What is the relationship between ISO, aperture, and shutter speed?
What is the "exposure triangle"?
Are two norms equivalent if they induce the same topology on a vector space? Ability to update profile from the Stack Exchange Android App It would be nice to update the profile page from within the app.  Perhaps not many people update their profiles more frequently, but when required to do so, I would prefer to do it from the app instead of the mobile browser. "Nikki's and Alice's X" vs. "Nikki and Alice's X" Which option is grammatical?        There will be readings from Nikki Giovanni’s and Alice Walker’s writings.   There will be readings from Nikki Giovanni and Alice Walker's writings.      Saying it out loud the latter sounds right, but looking at it the former looks better. "None" as plural indefinite pronoun In my grammar book (English Grammar, HarperCollins Publishers), I read that none is occasionally treated as plural, but it is usually regarded as singular. Can you give me an example of sentence where none is used as plural pronoun? Drop In Reputation - But No Record Of Why? Unable to correct problems, you have held broken packages After upgrading from 10.04 to 12.04 I am trying to install different packages.  For instance ia32-libs and skype (4.0).  When trying to install these, I am getting the 'Unable to correct problems, you have held broken packages' error message.   Output of commands:  sudo apt-get install -f Reading package lists... Done Building dependency tree        Reading state information... Done 0 upgraded, 0 newly installed, 0 to remove and 0 not upgraded.   After running this:  sudo dpkg --configure -a foo@foo:~$ sudo apt-get install -f Reading package lists... Done Building dependency tree        Reading state information... Done 0 upgraded, 0 newly installed, 0 to remove and 0 not upgraded. I want to add CaseComment and CaseHistory related list to my visualforce page.   &lt;apex:relatedList list=" " /&gt;  What should be the value for List attribute in the code defined above. When I added   &lt;apex:relatedList list="CaseHistory" /&gt; 'Histories' is also not working   &lt;apex:relatedList list="CaseComment" /&gt; 'CaseComments' is also not working  I get errors saying they are not valid child relationship name for entity Case.  Please help me out on this issue. Decoupling caps, PCB layout Do the druid's uses of the Wild Shape feature recharge while still in Wild Shape?  Say a 10th-level Circle of the Moon Druid spends two uses of Wild Shape to transform into an Air Elemental, whose form she can stay in for the next 5 hours. After 2 hours, she takes a short rest, but does not drop the Wild Shape. She has another couple of hours to keep the Air Elemental form.  My main concern: Does she get her two uses of Wild Shape back with that short rest? Or, does she have to drop the Air Elemental form first before taking the short rest to recharge Wild Shape? This might be a duplicate of  but that question is 5 years old and unanswered.  When I'm in drive.google.com and I open a G Suite file (either double-click or select &amp; press enter) in Firefox it opens in a new window whereas in Chrome it opens in a new tab.   Why do they do that? Is this a browser-specific quirk or a Google setting (that I haven't found)? Is there a way to control the behavior? I'd like them both to open in tabs, but presumably the same answer would be relevant in the opposite direction too. Showing diffeomorphism between $S^1 \subset \mathbb{R}^2$ and $\mathbb{RP}^1$ I am trying to construct a diffeomorphism between $S^1 = \{x^2 + y^2 = 1; x,y \in \mathbb{R}\}$ with subspace topology and $\mathbb{R P}^1 = \{[x,y]: x,y \in \mathbb{R}; x \vee y \not = 0  \}$ with quotient topology and I am a little stuck.  I have shown that both are smooth manifolds, and I used stereographic projection for $S^1$, but now I am runing into trouble when I give the homeomorphism between $S^1$ and $\mathbb{RP}^1$ as the map that takes a line in $\mathbb{RP}^1$ to the point in $S^1$ that you get when letting the parallel line go through the respective pole used in the stereographic projection.   If I use the south and north poles I get a potential homeomorphism, but I cannot capture the horizontal line in my image, but when I pick say north and east then my map is not well defined as I get different lines for the same point in $S^1$. Can somebody give me a hint how to make this construction work, or is it better to move to a different representation of $S^1$ ? What is a reasonable sample size for correlation analysis for both overall and sub-group analyses? I am running Pearson's correlation on an overall sample of 400 respondents.   When I isolate male and female responses, my sample becomes 220 male responses and 180 female responses.   If I further isolate male and female responses by (say) age groups, some sample sizes become as low as 35 responses (for example, for females over the age of 65).  My question: How good are these sample sizes for correlation analysis? (I am looking at the relationship between income levels and overseas travel.)   (I think this has something to do with margin of error but how does this apply to inferential analysis which is based on probability. I can understand its role in descriptive statistics such as results of a political poll). Writing test code for wrapper class I created a controller which looks like this  public with sharing class EventRegistrationController {      // A CONTROLLER FUNCTION     // FUNCTION RETURNS A LIST OF cSession      public List&lt;cSession&gt; getSessions() {            //DO STUFF       }     //A PUBLIC CLASS WITHIN CONTROLLER    @TestVisible public class cSession      {         public Session__c con {get; set;}         public Boolean selected {get; set;}          //This is the contructor method.          public cSession(Session__c c) {              con = c;             selected = false;         }     }  }   I need to write a test code for the controller, how can I create a list of cSession and call getSession function? Can you switch to the other Unarmored Defense by multiclassing? PHB p164 states:      If you already have the Unarmored Defense feature, you can't gain it again from another class.   So if I start as a Monk and gain the UD(Wis) feature, and then at next level up, take a level in Barbarian, can I switch to the alternate UD(Con)? Or am I stuck with UD(Wis), even if I take 19 levels in Barbarian?  I'm unclear if the rule is stating this or stating that you can't use both at the same time, which I know. Why is \[ ... \] preferable to $$ ... $$? I've heard that you should use \[ ... \] for displayed equations instead of  $$ ... $$, but why is that?  I'd assumed that it's so that you can more easily tell which are starting and which are ending delimiters, but if I always use a syntax-highlighting text editor, I can see that easily based on the color of the symbols.  Is there any reason for this suggestion? In the tense of present perfect, Are 'recent past' and 'hot news' the same? javascript object access performance How to pick a specific symbol from a specific font? What is the limit of $\lim\limits_{x→∞}\frac{\sin x}{x}$ How does entropy depend on location and scale? The entropy of a continuous distribution with density function $f$ is defined to be the negative of the expectation of $\log(f),$ and therefore equals  $$H_f = -\int_{-\infty}^{\infty} \log(f(x)) f(x)\mathrm{d}x.$$  We also say that any random variable $X$ whose distribution has density $f$ has entropy $H_f.$  (This integral is well-defined even when $f$ has zeros, because $\log(f(x))f(x)$ can be taken to equal zero at such values.)  When $X$ and $Y$ are random variables for which $Y = X+\mu$ ($\mu$ is a constant), $Y$ is said to be a version of $X$ shifted by $\mu.$  Similarly, when $Y = X\sigma$ ($\sigma$ is a positive constant), $Y$ is said to be a version of $X$ scaled by $\sigma.$ Combining a scale with a shift gives $Y=X\sigma + \mu.$  These relations occur frequently.  For instance, changing the units of measurement of $X$ shifts and scales it.  How is the entropy of $Y = X\sigma + \mu$ related to that of $X?$