While searching for an alternative synonym for the adjective starving, I found the word ahungered and I was intrigued by the use of the prefix a in this case. I looked up the etymology of  . Edit: While I am aware that there are similar questions concerning this prefix, I would need an explanation for this particular word: When I first came across , I intuitively thought that here a- implies that the noun it describes was made hungry, as opposed to simply getting hungry. Is this intuition correct? Can the prefix acquire a grammatical meaning, if I can use this expression?
For example,   If this van's a-rockin', don't come a-knockin'  (song title)   (song title)   I have a few related questions:   What is the "a-" or "-a" called? Is there a function beyond a rhythmic one? Why is "a-" attached to a word at all -- and why attach to a word at all?
Look at this if block:  #!/bin/bash  str="m.m" if [[ "${str}" =~ "m\.m" ]]; then     echo "matched" else     echo "not matched"     exit 1 fi  exit 0   This should print "matched", but it doesn't. Where am I going wrong? My goal is to produce a graph showing the linkages (and lack there of) between several fields that share a common subproblem by showing who cites whom.  There are many databases that show citations between papers: , , and Google Scholar.  However none allows me to download even part of their database.  Is there some database I have overlooked?  Has someone written a scrapper for one of these websites?    For reference, the fields I'm considering are Mechanics, Magnetic Resonance Imaging, Signal Processing, Geophysics, and several others. Simplify $\prod_{k=1}^5\tan\frac{k\pi}{11}$ and $\sum_{k=1}^5\tan^2\frac{k\pi}{11}$ My question is:  If $\tan\frac{\pi}{11}\cdot \tan\frac{2\pi}{11}\cdot \tan\frac{3\pi}{11}\cdot \tan\frac{4\pi}{11}\cdot \tan\frac{5\pi}{11} = X$ and $\tan^2\frac{\pi}{11}+\tan^2\frac{2\pi}{11}+\tan^2\frac{3\pi}{11}+\tan^2\frac{4\pi}{11}+\tan^2\frac{5\pi}{11}=Y$ then find $5X^2-Y$.  I couldn't find any way to simplify it. Please help. Thanks. I've watched the Vampire Knight anime. I really like the story so far but find it frustrating that the anime doesn't finish off the story. I'm trying to figure out if it is worth reading the manga.  Does the manga contain more story than the anime? Does it finish the story off? Computing the Lie bracket on the Lie group $GL(n, \mathbb{R})$ Consider the Lie group $GL(n, \mathbb{R})$. Since $GL(n, \mathbb{R})$ is an open subset of the space $M_{n,n}(\mathbb{R})$ of $n \times n$ matrices, we can identify the tangent space (Lie algebra) $T_{e}GL(n, \mathbb{R})$ with $M_{n,n}(\mathbb{R})$, where $e$ is the identity matrix. I'm trying to understand the following:  For all $x, y \in M_{n,n}(\mathbb{R}) = T_{Id}GL(n, \mathbb{R})$ we have $[x, y] = xy -yx$ where $[\cdot, \cdot]$ is the Lie algebra bracket.  According to the question , this seems to be the case for matrix Lie groups in general.  So far, I've worked out the following: Let $x \in M_{n,n}(\mathbb{R}) = T_{Id}GL(n, \mathbb{R})$ and let $X \in \Gamma^{inv}(TG)$ be the left invariant vector field corresponding to $x$, i.e. with $X(e) = x$. By openness, we can choose $\epsilon &gt; 0$ such that the curve $(-\epsilon, \epsilon) \ni t \mapsto e + tx$ through the identity is contained in $GL(n, \mathbb{R})$. For $g \in GL(n, \mathbb{R})$ let $L_g$ be the left multiplication by $g$ in $GL(n, \mathbb{R})$. Using left invariance of $X$ calculate: $$X(g) = ((L_g)_{*}X)(g) = D_eL_g(X(e)) = D_eL_g(x) = \frac{d}{dt}|_{t=0}g(e+tx) = gx$$ Now, the above implies for $f \in C^{\infty}(GL(n, \mathbb{R}))$ and $g \in GL(n, \mathbb{R})$: $$X(g)(f) = (D_gf)(gx)$$ where we identify the tangent vector $X(g)$ with the corresponding derivation at $g$.  Now how do I calculate $[x,y] \stackrel{def.}{=} [X, Y](e) \stackrel{\text{WHY?}}{=}xy-yx$ from this? What am I doing wrong? Joint Density of sum of random variables! So, I have this question:    And, what I have tried so far is I let $z_1 = \frac{X + Y}{2}$ and let $z_2 = \frac{X - Y}{2}$ to use change of variables for this question. However, when I work this out and plug it into my joint distribution of $X$ and $Y$ above, I end up with the $z_2$ disappearing and only having $z_1$ left in my joint distribution of $z_1$ and $z_2$. So, then when I go to find the marginal for just $z_1$ (which is $\frac{X + Y}{2}$ &lt;- what I am looking for), there is no $z_2$ therefore, integrating wrt to $z_2$, I get $z_2$ just come up (integral of 1). This is an issue because the bounds are from 0 to $\inf$. Obviously, I can't have infinite in my marginal density so what am I doing wrong?   