Solving the "bullet problem"
Cast ray to select block in voxel game
I'm trying to prove that the characteristic of any field $F$ is either $0$ or a prime number, but I have no idea what to do.  Help? Polar Plot x and y ticks and units Is there a word for people who always act too friendly in order to curry favor with their acquaintances? Is there a single noun or adjective for a person who is always flattering friends and acquaintances, not only to be liked and accepted but, at other times, to curry favor with them as well ?  I'm not looking for regionalisms but a word that will be understood in any English speaking country. I saw a video of Johann Cruyff , isn't that against the rules? What kind of questions can I expect to see on a qualifying exam? In mathematics, there are certain open questions which are the subject of current research (think of the newest papers in the top journals).  I have also heard that some graduate programs ask questions such as these on their qualifying exam.  How common is this practice?  What kinds of questions can I expect to see on a qualifying exam?  I know that a qualifying exam typically tests the knowledge gained in graduate school, but I'm not sure to what extent this knowledge is tested?  How "advanced" should I expect these questions to be? Can space expand with unlimited speed? just after the Big Bang and before inflation the currently observable universe was the size of a coin. One millionth of a second later the universe was the size of the Solar System, which is an expansion much much faster than speed of light. Can space expand with unlimited speed? How to make a ISO file out of a folder containing Windows setup files I copied the Windows 8 CD to my HDD. I want to convert that folder to an ISO and use that to create a bootable USB.  Please tell me how I can make an ISO image out of that folder containing files.  This is my folder which I want to convert to a ISO file: I need a binary search algorithm that is compatible with the C++ STL containers, something like std::binary_search in the standard library's &lt;algorithm&gt; header, but I need it to return the iterator that points at the result, not a simple boolean telling me if the element exists.  (On a side note, what the hell was the standard committee thinking when they defined the API for binary_search?!)  My main concern here is that I need the speed of a binary search, so although I can find the data with other algorithms, as mentioned below, I want to take advantage of the fact that my data is sorted to get the benefits of a binary search, not a linear search.  so far lower_bound and upper_bound fail if the datum is missing:  //lousy pseudo code vector(1,2,3,4,6,7,8,9,0) //notice no 5 iter = lower_bound_or_upper_bound(start,end,5) iter != 5 &amp;&amp; iter !=end //not returning end as usual, instead it'll return 4 or 6   Note: I'm also fine using an algorithm that doesn't belong to the std namespace as long as its compatible with containers. Like, say, boost::binary_search. Is $f(a)\!=\!0\!=\!f(b)\Rightarrow (x\!-\!a)(x\!-\!b)\mid f(x)\,$ true if $\,a=b?\ $ [Double Factor Theorem] I want to write a program for this: In a folder I have n number of files; first read one file and perform some operation then store result in a separate file. Then read 2nd file, perform operation again and save result in new 2nd file. Do the same procedure for n number of files. The program reads all files one by one and stores results of each file separately. Please give examples how I can do it. When I add a mirror modifier it sometimes doesn't mirror correctly, giving me an overlapping mesh. How can I fix this? If $p,q$ are primes $(pq,a)=1$ and $p-1|q-1$ then prove $a^{q-1}\equiv 1\pmod{pq}$ $p,q$  primes, $(pq,a)=1$ and $p-1|q-1$ then prove $a^{q-1}\equiv 1\pmod{pq}$   Got this in an exam today and had no idea how to do it. I installed Fedora 15 on my laptop and deleted XP (at least I think XP is deleted).  Then I installed Ubuntu as dual boot with Fedora 15.  Now I want to remove Fedora 15 and leave only Ubuntu (and XP if it is still available).  Can anyone help with the steps to uninstall Fedora?  Please give me simple steps to follow, I'm a nooby.  Thanks! How do Horcruxes work? A few questions regarding the Horcruxes.   Had Voldemort actually succeeded in using a Horcrux, would he come back the same age (biologically and/or aesthetically) he was when he made the Horcrux, or the age he would biologically be if he had never died (half died)? If Harry was a Horcrux, then in the graveyard, when Wormtail added Harry's blood to the potion to bring Voldemort back, didn't that technically use up the Horcrux inside of Harry? So in Deathly Hallows when Voldemort kills Harry, shouldn't Harry have actually died rather than just have the Horcrux inside him destroyed, seeing as it was technically used in the Goblet of Fire? What happens when one is affected by something such as energy drain, and permanently loses levels when one only has racial HD? Does the victim of the spell die? Or do they permanently lose racial HD? Drop Table and recreate Permissions So we followed an best practice by Andreas de Ruiter ()  The Idea behind it is, that you write SQL Views which are easy to maintain and deploy. You use stored procedures to use these views and create tables from it. He suggests dropping or truncating the tables to maintain consistency over the data. I think it's the easiest approach without writing any complex update logic.  On these tables we have the need to set specific user permissions. By dropping the table we would lose them. So for us the question is, how could we drop the table and recreate the existing permissions on the newly created table? Do I have to clear customs when transit via the US on my way to / coming from somewehere else? I shall arrive at Washington Dulles Airport (IAD) by Emirates flight to catch a united airlines flight to Detroit after 3.5 hours. What steps shall I have to go through? Is the connection time enough? I have US F1 visa. I would like to create a XeLaTeX layout where  multicol's columns (two in this case, no figures, text only) are tilted where they meet. The lines still should be ordinary lines below each other, but the start/end points of each line should glide a bit each line for it to look something like this:  xxxxxxxxxx  xxxx xxxxxxxxxx  xxxx xxxxxxxxx  xxxxx xxxxxxxxx  xxxxx SECTION   xxxxxx xxxxxxxx  xxxxxx xxxxxxx  xxxxxxx xxxxxxx  xxxxxxx xxxxxx  xxxxxxxx xxxxxx  xxxxxxxx xxxxx  xxxxxxxxx xxxxx  xxxxxxxxx xxxx  SUBSECTION xxxx  xxxxxxxxxx   So not the whole column is tilted, but one gets narrower while the other one gets wider.  I've seen examples using \parshape, but those I found are based that one counts lines and more or less manually defines the shape. I also would need that LaTeX keeps the multicol functionality (page breaks, text flow, ...) and does this automatically on each page for a longer chapter.  How do I create such a layout? If multicol is not easy to mix with this layout, what would be an alternative? Methods to find $\lim\limits_{n\to\infty}\frac1n\sum\limits_{k=1}^nn^{1/k} $ What would you suggest here?  $$\lim_{n\to\infty} \frac{1}{n} \sum_{k=1}^{n} n^{1/k} $$ Why does Worf want O'Brien to go to Minsk?