Predicting stellar evolution and life cycle of a star

Is there a way to model/predict the evolution and life cycle of a star based on certain initial conditions?  That is, whether it will become a red giant, brown dwarf, etc. I'm basically looking for equations defining the progress of different star-types and how varying initial conditions may affect that progress.


App submission: No binary but getting "redundant binary" error

When submitting the first release of my app for review on iTunesConnect, I'm getting a validation error that I need to upload a binary, but when I upload using Application Loader 3.0 I get an error ITMS-4238 "Redundant binary upload".  Validation error:    Upload error:   This happened after I uploaded the binary last week, filled in some of the app details, saved the page, came back to it today, completed the rest of the app details, and clicked "Submit for Review."  Any ideas how to fix this?  Unlike post #146330, I don't have another binary I want to submit - I want to use the one that's already uploaded. Unfortunately iTunesConnect doesn't seem to recognize there is one. I also don't have the source code and can't change the version or build number in Xcode because it was coded by a paid vendor.


Does a photon not having a reference frame result in logical inconsistency?

So, I know that SR makes two statements. One is the first assumption it has: "Speed of light is the same with respect to all reference frames".  Second, the statement: "A photon cannot have a reference frame". (Please correct me if the statements I wrote are not accurate.)  Aren't these two statements a bit paradoxical? One first says that Speed of this thing is the same with respect to all frames. And then says speed is not defined wrt to it's own frame, because there is no such frame.  The comparison has already been made in assumption one. It's not logical to say in the next statement the opposite, and say that no we are just not comparing with it's own reference frames. It's a contradiction.  Are Physics textbooks not accurate enough? or have I made a mistake somewhere in my thinking.  I don't really want to be correct, but just want to know my mistake.  But, so far, it seems like a Philosophical mistake in SR.  Any statement is only valid under the assumption applied on top of it.  I understand that the photon cannot have a frame of reference, but what I am pointing to, is that a comparison with "All" reference frames has already been made earlier. Before this statement is established that "Photon cannot have a frame of reference".  You cannot compare without defining. This seems like a paradoxical set of statements.  If you look at the current answers, this is exactly what I am referring to. We have a reason from statement 1 itself for statement 2 to be true, but if statement 2 is true, then it violates part of statement 1, because both cannot be absolutely true together.  I agree that statement 2 will follow from statement 1, but if statement 2 follows, then statement 1 cannot be absolutely true, because it was stated first. Statement 2 follows from it through reasoning.  Let me illustrate what I think could be wrong: We make statement 1: "Speed of light is same wrt to all reference frames" These statements are a subset of statement 1: Statement A: " Speed of light is same wrt to A reference frame" Statement B: " Speed of light is same wrt to B reference frame" Statement C: " Speed of light is same wrt to it's own reference frame".    If 1 is true, then A, B , and C all are true, so far.  But, now we say that it follows from 1, that C cannot be true, because there can be no reference frame for photon. This constitutes a contradiction, because C has already been said to be True.


How can I change my email on clash of clans?

I'm using my brother email to play clash of clans, and now I want to change it to use my email. So, How can I change this email?


Using a number system other than the decimal

Travelling in the Kingdom of Crystal Skull, Indiana Jones discovered a small box with notation  $$ 3 x^2 - 25 x + 66 = 0 \implies  x_1 = 4,\; x_2 = 9, $$ which seems to be incorrect. However after some reflection he realised a number system other than the decimal was used to determine the roots of the quadratic equation. What is the base of that number system?


i have a file is name  -ksh.l.15092015.log  to delete this file i do this: rm -rf -ksh.l.15092015.log  but i have this error:  rm: Not a recognized flag: k Usage: rm [-firRe] [--] File...  i have do this: rm -rf *ksh*  but i have the same errors, why ? Thx for your help !


example of noncommutative rings $A$ such that $A^2 \cong A$ as left $A$-modules

I am looking for an example of non-commutative rings $A$ such that $A^2 \cong A$ as left $A$-modules.  I am thinking about the simplest non-commutative ring $A=GL_n(\Bbb R)$ for $1 < n \in \Bbb Z_+$, could we find a suitable subspace of $A$?  Thank you for your help.


