A different icon with a different name appears when I click the launcher
Duplicate application icons in Ubuntu dock upon launch
Disk space usage doesn't add up with df & du I've noticed a distressing tendency for questions that seem basic or overly short to be immediately closed and downvoted into oblivion.  Case in point:   Within a minute of being asked, this question received 12 downvotes and was closed as "not a real question".  That particular question is a very real, non-trivial question, but it had somewhat poor grammar and looked a little like a much simpler question.  Can we try to be a little more accepting? Should the personal/research statement be technical? Related:   I know I must describe my past and current research in my personal/research statement or statement of purpose. But do I use technical terms?  I was given the advice that since the people reading my statement are mathematicians (I am applying to US for applied mathematics), they should know what I am talking about.  Although I am applying to applied mathematics, it would also be nice to hear from other fields (biology, computer science, engineering etc) about this. How to print a string at a fixed width? How to calculate the costs of a weapon enchantment? Questions like  dealing with Ancalagon in particular, and Middle-earth's dragons in general, clearly show that Ancalagon was ridiculously, absurdly, unimaginably enormous.      The non-canonical image above shows one person's impression of how the different dragons of Middle-earth stacked up, with Smaug looking absolutely tiny at the far left, and Ancalagon on the right, too big to even fit in the picture.    Below, a presumably canonical picture, painted by Tolkien himself, shows Smaug in relation to Bilbo.  The rough measurements I took from this image suggest that Smaug is about 11 times longer than Bilbo is tall.  Depending on how tall Bilbo is - almost certainly somewhere between 3'6" and 4' tall - Smaug is approximately 38-44 feet long.      If the first picture is even vaguely accurate, Ancalagon would appear to be a minimum of something like 720 feet long from the tip of his nose to the end of his tail:  the visible portions of his head and body are at least 6 times longer than Smaug is from end to end, and we have to assume that the portion of his body that is out of frame is at least 3 times longer still, perhaps even 4 times or more (so the upper range of his length might exceed 1,000 feet).  Does Tolkien give us any way to estimate how big Ancalagon was?  It isn't his normal practice to describe things in great detail, I realize, but he often gives a few hints that allow for some rough approximation to be made.  Does anything he says suggest that the first image is anything like what he had in mind?  Note:  I haven't read anything about Ancalagon from Tolkien's own pen, except a few quotes on this site;  the most important bit of information I've gleaned is that he smashed 3 volcanoes to pieces when he died (or something like that).  How accurate is this, and what else did Tolkien say?    This question is not a duplicate of "", because none of the answers to that question address Ancalagon's size in any detail - except my own, which is based on what little information I was able to glean from the two pictures I included in this question.  All the other answers address how Ancalagon was killed, not how big he was.  I have no interest in how he died, only how big he was, or rather, what hints we can find that might give some indication of how big he was.  I wouldn't ask this question, linking that question in my own, if it contained the information I am interested in.    Note 2:  Regarding the relative sizes and impressiveness of Smaug and Ancalagon:  Imagine a meeting between Smaug and Ancalagon in Dragon Heaven: Smaug: "How'd you die?" Ancalagon: "A flying boat full of fire made by the Angels and driven by a Magic Elf smashed into me, so I fell onto a mountain and broke it, and I died. The Magic Elf lives in outer space now, and the boat turned into a star. How'd you die?" Smaug: "Um... Some dude shot me with an arrow." For $p$ prime, show that $\Phi_{p^n}(x) = 1 + x^{p^{n-1}} + x^{2p^{n-2}} + \dots +x^{(p-1)^{p^n-1}}$ Well I attempted to try this but I failed to solve it: So $$\Phi_{p^{n}}(x)= \frac{x^{p^{n}} - 1}{\Phi_{1}(x) \Phi_{p^{2}}(x) \dots \Phi_{p^{n-1}}(x)}$$  Now I'm just stuck here. I saw a result somewhere on the net that said $\Phi_{p^n}(x) = \Phi_p(x^{p^{n-1}})$. I would just use that, but I don't see why that result is true or know how to show that's true.  How do I approach this? Correct way of declaring pointer variables in C/C++ I've read that abelian categories can naturally be enriched in $\mathbf{Ab}.$ How does this actually work? Wikipedia defines the notion of an abelian category as follows ().     A category is abelian iff         it has a zero object,   it has all binary products and binary coproducts, and   it has all kernels and cokernels.   all monomorphisms and epimorphisms are normal.      It later explains that an abelian category can naturally be enriched in $\mathbf{Ab},$ as a result of the first three axioms above.  How does this actually work? I need to put some formal statistics on the document itself somewhere in the middle, like "This document contains XXX figures and YYY tables (and may be even ZZZ formulas and PPP theorems)". Is there a common way to output the final value of some counter in the middle of the document?  Edited after answering: I have asked a more specific question before, "How to output the number of bibliographic entries referenced in the document?", which is now deleted because the answer to this one covers also this case.  For the reference, some useful counters, which can be used with totcount:   page - page count enumiv - bibliography entries count figure - figures count table - tables count ImportError: No module named dbus I was trying to update my Python and messed up my whole system.   