Login screen appears on second monitor
Is there to make the login screen appear on the external display in 18.04?
Split string into sentences using regex How can I bring back the old menu style on Chrome 28 onwards, now that the --disable-new-menu-style switch has been removed? K-Means clustering for mixed numeric and categorical data My data set contains a number of numeric attributes and one categorical. Say, NumericAttr1, NumericAttr2, ..., NumericAttrN, CategoricalAttr, where CategoricalAttr takes one of three possible values: CategoricalAttrValue1, CategoricalAttrValue2 or CategoricalAttrValue3. I'm using default . It works with numeric data only. So my question: is it correct to split the categorical attribute CategoricalAttr into three numeric (binary) variables, like IsCategoricalAttrValue1, IsCategoricalAttrValue2, IsCategoricalAttrValue3 ? How many spell slots does a Level 3 Warlock have? The Warlock Table in the PHB (p106) states that a Warlock has the following:   1 First-level spell slot at level 1. 2 First-level spell slots at level 2. 2 Second-level spell slots at level 3.   Does this mean that a third level Warlock has a cumulative 5 Spell Slots? (3 First-Level slots and 2 Second-Level slots)  Or do the new slots just replace old slots between levels such that a 3rd-level Warlock ultimately has only 2 second-level spell slots? Which of the following are correct and which are wrong?   The 2000-year-old computer The 2000 year-old computer The 2000 year old computer The 2000-years-old computer The 2000 years-old computer The 2000 years old computer   In a documentary, BBC4 used the title The 2000 year-old computer, which I believe to be wrong. Am I right? Check which IPs or web-sites an app is communicating with? Usually they do it behind the scenes. So I'd love to know where apps are actually sending data and from whom they are actually getting responses. There are n letters addressed to n eople at different addresses. The n addresses are typed on n envelopes.  A disgruntled secretary shuffles the letters and puts them in the envelopes in random order, one letter per envelope.  Find the probability that at least one letter is put in a correctly addressed envelope. [Hint: use the inclusion-exclusion formula.] What is the probability approximately, for large n ?    My attempt at a solution:  P(all correct) = $\frac{1}{n!}$  P(n-1 correct) = ${n \choose n-1} \frac{1}{n!} = \frac{1}{1!(n-1)!}$  ${n \choose n-1}$ ways of selecting n-1 correct letters.  P(n-2 correct) = ${n \choose n-2} \frac{1}{n!} = \frac{1}{2!(n-2)!}$  ...  P(n-n correct) = ${n \choose n-n} \frac{1}{n!} = \frac{1}{n!(n-n)!} = \frac{1}{n!}$  This all looks ok to me, but I tested this for a case of 4 people, (I think the theoretical value should be $\frac{9}{24}$ but obviously that is not what I got. Can someone correct my logic please? Also, with regards to the hint about inclusion/exclusion - where would that come in?  I read about derangements on Wikipedia but it did not make total sense to me (the derivation).  I would appreciate any advice whatsoever including references to other material. Is this a valid proof for the reverse triangle inequality: Given $x,\,y\in\mathbb{R}^n$, $\|x-y\|\ge |\|x\| - \|y\||$. $\def\a{{\bf a}} \def\b{{\bf b}}$ $\def\x{{\bf x}}$ $\def\y{{\bf y}}$  I've seen various methods of proving the reverse triangle inequality but I was wondering if this one is fine as well.   Prove the reverse triangle inequality:  Given $\x,\,\y\in\mathbb{R}^n$, $\|\x-\y\|\ge |\|\x\| - \|\y\||$.   $\textbf{Solution}$ Let $\x,\y \in \mathbb{R}^n$. Now, $\x=\x-\y+\y$ and so $||\x|| = ||\x-\y+\y|| \le ||\x-\y|| + ||\y||$ by triangle inequality. Thus, $||\x|| - ||\y|| \le ||\x-\y||$ [*].   Now for $\y$. Again, $\y = \y-\x+\x$ so $||\y|| = ||\y-\x+\x||$ implies $||\y|| \le ||\y-\x|| + ||\x||$ by triangle inequality. So, $||\y|| - ||\x||\le ||\x-\y||$. Hence, $-||\x-\y|| \le ||\x|| - ||\y||$ [**].   By [*] and [**], $-||\x-\y|| \le ||\x|| - ||\y|| &lt; ||\x-\y||$ implying $\bigl ||\x|| - ||\y|| \bigr\rvert \le ||\x-\y||$ for all $\x,\y \in \mathbb{R}^n$. Why do physicists think that the electron is an elementary particle? When we first discovered the proton and neutron, I'm sure scientists didn't think that it was made up of quark arrangements, but then we figured they could be and experiments proved that they were.  So, what is it about the electron that leads us to believe that it isn't a composite particle? What evidence do we have to suggest that it it isn't? Which is better: side quests after killing the warrior or Playthrough 2? My question is, once I beat the warrior should I do all the sidequests in Normal before starting TVHM or should I go right to TVHM once it becomes available?    