Limit of a trigonometric sequence
Convergence of $\sqrt{n}x_{n}$ where $x_{n+1} = \sin(x_{n})$
What is the JVM thread scheduling algorithm? I'm trying to install pandas. When I do, it's automatically installing to the python installation for v 2.7.   How do I force pandas to install to the python 3.5 installation? I have got a NFC key to enter in my room and i want to make a copy of this key in case of loss. I read the nfc tag key with my nexus 5 with Broadcom BCM20793M NFC controller. The phone reads the tag and retrivies all the infos but when i try to copy the tag it gives an "Error reading the tag" message. The tag is a  NXP MIFARE Classic. I read that it is not compatible with the newest chips so i wanna buy an Arduino NFC reader to read and copy the tag.  Might it works?    Below all the infos retrieved from the nfc key: I don't know much about this,  But I've some of the questions on which some user has answered (not helpful answer) also but I want to delete those questions, but whenever I go to delete that question. It is prompting with     What does it mean? Can someone tell me what would be the action taken by Stack Exchange if I delete more questions? Beam size and material for 15 feet long swing I need to create a 15 feet span beam for kid swing (300 lbs load / 150 lbs and 2 swings assumption). One end will bolt to the tree (just for convenience).  What "treated lumber" lumber size and material I should use? Or is it better / cheaper to use metal pipe (from the plumbing department)?  I guess 4x8x16 or two (2) 2x8x16 would do it according to this website . But I do like a clean look of metal. My wife would concern about big piece of lumber running on top of the kid (that looks heavy visually). Unknown error: '' ("The cache has no package named wine-staging-i386") In Italian, when I write a sentence about an action (e.g. eating fish, playing), I would use the infinitive, such as  mangiare pesce fa bene alla salute (which literally is "to eat fish is healthy"), or giocare aiuta ad imparare (which literally is "to play helps to learn").   I would use the gerund in giocando si impara, but that would roughly mean "When playing, you learn." and in this case the infinitive would not be correct. (Giocare si impara is not what you would say in Italian.)  Should I use the infinitive, or the gerund, in sentences similar to the following ones?   To play with fire is dangerous. To win the lottery is just a matter of luck. To escape from Alcatraz is impossible. To practice makes you perfect.   Is the infinitive always wrong, when the verb is the subject of a sentence? How does dark matter halo outside a galaxy help to explain galaxy rotation curve? How does a   outside a galaxy help to explain a ?  Suppose for simplicity we use a model of a star rotating about a more massive star in a fixed circular orbit. For another star at larger radius, the velocity should be smaller but observationally for spiral galaxies, the opposite happens (moves at even more speed or at least at the same speed as the closer star).  People hypothesize that dark matter halo may be present “surrounding” the system (i.e., halo exists outside the system) to account for such observation. I feel that exactly the opposite should be the case that is, dark matter halo should be inside the galaxy rather than outside. Reason being, if dark matter is outside the galaxy then the effective gravitational pull on the rotating star towards the center will be reduced due to outward attraction on the star exerted by dark matter existing outside. Thus, its speed of rotation should be reduced; but we observe the opposite. So how does dark matter halo "surrounding" a galaxy help to explain galaxy rotation curve? Where am I making mistake in argument? text-overflow: ellipsis in table-cell without width I was reading a website where common English sentence errors are written -     INCORRECT - He doesn't know to swim.      CORRECT - He doesn't know how to swim.   I know He doesn't know how to swim is a correct sentence. But why is the other one wrong, is my question?  I know that know is a transitive verb. So, the following are correct -   i) He knows swimming.  Swimming is a gerund. We can also use the infinitive form here - to swim  ii) He knows to swim. Genetically modified humans study insectoid alien miners with super-intelligent hive-mind This is a short story that appeared in a collection. Two genetically-modified humans (corporate anthropologists, basically) travel to a planetoid inhabited by an insect race that is mining the planet in order to study the race. While there, they are practically ignored, as the individual members of the race lack consciousness. The humans determine a type of pheromone is used to control the worker caste, and co-opt several members to create a living area. They make plans to put the mining towards human ends, but before that can happen they are discovered. The presence of the artificial pheromones wakes up a hive-mind, super-intelligent bug, who then bargains with the surviving member of the team (the man) after killing and taking over the female member of the team.  