What is the "substantial difference" that might occur between the google shares?
Why are there two ticker symbols for Google — GOOGL and GOOG?  They seem to be mostly identical, but their market values are different: currently, 551.64 for  and 548.79 for .
Sort order issue I'm having an issue sorting data in ascending order.   Right now the sort order is: 1.0.0  10.0.0 10.0.1 11.0.0 2.0.0 2.0.1 3.0.0 3.0.1 3.1.0  What I want is: 1.0.0 2.0.0 2.0.1 3.0.0 3.0.1 3.1.0 10.0.0 10.0.1 11.0.0  How can I achieve this? The datatype can't be number or currency because of the 2 decimals, so I used text-field. In  (2014) the human race seemed to be facing pretty poor odds until they discovered a convenient wormhole placed by an unknown entity expressed as "they". Later in the movie, we discover that       "they" are actually the human race in the future, reaching back in  time to save itself.   The end of the movie gets a little wild on the physics end, and I'm happy to take that ending as is - no need for it to make sense - but one very basic detail does bother me:  How could the human race have gone back in time to save itself from circumstances that would have caused us to go extinct without our own help (the convenient wormhole)? Convert a Pair of Integers to a Integer, Optimally? what is the C++/CLI syntax to subscribe for events? I'm updating some old Managed C++ code with lines like this:  instanceOfEventSource-&gt;add_OnMyEvent(      new EventSource::MyEventHandlerDelegate(this, MyEventHandlerMethod) );   where   EventSource is the class that publishes events instanceOfEventSource is an instance of that class EventSource::MyEventHandlerDelegate is the delegate type for the event MyEventHandlerMethod is a (non-static) method within the current class (of which "this" is an instance) with the signature matching EventSource::MyEventHandlerDelegate   What is the right syntax for this in C++/CLI? In the first half of Tenet, there is a scene where The Protagonist and Neil break into Freeport and find a glass wall with bullet holes (could only find a good photo with Christopher Nolan in it):  In the next scene, we find out that these bullet holes were caused by an inverted armed man entering the room (exiting the room from their perspective) and reverse-shooting the glass, which removes the bullet holes from the future-facing perspective. This all makes sense, but raises a question: how long were the bullet holes there in the first place? Were they in place as soon as the glass was installed, possibly years ago? Or even back when the glass was manufactured? How do lexical closures work? Punctuation with units I remember reading somewhere that if a unit is abbreviated as one character, there must not be a space between the number and the unit (e.g., 5m, 26K). If the unit is abbreviated as two or more Characters, there must be a space between the number and the unit (e.g., "10 km", "USD 5").   Can you please help me find the source again? Is this recommendation correct? What are the advantages of using the optical viewfinder over live preview to take photos on a DSLR? Forgive this novice question, I am basically a complete newbie to photography.  Really, all I've ever used for most my of short life have been point-and-shoots; I've only recently started to pick up some curiosity.  Anyway, from what I've gathered, reading through many of the  questions, most serious photographers use the optical viewfinder as their primary tool to determine what makes a good shot.  Live-preview isn't used much at all; it seems its help is to primarily set up the shot.  Reading a Wikipedia article seems to confirm this view, adding that      [l]ive preview in DSLRs does not typically serve as their principal means of framing and previewing before taking a photograph, with this function still being mainly performed with optical viewfinder. While initially largely a novelty feature, live-preview functionality has become more common on DSLR cameras...    My questions are:   What are the myriad advantages of using the viewfinder over live preview, what does it help one accomplish in achieving the goals of photography? What are some interesting ways serious photographers use live preview to take better shots they might have otherwise missed? How can I change (or remove / reset ) my name on a site in Stack Exchange network? What's the "official" explanation for Harry's (and everyone else's) absence from muggle school? So a bunch of kids all of a sudden "go missing" from school.  Harry Potter having attended school for a couple of years before starting at Hogwarts, one semester just doesn't show up.  How is this solved? What do parents say when a school teacher calls and wonders where their pupil is?  