Invoke form controls (Better than mine)
What is the preferred way to find focused control in WinForms app?
There are two 9-digit numbers on the back of the Global Entry card. The one on the upper left corner is the Known Traveler Number or PASSID. But on the upper right hand corner there is another 9-digit number, slightly larger than the PASSID. What is the purpose of this second 9-digit number? I'm running an SSH server on my personal computer. The log had many people(or bots?) repeatedly trying to log in to my server (that is before I changed the default port), which made me a little freaked out. I was worried about their dictionary attacks or brute force password guessing.  But then if you type wrong password (or wrong username), the server waits for about 2 seconds before it asks for password again. So an attacker can try one password per 2 seconds. So I concluded that these attacks aren't that great a threat (as long as your password does not consist of dictionary words.) Am I correct? Calculate sum of series $\sum \frac{n^2}{n!}$ I have to calculate sum of series $\sum \frac{n^2}{n!}$. I know that $\sum \frac{1}{n!}=e$ but I dont know how can I use that fact here.. How could I adjust the size and placement of chapter heading in my custom class? I am using report class as my base. When I used titlesec package inside my custom class, it threw error     ! Package titlesec Error: Not allowed in `easy'   settings. My question is really ''what is the definition of a conservative vector field''?  I've consulted 3 textbooks that all say a vector field $\vec{F}$ is conservative by definition if there exists a scalar potential $\phi$ such that $\nabla \phi = \vec{F}$. Then, they go on to talk about connected domains, path independence and the equality of mixed partials and how they are all related.   In particular, they emphasize that e.g. in $\mathbb{R}^2$ given $\vec{F} = \bigl&lt;F_1,\,F_2\bigr&gt;$, if $\frac{\partial F_1}{\partial y} = \frac{\partial F_2}{\partial x}$ on a simply-connected domain, then $\vec{F}$ is conservative on that domain.  However, without fail, all of them then offer the example of $\vec{F} = \bigl&lt; \frac{-y}{x^2+y^2},\, \frac{x}{x^2+y^2} \bigr&gt;$, pointing out:   it's line integral is not path independent, even though $\frac{\partial F_1}{\partial y} = \frac{\partial F_2}{\partial x}$   and this is explained by pointing out that the domain is not simply connected (if the path contains the origin).  That much makes sense to me: we cannot conclude $\vec{F}$ is conservative based on the partial derivatives, because the domain is not simply connected - totally consistent with what has been presented.  What none of them address is why $\vec{F} = \bigl&lt; \frac{-y}{x^2+y^2},\, \frac{x}{x^2+y^2} \bigr&gt;$ is not conservative when there exists a potential $\phi = \arctan(y/x)$ such that $\nabla \phi = \vec{F}$. None of the texts mention any necessary conditions on the scalar potential. So is the existence of a scalar potential the definition of a vector field being conservative or not? The legacy tray (see the screenshot below) will be removed in GNOME 3.26. I want to wean myself off it before the change arrives in Ubuntu (17.10 or 18.04).    Can I disable the legacy tray in Ubuntu GNOME 17.04? How can I connect a texture node to a material with Python? I have installed Ubuntu 12.04-64 bit on my Lenovo IdeaPad laptop, and the wired Ethernet (LAN) connection doesn't work.  Running the lspci -vv | grep Atheros command from the terminal shows me I have the AR8161 Gigabit Ethernet controller:  02:00.0 Ethernet controller: Atheros Communications Inc. AR8161 Gigabit Ethernet (rev 08)   This looks like a new product whose drivers are not built into Ubuntu.  How do I install drivers to get the AR8161 working? The runtime arguments are as follows: $1 is the path to the file containing the list of files $2 is the path to the directory containing the files What I want to do is check that each file listed in $1 exists in the $2 directory  I'm thinking something like:  for f in 'cat $1' do if (FILEEXISTSIN$2DIRECTORY) then echo '$f exists in $2' else echo '$f is missing in $2' sleep 5 exit fi done   As you can see, I want it so that if any of the files listed in $1 don't exist in the directory $2, the script states this then closes. The only part I can't get my head around is the (FILEEXISTSIN$2DIRECTORY) part. I know that you can do [ -e $f ] but I don't know how you can make sure its checking that it exists in the $2 directory. Is $f(x)=10$ a periodic function? Intellij shortcut for quick call hierarchy Is there a shortcut key to bring up the call hierarchy of a method inline with the code, in the quick menu format, rather than bringing up the call hierarchy panel? Evaluate $\int \frac{1}{(x^2+1)^2}dx$ $$\int \frac{1}{(x^2+1)^2}\mathrm dx$$ Look simple, but I stuck a little bit. What method is better in this situation? Please, help. Bearing in mind I am a layman - with no background in physics - please could someone explain what the "big deal" is with quantum entanglement?  