Freewheeling diode position
Is a diode needed for this simple mini solenoid circuit?
I am trying to install php curl like so:  sudo apt-get update sudo apt-get install php5-curl   But I keep getting an error.  Reading package lists... Done Building dependency tree        Reading state information... Done php5-curl is already the newest version. 0 upgraded, 0 newly installed, 0 to remove and 3 not upgraded. 2 not fully installed or removed. After this operation, 0 B of additional disk space will be used. Do you want to continue? [Y/n] Y Setting up runit (2.1.2-3ubuntu1) ... start: Unable to connect to Upstart: Failed to connect to socket /com/ubuntu/upstart: Connection refused dpkg: error processing package runit (--configure):  subprocess installed post-installation script returned error exit status 1 dpkg: dependency problems prevent configuration of git-daemon-run:  git-daemon-run depends on runit; however:   Package runit is not configured yet.  dpkg: error processing package git-daemon-run (--configure):  dependency problems - leaving unconfigured No apport report written because the error message indicates its a followup error from a previous failure.                           Errors were encountered while processing:  runit  git-daemon-run E: Sub-process /usr/bin/dpkg returned an error code (1)   when I try sudo dpkg --configure -a I get:  dpkg: dependency problems prevent configuration of git-daemon-run:  git-daemon-run depends on runit; however:   Package runit is not configured yet.  dpkg: error processing package git-daemon-run (--configure):  dependency problems - leaving unconfigured Errors were encountered while processing:  git-daemon-run   when I try sudo apt-get install --reinstall runit I get:  Reading package lists... Done Building dependency tree        Reading state information... Done 0 upgraded, 0 newly installed, 1 reinstalled, 0 to remove and 8 not upgraded. 2 not fully installed or removed. After this operation, 0 B of additional disk space will be used. E: Internal Error, No file name for runit:amd64   when I try sudo apt-get install runit I get:  Reading package lists... Done Building dependency tree        Reading state information... Done runit is already the newest version. 0 upgraded, 0 newly installed, 0 to remove and 8 not upgraded. 2 not fully installed or removed. After this operation, 0 B of additional disk space will be used. Do you want to continue? [Y/n] Y Setting up runit (2.1.2-3ubuntu1) ... start: Job is already running: runsvdir dpkg: error processing package runit (--configure):  subprocess installed post-installation script returned error exit status 1 dpkg: dependency problems prevent configuration of git-daemon-run:  git-daemon-run depends on runit; however:   Package runit is not configured yet.  dpkg: error processing package git-daemon-run (--configure):  dependency problems - leaving unconfigured No apport report written because the error message indicates its a followup error from a previous failure.                                                                                                           Errors were encountered while processing:  runit  git-daemon-run E: Sub-process /usr/bin/dpkg returned an error code (1)   when I try sudo apt-get install --reinstall git-daemon-run I get:  Reading package lists... Done Building dependency tree        Reading state information... Done 0 upgraded, 0 newly installed, 1 reinstalled, 0 to remove and 8 not upgraded. 2 not fully installed or removed. After this operation, 0 B of additional disk space will be used. E: Internal Error, No file name for git-daemon-run:amd64   How can I fix this?  System Specs:  Processor: Intel® Core™ i7-3630QM CPU @ 2.40GHz × 8 Graphics: Gallium 0.4 on AMD TURKS (DRM 2.43.0, LLVM 3.6.2) OS Type: Ubuntu 15.10 64-bit Managing CPU intensive threads on iOS Is there a destructor for Java? Is there a destructor for Java? I don't seem to be able to find any documentation on this. If there isn't, how can I achieve the same effect?  To make my question more specific, I am writing an application that deals with data and the specification say that there should be a 'reset' button that brings the application back to its original just launched state. However, all data have to be 'live' unless the application is closed or reset button is pressed.  Being usually a C/C++ programmer, I thought this would be trivial to implement. (And hence I planned to implement it last.) I structured my program such that all the 'reset-able' objects would be in the same class so that I can just destroy all 'live' objects when a reset button is pressed.  I was thinking if all I did was just to dereference the data and wait for the garbage collector to collect them, wouldn't there be a memory leak if my user repeatedly entered data and pressed the reset button? I was also thinking since Java is quite mature as a language, there should be a way to prevent this from happening or gracefully tackle this. What does "65" mean? K-2SO beats up the troopers easily. Up in the sky, the bombers are preparing to attack. Just as they start the attack run, TIE fighters come in from the shield and swarm the rebel fleet.  