How long does it take to install Ubuntu 13.04
How long does the ubuntu installation take and what to do after it?
So I was reading this:  and while the answers for the first question are good, nobody gave much attention to the second one. In fact, people only said that it can be proved without giving any proof or any.  So, if I have a Lagrangian and ADD an arbitrary function of $\dot{q}$, $q$ and $t$ in such a way that the equations of motion are the same, does this extra function MUST be a total time derivative?   EDIT Ok, I changed my question a little bit:  Question: If I have a function that obeys the Euler-Lagrange equation off-shell, this implies that my function is a time derivative? (This was used in Qmechanic's answer of this other question: , equation 14.)  Also, why people only talk about things that change the Lagrangian only by a total derivative? If this is not always the case that keeps the equation of motion the same, so why is it so important? And why in the two questions I posted about the same statement on Landau&amp;Lifshitz's mechanics book only consider this kind of change in the Lagrangian? Prove that if $\sum{a_n}$ converges absolutely, then $\sum{a_n^2}$ converges absolutely I'm trying to re-learn my undergrad math, and I'm using Stephen Abbot's Understanding Analysis. In section 2.7, he has the following exercise:  Exercise 2.7.5 (a) Show that if $\sum{a_n}$ converges absolutely, then $\sum{a_n^2}$ also converges absolutely. Does this proposition hold without absolute convergence?  I'm posting about this here because my answer to that last question about whether the proposition holds without absolute convergence is "Yes", but my suspicions are raised by him merely asking the question. Usually questions like this are asked to point out that certain conditions are necessary in the statement of propositions, theorems, etc. I just want to see if I'm missing something here.  Anyway, here's how I prove the absolute convergence of $\sum{a_n^2}$, and note that I never use the fact that $\sum{a_n}$ is absolutely convergent:  Proof: Let $s_n = \sum_{i=1}^n{a_n^2}$. I want to show that $(s_n)$ is a Cauchy sequence. So, let $\epsilon &gt; 0$ and $n &gt; m$, and consider, \begin{equation}   \begin{aligned}     |s_n - s_m| &amp;= |(a_1^2 + a_2^2 + \cdots a_n^2) - (a_1^2 + a_2^2 + \cdots a_m^2)|\\                 &amp;= |(a_{m+1})^2 + (a_{m+2})^2 + \cdots + a_n^2|\\                 &amp;= |a_{m+1}|^2 + |a_{m+2}|^2 + \cdots + |a_n|^2\\   \end{aligned} \end{equation} Now, since $\sum{a_m}$ converges, the sequence $(a_m)$ has limit 0. Therefore I can choose an $N$ such that $|a_m| &lt; \sqrt{\epsilon/n}$ for all $m &gt; N$. So for all $n &gt; m&gt; N$,  we have, \begin{equation}   \begin{aligned}     |s_n - s_m| &amp;= |a_{m+1}|^2 + |a_{m+2}|^2 + \cdots + |a_n|^2\\                 &amp;&lt; \left(\sqrt{\frac{\epsilon}{n}}\right)^2 + \left(\sqrt{\frac{\epsilon}{n}}\right)^2 + \cdots + \left(\sqrt{\frac{\epsilon}{n}}\right)^2\\                 &amp;&lt; \left(\sqrt{\frac{\epsilon}{n-m}}\right)^2 + \left(\sqrt{\frac{\epsilon}{n-m}}\right)^2 + \cdots + \left(\sqrt{\frac{\epsilon}{n-m}}\right)^2\\                 &amp;= \epsilon   \end{aligned} \end{equation} Therefore $(s_n)$ is Cauchy and $\sum{a_n^2}$ converges. And since $\sum{a_n^2} = \sum{|a_n^2|}$, the series $\sum{a_n^2}$ is absolutely convergent. &#x220E;  Am I doing something wrong here? Am I right in thinking that $\sum{a_n}$ need not be absolutely convergent for $\sum{a_n^2}$ to be absolutely convergent? I need to build a list of files present in a directory but also pass in a file containing a list of directories to exclude.  I've seen the below suggestion but I've had no luck with it when it comes to the type flag:  find $dir_name $(printf "! -name %s " $(cat $exclude_file))   Is there a way I can do it or will I need to create the entire list and then work through it removing ones that partially match ones in the exclude directory. Do you need line of sight to cast spells on someone? Pacf lag axe , is not an integer Can a wealthy investor invest in or make a deal with a company before it goes public / IPO? Can a wealthy investor invest his money in any company before it goes public / IPO? I am referring to a recent Goldman Sachs and Facebook deal worth $450 Million at a valuation of $50 Billion dollars.   I want to know what is the procedure and how are these valuations made prior to the company going public? Is is possible that an investor could raise capital from investment banks, private equity, or commercial banks to re-invest in a pre-IPO deal at some valuation?  Knowing that angel investors don't provide so much money, can they play their role here with a normal investor? In  (the original movie), Marty comes back from 1955 10 mins early to prevent Doc from being shot (which he fails at). He then rolls up to the Lone Pine Mall and sees himself hit 88 mph and shoot back to 1955 (again). Marty then carries on with this life as usual. What happens to the Marty that goes back to 1955 at the end of the film?  