What's the ranges of ratios of Focal Length to Sensor Height to approximate a human eye's view?
What lens focal length most closely resembles the perspective of the human eye?
What is the most ruby-ish way of accessing nested hash values at arbitrary depths? How to modify the space between the numbers and text of sectioning titles in the table of contents? I'm preparing a document using the book class. In the table of contents, the space between the subsection number and title is too wide. How to reduce it? Undefined reference to `pow' and `floor' how does LEA and several instruction work? Negative quotients and their remainders Since $16 \div{-3} = -5.\overline{3}$, I thought I could also express this as $16 \div{-3} = -5\:R\:1$ or in other words $16\mod{-3} = 1$. My calculator tells my it is in fact $-2$.  Along the same lines, I see that $-16\mod{3} = 2$. So, while the true answer evaluates to $-5.\overline{3}$ again, the "remained notation" is $-6\:R\:2$ here, and $-6\:R\:-2$ in the first example.  Why do we go "past" $15$ to $18$ (or in the second example, past $-15$ to $-18$) and calculate the remainder from there?  Further warping my brain, $-16\mod{-3} = -1$, so it looks like we "stop" at $-15$ in this example. How can I determine if it is possible to check luggage during a layover? A common desire among some travelers with long layovers is to leave the airport for a while, and perhaps do some shopping, or even buy goods in the airport.  But this then often necessitates the ability to check additional luggage during the layover, for the remainder of the journey.  There might be other reasons to want to check luggage mid-journey as well.  Are there any general rules one can use to determine whether this is an option in a given airport when traveling with a given airline, and the associated costs (when it is possible)? What is the $\sqrt{i^4}$?   $i^4$ = $(i^2)^2$ So is $\sqrt{i^4}$ = $\sqrt{(i^2)^2}$ = $i^2$ = $-1$?  Or is $\sqrt{i^4}$ = $\sqrt{1}$ = $1$?  When I plug it into my TI-89 Titanium, I get $1$.  Edit: I now see why $i^4 \neq -1$. $$\sqrt{x^2} = \left|{x}\right| $$ So$$\sqrt{(i^2)^2} = \left|i^2\right| = \left|-1\right| = 1$$ I'm trying to find a way with javascript to highlight the text the user selects when they click some odd highlight button (as in &lt;span style="background-color:yellow"&gt;highlighted text&lt;/span&gt;). It only has to work with either WebKit or Firefox, but it seems to be well nigh impossible because it has to work in the following cases:  &lt;p&gt;this is text&lt;/p&gt; &lt;p&gt;I eat food&lt;/p&gt;   When the user selects from "is text" through "I eat" in the browser (can't just put a span there).  and this case:  &lt;span&gt;&lt;span&gt;this is text&lt;/span&gt;middle text&lt;span&gt;this is text&lt;/span&gt;&lt;/span&gt;   When the user selects from "is text" to "this is" in the browser (even though you can wrap your highlight spans around each element in the selection, I'd like to see you try to get that middle text highlighted).  This problem doesn't seem to be solved anywhere, frankly I doubt it's possible.  It would be possible if you could get the Range that you get from the selection as a string complete with html which could be parsed and then replaced, but as far as I can tell you can't get the raw html of a Range.. pity. I duplicated a few objects with Alt+D and now I want to apply some modifiers to them, however I can't, because they are multi-user objects.  I tried U > Objects but I still can't apply the modifier.  How to make multi user objects single user? In the Stack Overflow podcast #36 (), this opinion was expressed: Once you understand how easy it is to set up a state machine, you’ll never try to use a regular expression inappropriately ever again. I've done a bunch of searching.  I've found some academic papers and other complicated examples, but I'd like to find a simple example that would help me understand this process.  I use a lot of regular expressions, and I'd like to make sure I never use one &quot;inappropriately&quot; ever again. On Linux can I keep a program running in background even after I disconnect? If I'm logged into a remote Linux machine, I know I can suspend a process (cntr-z) and move it to the background (bg 1) but if I disconnect from the machine, the process stops.  Is there a way I can leave it in the background and have it there when I log back in? This is a very long running process.  On Ubuntu, logged in via SSH. Edit a truetype font I'm trying to find a free tool (on windows ) that would enable me to change some settings on a TrueType font. Specifically, I'm trying to fix the following errors:  E1311 The macStyle bold bit doesn't match the name table's font subfamily string macStyle bold bit is set, but subfamily is Regular  W2000 The subfamily string is inconsistent with the style of the font OS/2.fsSelection bold bit is set, but subfamily string = 'Regular'  I can do that with fontographer, but would prefer to use something free.  Fontforge doesn't seem to work with this font, when saved it corrupts the cyrillic letters in the font. Space war, humans recreated, grown from plants with an alien female supervisor This was a small hardback book I read in the UK in the late eighties. No memory of the cover.  Some kind of space war and a long lived alien female escapes the conflict in her starship, her side had lost.  An evil enemy that she needs to trap so she gets (I think) human  DNA from space dust and sets up on a habitable planet. The story then gets like episodic and looks at the world every couple of generations while she hides out there.  Plants bud on the world and people pop out from big seedpods, the population listens out for babies crying and rescue them.  There are legends of the 'Earth mother’ who secretly guides them to become high tech.   In reality she is creating attractive food bait for the bad aliens.  I think an early human and her are attracted to each other and she (maybe) gives him long life or (maybe) uses reincarnation to keep seeing him.  Edit:- the name 'Rimstalker' has just now popped up in my brain! After update, get "error: file not found." followed by "grub rescue> _" Show that the quotient space is homeomorphic to the n-disc Are Constitution changes retroactive when calculating max HP? Lets say I'm a fighter that just leveled up to level 4, and decide to bring my Constitution up from 16 to 18. How many hit points do I have?  Level 1 = 10 (base) + 3 (Con mod) = 13.  Level 2 = 10 + 6 (average HP per fighter level) + 3 (Con mod) x 2 = 22  Level 3 = 10 + 6 (average) x 2 + 3 (Con mod) x 3 = 31  Level 4 = 10 + 6 (avg) x 3 + 3 (Con mod) x 3 (3 level-ups) + 4 (increased Con mod, which is now 4) x 1 = 41?  OR  Level 4 = 10 + 6 (avg) x 3 + 4 x 4 (4 times current Con mod) = 44?  If it's the first option, it's simply better to level Constitution up at earlier levels. Retrieve the position (X,Y) of an HTML element relative to the browser window I want to know how to get the X and Y position of HTML elements such as img and div in JavaScript relative to the browser window. Does Windows 7 allow auto-login with a stored password, like TweakUI did? Prevent windows from going into sleep when my program is running? is $\sqrt{x}$ always positive?