OK I'm new to linux, and so there's a learning curve. But, although I worked for years with unix ksh production scripts and user support, at the moment I need to take another break.  I first installed 14.04 64-bit last week and just yesterday got past numerous stop/startovers to a system that seems(!) to work OK with one additional app installed. So now I'm encouraged. Breakthrough. Learned some things. Surely a popular package like TB won't be a problem. Not so, but far otherwise....   from Mozilla doesn't do much after a download. It points to another page for installing onto 10.10, but that page assumes that a version of TB is already installed.  For using a package manager, the page above simply refers you to the documentation of the Linux distribution you're using. I used a PPA for java yesterday for my other app.  Is that the same thing? Where is doc that explains them and how to use them on 14.04? Web search hits return all kinds of commentary, but there are 47 ways to do everything (a good thing, but...), not all of the doc is complete (assumes other knowledge), and some refers to older versions (10, 12, etc.). It makes sense to me that this function would work the same across versions, but what I assume/makes sense to me isn't always right.  For installing outside a package manager, it gives a link to a list of the libraries needed -- but no indication how to get them. Apparently I need those, because I downloaded TB per those instructions, ran ~/thunderbird/thunderbird, and nothing happened. I don't see an icon for it, either, which it seems is done by a package manager and which might be obtainable by other means -- but at this point I just want to get it working at all. The directory and files are there, but...nothing. Thought TB might be popular enough to be part of ubuntu. I'm not interested in any of the numerous apps in Launchpad, but I didn't see it there or in the Software Center.  Then this morning, looking for more info with yet more search strings, I see a comment that TB is "stock in 14.04" (not just "Lucid Lynx"?) and to wait a few days for a "push" from Canonical. That sounds promising, but what does that mean in practice? Is it available somewhere in the 14.04 (64-bit) that I just installed?   What do I need to do next? I only have the native 14.04 (64-bit) installed plus one other app. Not interested in Launchpad, if that matters.
Similar to , what's the best way to stay up to date with the latest stable releases of Thunderbird?
Laser positioning on barn door tracker I used to be able to go to Accounts and Import → Add another email address you own and add an email account that's only a forwarding address. That is, it's not a mailbox and I don't have SMTP access to it.  Gmail would send me a confirmation email to that address, I'd confirm it's mine, and done. Now it only gives me the option to add SMTP credentials.  Did they stop supporting the previous method? Is there any other way I can get that option back? Compact vs Mirrorless - why pick one over another? What would be a reason for one to pick the compact (whatever it'd be P&amp;S or something more advanced) over mirrorless compact system camera  ?  Right now market is quite confusing — we have huge market of tiny-sensor compacts, we have mirrorless that use sensors in a size of these from P&amp;S cameras (Nikon 1 being notable example), we have compacts with sensors bigger than most popular mirrorless system (Canon G1X vs m4/3), we have lot of APS-C sensor mirrorless which are matched by some of the compacts (Fuji X100 being most notable example, but even Leica has its X2),  and to make it even more confusing — Sony released RX1 with full frame sensor, beating crap out of every mirrorless on a market.  So what are your arguments to pick compact over a mirrorless?  Why are they better, what's the reason behind logic of companies like Fujifilm which at the same time offers P&amp;S and X-mount mirrorless using same sensor size? Is dimensionality reduction almost always useful for classification? How can I play Pokémon GO without Internet? I downloaded Pokémon GO on my Samsung Galaxy Express and I can play it at home, but when I go outside I can't play because there is no Internet.  How can I play Pokémon GO without Internet outside? JavaScript Regex, where to use escape characters? How do I hide a parent div if the child div doesn't contain an  tag? I have been attempting to solve this integral for several days in preparation for an exam and keep reaching dead ends.  I(a,b) = $\int_0^{\pi/2} \ln(a^{2}\cos^2(x)+b^{2}\sin^2(x)) dx$, where $a,b&gt;0$  My best approach so far is defining:  $F(x) = I(x, b)$  Then, I know:  $F(b) = I(b, b) = \pi/2 * \ln(b^2)$  Then I am now attempting to find $F'(x)$ using differentiation under the integral sign, and integrating from b to a.  