When to use standalone lightmeter when your camera already has it?
Why use a dedicated light meter instead of the one built into the camera?
In Inkscape when I apply a dash stroke, then set a mid marker shape, it does not show anything. Sum of compact sets Let $A,B$ two non-empty compact subsets of a normed space X. How can we prove that the set $S=A+B=\{a+b : a \in A, b \in B\}$ is compact?  Here's my reasoning:  Let $\Omega = \{\Omega_1, \Omega_2,…\}$ be an open cover of $S$. $\Omega$ induces two open cover $X,Y$ respectively of $A,B$, where   $X_i = \{a \in A : a+b \in \Omega_i~~for~some~b\}$   $Y_i = \{b \in B : a+b \in \Omega_i~~for~some~a\}$  in practice $\Omega_i = X_i + Y_i$.  Now my idea is build a finite subcover this way: consider a finite subcover $X_F = \{X_j : j \in J\}$ where $J$ is a finite set of indices. If $Y_F = \{Y_j : j \in J\}$ is a finite subcover of $B$, then we are done as $\{\Omega_j : j \in J\}$ is a subcover of $\Omega$. Otherwise we can keep adding indexes to set $J$ until $Y_F$ becomes a finite subcover of $B$.   This is not too formal but I don't want to make a simple question unreadable, I think the idea should be clear.   Does this works? Is there a better/easier way to get the same result? How can I put two figures side-by-side? Not two sub-figures, but two actual figures with separate "Fig.: bla bla" captions.  A figure is supposed to spread over the entire text width, but I have two figures which are narrow and long, and I need to save the space in order to withstand the pages limit. How can I programmatically force-stop scrolling in a UIScrollView? I was checking on something in the Harry Potter wiki and saw Harry listed as "Half-Blood."  Both his parents were magical, but, as we know, his grandparents on his Mother's side were muggles.  This reminds me of the racially loaded terms like octoroon.  (In the south, you still hear those terms every once in a while.)  When there was still segregation, having only 1 great-grandparent of an ethnic group was enough to classify a person of that group.  So how far down the line did it go in the Harry Potter universe?  Just how many generations removed from a muggle-born would a person have to be before they're no longer classified as half-blood or something similar? Will acceleration rate of expansion of space become faster than speed of light? Black holes and positive/negative-energy particles I was reading Brian Greene's "Hidden Reality" and came to the part about Hawking Radiation. Quantum jitters that occur near the event horizon of a black hole, which create both positive-energy particles and negative-energy particles, produce the so-called Hawking radiation. However, I do not understand why only the negative-energy particles are being absorbed into the black hole, while the positive-energy particles shoot outward. Shouldn't there be 50/50 chance that each type of particle is being absorbed by the black hole? Also, the book mentions that a negative-energy particle would appear to an observer inside the black hole as positive. Why? First I tried to use integration: $$y=\lim_{n\to\infty}\frac{a^n}{n!}=\lim_{n\to\infty}\frac{a}{1}\cdot\frac{a}{2}\cdot\frac{a}{3}\cdots\frac{a}{n}$$ $$\log y=\lim_{n\to\infty}\sum_{r=1}^n\log\frac{a}{r}$$ But I could not express it as a riemann integral. Now I am thinking about sandwich theorem.  $$\frac{a}{n!}=\frac{a}{1}\cdot\frac{a}{2}\cdot\frac{a}{3}\cdots\frac{a}{t} \cdot\frac{a}{t+1}\cdot\frac{a}{t+2}\cdots\frac{a}{n}=\frac{a}{t!}\cdot\frac{a}{t+1}\cdot\frac{a}{t+2}\cdots\frac{a}{n}$$ Since $\frac{a}{t+1}&gt;\frac{a}{t+2}&gt;\frac{a}{t+1}&gt;\cdots&gt;\frac{a}{n}$ $$\frac{a^n}{n!}&lt;\frac{a^t}{t!}\cdot\big(\frac{a}{t+1}\big)^{n-t}$$ since $\frac{a}{t+1}&lt;1$, $$\lim_{n\to\infty}\big(\frac{a}{t+1}\big)^{n-t}=0$$ Hence, $$\lim_{n\to\infty}\frac{a^t}{t!}\big(\frac{a}{t+1}\big)^{n-t}=0$$ And by using sandwich theorem, $y=0$. Is this correct? If $g \circ f$ is surjective, show that $f$ does not have to be surjective? Suppose $f: A \to B$ and $g: C \to D$ are functions, and that $B ⊆ C$.  I need to come up with an example where $g \circ f$ is surjective but $f$ is not. I'm confused on how exactly to do that, but I understand that to show something is surjective you have to have the range of the function equal to the codomain of the function. Here's my attempt:  So if $g(x) = x^2$ with a codomain of $ℝ$, and $f(x) = \sqrt{x}$ with a codomain of $ℝ$, then $g(f(x)) = (\sqrt{x})^2 = x$. Since the range of this function and codomain are the same, this is surjective.  But, since $f(x) = \sqrt{x}$, its range is only $[0, ∞)$, which is smaller than its codomain of $ℝ$, meaning $f$ is not surjective. How can I understand and prove the "sum and difference formulas" in trigonometry? I am looking for an animated series, shown in the 90s. I remember an episode where the boy went into VR and fought a medusa-like monster.  