I am currently now able to start my Software Centre. I tried Googling multiple fixes but nothing helped. My Software Centre can't start.   When I try starting it up, this error shows:  astephen@localhost:/usr/bin$ ./software-centerGtk-Message: Failed to load module "gtk-vector-screenshot" Traceback (most recent call last): File "./software-center", line 36, in &lt;module&gt; from softwarecenter.utils import ( File "/usr/share/software-center/softwarecenter/utils.py", line 19, in &lt;module&gt; import dbus ImportError: No module named dbus   I tried reinstalling dbus using:  apt-get install --reinstall dbus   But it did not help.  astephen@localhost:/usr/bin$ sudo apt-get install --reinstall dbusReading package lists... Done Building dependency tree        Reading state information... Done 0 upgraded, 0 newly installed, 1 reinstalled, 0 to remove and 0 not      upgraded. Need to get 0 B/231 kB of archives. After this operation, 0 B of additional disk space will be used. (Reading database ... 676272 files and directories currently installed.) Preparing to unpack .../dbus_1.6.18-0ubuntu4.3_amd64.deb ... Unpacking dbus (1.6.18-0ubuntu4.3) over (1.6.18-0ubuntu4.3) ... Processing triggers for ureadahead (0.100.0-16) ... Processing triggers for man-db (2.6.7.1-1ubuntu1) ... Setting up dbus (1.6.18-0ubuntu4.3) ... "Have been having classes" or "have had classes for three months"? Which sentence is correct:  "I have been having classes for three months."  or  "I have had classes for three months." Why does the sum of the reciprocals of factorials converge to $e$? I've been asked by some schoolmates why we have $$ \sum_{n=0}^\infty \frac{1}{n!}=e.$$ I couldn't say much besides that the $\Gamma$ function, analytic continuation of the factorial, is defined with an integral involving $e$. Then I also know that actually $$ \sum_{n=0}^\infty \frac{x^n}{n!}=e^x.$$ Is there a reason for these facts?  P.S. I added the tag "intuition", please remove it if you think it is not pertinent. Stars and pins are retained when chat messages are moved! In the chat system, stars and pins are retained when moved to another room. This is probably a bug. Here a picture:  When a room owner pins a message, they can move it to another room, and they cannot unpin it. However when a starred message is moved to another room, the user can unstar it in the room it was moved to. Conversation source:  * is irrelevant and does not have to do with this bug report. Many thanks to . I am having the following equation:  \begin{equation}   Q(\lambda,\hat{\lambda}) = -\frac{1}{2} P(O \mid \lambda ) \sum_s \sum_m \sum_t \gamma_m^{(s)} (t) \left( n \log(2 \pi ) + \log \left| C_m^{(s)} \right| + \left( \mathbf{o}_t - \hat{\mu}_m^{(s)} \right) ^T C_m^{(s)-1} \left(\mathbf{o}_t - \hat{\mu}_m^{(s)}\right) \right) \end{equation}   which does not very well fit on one line. How can I split this over two lines? What I have in mind is that I specify the splitting place, and that the first line is left aligned and the second line right aligned to make clear that it is still the same equation.  The linebreak \\ does not work. Are the rationals a closed or open set in $\mathbb{R}$? I am reviewing take aways. I am having trouble  How do I do $342 - 58$?  For the ones column I made the $2$ into a $12$ so I can do $12 - 8 = 4$ but I must take away one tens. So I get $3 - 5$ in tens column but I cant do $3 - 5$. What do I do now do I borrow something else? How to fix apt: Signature by key uses weak digest algorithm (SHA1)? I started setting up by adding repositories and then went to run a sudo apt-get update again before I started installing other software, and I get the Signature key lines and it stops. So it essentially won't let me update any packages now.  d@EliteBook:~/Downloads$ sudo apt-get update Ign:1 http://dl.google.com/linux/chrome/deb stable InRelease Hit:2 http://dl.google.com/linux/chrome/deb stable Release                      Hit:4 http://security.ubuntu.com/ubuntu xenial-security InRelease               Get:5 http://ca.archive.ubuntu.com/ubuntu xenial InRelease [247 kB] Hit:6 http://ca.archive.ubuntu.com/ubuntu xenial-updates InRelease Hit:7 http://ca.archive.ubuntu.com/ubuntu xenial-backports InRelease Fetched 247 kB in 0s (256 kB/s)                    Reading package lists... Done W: http://dl.google.com/linux/chrome/deb/dists/stable/Release.gpg: Signature by  key 4CCA1EAF950CEE4AB83976DCA040830F7FAC5991 uses weak digest algorithm (SHA1) d@EliteBook:~/Downloads$   I've never seen this before whenever I setup and start installing things in Ubuntu. Is there something else I can do? How to specify font size less than 10pt (or more than 12pt)? I have an existing trigger which converts leads into peron accounts if the company name is blank.  Trigger AutoConvert on Lead (after insert) {      LeadStatus convertStatus = [           select MasterLabel           from LeadStatus           where IsConverted = true           limit 1      ];      List&lt;Database.LeadConvert&gt; leadConverts = new List&lt;Database.LeadConvert&gt;();       for (Lead lead: Trigger.new) {           if (!lead.isConverted &amp;&amp; lead.Company == null) {                Database.LeadConvert lc = new Database.LeadConvert();                String oppName = lead.Name;                 lc.setLeadId(lead.Id);                lc.setDoNotCreateOpportunity(true);                lc.setConvertedStatus(convertStatus.MasterLabel);                 leadConverts.add(lc);           }      }       if (!leadConverts.isEmpty()) {           List&lt;Database.LeadConvertResult&gt; lcr = Database.convertLead(leadConverts);      } }   I need to also write a trigger that stops records from coming into Salesforce if that email already exisits in a contact or an account (we use person accounts).  The issue is how do I get it working with the existing trigger (I need it to run before the trigger that converts it into a person account is run).   Is there a way to combine the two or add the functionality to create the record only if the email address doesn't already exist as a contact in the org?