Also, for question 5, I work it out similarly except I let $z_2 = X$ but I just end up with the exact same density as $f_{x,y}$ as seen in question 4 - is that normal? Please help, I been doing this question for a long time trying various dummy transformations.  Also, for question 4, I found the marginals of $x$ and $y$ and realized that the independence consequence (of the product being equal to the joint) is satisfied but using convolution, I get the same issue of my integral coming out to infinite! Thank you for all the help!   EDIT: Am I doing my bounds wrong? the bound for z_2 is from 0 to inf or 0 to z_1? How can I compare time in SQL Server? Why is the colour picker displaying tinted colors? The colour picker is behaving not as I expect it to. I cannot move the selector towards most of the edges, setting the RGB to 1.00 for red and the rest to 0 just gets an orange colour. Also I cannot simply keep the "value" the same and select a different shade, the "value" resets.  I'm not sure if i've pressed something in error or there is a setting in the user preferences/elsewhere that needs changing. I'm using the cycles renderer. The issue occurs with any colour picking :- material, background etc. Quitting Blender and restarting does not resolve the issue. Version 2.79.6 I bought an Acer laptop and installed Ubuntu 14.04LTS but WiFi drivers are not available for it. So I am trying to install a windows driver using wifidocs/driver/ndiswrapper.  On doing lspci -vvnn, it gives:  Network controller ［0280: Qualcomm Atheros Device ［168c:0042］ (rev 30)   Then I also disabled the atheros drivers. Using lspci and lspci -n, I can say PCI id is 168c:0042. But Acer website has three atheros drivers. I could not figure out which one to download but downloaded one on a windows PC and pasted the zip file on my desktop then unzipped it from the terminal using unzip &lt;filename&gt;.zip. The page says you have to go to control panel system hardware and all that on the windows system. I did not do it. Windows computer not being mine, I am afraid I should not install any additional driver on it. After unzipping it has one .inx file and one .bin file but no .sys file. I don't know whether I am completely right till here or have I missed something? And if I am right then how to proceed from here? I also made a new directory and copied the unzipped .inx and .bin files in it. Then in that directory I ran the ndiswrapper -i &lt;filename&gt;.inf but it says ndiswrapper not installed and when I do sudo apt-get install ndiswrapper-common, I get the reply that ndiswrapper-common is already the latest version. What to do? here is my dmesg | grep ath10k result  [   7.882758] ath10k_pci 0000:03:00.0: pci irq msi-x interrupts 8 irq_mode 0 reset_mode 0 [    8.190016] ath10k_pci 0000:03:00.0: Direct firmware load for ath10k/cal-pci-0000:03:00.0.bin failed with error -2 [    8.334587] ath10k_pci 0000:03:00.0: Direct firmware load for ath10k/QCA9377/hw1.0/board-2.bin failed with error -2 [   10.140677] ath10k_pci 0000:03:00.0: qca9377 hw1.0 (0x05020000, 0x003820ff sub 105b:e09a) fw WLAN.TF.1.0-00267-1 fwapi 5 bdapi 1 htt-ver 3.1 wmi-op 4 htt-op 3 cal otp max-sta 32 raw 0 hwcrypto 1 features ignore-otp [   10.140682] ath10k_pci 0000:03:00.0: debug 0 debugfs 0 tracing 0 dfs 0 testmode 0 Here is the output of lspci -nnk | grep -iA2 net  02:00.0 Ethernet controller [0200]: Realtek Semiconductor Co., Ltd. RTL8111/8168/8411 PCI Express Gigabit Ethernet Controller [10ec:8168] (rev 15)     Subsystem: Acer Incorporated [ALI] Device [1025:098a]     Kernel driver in use: r8169 03:00.0 Network controller [0280]: Qualcomm Atheros Device [168c:0042] (rev 30)     Subsystem: Foxconn International, Inc. Device [105b:e09a]     Kernel driver in use: ath10k_pci LaTeX Editors/IDEs Bold row in table aligned with dcolumn I'm very confused about tenses.  I have examples in two different situations here. Situation 1: I went to New York two months ago and was talking to someone about it.  A. This is the first time I've been to New York. B. That was the first time I'd been to New York.  Which is correct in a daily conversation?  Situation 2: I'm going to New York next month and talking to someone.  