I used to think I understood it - that 2 particles, say a light-year apart spatially, could affect each other physically, instantly.  Here I would understand the "big deal".  On further reading I've come to understand (maybe incorrectly) that the spatially separated particles may not affect each other, but in knowing one's properties you can infer the other's.  If that it the case, I don't see what the big deal is... 2 things have some properties set in correlation to each other at the point of entanglement, they are separated, measured, and found to have these properties...?  What am I missing? Is it that the particles properties are in an "un-set" state, and only when measured do they get set?  (i.e. the wave-function collapses).  If this is true - why do we think this instead of the more intuitive thought that the properties were set at an earlier time? Choosing research ideas to include in a statement of purpose How to fix "Package is in a very bad inconsistent state" error? I can't update my system because it freezes while installing a third-party update (zramswap-enabler)! Sometimes I get the following message in Update manager:  Could not initialize the package information An unresolvable problem occurred while initializing the package information. Please report this bug against the 'update-manager' package and include the following error message: E:The package zramswap-enabler needs to be reinstalled, but I can't find an archive for it.  I tried to remove the zramswap-enabler, but it's impossible because I get the following message: dpkg: error processing zramswap-enabler (--remove):  Package is in a very bad inconsistent state - you should  reinstall it before attempting a removal. Errors were encountered while processing:  zramswap-enabler E: Sub-process /usr/bin/dpkg returned an error code (1)  Actually I would really reinstall that package, but it is unable to do it! If I remove this third-party PPA then the system is warning me about a very very serious problem. So why can I not install/reinstall/remove/update this package and why freezes the updater if I try to update? My current prompt is colorized and edited as so -  #!/bin/bash  # GIT Prompt help if tput setaf 1 &amp;&gt; /dev/null; then     tput sgr0; # reset colors     bold=$(tput bold);     reset=$(tput sgr0);     txtund=$(tput sgr 0 1);     black=$(tput setaf 0);     blue=$(tput setaf 33);     cyan=$(tput setaf 37);     green=$(tput setaf 64);     orange=$(tput setaf 166);     purple=$(tput setaf 125);     red=$(tput setaf 124);     violet=$(tput setaf 61);     white=$(tput setaf 15);     yellow=$(tput setaf 136); else     bold='';     reset="\e[0m";     black="\e[1;30m";     blue="\e[1;34m";     cyan="\e[1;36m";     green="\e[1;32m";     orange="\e[1;33m";     purple="\e[1;35m";     red="\e[1;31m";     violet="\e[1;35m";     white="\e[1;37m";     yellow="\e[1;33m"; fi; ORIG=$PS1 HOST=$HOSTNAME PS1="\[${txtund}${green}\]${HOST}\[\[${reset}\]"; PS1+="\$(prompt_git \"\[${white}\] on \[${violet}\]\")"; PS1+="\[${reset}\]"; PS1+="\[ at - ${orange}\W\]"; PS1+="\[${reset}\]"; PS1+="\[ - \u \]"; PS1+="\n\$ ";   I know that the line  PS1+="[ - \u ]"; will show me my current user. However, I want that section to be red if it is root. All other users should be the default color of gray. Is there a way to change the color in that section based off of current user or should I just declare a variable and use an IF statement to insert that section or a modified section with red as a color?  My expected output is gray named user for all normal users. Root should be red. This is BASH. Sequences or 'chains' of adjoint functors Suppose we have (some categories and some functors such that) $F_1$ is left adjoint to $G_1$, $G_1$ left adjoint to $F_2$, $F_2$ left adjoint to $G_2$. Will $F_1$ then be equal to $F_2$ (and $G_1$ to $G_2$)?  Or can there exist arbitrarily long 'chains' of adjoint functors that do not trivialize? Simple enough question: What math should all game programmers have a firm grasp of in order to be successful?  I'm not specifically talking about rendering math or anything in the niche areas of game programming, more specifically just things that even game programmers should know about, and if they don't they'll probably find it useful.  Note: as there is no one correct answer, this question (and its answers) is a community wiki.  