This is probably a beginner question, but it's always been throwing me off about LaTeX, especially because when I'm showing new people the basics, I can't explain why that is.  So the question is: Why does \large have to be wrapped inside {} to not make everything after it become large as well? When I type \large{Some text} it doesn't mean at all what one might expect ({Some text} isn't an argument apparently). For commands like \textbf it works the way I'm used to for most commands: Without braces, it just affects the next token, with curlies, it affects that whole argument inside the curlies and nothing beyond that.  Is there a term for these kinds of commands? I don't recall having seen very many others that behave like this.
I've always been confused by the differences in behavior of font commands.  For example, we have \mathrm{} and \texttt{}, which can be used like this: \texttt{hello} world.  And then we have \it and \bf which must be used as {\it hello} world. If one uses \it{hello} world, both words are italicized.  Internally, what is the difference here? And was this difference a conscious design decision? If so, why?
I came across this strange limit whilst showing convergence of a series: $$\lim_{n \to \infty}\sqrt[n]{\frac{2^n+3^n}{3^n+4^n}}$$ How can I calculate this limit? Marginal probability derived from joint probability distribution of a poisson process and binomial process I thought I figured out this problem, but my answer is different than the solutions manual. Hoping someone here can stear me in the correct direction:     Assume the number of automobile collisions that occur on a given stretch of highway per year is a Poisson random variable $X$ with $\mu = 20$. The probability is $p=0.05$ that there will be one or more fatalities in each accident; occurrences of fatalities are independent from one collision to the next. If $Y$ is the number of collisions with one or more fatalities on this stretch of road in one year, find the probability law for $Y$.   So as said, X is poisson, so:  $$p_X(x) = \frac{20^x}{x!}e^{-20}$$  The conditional probability of $Y$ given $X=x$ is a Binomial random variable:  $$p_{Y\mid X}(y\mid x) = \binom{x}{y}p^yq^{x-y}$$  where $Y =$ number of fatal traffic accidents and $x =$ given number of accidents (from poisson distribution)  Therefore the joint probability for $X$ and $Y$ is:  $$p_{X,Y}(x,y)= p_{Y\mid X}\cdot p_X(x) = \binom{x}{y}p^yq^{x-y}\frac{20^x}{x!} e^{-20}$$  to find the marginal probability of $Y$, I sum over $P_{X,Y}$ for all $x$:  \begin{align} p_Y(y) &amp; = \sum_{x=y}^\infty{\binom{x}{y}p^yq^{x-y}\frac{20^x}{x!}e^{-20}} = \frac{(20p)^ye^{-20}}{y!} \sum_{x=y}^\infty {20^{x-y}\frac{q^{x-y}}{(x-y)!}} \\[10pt] &amp; = \frac{(20p)^ye^{-20}}{y!} \sum_{x-y=0}^\infty {20^{x-y}\frac{q^{x-y}}{(x-y)!}} = \frac{(20p)^ye^{-20}}{y!}e^{20q} \end{align}  So:   $$p_Y(y) = \frac{(20p)^ye^{-20p}}{y!}$$  however, the correct answer is apparently $p_Y(y)=\dfrac{e^{-1}}{y!}$ Just curious as to how to obtain item drops from the last update.  To clarify, item drops as in weapon skins, crates, anything else Valve added without letting us know, etc.  It seems that after playing a bit, I've gotten no drops, but I've seen players who've gotten drops after a few short minutes of gameplay, but I've been playing for hours.  Is the item drop system like TF2, where you can just idle, get an item drop, come back? Is it like Dota2, where you have to be in the matchmaking system and complete matches for the chance to get drops? Or do you have to be MvP to get item drops? Is it a certain time you play the game?   Also, are weapon and crate drops independent or dependent on each other? Meaning, is the drop counter shared between Weapons and Crates, or are they both separate drop counters? Declare a const array How do you parse and process HTML/XML in PHP? Why does a wireless network give a more accurate location than a wired network? I build a simple HTML5 website that takes my location (in latitude-longitude), and simply shows my location in Google maps.  I opened the HTML document with my laptop Asus K53E-B1 and I found that when I connected to a wireless network, it showed almost my precise location (about 100 meter of inaccuracy),  while when I plug in the network cable, and test again, it's a bit Inaccurate. (showed a street 12KM away from me).  Can you explain me why is a wireless network gives more accurate location?  Tested with Google Chrome. Evaluating a mathematical expression in a string XML - Data At Root Level is Invalid What desktop environments can group window icons in the taskbar like Windows 7? I find it much faster to identify a window in the taskbar (window list) by its icon,    rather than by its text:    The problem with most graphical interfaces I've  is that they don't group windows, and if you have more terminals or file managers, they'll just clutter the taskbar and you won't know which is which. Windows 7 offers a relatively elegant solution to this by grouping similar window icons together.  Question: What Linux  have this functionality? If addons exist that provide it, that's alright.  For reference, a Cinnamon applet that sort of does this is . zsh scripting - How do I NOT match a pattern in filename generation? Bounded operator that does not attain its norm What is a bounded operator on a Hilbert space that does not attain its norm? An example in $L^2$ or $l^2$ would be preferred.  All of the simple examples I have looked at (the identity operator, the shift operator) attain their respective norms. The Maximum possible order for an element $S_n$ How does the PPA fit into the scenario of publishing an application to the Ubuntu Software Center? I've been going through docs for the past couple of hours but I haven't understood what the PPA is? I have a cross-platform Java application that I'd like to publish to the Ubuntu Software Center. My application is open-source and I'm using Github.   