I just bought the game and have been playing with some friends who are higher level than me so that we could enjoy the Tiny Tina DLC together.  As a result, I leveled up pretty fast without doing much of the main story quest or side quests.  Now I'm a level 32 commando and haven't finished the main storyline in normal (Just finished "Where angels fear to treat Pt 2").  I get almost no XP from kills on missions.  I still have tons of sidequests.  I imagine some of them might give good loot, or be fun to play.  It it better to go to Playthrough 2 or should i do the sidequests in Normal first?  EDIT: changed question title and some wording for clarity How to show $\alpha\int_a^cf(x)dx+\beta \int_c^b f(x)dx =0$ means $f(x)=0$ everywhere $?$ Question :  Let $$f\ :\ [a,b]\rightarrow \mathbb R$$   be  continuous . And  there  exist  constants  $\alpha$  $\beta$  such  that  $\forall c\in [a,b]$  $$\alpha \int_a^c f(x)dx +\beta \int_c^b f(x)dx =0 $$   Prove  that  $f=0$  allover  $[a,b]$.  Attempt :(not much useful )   Since  the  equation  holds  for  all  $c\in [a,b]$   , if  take  $c=a$  then  we  have $$\beta \int_a^b f(x)dx =0 $$  And  taking  $c=b$  we  get $$\alpha \int_a^b f(x)dx=0 $$  See  if  both  $\alpha=0$  and  $\beta=0$  hold  then  there  is  nothing  to  do . If  only  one  of  them  is  $0$   and  the  other  is  non-zero  then  from  the  last  two  equations  we  get $$\int_a^b f(x)dx =0 $$ and  this  does   not  ensure   $f$'s  being  identically  $0$  on  $[a,b]$ (for  example : $f(x)=sin x$  and $a=0$,$b=2\pi $ ) .   So  our  only  possibility  is  that  both $\alpha \neq 0$  and $\beta \neq 0$  must  hold .  Now  I  cannot  proceed  any  further  from  this  point . Please  give  me  some   hints  as  to  what  to  do  next .  Thaanks. I live in a town where fresh or whole milk is not readily available. I was wondering if I could make cheese from UHT Milk. If so, what kind of cheese and what method I should use? Or rather, Should I? How can I customize a system locale? I want to do this using the Math.Round function 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? Which SUSY models are affected by the recent LHCb result? The LHCb has recently  the observation of $B_s \rightarrow \mu^+ \mu^-$ with a branching ratio that agrees with the Standard Model (SM). There are many blog posts about it (See: ).  The result initiated a debate over its implication on Supersymmetry in general, which I don't want to discuss here. But it certainly affects some Supersymmetric models that may have a different prediction than that of the SM.   My questions are,   Which models in particular are affected (or variants of models)? What is the MSSM status? The NMSSM? Does the result affect some of the parameter space of a particular model, or does it rule out an entire model/or variant of a model? Completing a 3x3 correlation matrix: two coefficients of the three given I was asked this question in an interview.  Lets say we have a correlation matrix of the form \begin{bmatrix}1&amp;0.6&amp;0.8\\0.6&amp;1&amp;\gamma\\0.8&amp;\gamma&amp;1\end{bmatrix}  I was asked to find the value of gamma, given this correlation matrix. I thought I could do something with the eigenvalues, since they should be all greater than or equal to 0.(Matrix should be positive semidefinite) - but I don't think this approach will yield the answer. I am missing a trick.  Could you please provide a hint to solve for the same? On the three Stack Overflow chat servers, the  page displays the following image:    Is it from an actual episode, or is it a 'shop? Several badge descriptions contain raw HTML I was reading through some badge descriptions and noticed that Synonymizer's description needs to be updated. As it stands, there is raw HTML (an href) in the description:    EDIT: after reading comments by @ColeJohnson, I have come to the understanding that this post comes off as whiny. I want to make it very clear that I wasn't ever trying to complain. My first reaction was to fix the perceived error myself. When I realized I was unable to do so, I figured the best course of action would be to find someone who would be able to make the necessary edits. Hence the post here. If $f \circ g$ is surjective, then f is surjective Let $f: X \rightarrow Y$ and $g: Y \rightarrow X$  If $f \circ g$ is surjective, then f is surjective, too.  I think that is true.   Question: How can I proove that? I have so far:   $\forall y \in Y: \exists x \in X : f(x)=y$  $\forall x \in Y : \exists y \in Y : f \circ g(y)= x$