This obviously is a recursive problem where it would create another timeline and Marty would keep coming back 10 mins early to view another Marty zip back to 1955? How can I monitor internet usage in my network? I need to know which computer is consuming my bandwidth. Is there a tool to do this? Finding value of an expression If $x^2-3x-1=0$ then find the value of $(x^6+1)/x^3$ I tried to solve the quadratic but it became too complicated any way of doing this without a calculator Let $a,b,c$ real numbers. Prove the inequality $|a-b| \leq |a-c| + |c-b|$. Prove that equality holds if and only if $a \leq c \leq b$ or $b \leq c \leq a$.   I've tried starting with just $a \leq c$ and using field properties to reconstruct the inequality, however I haven't been able to make it work. I also tried making the negatives positive and stripping the inequalities and making something happen but again I don't know if that's a proper rule and it didn't seem to get me anywhere. I want to install Ubuntu on the C: partition where my Windows 7 is, simply to replace the systems. I've also tried to install it on another partition (without formating it), which failed!  All I get is:      No root file system is defined. Please correct this from the partitioning menu.   I want to install Ubuntu without formatting any of my partitions. Is that possible? Let's consider two statements: Zorn's lemma and theorem about existence of maximal ideals in commutative ring with $1$.  It's easy to prove that Zorn's lemma implies existence of maximal ideals.  I wonder if the converse proposition is true, i. e., does existence of maximal ideals implies Zorn's lemma? My approach was to construct a ring structure on an ordered set which satisfies Zorn's lemma condition such that existence of maximal ideal implies existence of maximal element in the set, but I didn't succeed. I would like to filter the markers on my (geojson) layer according to two features: year and type of event, ideally using both filters (year and eventType) as check-boxes without using layerGroup at all. I would like to be able to click on a checkbox and update dynamically the markers by filtering them according to feature.properties.eventType too, in addition to the year displayed, something like    &lt;input type="checkbox" id="all" name="all" value="all"&gt;   &lt;label for="all"&gt;All&lt;/label&gt;   &lt;input type="checkbox" id="funfair" name="funfair" value="newsletter"&gt;   &lt;label for="funfair"&gt;Funfair&lt;/label&gt;   &lt;input type="checkbox" id="trade" name="trade" value="trade"&gt;   &lt;label for="trade"&gt;Trade&lt;/label&gt;   &lt;input type="checkbox" id="exhibition" name="exhibition" value="exhibition"&gt;   &lt;label for="exhibition"&gt;Paid exhibition&lt;/label&gt;   etc... which would trigger a  filter: function(feature, layer) {   return feature.properties.eventType == value-of-checkbox; }   I have five types of eventType. So, for instance, if 1890 is checked, the map is showing all 1890 events, no matter what kind of event it is (because by default it would show all events). If the user checks the 'funfair' and the 'trade' checkbox, though, I want the map to show only the 1890 events of the funfair and trade kind, and not other kind of events.  This is my complete script, which so far is working fine with filtering by year.  var oldmap = L.tileLayer('address', {   maxZoom: 12 }),  var modernmap = L.tileLayer('https://api.tiles.mapbox.com/v4/{id}/{z}/{x}/{y}.png?access_token={accessToken}', {   maxZoom: 12,   id: 'mapbox.streets',   accessToken: 'mytoken' });  var map = L.map('map', {   center: [40.1857864,-4.5536861],   zoom: 7,   layers: [oldmap, modernmap] });  var baseMaps = {   "Old map": oldmap,   "Modern map": modernmap };  var jsontest = {"type": "FeatureCollection",   "features": [     {       "type": "Feature",       "geometry": {         "type": "Point",         "coordinates":  [ -16.5471268,28.4136726 ]       },       "properties": {         "Name":"Point1",         "year":'1892',         "eventType":"funfair",         "notes":""       }     },     {       "type": "Feature",       "geometry": {         "type": "Point",         "coordinates":  [ 2.1753895,41.3767925 ]       },       "properties": {         "Name":"Point2",         "year":'1890',         "eventType":"trade demonstration",         "notes":""       }     }   ]};  var mapLayerGroupsYear = [];  function onEachFeature(feature, layer) {   var year = mapLayerGroupsYear[feature.properties.year];   if (year === undefined) {     year = new L.layerGroup();      //add the layer to the map     year.addTo(map);      //store layer     mapLayerGroupsYear[feature.properties.year] = year;   }    //add the feature to the layer   year.addLayer(layer);    }   var myLayer = L.geoJSON(jsontest, {   onEachFeature: onEachFeature })  L.control.layers(baseMaps, mapLayerGroupsYear).addTo(map);   I am a beginner with leaflet so please forgive the dumb question, in case it is. I want to use the get_option() function of wordpress in one of my theme's files, which is not related to WP, it is just located in the same directory of the other theme files. I need this file because of some extra IPN paypal related actions, but I need some values from the options table that exists in WP to be called in this page in order for it to work. I know I can't just use get_option() as this file is overlooked by wordpress. Is there any approach by including some parts of wordpress in my theme to make this functionality only work? Uninstall apps locked by phone vendor Delegates: Predicate vs. Action vs. Func Can someone provide a good explanation (hopefully with examples) of these 3 most important delegates:   Predicate Action Func I have a new computer with a Seagate ST500DM002 SATA internal hard drive.  