It may be that this was the premise for the whole series: That the children heroes go into VR every time to fight the evil guys.   I am not sure if the whole series were computer-animated but surely there were such elements together with classic animation.  The style of the series was quite dark and cool for teenage boys. How to use -exec option in find command I wanna solve some problems in compiz with my brain and hands.  By the way I entered following command to build compiz from source in Ubuntu 12.04  find /opt/compiz-built/share/gconf/schemas -exec gconftool-2 --install-schema-file={};   I referred that command at   And following message is shown.  How to use -exec option in find command, I guess that it's my mistake. Unable to install "": snap "" has "install-snap" change in progress I just finished the installation of the Ubuntu 18.04, but whenever I try to install any application from Ubuntu Software the same error occurs (for example "vlc"):     unable to install "vlc": snap "vlc" has "install-snap" change in progress   I hope somebody can tell me what I've done wrong. Heathrow change in terminal flight UK Border control check? I am traveling from NYC to Mumbai via London. Assume my connecting flight belongs to different terminal. If I have to change terminal at Heathrow, do I need to go through UK Border control ? Java: Sorting user-input array upon return I got some new hard discs and would like to set my PC up in the following way:   Ubuntu is currently installed on one drive I want to put Windows on a second drive I would like a third drive for shared content (music and stuff) that both OSes can access     What I need to know is what format should the content drive be?  How should I configure the drive order in my bios for GRUB to be boot manager and how to configure GRUB for multi-HDD booting? On thanksgiving day a woman posted in a facebook group that her father had just passed away (left her money) and in good deed because it was thanksgiving she was offering to pay people’s debts. Well I inboxed her and she pretty much wants me to open up a bank account with First Tech Credit Union and give her my log in and password info. Ofcourse its sketchy!   So I questioned her and asked why she wanted that instead of her sending me the money directly from her bank to mine. She then responded because she wants to keep records of my debts. (She asked for proof and I sent her screenshots ONLY of my outstanding balances) I heard about the depositing checks scam so I questioned her about how she would deposit the funds and she said cash.  Her facebook page is 100% legit, I screenshotted her pics and family profiles etc. We came to an agreement that I would only accept her help if she sends me a picture of her ID before me sending this info.   She literally just wants to deposit the money to me, She isn’t asking me to send nobody money from that account or anything. Of course the account will be empty when I provide it to her. When she does deposit the money I am planning to immediately change the password and obviously stay watching my account activity while she deposits the funds.   She actually also provided pics of other accounts she funded. My question is, is this a scam? And if so how could she possibly scam me? Specially if i have her information and A pic of her ID. She is a christian lady and looks like she has a good heart, We talked about my struggles and she actually looked into why I needed to be assisted with the money. By no means was she pushy or anything. I want to believe that she just wants to help me but I am also too skeptical. How to (properly) remove the parentheses around the year in authoryear style? (v3) I have a question that has been answered a few times, but does not work for me (and also not for another commenter in a previously asked question).   I want to remove the parenthesis around the yead in the bibliography with biblatex style authoryear, and ideally also add a comma and space before it. I have looked at the following questions:        I use biber 2.10 and TexLive 2017/W32Tex.  This MWE should work according to the question v2 above, but does not work for me, i.e. the output is still Author, Anne (2001a). Alpha. The output I need is Author, Anne, 2001a. Alpha.  \documentclass{article}  \usepackage[style=authoryear,dashed=false]{biblatex} \usepackage{xpatch,filecontents}  \begin{filecontents}{\jobname.bib} @misc{A01,author={Author, Anne},year={2001},title={Alpha}} @misc{A02,author={Author, Anne},year={2001},title={Beta}} \end{filecontents} \addbibresource{\jobname.bib}  \xpatchbibmacro{date+extrayear}{%   \printtext[parens]% }{%   \setunit*{\addperiod\space}%   \printtext% }{}{}   \begin{document} \nocite{*} \printbibliography \end{document} Is it true that if $A$ is a nonnegative primitive matrix, then $AA^T$ is also primitive? Obviously $A^T$ is primitive but in general product of primitive matrices is not primitive.  Any hint? Skype window problem in Ubuntu 14.04