I've just decided to jump into the world of Ubuntu, so far I encountered no problems until I tried to connect to my wireless network. I'm running Ubuntu on my laptop, Acer Aspire 5333-2880, which has an Acer Nplify 802.11b/g/n wireless card.  After browsing for an answer, I think the problem is a missing driver. input:   lspci | grep Network   output:     02:00.0 Network controller; Atheros Communications Inc. AR9285 Wireless Network Adapter (PCI-Express) (rev 01)   I found a couple of answers that might be right, but I have problems with both of them.    It requires me to load the site in my laptop, but I can't do it without internet and I have no idea how to save this into a USB.  But I have no idea how to really run or use this, and I wouldn't like to screw it up.    Any advice or other possible solutions will be greatly appreciated!   EDIT.  Thanks a lot for your input Marko and Jorge. I am sure the problem was with one of the drivers, but I was too distracted, or tired yesterday to realize I didn't restart my computer after installing. As soon as I got turned on my computer again, it was working. Annoyingly, I am not sure what the problem was exactly nor what exactly fixed it.  But still, thanks a lot Marko for the intel on how to build packages, I am sure it will be very useful later on!


Will a PCI Express x16 3.0 card work in a PCI Express x16 slot?

I have a motherboard with a PCIexpress x16 slot.  I want to purchase a card called AMD Radeon HD 7770, which uses PCIe version 3.0.  Is that backwards compatible?


How do I vertically center a single cell within a table?

I can't find a way to vertically center a single line within a table cell.  Take a look at this screenshoot:    I'd like to vertically center the text within the bottom right cell and I just can't find a way to do it. I tried \usepackage{array} but I couldn't figure out how to apply the \centering\arraybackslash, which seems to align things vertically within cells, just to this single cell.  (I'm also not sure why the right border is missing for this cell.)  Here is the LaTeX code that generates this table:  \documentclass{article}  \usepackage[left=1cm,top=1cm,right=1cm,bottom=1cm,nohead,nofoot]{geometry}  \usepackage[pdftex]{hyperref} \usepackage{verbatim} \usepackage{listings} \usepackage{array}  \hypersetup{colorlinks}  \lstset{basicstyle=\ttfamily}  \pagestyle{empty}  % -----------------------------------------------------------------------  \begin{document}  \begin{tabular}{|p{5.5cm}|p{12.2cm}|} \hline \large\textbf{Redirection} & \large\textbf{Description} \\ \hline \verb|> file| & Redirect standard output (stdout) to a file. \\ \hline \verb|1> file| & Same as \verb|> file|. \verb|1| is the default file descriptor for stdout. \\  \hline \verb|2> file| & Redirect standard error (stderr) to a file. \verb|2| is the default file descriptor for stderr. \\ \hline \verb|>> file| & Append stdout to a file. \\ \hline \verb|2>> file| & Append stderr to a file. \\ \hline \verb|&> file| & Redirect stdout and stderr to a file. \\ \hline \verb|>file 2>&1| & Another way to redirect both stdout and stderr to a file. This \textbf{is not} the same as \verb|2>&1 >file|. \textbf{Redirection order matters!} \\ \hline \verb|> /dev/null| & Discard stdout. \\ \hline \verb|2> /dev/null| & Discard stderr. \\ \hline \verb|&> /dev/null| & Discard stdout and stderr. \\ \hline \verb|< file| & Redirect the contents of the file to the stdin. \\ \hline \verb|<< EOL| \\  \verb|foo| \\ \verb|bar| \\ \verb|baz| \\ \verb|EOL| & Redirect a bunch of lines to the stdin. \\ \hline \end{tabular}  \end{document}