I assume that Hogwarts isn't an officially recognized school (though perhaps it is?), and due to education being compulsory, someone would do the math and find that low-hundreds of kids go missing in the transition from primary to secondary school every year. Proving that $\lim_{k\to \infty}\frac{f(x_k)-f(y_k)}{x_k-y_k}=f'(c)$ where $\lim_{k\to \infty}x_k=\lim_{k\to \infty}y_k=c$ with $x_k<c<y_k$ Question.  Suppose that a function $f$ is defined on an interval $I$, $c$ is a point of $I$, and {$x_k$} and {$y_k$} are any two sequences in $I$ such that $\lim_{k\to \infty}x_k=\lim_{k\to \infty}y_k=c$ with $x_k&lt;c&lt;y_k$ for all $k$. Prove that, if $f'(c)$ exists, then $\lim_{k\to \infty}\frac{f(x_k)-f(y_k)}{x_k-y_k}=f'(c).$   My Attempt.  Let $\epsilon_k=\frac{1}{k}$ be given.  For $\epsilon_1=1,$ there exists $\delta_1&gt;0$ such that $x_1,y_1\in I, x_1,y_1\in N'(c;\delta_1)$ implies $\vert \frac{f(x_1)-f(y_1)}{x_1-y_1} -f'(c) \vert&lt;\epsilon_1.$  For $\epsilon_2=\frac{1}{2},$ there exists $0&lt;\delta_2&lt;$min$\{\vert x_1-c \vert,\vert y_1-c \vert,\epsilon_2\}$ such that $x_2,y_2\in I, x_2,y_2\in N'(c;\delta_2)$ implies $\vert \frac{f(x_2)-f(y_2)}{x_2-y_2} -f'(c) \vert&lt;\epsilon_2.$  Similarly, for $\epsilon_{k}=\frac{1}{k},$ there exists $0&lt;\delta_k&lt;$min$\{\vert x_{k-1}-c \vert,\vert y_{k-1}-c \vert,\epsilon_k\}$ such that $x_k,y_k\in I, x_k,y_k\in N'(c;\delta_k)$ implies $\vert \frac{f(x_k)-f(y_k)}{x_k-y_k} -f'(c) \vert&lt;\epsilon_k.$  Then by taking the limit to infinity, we obtain $\lim_{k\to \infty}\frac{f(x_k)-f(y_k)}{x_k-y_k}=f'(c).$   It really took me a lot of time to finish the proof and I need this to be checked by an expert:) Is the proof okay? Any response would be appreciated! How to visualize a value resulted from math node,or just to know it. I tried the way of scaling this value to the scene size and then pick the color and get the value but I want more effective way to do this. What does ` (backquote/backtick) mean in commands? I came across the following command:  sudo chown `id -u` /somedir   and I wonder: what is the meaning of the ` symbol. I noticed for instance that while the command above works well, the one below does not:  sudo chown 'id -u' /somedir How to convert coordinates from vertex to world-space? How do I convert from object-space to world-space?  I suspect it is:  vert_os = obj.vertices[foo] vert_ws = vert_os.getPositionFromMatrix(obj.matrixWorld)   but does the matrix also handle translations, or do I need to handle that separately?  Can someone link to the relevant documentation? To power my microcontroller (ATmega8), I am using a ~5.4V voltage source. I want to ensure that I don't accidentally connect the voltage source in reverse, and figured a diode would be a nice way to accomplish this as from what I have learned so far, a diode allows current to flow in one direction, and blocks it in the other.  But what I also learned is that diodes create drops in voltage. I have a few of the typical diodes (1N4001, 1N4148, etc.), and would like to use them to achieve the aforementioned result without dropping the voltage as it would be too low to power the IC.  My question is, is there any way to do this with a diode? Or do I need some other component (if so, what would you recommend)? What is the difference between client-side and server-side programming? Is "po-TAH-to" an acceptable pronunciation for "potato"? Immortalized in the George and Ira Gershwin song "Let's Call the Whole Thing Off" is the nitpicking of pronunciation differences:      You like potato and I like potahto,   You like tomato and I like tomahto,   Potato, potahto, tomato, tomahto!   According to  and other sources, the English do pronounce tomato as tə-MAH-toh rather than tə-MAY-toh. But this doesn't seem to be the case when it comes to potato.     (From the O.E.D.)           –  Pronunciation: /təˈmɑːtəʊ/     –  Pronunciation: /pəˈteɪtəʊ/   Is "potahto" actually an acceptable way to pronounce potato? Or is the song just wrong? Holomorphic functions: is it true that $f(\bar{z})=\overline {f(z)}$? Run TTY script every time I open a GUI terminal When I log in to a TTY I get the following nice text:  Ubuntu 16.04.03 LTS Log-in: username Password: Last log-in date/time Welcome to Ubuntu 16.04.03 LTS   * Documentation:  * Management:  * Support:  9 packages to update 4 updates are security updates   I would like the last 2 lines repeated every time I open a GUI terminal for all users in the adm group (but will settle for having the entire thing displayed each and every time I open a GUI Terminal for all users)  I tried the obvious:  fab-root@fab-ux-predator:~ $ cd /etc/update-motd.d/ fab-root@fab-ux-predator:/etc/update-motd.d $ ./90-updates-available  fab-root@fab-ux-predator:/etc/update-motd.d $ cat /var/lib/update-notifier/updates-available cat: /var/lib/update-notifier/updates-available: Permission denied fab-root@fab-ux-predator:/etc/update-motd.d $   What am I missing?  P.S. Obviously I can chmod o+r the file, but how future-proof would that be? How can I get query string values in JavaScript?