When do I need to re-install instead of upgrading? Actually i need to know if i'm using 14.04 or 15.04 then do i'll need to a fresh installation of os after several time 5 yrs or 9 months?
What's the difference between a Long Term Support Release and a Normal Release? What are the differences between an Ubuntu Long Term Support release (LTS) and a normal release?
Expected Value of Max of IID Variables What is the expected value of the maximum of 500 IID random variables   with uniform distribution between 0 and 1?   I'm not quite sure of the technique to go about solving something like this. Could anyone point me the right direction?  Thanks Problem with typesetting maths content in an unusual font in beamer $f(f(x)f(y))+f(x+y)=f(xy)$ Find all functions $f\colon \mathbb R\rightarrow \mathbb R$ such that for all reals $x$ and $y$:   $$f(f(x)f(y))+f(x+y)=f(xy).$$   It was six hours ago in IMO 2017 (problem 2).  I tried  the standard way: $x=0$, $x=y$, $x=1$,etc. but without any success.   Let $f(0)=a$. Hence, for all $x\in\mathbb R$ we have $f(a(f(x))+f(x)=a$. What is the rest?   Also we have $(x-1)(y-1)-1+x+y-1=xy-1$ and  $1-(1-x)(1-y)+1-x-y=1-xy$. There are many beings that have very big powers. There are beings that are worshipped as gods (Asgardians; and I would lump Azazel into that as well since Marvel seems to imply that he's - while a mutant - someone people consider to be "Devil"). There are mutants whose power would clearly have been considered as "god like" by people worshipping Greek or other polytheistic pantheons where the threshold to what made you a god was pretty low.  But are there any actual major "Gods" in Marvel universe?  Since there are many different definition of what a "god" is, the one that is pertinent to this question:   Power wise, being able to create Universe(s); e.g. gods more in a sense of Christianity/Judaism scale rather than "Pan" or "Hestia" in Greek pantheon who merely have some limited supernatural powers over small domain of natural events. Effectively immortal, at least excluding specific exotic attacks. Origin-wise, be "supernatural", not merely a human mutant or a powerful alien with advanced technology. Desire/demand/like followers' worship or prayers. I have two passports/nationalities. How do I use them when I travel? I am a citizen of two different countries, and have two passports.  How should I use my passports when traveling? Which arena do free and crown chests use when determining the cards you will get? If I am in arena X when I collect my tenth crown for the crown chest, or a free chest becomes unlocked, then proceed to climb to arena X+1 before opening the chests, which arena will be used to determine the cards I get? Will it use the arena I was in when I unlocked the chests in, or the arena I opened them in? Do positive semidefinite matrices have to be symmetric? Can you have a non-symmetric matrix that is positive definite? I can't seem to figure out why you wouldn't be able to have such a matrix, but all my notes specify positive definite matrices as "symmetric $n \times n$ matrices."  Can anyone help me with an example of a non-symmetric positive definite matrix, or some insight into a proof for why it would need to be symmetric should that be the case? Thanks! How to change color for a block of texts? How to dismiss the Windows 8.1 Upgrade banner? Wildcard not working in subprocess call using shlex We have a group of three characters: The lawful good paladin (acolyte), the lawful good fighter (soldier) and the chaotic good druid (criminal). All try to help NPCs in need, won't fight between themselves, but of course have different alignments and personalities. The druid is greedy, but otherwise a good guy. This brought up the question for our group whether greed can be considered a contradiction to having a chaotic good alignment? I understand it as "acting upon what is good, but having your own understanding of 'good'". But I am not sure if the PC being is played 'wrong'.   How do you determine if a given action is in line with a PC's alignment? And should the GM intervene if a PC is played differently that his/her alignment indicates?  Example: There is a Chaotic Good druid with a criminal background. The druid attacked caravans who destroyed his homeland, which he was protecting as his druidic duty, to make way for faster trade routes. Thus he made a name of himself and soon had quite a pile of goods in his territory. The thieves guild caught wind of that and made a deal with him to smuggle wares through his territory as long as they won't hurt the wildlife. So far, seems like a reasonable match between criminal and CG.  Upon opening a chest in a dungeon the druid found a magic chainmail and a bag filled with 420gp. As he was the only one next to the chest, he turned around and told his two comrades there were 360gp in the chest, keeping an extra 60gp to himself without them knowing. Later after finishing a task for the mayor the druid and the paladin persuaded him to give them 550 instead of 500gp, while the fighter was drunk outside. The druid told the paladin to keep his share of those 10% extra, as a gift for always being successful on those charismatic tasks. This was done to check out the personality of the paladin. He accepted without a second of doubt and didn't even contradict when the druid told him not to tell the fighter anything about the extra.   