JON VANDER (GOLD LEADER): Red Leader, this is Gold Leader, we’re starting our attack run on the  shield gate. Keep it tight and watch out for those towers. GOLD PILOT: More fighters. Form up, at 65.  What does &quot;65&quot; mean? Limit of $(\cos1/n)^{n^2}$ when $n\to\infty$ I've been trying to solve this limit: $$\lim_{n\to \infty} \left(\cos\left(\frac{1}{n}\right)\right)^{n^2}$$ I solved it using l'hopital but I have to try in another way. I tried to make the expression:  $$ \lim_{n \to \infty}\exp\left(n^2\ln\left(\cos\left(\frac{1}{n}\right)\right)\right)$$  but it didn't work out for me... VS Code Setup - Create project with manifest error When I try to create project with manifest it is giving me this error:    Starting SFDX: Create Project  12:39:56.757 sfdx force:project:create --projectname Dev --outputdir c:\ --template standard --manifest { AssertionError [ERR_ASSERTION]: Trying to copy from a source that does not exist: C:\Program Files (x86)\Salesforce CLI\client\node_modules\salesforcedx-templates\lib\templates\project\standard\ScratchDef.json     at EditionInterface.exports.copy (C:\Program Files (x86)\Salesforce CLI\client\node_modules\salesforcedx-templates\node_modules\mem-fs-editor\lib\actions\copy.js:49:3)     at EditionInterface.module.exports [as copyTpl] (C:\Program Files (x86)\Salesforce CLI\client\node_modules\salesforcedx-templates\node_modules\mem-fs-editor\lib\actions\copy-tpl.js:29:8)     at ProjectGenerator.writing (C:\Program Files (x86)\Salesforce CLI\client\node_modules\salesforcedx-templates\lib\generators\projectGenerator.js:57:17)     at Object.&lt;anonymous&gt; (C:\Program Files (x86)\Salesforce CLI\client\node_modules\salesforcedx-templates\node_modules\yeoman-generator\lib\index.js:427:27)     at C:\Program Files (x86)\Salesforce CLI\client\node_modules\run-async\index.js:25:25     at new Promise (&lt;anonymous&gt;)     at C:\Program Files (x86)\Salesforce CLI\client\node_modules\run-async\index.js:24:19     at self.env.runLoop.add.completed (C:\Program Files (x86)\Salesforce CLI\client\node_modules\salesforcedx-templates\node_modules\yeoman-generator\lib\index.js:428:13)     at runCallback (timers.js:705:18)     at tryOnImmediate (timers.js:676:5)   generatedMessage: false,   name: 'AssertionError [ERR_ASSERTION]',   code: 'ERR_ASSERTION',   actual: false,   expected: true,   operator: '==' } { AssertionError [ERR_ASSERTION]: Trying to copy from a source that does not exist: C:\Program Files (x86)\Salesforce CLI\client\node_modules\salesforcedx-templates\lib\templates\project\standard\ScratchDef.json     at EditionInterface.exports.copy (C:\Program Files (x86)\Salesforce CLI\client\node_modules\salesforcedx-templates\node_modules\mem-fs-editor\lib\actions\copy.js:49:3)     at EditionInterface.module.exports [as copyTpl] (C:\Program Files (x86)\Salesforce CLI\client\node_modules\salesforcedx-templates\node_modules\mem-fs-editor\lib\actions\copy-tpl.js:29:8)     at ProjectGenerator.writing (C:\Program Files (x86)\Salesforce CLI\client\node_modules\salesforcedx-templates\lib\generators\projectGenerator.js:57:17)     at Object.&lt;anonymous&gt; (C:\Program Files (x86)\Salesforce CLI\client\node_modules\salesforcedx-templates\node_modules\yeoman-generator\lib\index.js:427:27)     at C:\Program Files (x86)\Salesforce CLI\client\node_modules\run-async\index.js:25:25     at new Promise (&lt;anonymous&gt;)     at C:\Program Files (x86)\Salesforce CLI\client\node_modules\run-async\index.js:24:19     at self.env.runLoop.add.completed (C:\Program Files (x86)\Salesforce CLI\client\node_modules\salesforcedx-templates\node_modules\yeoman-generator\lib\index.js:428:13)     at runCallback (timers.js:705:18)     at tryOnImmediate (timers.js:676:5)   generatedMessage: false,   name: 'AssertionError [ERR_ASSERTION]',   code: 'ERR_ASSERTION',   actual: false,   expected: true,   operator: '==' } 12:40:03.206 sfdx force:project:create --projectname Dev --outputdir c:\ --template standard --manifest  ended with exit code 0   Can you please let me know what I am missing:   I have:   installed vs code, salesforce extension pack, salesforce cli, set the environment variable for my user, there is jdk installed (I have not set the path for it, not sure if it is required?)    What I am missing?   Thanks in Advance!! How can you prove that a function has no closed form integral? In the past, I've come across statements  along the lines of &quot;function $f(x)$ has no closed form integral&quot;, which I assume means that there is no combination of the operations:  addition/subtraction multiplication/division raising to powers and roots trigonometric functions exponential functions logarithmic functions  which when differentiated gives the function $f(x)$. I've heard this said about the function $f(x) = x^x$, for example. What sort of techniques are used to prove statements like this? What is this branch of mathematics called?  Merged with &quot;&quot; by : Sometimes we are told that some functions like $\dfrac{\sin(x)}{x}$ don't have an indefinite integral, or that it can't be expressed in term of other simple functions. I wonder how we can prove that kind of assertion? For which real values of t does the following system of linear equations:  $$ \left\{  \begin{array}{c} tx_1 + x_2 + x_3 = 1 \\  x_1 + tx_2 + x_3 = 1 \\  x_1 + x_2 + tx_3 = 1 \end{array} \right.  $$  Have:  a) a unique solution?  b) infinitely many solutions?  c) no solutions?  I haven't done linear algebra in almost a year, so I'm really rusty and could use some pushes in the right direction. Retrieving Data from remote database How does the formation of a solar system not break the second law of thermodynamics? Please forgive: I am a layman when it comes to physics and cosmology, and have tried finding an answer to this that I can understand, with no luck.  As I understand it, the solar system evolved from a massive molecular cloud. To me, this seems to break the second law of thermodynamics, as I think it suggests order from disorder.  I know there must be something wrong with my logic, but am really stuck.  Can anyone explain this one in layman's terms?  (Posting to both "Astronomy" and "Physics", as it seems to overlap these subjects) When should a verb be followed by a gerund instead of an infinitive? returning a local variable from function in C Proving that $\frac{\phi^{400}+1}{\phi^{200}}$ is an integer. How do we prove that $\dfrac{\phi^{400}+1}{\phi^{200}}$ is an integer, where $\phi$ is the golden ratio?  This appeared in an answer to a  I asked previously, but I do not see how to prove this.. Does a Rogue using Use Magic Device for a scroll or wand also need to emulate a class feature? I'm confused about Rogues and Use Magic Device. I've searched the core book and the Internet for the past 4 hours and can't find the answer to my simple question.   Since a Rogue doesn't have any spells, a spell list or caster level, do you have to emulate a class feature in addition to all other necessary checks to use items like scrolls and wands? Is it possible to only allow specific packages updates from a PPA Question is :  Suppose $Y\subset X$ and $X,Y$ are connected and $A,B$ form separation for $X-Y$ then, Prove that  $Y\cup A$ and $Y\cup B$ are connected.  What i have tried is :   Suppose $Y\cup A$ has  separation say $C\cup D$ then all i could see is that   Either $Y\subset C$ or $Y\subset D$ as $Y$ is connected and $ C\cup D$ is separation for a subset that contains $Y$.  Without loss of generality we could assume $Y\subset C$  As $Y\cup A=C\cup D$ and $Y\subset C$  i can say $D\subset A$ (I do not know how does this help)  I have $X-Y=A\cup B$ with $A\cap B=\emptyset$  I have not used connectedness of $X$ till now, So i thought of using that and end up with following :   $X-Y=A\cup B\Rightarrow X=Y\cup A\cup B=(Y\cup A)\cup (Y\cup B)$  I do not know what to conclude from this...   I would be thankful if some one can help me by giving some "hints"  Thank you Can someone tell me what's wrong with this? because i can't figure out where the missing \right( is.  \begin{equation}  \begin{split} Μ=&amp;-\pi \rho \frac{c^{2}}{4}    \left[c\left(\frac{α}{c}-\frac{1}{2}\right)\ddot{h}+Uc\left(\frac{3}{4}-     \frac{α}{c}\right)\dot{\alpha} +\frac{c^{2}}{4}\left(\frac{9}{8}+      \frac{4α^{2}}{c^{2}}-\frac{4α}{c}\right)\ddot{\alpha} \\  &amp;-\left(\frac{4α}{c}-1\right)U C(k) \left(-\dot{h} +U\alpha + c \left(\frac{3}{4}-\frac{α}{c}\right)\dot{\alpha}\right)\right]  \end{split} \end{equation} Should I use "who" or "that" when referring to an organisation? I generally use the rule of thumb of using who when referring to a person and that when referring to an object. Example:  Jim is someone who makes me smile. I was nearly knocked out by the ball that hit me.  But what about when we're talking about an organisation?  I am forever indebted to the charities who helped me. I am forever indebted to the charities that helped me.  The former seems somewhat warmer, if that makes sense, although the latter feels more correct. What should I use? And how about this:  I'm really happy with the insurance company who helped me with my claim. I can't stand them, they're the insurance company that ripped me off.  To me the former evokes a team of helpful people while the latter evokes a cold heartless corporate entity. Is this just a matter of style and so should go with my instincts, or should I aim for what is 'correct?' What's the best way of handling permissions for Apache 2's user www-data in /var/www? Has anyone got a nice solution for handling files in /var/www? We're running Name Based Virtual Hosts and the Apache 2 user is www-data.  We've got two regular users &amp; root. So when messing with files in /var/www, rather than having to...  chown -R www-data:www-data   ...all the time, what's a good way of handling this?  Supplementary question: How hardcore do you then go on permissions?  This one has always been a problem in collaborative development environments. Show all comments if there is just "1" extra comment to show When looking at a question or answer with comments, I think it would be better to just show that one extra comment if the threshold is "Show 1 more comment".  In other words, if there are 6 comments, show all 6 comments.  If there are 7 comments, then show 5 comments and the link "Show 2 more comments".  Etc for more comments.