I am trying to install Ubuntu 11.10 64-bit on it but the installer does not recognize/detect/see the hard drive. When I reach the Installation type step, the panel which is supposed to show devices and partitions looks empty.  sudo fdisk -l shows only /dev/sda1, the USB drive from which I am running the installation. I have already tried the following two solutions without any success:   sudo apt-get remove dmraid Switch the SATA mode in the BIOS from IDE to AHCI   I am sure it's not a hardware related problem as I have already successfully installed another operating system on the same computer.  The output of sudo lshw -class storage -class disk follows:    *-ide UNCLAIMED                 description: IDE interface        product: ASMedia Technology Inc.        vendor: ASMedia Technology Inc.        physical id: 0        bus info: pci@0000:06:00.0        version: 01        width: 32 bits        clock: 33MHz        capabilities: ide msi pm pciexpress cap_list        configuration: latency=0        resources: ioport:d040(size=8) ioport:d030(size=4) ioport:d020(size=8) ioport:d010(size=4) ioport:d000(size=16) memory:fe400000-fe4001ff   *-storage        description: SATA controller        product: 6 Series/C200 Series Chipset Family 6 port SATA AHCI Controller        vendor: Intel Corporation        physical id: 1f.2        bus info: pci@0000:00:1f.2        logical name: scsi1        version: 05        width: 32 bits        clock: 66MHz        capabilities: storage msi pm ahci_1.0 bus_master cap_list emulated        configuration: driver=ahci latency=0        resources: irq:44 ioport:f0b0(size=8) ioport:f0a0(size=4) ioport:f090(size=8) ioport:f080(size=4) ioport:f060(size=32) memory:fe705000-fe7057ff      *-cdrom           description: DVD-RAM writer           product: DVDRAM GH22NS70           vendor: HL-DT-ST           physical id: 0.0.0           bus info: scsi@1:0.0.0           logical name: /dev/cdrom           logical name: /dev/cdrw           logical name: /dev/dvd           logical name: /dev/dvdrw           logical name: /dev/scd0           logical name: /dev/sr0           version: EX00           capabilities: removable audio cd-r cd-rw dvd dvd-r dvd-ram           configuration: ansiversion=5 status=nodisc   *-scsi:0        physical id: 1        bus info: usb@1:1.2        logical name: scsi6        capabilities: emulated scsi-host        configuration: driver=usb-storage      *-disk           description: SCSI Disk           physical id: 0.0.0           bus info: scsi@6:0.0.0           logical name: /dev/sda           size: 14GiB (16GB)           capabilities: partitioned partitioned:dos           configuration: signature=0004e5a4   *-scsi:1        physical id: 2        bus info: usb@1:1.3        logical name: scsi7        capabilities: emulated scsi-host        configuration: driver=usb-storage      *-disk           description: SCSI Disk           product: Storage Device           vendor: USB Mass           physical id: 0.0.0           bus info: scsi@7:0.0.0           logical name: /dev/sdb           capabilities: removable         *-medium              physical id: 0              logical name: /dev/sdb   Any idea on what I could do to fix this problem? As a physics student, I have occasionally run across the gamma function  $$\Gamma(n) \equiv \int_0^{\infty}t^{n-1}e^{-t} \textrm{d}t = (n-1)!$$  when we want to generalize the concept of a factorial.  Why not define the gamma function so that   $$\Gamma(n) = n!$$  instead?  I realize either definition is equally good, but if someone were going to ask me to choose one, I would choose the second option.  Are there some areas of mathematics where the accepted definition looks more natural?  Are there some formulas that work out more cleanly with the accepted definition? Getting a vector into a function that expects a vector Not sure if this option ever existed, but the new QGIS version hides a lot of things somewhere else and this seems so simple that I'm kind of convinced it was possible to do this before. I have quite a large data set with ship tracks. I now want to analyse individual ship tracks (made from point layer with  Plugin). However, it is so crowded that it is hard to look at individual tracks. I don't want to save each single track as a new layer, so I wonder if it is possible to select one track in the Attribute table and display only that one on the map/hide the others?