A. This will be the first time I've been to New York. B. This is the first time I've been to New York. C. This will be the first time I go to New York.  Which sentence is appropriate?  According to a grammar article I've read before, I think it says that I can use this sentence in both cases:  This is the first time I've been to New York.  But I'm not sure if this is really so. So I'd like to know which tense I should use in each case. Could you explain it? How are one-time pads distributed? It seems that OTP encryption is unbreakable. I have read some articles (Wikipedia, Blogpost, etc.), but I could not find any information about how they are used.  If I wanted to create a messenger service, how would I distribute the OTP keys? Both the sender and the receiver need this key before the message is sent, right?   And how do I make sure no one else gets these keys? Convert ls -l output format to chmod format Texture disappear on joining I had a heck of time while editing my  question. But, I guess, I discovered a new weird problem in the editor while formatting hyperlink text next to  tag.  To illustrate this problem better, I would like to give the following examples:  Has problem with one or none white-space in between:  [meta-tag:status-planned] [details page reads:][2] [meta-tag:status-planned][details page reads:][2]     Gives weird output as:   [details page reads:]   [details page reads:]   But, its okay with two white-spaces in between:  [meta-tag:status-planned]  [details page reads:][2]   Gives the correct output as:      Something is strange here. I don't understand why do I have to insert two white-spaces instead of just one? Are the two white-spaces are mandatory when using [meta-tag:some-tag] with hyperlink text adjacent to it? Or, is it one of those  thing?  But wait, it's get even further complicated if I do like:   1. No white-spaces in between:  [meta-tag:status-planned][meta-tag:status-completed][Moderator-only Tags][3]     2. One white-space in between:  [meta-tag:status-planned] [meta-tag:status-completed] [Moderator-only Tags][3]       3. Two white-spaces in between:  [meta-tag:status-planned]  [meta-tag:status-completed]  [Moderator-only Tags][3]         They all seems to work perfectly fine. Now, thats very strange! Why would the two [meta-tag:some-tag] works like a charm with or without requiring to insert any white-spaces? Can anyone explain this in a better way. I don't want to jump on the conclusion by calling this as a bug yet, so I used  tag instead of  tag. Please share your thoughts. Deriving Sum of a Geometric Progression What is the purpose of the first test in an inductive proof? Learning about proof by induction, I take it that the first step is always something like "test if the proposition holds for $n = \textrm{[the minimum value]}$"  Like this:       Prove that $1+2+3+...+n = \frac{n(n + 1)}{2}$ for all $n \ge 1$.   Test it for $n = 1$:  $$n = \frac{n(n + 1)}{2} \implies 1 = \frac{2}{2}\textrm{, which holds.}$$  * The rest of the proof goes here *    So, I do it all the time (like a standard). But I never really thought about why. Why do I do such test? I can see that if the test does not hold, it cannot be proven by induction, I guess. But is there another reason we do this? How to say that you have plans to go to the movies tonight (but you are not sure yet, maybe you will have a pizza)? I mean there are options:     I am going to the cinema tonight.   Way too much certainty in this. For me it means that you have already bought tickets, the least.     I am going to go to the cinema tonight.   Sounds a bit awkward.     I will go to the cinema tonight.   Sounds too formal to me. There is something strange going on with Books on iPad and iPhone. It keeps deleting some books locally, keeping them in the cloud.  It's frustrating because it happens when I'm offline and I simply lose the access to them.  Why is this happening at all? And how can I stop it?  I enabled syncing things over iCloud Drive and everything, but I can't see an option to disable such optimizations.    PS: the same thing happens with Photos, Numbers and Pages. The Photos app has an optimize storage option. But there doesn’t seem to be such an option for Books, Numbers and Pages.   A clear example: just a few hours I was reading a book on Books, I took a nap, and when I opened the Books app, the book was not available offline anymore. Since I don’t have internet right now, it’s simply impossible to access the document.