I want to update from 15.10 to 16.04 . I am new to ubuntu so please i need your help . Also , i don't want to lose my data .
What are the different ways I can use to upgrade Ubuntu from one release to another?
In an Integral Domain is it true that $\gcd(ac,ab) = a\gcd(c,b)$? In my algebra class I was given as homework assignment to prove that:     Given an integral domain $A$ and $a,b,c,d,e \in A$. Then if $d = \gcd(b,c)$ and $e = \gcd(ac, ab)$ then $e = ad$.   It is easy to see that $ad \mid ab$ and $ad \mid ac$, so this implies that $\exists q \in A; e = q(ad)$. Now I'm having problems showing that $q = 1_A$. Working through some equalities, I proved that $\forall n\in \mathbb{N}, q^n \mid d$ so this gives me the light suspicion that I might be going the right way, but I'm pretty positive that this does not imply $q = 1_A$.  Does anyone want to give me a hint?  Thanks in advance :) Is a set without limit points necessarily closed? According to the definition on Rudin' Principles of Mathematicial Analysis, closed set is defined as:      $E$ is closed if every limit point of $E$ is a point of $E$.   Then I have a question: if a set has no limit point, is it necessarily closed? I think this idea doesn't contradict the definition of closed sets. Am I right?  And another question is #10 in Chap.2 of Rudin's:      Let $X$ be an infinite set. For $p\in X$ and $q\in X$, define    $d(p,q)=0$ when $p=q$. Otherwises,$d(p,q)=1$.    I have known that every set in the metric space is closed. To prove it, we can show that the complement of any set is open, which is quite trivial. My question is: how can we prove that every set is closed just by checking according to the definition of closed set, i.e. how can we show that every limit point of any arbitrary set $E$ in the metric space is a point of $E$?   Thanks in advanced! What is the Necessity of $...$ Around Numbers? I typed up an assignment with a lot of numbers in LaTeX and turned it in to my adviser.  When he returned it to me with some corrections, one of which was a lot of $ around my numbers.  I understand that $ are necessary around some mathematical formulas, but I was just using numbers like -2 and 4.  I did not see any change in the font of the numbers when I added the $ either.  Since my adviser did not want to give me an explanation, what is the rationale? Make Google stop sending 'new sign in from ...' emails I get at least two emails from Google every time I sign in to my account and I want it to stop.  I tried changing the notification settings in Gmail, but they're still coming and they're useless.  How can I stop this? Atlas generation for different extents Why do return flight costs vary depending on the country of origin? A word or short phrase for 'better in every way'? When we're comparing two or more things, there are times when we have to weigh the advantages or disadvantages of each one.  There are other times when one of the things is better for every way in which it's being judged, and the final decision is not based upon trade-offs.  I know that I've heard a phrase for this (I want to say it was two words), but I've had no luck in remembering it.    I don't think 'clearly superior' or 'clear winner' quite fit the bill, as that might still suggest that the disadvantages are significantly outweighed by the advantages.  Is there such a phrase, or even a single word, that would convey this meaning without using idioms? What hash is concatenating with the data to be signed in TLS 1.3 CertificateVerify message? According to specification, to create data that will be signed with server private key for CertificateVerify message, we need to concatenate 64 space characters, the string &quot;TLS 1.3, server CertificateVerify&quot;, null and the hash of all handshake messages to this point. During the handshake process, we choosing the cipher suite and signature scheme... So, if the cipher suite is, for example, TLS_AES_256_GCM_SHA384 and the signature scheme is rsa_pss_rsae_sha256 (different hash algorithms), hash of which algorithm should be used as handshake hash in data to sign, SHA-384 or SHA-256? How do I lock a file in Perl? What is the best way to create a lock on a file in Perl?  Is it best to flock on the file or to create a lock file to place a lock on and check for a lock on the lock file? I would like to install the restricted extras package, which I didn't select during the install. How can I do that?        is a meta-package that installs:         Support for MP3 and unencrypted DVD playback   Microsoft TrueType core fonts   Flash plugin   codecs for common audio and video files $F$ is a finite field of order $q$. What is the size of $\operatorname{GL}_n(F)$ ?  I am reading Dummit and Foote "Abstract Algebra".  The following formula is given:  $(q^n - 1)(q^n - q)\cdots(q^n - q^{n-1})$.  The case for $n = 1$ is trivial.  I understand that for $n = 2$  the first row of the matrix can be any ordered pair of field elements except for $0,0$. and the second row can be any ordered pair of field elements that is not a multiple of the first row.  