how can you tell which version of an Ubuntu package includes a particular patch?
Checking if Ubuntu package contains desired update
Closure of a Ball is Contained in Closed Ball (usual metric) Let $\overline{B_d (x, r)}$ be the closure of an open ball, and let $\hat B_d (x, r)$ be a closed ball. Show that in any metric space $(X, d)$, $\overline{B_d (x, r)} \subseteq \hat B_d (x, r)$ for all $x \in X$ and $r &gt; 0$.    I used the definition of closure: $\overline{B}$ = $B \bigcup B'$. If $x \in \overline{B}$, then $x \in B$ or $x \in \overline{B}$, or both. If $x \in B$, then clearly $x \in \hat B$ since $B \subseteq \hat B$. But, if $x \in B'$, then $x$ is an accumulation point. Since $\hat B$ is closed, it contains all accumulation points of $B$. Thus, $x \in \hat B$.  Is this approach correct, or at least in the right direction? Should I be using the closure definition, or try another one? Thank you. Family name pluralization When pluralizing family (last) names that also happen to be common English words, does the pluralization follow the same rules as the common word?  For example, "the Smith family" can be pluralized as "the Smiths", but what if the family name is "Wolf" or "Fish"?  Would the correct pluralization be "the Wolfs" or "the Wolves"? How can I get a reference to a method? Why is Earth's gravity stronger at the poles? Many sources state that the Earth's gravity is stronger at the poles than the equator for two reasons:   The centrifugal "force" cancels out the gravitational force minimally, more so at the equator than at the poles. The poles are closer to the center due to the equatorial bulge, and thus have a stronger gravitational field.   I understood the first point, but not the second one. Shouldn't the gravitational force at the equator be greater as there is more mass pulling the body perpendicular to the tangent (since there is more mass aligned along this axis)? I have my A* pathfinding algorithm right now working such that given a graph it can find the route from one starting node to one goal node.   This works well for many problems, but sometimes I find that multiple goal nodes are valid.  For example, in a game, an NPC might have to go to a switch to shut a door. If there are multiple switches that shut the door in question, it doesn't matter which switch it goes to - it just needs to go to one of them.  How can I augment my pathfinding algorithm to find the path to the best goal (the shortest path)? As in, the algorithm searches for multiple goals and when it finds just one, it returns the path to that one.  One solution would be to run the algorithm as many times as there are valid goals, but you can guess why that might be inefficient. How to remove local (untracked) files from the current Git working tree Conditions for vertical circular motion If a bob attached to a string is swinging in vertical circular motion, we say that the bob leaves the circular path when the tension in the string becomes zero, but even when tension becomes zero, there's always a component of the bob's weight towards the center of the circle. Why then does the bob leave the circular trajectory? I've just received my new SSD since the old one died. This Intel 320 SSD supports TRIM. For testing purposes, my dealer put Windows on it, but I want to get rid of this and install Kubuntu on it.  It does not have to be a "secure wipe", I just need the empty the disk in the most healthy way. I believe that dd if=/dev/zero of=/dev/sda just fills the blocks with zeroes and thereby taking another write (correct me if I'm wrong).  I've seen the answer , but it looks like it's suited for clearing empty blocks, not wiping the disk.  hdparm seems to be the program to do it, but I'm not sure if it clears the disk OR cleans empty blocks. From its manual page:     --trim-sector-ranges           For  Solid State Drives (SSDs).  EXCEPTIONALLY DANGEROUS. DO NOT           USE THIS OPTION!!  Tells the drive firmware to discard  unneeded           data  sectors,  destroying  any  data that may have been present           within them.  This makes those sectors available  for  immediate           use  by  the firmware's garbage collection mechanism, to improve           scheduling for wear-leveling of the flash  media.   This  option           expects  one  or  more  sector range pairs immediately after the           option: an LBA starting address, a colon, and  a  sector  count,           with no intervening spaces.  EXCEPTIONALLY DANGEROUS. DO NOT USE           THIS OPTION!!              E.g.  hdparm --trim-sector-ranges 1000:4 7894:16 /dev/sdz   How can I make all blocks appear as empty using TRIM? Get list of all tables in Oracle? How do I query an Oracle database to display the names of all tables in it? Find the smallest disk in complex plane containing the eigenvalues of a matrix (NBHM 2012) Consider the given matrix  $$\left[\begin{matrix}1&amp; -2&amp; 3&amp; -2 \\1&amp; 1&amp; 0&amp; 3\\-1&amp; 1&amp; 1&amp; -1\\0&amp; -3&amp; 1&amp; 1&amp;\end{matrix}\right]$$  Find out the smallest disk like ($|z-1| &lt; r$ ) in the complex plane containing the eigenvalues of the given matrix.  