This is where I am stuck - no matter what I do, I cannot solve the integral. Am I in the right direction or should this be solved in a different manner? I also considered something elliptical due to the acos, bsin in the original integral, yet it has also reached a dead end. Rotation Path Not Shown in Graph Editor I created a couple of LocRot keyframes but the rotation path and keyframes aren't shown in the graph editor (no, they aren't hidden). Irreducible conics An algebraic set (not necessairly a variety) $X \subseteq \mathbb{A}^2$ defined by a polynomial of degree $2$ is called a conic.  The problem is:     Show that any irreducible conic is isomorphic either to $Z(y-x^2)$ or to $Z(xy-1)$ after an affine change of coordinates in $\mathbb{A}^2$.   However, with this definition of conic, I only can conclude that if the polynomial is irreducible, then the conic is irreducible (because $f$ irreducible $\Rightarrow Z(f)=X$ is irreducible)     What can I do to prove that if a conic is irreducible, then the polynomial that defines the conic is irreducible?   And for the main problem, how can I do the affine change of coordinates?  Thanks The stress tensor can be written as: $$\sigma_{ij}=-p \delta_{ij}+\sigma'_{ij}\label{1}\tag{1}$$ where $\sigma_{ij}'$ is called the extra stress tensor.   From what I understand pressure is pressure is force per unit area, so that the force acting on the surface $d\vec A$ is given by:  $$\vec F=-p d\vec A\label{2}\tag{2}$$ (This has the effect that the force on an infinitesimally thin surface due to a continuous pressure is zero). However, $\sigma_{ij}$ represent the force in the $i$ direction on a surface with normal in the $\hat e_j$ direction. So the force acting on a surface $d \vec A$ must be: $$F_i=\sigma_{ij}dA_j\label{3}\tag{3}$$ Equations (2) and (3) clearly do not agree (even if we look soley at the force in the $d\vec A$ direction they don't agree). So my question is what is the exact meaning of pressure in expression (1) and why do we not have: $$\sigma_{ii}=-p$$ Deriving Newton's Third Law from homogeneity of Space I consider the co-finite topology on $\mathbb{R}$ that is $$\{G\subset \mathbb{R}, card(\mathbb{R}\setminus G)&lt;+\infty\}\cup \{\emptyset\}$$  What are the convergent sequences in this space .  thank you I have been trying around different ranges of summations:  $$ \sum_{(m,n) \in \mathbb{Z}^2} \frac{m^2 - n^2}{(m^2 + n^2)^2} = 0$$  That's not any good.  What about if we restrict to $m, n \in \mathbb{Z}$ as positive integers.    $$ \sum_{m &gt; 0, n &gt; 0} \frac{m^2 - n^2}{(m^2 + n^2)^2} = 0$$  Now here's an anti-symmetry.  I do not like taking out the symmetry, but perhaps I can ask about:   $$ \sum_{m &gt;  n &gt; 0} \frac{m^2 - n^2}{(m^2 + n^2)^2}  = \; ? \tag{$*$} $$  There doesn't seem to be a change of variables that can work.  And we've used symmetry about as much as we can.  This looks related to:  $$  \sum \frac{1}{n^2} = \frac{\pi^2}{6}$$  Perhaps this other series ($*$) also has a special value. Blank lines in an equation and some other similar function Why blank lines between equation makes error? there are a lot of commands in latex and almost for all of them these blank lines are not important,  but why in this case is important and is there any similar function? I am writing a client-side Swing application (graphical font designer) on Java 5. Recently, I am running into java.lang.OutOfMemoryError: Java heap space error because I am not being conservative on memory usage. The user can open unlimited number of files, and the program keeps the opened objects in the memory. After a quick research I found  and others saying on Windows machine the JVM defaults max heap size as 64MB.  Given this situation, how should I deal with this constraint?  I could increase the max heap size using command line option to java, but that would require figuring out available RAM and writing some launching program or script. Besides, increasing to some finite max does not ultimately get rid of the issue.  I could rewrite some of my code to persist objects to file system frequently (using database is the same thing) to free up the memory. It could work, but it's probably a lot work too.  If you could point me to details of above ideas or some alternatives like automatic virtual memory, extending heap size dynamically, that will be great. To translate a vector by 10 unit in the X direction, why do we have to use a matrix?    We can just add 10 to the mat[0][0], and we got the same result too. Rotate Geographic map Do you ever need to specify 'javascript:' in an onclick? Where can I find Vagrant packages? is a tool to build and manage virtual machines for developers.  It has a  guide that contains iffy-looking suggestions like  $ sudo ln -s /usr/bin/ruby1.8 /usr/bin/ruby  # wtf???   or installing RubyGems from source rather than from Ubuntu packages, and then using gem install to install vagrant itself.  I'm not feeling comfortable just following those instructions.  Is there perhaps a PPA?  Are there, perhaps, alternative tools that are packaged for Ubuntu?