So for $n = 2$  there are $(q^n - 1)(q^n - q)$ invertible matrices.  For $n\geq 3$, I cannot seem to understand why  the formula works.  I have looked at Sloane's OEIS A002884.  I have also constructed and stared at a list of all $168$ $3\times 3$ invertible matrices over $GF(2)$.  I would most appreciate a concrete and detailed explanation of how say $(2^3 - 1)(2^3 - 2)(2^3 - 2^2)$ counts these $168$ matrices. Assuming convergence of the following series, find the value of $\sqrt{6+\sqrt{6+\sqrt{6+...}}}$ Assuming convergence of the following series, find the value of $\sqrt{6+\sqrt{6+\sqrt{6+...}}}$  I was advised to proceed with this problem through substitution but that does not seem to help unless I am substituting the wrong parts. If i substitute the $6$, well then i am just stuck with above.   Any ideas on how to proceed. Also, what is the purpose of stating that it is convergent. MySQL shutting down without warning, out of memory? Can I mask an input text in a bat file? Using the itemize environment inside a caption The following code does not compile. However, if I remove the itemize environment it does. I googled for this problem, and found suggestions that using the caption package would solve the problem, though I did not find any clear description of why the problem occurred in the first place. See for example    I'm using Debian squeeze with TeX Live 2009-11. The included version of caption has   \ProvidesPackage{caption}[2009/10/09 v3.1k Customizing captions (AR)]   I also tried downloading and using the caption package from     but this doesn't change anything. I put the sty files in my current directory. I assume that overrides the system files. This one corresponds to  \ProvidesPackage{caption}[2010/01/09 v3.1m Customizing captions (AR)]   Error message and example file follow.  *******************************************     ERROR: Argument of \@caption has an extra }.  --- TeX said --- &lt;inserted text&gt;                  \par  l.13     }  --- HELP --- From the .log file...  I've run across a `}' that doesn't seem to match anything. For example, `\def\a#1{...}' and `\a}' would produce this error. If you simply proceed now, the `\par' that I've just inserted will cause me to report a runaway argument that might be the root of the problem. But if your `}' was spurious, just type `2' and it will go away. ******************************************************  \documentclass{article} \usepackage{caption} \begin{document}  \begin{figure}     \captionsetup{singlelinecheck=off}     \caption     {       foo       \begin{itemize}       \item bar       \end{itemize}     } \end{figure} \end{document} Replicate data from one list to another list sharepoint I have a list A with columns Emp ID, First name &amp; last name and list B wih column name Emp ID, First name, last name , phone number and address.  I want functionality such that when i enter item in List A and save same data should get copied in 3 columns of list B. Can someone help me with the approach. Thnks Is it ok to answer based someone's older answer on SE? Possible Duplicate:             This question will probably be closed in a few minutes. It is a duplicate but I couldn't find the question using with meta search.  Anyway, , . In this case, is vote to close the new question as a possible dublicate not the best choice? Looks to me a little bit not ethical. How do I automate a key press in AppleScript? Is it possible to automate the key press of a key (such as "a" or "&lt;") in Mozilla Firefox, Google Chrome or Safari (in this order)? I'd like to automate the key press of "a" for example in Mozilla Firefox for 100 times every x seconds. With x being a value between 1 second and 10 seconds chosen randomly at every key press. What Applescript could make the trick?  Also, where can I find a list of all codes for each key of the keyboard? A particular big Delta I would like to insert the below mathematical symbol, it looks like a big Delta but different. Is there command to obtain a similar shape? How to mix a jpeg background image with a 3D scene generated using Filmic Blender? I want to compose 3D-model over image, and I use filmic to get more suitable result. But I want the background image to remain in the original colors. So I try to use this setting:    but it haven't setting "look" ("high contrast", "low contrast", ets..) here, so color changes..  How to solve this?  Of course, I can save my render and compose it with jpg-image in different place - no problem here, but my question is about how to make it in place. It will give ability to control colors in filmic color space and see the results immediately.   UPD: image is from image node:    UPD2:     you can't really convert a display referred image to the scene   referred domain; the information has been permanently lost   Ok, but how to make the colors at the output looks close to the original?  UPD3:  This filmic version is from daily build.