Proof $\mathbb{Z}[i]/(2- i) \cong \mathbb{Z_5}$
$\mathbb Z[i]/ \langle 1+2i \rangle \cong \mathbb Z_5$
Kinematic Viscosity How would you define ? What does it physically represent? Around the Internet I've found it defined as just a ratio, and that's it.  I saw in an answer that I can think of it as "diffusivity of momentum". What does this mean? One of my associates had their Hotmail account broadcasting spam, and presumably hacked. They managed to change the password, but after that, the account got locked; Hotmail asks you for a phone number, and they're supposed to call you with a code.  This person requested the code several times, with different numbers (even two of mine!), but never received any call with the confirmation code.  I referred them to the full-length process, which includes answering the security question; apparently, they forgot their question (having entered it over a decade ago and never reviewed it since).  What options, if any, exist to restore access to this person's account? They only want to grab their contacts; they plan to operate full-force on GMail going forward. I want to create an image like below, so a balloon with text on it.     I have been googling for ideas (text, sphere, ....) and came on  earlier question. So I tried Shrinkwrap and Cast modifier.   Here is the situation before applying the modifiers.    This was after trying Shrinkwrap    And this after Cast modifier.    For me it does not look like it is going to work with one of these modifiers.  Question How to create the image of a balloon with text on it ? With one of these modifiers or should I try a complete other approach ?? How to do this ? Pure significance of line integrals of vector fields I can understand how the line integral of a scalar function has pure-mathematical significance, representing an area beneath a curve. But is there a pure significance to the line integral of a vector field? The only understanding I have of this is the physical example of work done on a moving particle. Thanks for any insight. Are there rules for disassembling a slain creature, especially dragon? Install Nvidia driver instead of nouveau I've installed Ubuntu 14.04 and I'm experiencing a fuzzy/blurry screen and bad support for multiple screens.  I realized that Ubuntu installs nouveau as default, but I need to install nvidia drivers, so I tried this:   sudo apt-add-repository ppa:ubuntu-x-swat/x-updates apt-get update apt-get install nvidia-current apt-get upgrade       Now that nvidia is installed, you need to blacklist the nouveau driver   so it don’t pop out when you will reboot. Create or edit the following   file:  nano /etc/modprobe.d/blacklist-nouveau.conf       …and add these lines at the end:  blacklist nouveau blacklist lbm-nouveau options nouveau modeset=0 alias nouveau off alias lbm-nouveau off    I checked via the software &amp; updates if nvidia driver got installed successfully, and it says the driver installed is nvidia 304.117  I then tried to run:  lshw -c video | grep 'configuration'   and the result is that the driver is still nouveau:  configuration: driver=nouveau latency=0   So how do I install and use the nvidia drivers? Permutations with repeating digits My question is this : how many distinct two digit numbers can be produced from numbers $4, 3, 3, 1$? When applying the formula $$\frac{4!}{(4-2)!2!}$$ you come up with $6$, yet when doing the problem manually, I come up with $7$ numbers, namely $41, 43, 14, 13, 33, 31, 34$. Can anybody explain this discrepancy?  Thanks. Why can't I edit attribute table imported through 'text as layer' I imported the coordinates from an Excel table. They show as single points as intended. Now I want to add columns to the attribute table, but I'm not able to edit it. I wanted to import the following columns from Excel as well, but that doesn't seem to work either.  Sorry for the noob-question, but I couldn't find anything relating the theme through google and such.  Ok, with pictures then: I want to use that to add columns with information to these       You see, the small pensil thingy is greyed out, so I can't edit anything in this layer and I can't add any information to my points.  If I try Ale suggestion I get this error: Find $\lim_{n\to\infty}2^n\underbrace{\sqrt{2-\sqrt{2+\sqrt{2+\dots+\sqrt2}}}}_{n \textrm{ square roots}}$. Find $\displaystyle \lim_{n\to\infty}2^n\underbrace{\sqrt{2-\sqrt{2+\sqrt{2+\dots+\sqrt2}}}}_{n \textrm{ square roots}}$.   By geometry method, I know that this is $\pi$. But is there algebraic method to find this ?   Thank you. How to setup a restricted SFTP server on Ubuntu? I would like to know how to set up root, sudo, sftp-only user accounts which won't be required public key authentication at log in. I would also like to know how to set up sftp-only users' home directories where they can't access upper level other directories. How to accumulate values of each two rows across a line in linux? PHP not working after upgraded to Ubuntu 17.10 After I upgraded to Ubuntu 17.10, PHP totally stopped working. Everything works fine in Ubuntu 17.04. The code for info.php as follows does not work:   &lt;?php  phpinfo(); ?&gt;   It is not showing PHP information, it only shows the source code like above. What software can I use to write on PDFs? I'm used to OS X where the system PDF viewer will let you draw and write text on top of any PDF document. You can then flatten it and save as a new PDF. It saves paper and time so you can fill in any form without printing it and scanning it back to the computer.  It also lets you insert a scanned image of your signature.  Is there software for Ubuntu that would do that? Why are heatmaps on qgis 2.8.1 produced in the wrong CRS? Mortarboard badge not awarded "a ten years old boy" or "a ten year old boy" 1) a ten years old boy is sitting on the couch.      2) a ten year old boy is sitting on the couch.      3) a ten-years old boy is sitting on the couch.      4) a ten-year old boy is sitting on the couch.   Which is correct? JavaScript raises SyntaxError with data rendered in Jinja template Difference between "git add -A" and "git add ." The command git add [--all|-A] appears to be identical to git add .. Is this correct? If not, how do they differ? What do I need for extreme macro photography? I am wanting to venture into some extreme macro photography, specifically insects, such as . After doing some research I have believe that my 1::25 macro lens will be sufficient if I am to use some extension tubes (which I have bought).  I would like to shoot the in the wild, is this possible/likely? Or is this always a catch, then release style of shooting?  Regarding the link I've posted, would this be possible with a 1:25 macro and extension tubes? I have a set of three (21mm, 31mm and 13mm). How would you go about shoot a blue bottle for example? Surely they are going to fly away? Should I use a tripod or will that cause more of a hindrance than a help? Are there any techniques/tricks I could use to get a sharp focus on my subject? I really like the new sidebar. With the new top bar eliminating the &quot;Hot Questions&quot; area there, I think this is the perfect place for it. One-click access to time-wasting questions about topics I may or may not have an interest in. Seriously, it's a procrastinator's dream come true. The only suggestion I can add is to extend it. I assume the &quot;hot&quot; algorithm can spit out more than 12 questions, and since we now have a huge amount of room for it(without being restricted to a weird drop-down scrollbox), why not show more? If there's something else planned for that spot, disregard. At a minimum, the title could link to the , as ShaWizDowArd suggested in comments. I've been using SE for a couple years now, and I've never seen that page, so it would add visibility there.    Update: They added a link! Just noticed this, I'm pretty sure it wasn't there yesterday. When you click it, it loads 12 more. At the moment, the link disappears once clicked, so you can see a total of 24 here now. Not a link to the full list, but better: