permissions as the other class accounts.   Turns out the problem was the permissions set on my own home directory. Passwordless authentication did not work when the permissions on my HOME directory were set to 770 (regardless of the permissions set for .ssh/), but it worked with permissions set to 755 or 700.   Anyone know why SSH does this? Is it because the home directory permissions are too permissive? Why does SSH refuse to authenticate with the public/private keys when the home directory is set more permissive than 700? Is multiplication not just repeated addition? If multiplication is not repeated addition, what is it? How do you define multiplication? All of us had to memorize the multiplication table in elementary school, but how did they come up with it if so many people claim that it is wrong to think of it as repeated addition? Voodoo magic? Shell command to sum integers, one per line? I am looking for a command that will accept (as input) multiple lines of text, each line containing a single integer, and output the sum of these integers.  As a bit of background, I have a log file which includes timing measurements. Through grepping for the relevant lines and a bit of sed reformatting I can list all of the timings in that file.  I would like to work out the total. I can pipe this intermediate output to any command in order to do the final sum.  I have always used expr in the past, but unless it runs in RPN mode I do not think it is going to cope with this (and even then it would be tricky).  How can I get the summation of integers? Guid vs INT - Which is better as a primary key? I've being reading around reasons to use or not Guid and int.  int is smaller, faster, easy to remember, keeps a chronological sequence. And as for Guid, the only advantage I found is that it is unique. In which case a Guid would be better than and int and why?  From what I've seen, int has no flaws except by the number limit, which in many cases are irrelevant.  Why exactly was Guid created? I actually think it has a purpose other than serving as primary key of a simple table. (Any example of a real application using Guid for something?)  ( Guid = UniqueIdentifier ) type on SQL Server Ctrl+Alt+← can usually be set to restart X, however I can't find the option to allow this (it is disabled by default).  I have looked in System-&gt;Preferences-&gt;Keyboard and System-&gt;Preferences-&gt;Keyboard Shortcuts but I can't find an option to enable it.  Where can I change this setting? Show that $\dim H^0(\mathbb{P}^n, \mathcal{O}_{\mathbb{P}^n}(m)) = {n + m \choose n}$ if $m \geq 0$, and $0$ otherwise. How to import a .max model into Blender? I've tried to import but I don't see the (.max) file as an option when importing. Is there another way to import the 3DMax model into Blender for rigging and animation? Is the sizeof(some pointer) always equal to four? I'm looking for a way to access raster layers in an Esri File-GeoDatabase without using ArcObjects or ArcPy, specifically I would like to access the raster layers with GDAL. I understand that the GDAL FileGDB and OpenFileGDB give access to vector datasets within File-GeoDatabases, and that ESRI's own FileGDB C++ API does not support raster access.   Is anyone out there aware of any open source solutions? No Badge Progress color for Golden Badges?