One easiest method is to find out the eigenvalues from the characteristic equation of the matrix. I can do it so no problem with it.   I am looking for a method to solve the problem without the above method that can be evaluated in very short time. This type of method is possible, I believe.  Thank you for your help What is the meaning of “runneth” in ? Suppose I wish to allow only users who have scored at least 15 in the particular tag to answer my question, Is it possible to set a condition like this while asking a question? So that I can avoid strangers/answers from dummy users. How to replace the domain name in a Wordpress database? I have a Wordpress database which was installed in a development environment... thus, all references to the site itself have a fixed IP address (say 192.168.16.2). Now, I have to migrate that database to a new Wordpress installation on a hosting. The problem is that the SQL dump contains a lot of references to the IP address, and I have to replace it with: my_domain.com.  I could use sed or some other command to change the that from the command line, the problem is that there are a lot of configuration data which uses JSON. So what? Well, as you know, JSON arrays uses things like: s:4: to know how many chars an element has, and thus, if I just replace the IP with the domain name, the configuration files will get corrupted.  I used an app for Windows some years ago that allows to change values in a database and takes care of the JSON arrays. Unfortunately, I forgot the name of the app... so the question is: do you know any app that allows me to do what I want? What is "my guy syndrome" and how do I handle it? I've been reading forum posts and blogs who mention "my guy" syndrome as a specific type of difficult player, but I can't seem to find a solid definition for the term. Can someone explain this particular kind of problem player to me? How do you deal with this kind of problem? Finding the radius of a third tangent circle Sorry if this is a foolish question, but I'm having difficulty understanding how to solve for $r_3$ in the following diagram...    According to WolframAlpha's page on tangent circles, the radius of $c_3$ can be calculated using the following formula $r_3=\frac{r_1 \times r_2}{(\sqrt{r_1}+\sqrt{r_2})^2}$, which can be simplified to $\frac{1}{\sqrt{r_3}}=\frac{1}{\sqrt{r_1}} + \frac{1}{\sqrt{r_2}}$.  To be completely honest, I'm having a hard time understanding understanding how this formula works (as I'm a very visual person). What exactly is happening here? Limit of $n/\ln(n)$ without L'Hôpital's rule I am trying to calculate the following limit without L'Hôpital's rule:     $$\lim_{n \to \infty} \dfrac{n}{\ln(n)}$$   I tried every trick I know but nothing works. You don't have to prove it by definition. How do you prove the set $G = \{(x, f(x)) \mid x \in \mathbb R\}$ is closed? Let $f : \mathbb R \to \mathbb R$ continuous. Prove that graph $G = \{(x, f(x)) \mid x \in \mathbb R\}$ is closed.  I'm a little confused on how to prove $G$ is closed. I get the general strategy is to show that every arbitrary convergent sequence in $G$ converges to a point in $G$.  Here is what I tried so far:   Let $x_k$ be a sequence which converges to $x$. Since $f$ is continuous, this implies that $f(x_k)$ converges to $f(x)$. At this point, can you say every $(x_k, f(x_k))$ converges to a $(x, f(x))$, so $G$ is closed? Every natural number $n$ can be written as $n=s-t$ with $\omega(s)=\omega(t)$ Can we prove the following statement ?  Let $\omega(m)$ denote the number of all distinct prime factors of a positive integer $m$. Prove that every  natural  number $n$ can  be  written  as $n=s-t$, where $s$ and $t$ are positive integers with $\omega(s)=\omega(t)$, in other words, as the difference of two positive integers with the same number of distinct prime factors.   If $n=1$ , we can choose $\ s=3\ $ and $\ t=2$.  If $n$ is even , we can choose $\ s=2n\ $ and $\ t=n$. How to zero out a drive? Analyzing a sentence Do my analyze is correct? If don't then correct it.  Sentence: The tsunami and the undersea earthquake which triggered it, the largest ever recorded in the region, killed nearly 20,000 people, destroyed over 100,000 homes and threw the lives of tens of millions into turmoil.  Subject: The tsunami and the undersea earthquake Principal verb: triggered Adjective clause of subject:the largest ever recorded in the region, killed nearly 20,000 people, destroyed over 100,000 homes Use of parallelism:threw the lives of tens of millions into turmoil.