The collection was read at some point between 2000-2005. Why does $F=ma$? Is there a straightforward reason? Why is force = mass $\times$ acceleration? I have searched in many sites but didn't actually get at it. Simply I want to know that if a mass in space moves (gains velocity thus further accelerates), how can I think, postulate and further believe that force = multiplication  of mass and its acceleration ? Constrain to any 2 axes during transform? I want to be able to lock my translation/scale operations to two axes at a time, say xy, xz or yz. It currently takes two operations (one for each axis).  Example, say for a cylinder, I would like to reduce the radius. I currently have to scale on the x axis first, then on the y axis, or I have to manually input the scale values in the object properties panel.  This option is easily accessible in 3dsmax via the axis constraints command bar. Or I can click the intersecting area between the 3d manipulator of the axes in question and move in that plane. Number of solutions to the congruence $x^q \equiv 1 \mod p$. Let $p, q$ be distinct odd primes, I would like to compute the number of solution $\mod p$ to the congruence $x^q \equiv 1 \mod p$. (Show that it's $gcd(q, p - 1))$  If $x^q \equiv 1 \mod p$, since $q$ is prime, this must mean that $x$ is either $1$ or has order $q$.   Hence, the problem reduces to finding the number of elements of $U_p$ which is either $1$ or has order $q$.  If $ q \nmid  p - 1$, then there is only one element, namely $1$.  If $q \mid p - 1$, then the number of elements of order $q$ is $\phi(q) = q - 1$, and so the number of solutions to the congruence $\mod p$ is $q - 1 + 1 = q$, and in either case the number of solutions is $\gcd(q, p - 1)$.  Does this look fine? How does gravity work underground? Would the effect of gravity on me change if I were to dig a very deep hole and stand in it? If so, how would it change? Am I more likely to be pulled downwards, or pulled towards the edges of the hole? If there would be no change, why not? I want to install Oracle's JRE and to update to the latest version with the Software Updater when they released. Is there a Ubuntu package that is provided by Canonical or Oracle?  Before release Java 7, I followed  to install Java 6.  But it doesn't work for Java 7. There is no package sun-java7-xxx. How can you install Java 7? How to calculate a confidence interval for estimating a proportion when the population is very small? I plan to execute a little study on whether dentists tend to grant privately insured patients (PRIV) a sooner appointment compared with publicly insured patients (PUB). I want to restrict this study to the dentists of a single town in Germany.  In this town there are about 500 dental practices and I am willing to call maximum 100 practices (twice, once as a PUB and once as PRIV). (A sample without replacement of size up to 100)  So the result of this examination would be a list of up to 100 practices with an associated value of 1 - if the appointment for the PRIV was more than two days sooner - and a 0 - if not. The proportion of 1s is what I want to estimate.  Now the sources I have been reading always assumed a much larger population with a finite population correction close to 1. This is why I doubt that blindly using a conservative or approximate confidence interval would lead to a statistically meaningful result.   So my first question is, of course, whether it is reasonable at all trying to estimate the proportion using a confidence interval in this case? And if yes, then what statistical technology/method (leading to a CI) would be a good choice for this use case?   One idea that comes to mind is using a sample size of 25 f.x., in that case the FPC would be 0.95 - "close enough" to 1. But it seems stupid trying to improve the quality of an estimation by reducing the information used for the estimation. String answer1 = "yes"; if (answer1 == "yes") gives false. Why? irrationality of $\sqrt{2}^{\sqrt{2}}$. The fact that there exists irrational number $a,b$ such that $a^b$ is rational is proved by the law of excluded middle, but I read somewhere that irrationality of $\sqrt{2}^{\sqrt{2}}$ is proved constructively. Do you know the proof? What can I do if my USB flash drive is write-protected or read-only? When I plug in my USB flash drive, it shows up on my computer as write-protected or read-only. I am unable to transfer data to it, nor can I modify or delete any files already stored on it. I also cannot repartition or reformat the drive using Windows Disk Management, DiskPart, GParted, or other tools. The drive does not have a write-protect switch.  Why did this happen and what can I do about it? Is there a way to remove the write protection?  (Note that this can happen with some memory cards, too, as they often use controllers similar to those used in flash drives. In some cases, the system may report that the drive or card was formatted successfully even though it was never actually formatted; the original data reappears when the device is reinserted.)     This question comes up often and the answers are usually the same. This post is meant to provide a definitive, canonical answer for this problem. Feel free to edit the answer to add additional details.