I am now confused about whether this is just unlawful or also not good, and if so what should I as DM do about it? Search in favorited questions? is it possible to raise the tip while raising the back and lowering the center of the tongue when making /R/ sound? Following , this is how we correctly make the r sound:   Let the throat vibrate since it is voiced. Round the lip a little. Raise the tip of the tongue towards the hard bump behind the upper front teeth,  but do not let the tip of tongue touch the bump. This also makes the center of the tongue go down. The back part of the tongue is raised because you pull it into a tight ball Fold and raise the sides of the tongue so they touch the upper side-teeth.   If we follow the above requirement, our tongue should have an s shape when we pronounce the r sound as depicted in the following sketch:    Is it possible to raise the tip while raising the back and lowering the center of the tongue when making an r sound?   How do native speakers make an r?  P.S. My tongue is very short anyway! I'm about to use this diagram to make computing 3x3 determinants clear and easy for my students. I tried to add this picture to my lecture but it's blurred due to the bad quality of the picture. So i want to create exactly the same figure using latex.  I've searched and read a few topics about highlighting elements and diagonals in matrix but it does not work in this case. I want to add plus signs and minus signs as in the picture, and highlight elements in the matrice with elements outside the matrice.  I appreciate all your help and your advice. Thank you in advance ! Atiyah Macdonald, Exercise 8.3. Let $k$ be a field and $A$ a finitely generated $k$-algebra. Prove that the following are equivalent:   (1) $A$ is Artinian.   (2) $A$ is a finite $k$-algebra.   I have a question in the proof of (1$\Rightarrow$2): By using the structure theorem, we may assume that $(A,m)$ is an Artin local ring. Then $A/m$ is a finite algebraic extension of $k$ by . Since $A$ is Artinian, $m$ is the nilradical of $A$ and thus $m^n=0$ for some $n$. Thus we have a chain $A \supseteq m \supseteq m^2 \supseteq \cdots \supseteq m^n=0$. Since $A$ is Noetherian, $m$ is finitely generated and hence each $m^i/m^{i+1}$ is a finite dimensional $A/m$-vector space, hence a finite dimensional $k$-vector space.  But now how can I deduce that $A$ is a finite dimensional $k$-vector space? Short story as a letter to original colonisers of earth Prove that the derivative of $x^w$ is $w x^{w-1}$ for real $w$ Can anyone give a proof of the derivative of this type of function? Specifically showing that  $\dfrac{d(x^w)}{dx} = wx^{w-1}$ for a real $w$?  I tried to use the Taylor series expansion for $(x+dx)^w$ and got the correct result. However, the proof of the Taylor series requires knowledge of the derivative of these functions. So this is essentially circular reasoning. I know that the same series is also given by the binomial expansion, but that's not entirely satisfactory either, because where's the proof that the binomial expansion works for all reals (isn't it only apparent for integers)? So far all of the arguments I've come across involve circular reasoning. I was thinking of showing that the binomial expansion is true for all reals using some form of proof by induction e.g. something like this.  I'm really not sure. Do I need a transit visa for a technical stop in Australia? I'm travelling to New Zealand, and my itinerary mentions a technical stop in Australia.  Will I need to apply for an Australian transit visa for this? How can I avoid "please insert CD/DVD" error when updating Ubuntu? I can't update 12.04 LTS. The Update Manager shows this:  CD/DVD 'Ubuntu 12.04 LTS _Precise Pangolin_ - Release i386 (20120423)' is required Please insert the above CD/DVD into the drive '/media/cdrom/' to install software packages from it.   The image I downloaded and burned to CD is from  the PC (Intel x86) desktop CD version. I burned many CDs but the result is the same. Why is $\frac{\operatorname dy'}{\operatorname dy}$ zero, since $y'$ depends on $y$? I know that $\frac{dy'(x)}{dy}=0$ (where $y'=\frac{dy(x)}{dx}$). The reason explained is that $y'$  does not depend explicitly on $y$. But intuitively, $y'$ depends on $y$, since if you vary $y$ you will modify $y'$. Why is my reasoning wrong (my reasoning sounds like it's related to functional calculus, instead of standard calculus)?  I tried to write  $\frac{dy'(x)}{dy}=\frac{d}{dy}\frac{dy}{dx}=\frac{d}{dx}\frac{dy}{dy}=\frac{d}{dx}1=0$, but this proof doesn't convince me.  I think that other way to see this is saying that if a function is of the form $f(y)$, it will not dependend on the variable $y'$.  But the same way you write $f(y)=y^2$, you could write $f(y)=\frac{d}{dx}y$, which clearly depends on $y'$. So I don't know if there are some types of operations which are restricted (for example, taking limits):  Note: The problem raises in the context of Classical Mechanics, where: $\frac{\partial L(\dot{x},t)}{\partial x}=0$.