Also, if you would like fancy latex math equations, feel free to use . In  thread, the question was to find a $f: \mathbb{R} \to \mathbb{R}$ such that  $$f(f(x)) = f(x) + x$$  (which was revealed in the comments to be solved by $f(x) = \varphi x$ where $\varphi$ is the  $\frac{1+\sqrt{5}}{2}$).    Having read about  shortly before though, I came up with this train of thought:  $$f(f(x)) = f(x) + x$$ $$\Leftrightarrow f^2 = f^1 + f^0$$ $$f^2 - f - f^0 = 0$$  where $f^n$ denotes the $n$'th iterate of $f$.  Now I solved the resulting quadratic equation much as I did with plain numbers  $$f = \frac{1}{2} \pm \sqrt{\frac{1}{4} + 1}$$ $$f = \frac{1 \pm \sqrt{1+4}}{2} = \frac{1 \pm \sqrt{5}}{2}\cdot f^0$$  And finally the solution $$f(x) = \frac{1 \pm \sqrt{5}}{2} x .$$  Now my question is: *Is it somehow allowed to work with functions in that way?** I know that in the above, there are denotational ambiguities as $1$ is actually treated as $f^0 = id$ ... But since the result is correct, there seems to be some correct thing in this approach.  So can I actually solve certain functional equations like this? And if true, how would the correct notation of the above be? I am on a MacBook Pro 13 running latest Sierra. I have an external Seagate solid state hard drive that was working and out of the blue stopped working. The only thing on it was my Adobe Lightroom images/videos. Not the LR DB files. I'm sure you have all heard this woe before, so I won't dwell on that. And yes, I back up to the cloud. AWS S3 specifically. Though I am traveling South East Asia for the last year, and staying in cheap hostels. So good internet is hard to come by sometimes. I can't back it up after every export. While most of it is backed up, there is some that is not.  Moving on. The symptoms seems to change every time I plug it in. The first sign was it ejected on it's own. I plugged it in again, and it wouldn't mount. Disk Utility recognized it, so did the command line diskutil list but it wouldn't mount. I rebooted and it worked for a second. Then I could only get to it from the command line. Then trying to frantically back up to my local what was not backed up to the cloud, it all failed. Basically just a cp -R [directory] [local-directory] command.  After some more frantic unplugging and re-plugging plus some command line manual mounts, I finally got it to where the Disk Utility would be able to run first aid on it. It failed. I don't recall the error. So I put it in a freezer. After a few hours I tried again. It is not any better. It still will not mount. Now Disk Utility sees it, but with no partition. I can't even give me information about how much space is used on it.  I have also tried it from a Windows machine. It did not mount. I have tried other cables. No success. As well as tried my other USB port. I also have another working external hard drive exactly like the one giving me issues. It works on all cables and USB ports.  I do have Docker running with a Ubuntu container, I'm trying to think of a way to see if I can try to get to the USB from there. I also have a USB that I have thought about running a live Ubuntu on there to see if I can mount and retrieve the data or fix the HDD that way. But if it will not mount, I doubt these will work.  Can anyone else think of any other tricks I can try myself to see if I can repair this or at least retrieve the data without paying for a service or software? If not, those suggestions are also welcome.  Update   I made the mistake in original post that it was a Solid State Drive. This is my mistake, it is actually a spinning disk hard drive. I bought them long ago and have been traveling with them for so long I just forgot. Question is updated to reflect this. Now diskutil list does not show it at all. The Disk Utility app also does not see it. Based on suggestion from @Allen I seeked out the USB to SATA cable. I did not quite find it, as my options are extremely limited where I am at. Though a local expat on a facebook group was able to help me with a empty 2.5 casing that I was able to extract the drive from original casing and put it in his blank case. It now mounts. Though it has the "click of death" sound to it. And data is not really reachable. While I can ls the directories and Adobe Lightroom does not have the exclamation mark when it can not reach the actual external files. Right clicking on the images and clicking on "Show in Finder" or any other variation of trying to get to the files through Finder or terminal, I have no success. It usually hangs and I get the spinning wheel. Since Adobe Lightroom imports these images into directories named by date, I am going to send the drive off to a data recovery service and ask to recover just unbacked up directories i.e. dates. Next time I will make harder efforts to backup and probably get an actual SSD.   I think this can be closed, due to my low reputation points I can not close this myself.