Apparently, publishing applications to the store isn't as simple as uploading a deb package - am I right? I need to create an account on Launchpad and put all my code there.  I don't intend to move from Git to Bzr merely for the sake of publishing to the app store but luckily, one is able to set up source-code mirroring from Github to Launchpad.  Since my application is still very premature, it'll have updates fairly often. When I build my application on my machine, do I simply go my Ubuntu App Developer page and upload the new DEB package or do they build my application from source?  What exactly is the PPA for? I don't think I'll need too many of the Launchpad features so I'd like to stick to Github if possible. Reverting back to Unity (Unity 7) Applying Insufficient Explanation Post Notice to One-line Questions? Moderators currently have a tool to add a Post Notice that says:     insufficient explanation       We're looking for long answers that provide some explanation and   context. Don't just give a one-line answer; explain why your answer is   right, ideally with citations. Answers that don't include explanations   may be removed.   However, there seems to be no equivalent wording for one-line questions.  Could the wording be changed to something like below to cover both one line questions and one-line answers?     insufficient explanation       We're looking for longer posts that provide some explanation and context.          Don't just ask a one-line question; provide some background like a brief description of your research prior to asking   Don't just give a one-line answer; explain why your answer is   right, ideally with citations.          Questions and answers that don't include explanations may be removed.   Sometimes such questions can simply be closed for being unclear or too broad but on the two sites I moderate there is an aversion to closing questions from new users, so to give them some guidance about what is expected, without spending time writing the same comment over and over, a post notice like this would provide a good "couple of clicks" alternative. I have the following problem illustrated by a simple example: If I cite the paper of an author T. Coven in my document, the outcome is 'Coven (2004b)'. If I cite the appendix to this paper, the outcome is 'Coven (2004a)'. Now the appendix pops up much less frequently than the original paper, therefore I would like to reverse the order (exchange 'a' and 'b' in the citations). Is this possible?  I am using Biblatex. Here is the bib-file of the above example (named: lib.bib):  @article{co:2004, author = {T. Coven}, title = {Title A}, journaltitle = {The X Journal}, date = {2004} } @article{coapp:2004, author = {T. Coven}, title = {Appendix to Title A}, journaltitle = {The X Journal}, date = {2004} }   MWE:  \documentclass[a4paper, 12pt, headsepline, headings=small,]{scrreprt} \usepackage[backend=bibtex8,     style=authoryear-icomp,     dashed=false,     autocite=footnote,     maxcitenames=3,     mincitenames=1,     maxbibnames=100,     firstinits=true,     sorting=nty     ]{biblatex} \bibliography{lib}  \begin{document} \cite{co:2004} and \cite{coapp:2004} \end{document} YA novel where clumsy boy gains wings I'm trying to remember the name of a novel I read as a pre-teen.  If I recall correctly, it would have come out in the 90s (though it may have been a reprint).  The novel is set in modern times.  I recalled this because I've been reading a lot of urban fantasy lately, and this may be the first 'urban fantasy' book I read - our world, but with a touch of magic.  There's a somewhat clumsy, out of shape teenaged (or almost teenaged) boy who doesn't have a father.  His father had been a stage magician who was constantly frustrated by his son's complete inability to preform stage magic, despite a prediction saying he would have a great or powerful magic.  His father had died before the book started, I don't recall how long before.  The boy does something nice for an old woman (I don't recall what) and she gifts him a magical potion.  A drop of it, rubbed on his shoulder blades, will make him grow wings.  The book follows him for the summer, as he spends his evenings flying.  He makes himself a toga-like shirt out of some old curtains and spends time flying around at night.  I recall one scene where he learns about two children out in the middle of the bay (perhaps the book is set in San Fran?  I don't recall) in a rowboat with one oar.  He saves them (by pulling them back to shore using a rope they had with them) and gets mentioned in the paper as an angel.  At the end of the book, the potion has run out.  There's only a tiny little bit left, and when he rubs it in, it creates only a single feather.  Around that point, the boy realizes that he's no longer getting winded going up several flights of stairs and he's gained a lot of self-confidence.  From what I remember of the copy I read, the cover featured a shirtless boy wearing jeans standing in front of a mirror, looking at the large white feathered wings that had grown from his back. What's the difference between passing by reference vs. passing by value? What is the difference between    a parameter passed by reference a parameter passed by value?   Could you give me some examples, please? Roots of unity filter, identity involving $\sum_{k \ge 0} \binom{n}{3k}$ How do I see that$$\sum_{k \ge 0} \binom{n}{3k} = (1 + 1)^n + (\omega + 1)^n + (\omega^2 + 1)^n,$$where $\omega = \text{exp}\left({2\over3}\pi i\right)$? What is the underlying intuition behind this equality? Show that a matrix $A$ is singular if and only if $0$ is an eigenvalue. I can't find the missing link between singularity and zero eigenvalues as is stated in the following proposition:  A matrix $A$ is singular if and only if $0$ is an eigenvalue.  Could anyone shed some light?