Infinite Collection of Sets with These Properties

I passed by this problem in Abbott's "Understanding Analysis", page 11:  Produce an infinite collection of sets $A_1, A_2, A_3,...$ with the property that every $A_i$ has an infinite number of elements, $A_i ∩ A_j = \phi$ for all $i \not= j$ , and $\bigcup_{i=1}^{\infty} A_i = \mathbf N$   Finding the solution was not difficult conceptually (that is, if my attempt is correct), but I have no idea how to formulate it. My idea is as follows: If the question asked for two sets, an answer would be the sets of even and odd numbers. If they're $3$ sets, I would then give $A_1$ all the numbers starting from $1$ and increment $3$ to get $A_1 = \{1,4,7,...\}$, similarly, for $A_2$, starting from $2$ and incrementing by $3$, etc... For $n$ sets, $A_i = \{i, i+n,i+2n,...\}$. However, for an infinite number of sets, formulating a more formal solution is confusing to me.  My other question is this: Is this the only way to solve this problem, and why?


Draw character silhouette when not visible

I have a mesh representing my character. I want to give it a partially transparent greyish silhouette when other objects are blocking it from view of the camera.  I'm using Ogre3D, and GLSL as a shading language, but this is a pretty technology/language agnostic question.


I received a rejection for my UK visa application. The letter in part says:  You have stated that you are employed by Al Majal Alarabi Group as an Electrical Engineer and that your total monthly income is  SAR (  as at 26/10/2020). I note that you have provided bank statement showing salary payments, however this bank statement shows number of additional cash deposits made to the account in the last few months. The origin of these funds have not been demonstrated and I note that you have declared that you do not have any additional income or savings. As such I am not satisfied that the statements made in your application form reflect your current personal circumstances regarding your employment, occupation or income  Can any body advise me how i can justify this one cash deposit. and what procedure i have to follow???


Series $\sum \limits_{k=1}^{\infty}f_{n}(x)$ converges uniformly, but $\sum \limits_{k=1}^{\infty}|f_{n}(x)|$ converges only pointwise

Is there a sequence $f_{n}:\mathbb{R} \to \mathbb{R}$ such that the series $\sum \limits_{k=1}^{\infty}f_{n}(x)$ converges uniformly to $f(x)$, but $\sum \limits_{k=1}^{\infty}|f_{n}(x)|$ converges only pointwise, for all $x\in \mathbb{R}$?  I tried limiting the domain to $(0,1)$ and using Dirichlet Eta function, but that approach failed. I know that the sequence $f_{n}$ cannot be strictly positive and can't be equibounded, otherwise  $\sum \limits_{k=1}^{\infty}|f_{n}(x)|$ would converge uniformly by Weierstrass M-test.


When Money and Rupees are countable nouns why is "Much" used with them instead of "MANY" when asking a question like:  How much money do you have? or How much does


I would like to write some text in latex, then replace the black of the letters by a transparent layer, and overlay on top of a PDF photo. I could do it by exporting to photoshop, but I would like a latex-only solution. Thanks!


Cross check email addresses and delete the entire row of duplicates?

I need to merge 2 files into 1 and would like to crosscheck the email addresses to find duplicates and delete the entire row that it's contained in. Is this possible?  So far I just copy pasted all the data in one single sheet but each on a new page/worksheet but can't seem to find anything to do what I need. Any advice? Thanks in advance for any help


How to limit the width of the focus box to the length of the text on a web page

I've a text in a table. When you click on this text a focus box should be displayed as close as possible around this text. With my code the displayed focus box is as wide as the table width. How can I limit the width of the focus box to the length of the text? Note: The text must be in that table. I already tried:  float: left;, but then the text is no longer centered. position: absolute; left: 50%; transform: translate(-50%, 0);, but then the text isn't exactly at the same position as it was before (the text jumps around when it gets the focus) and this doesn't work in Safari.  And here's my code:

Click this text. The focus box should be as close as possible around this text.


Does gravitational field 'attract itself'?

In an article at the "Gravity Probe B" website,  the following statement is included: "... the gravitational field carries energy and thus "attracts itself"; ..." What does it mean? Edit: I was made aware of the following question:  . The answers given there are related, indeed. However, I would be grateful if the explanation of 'self-interaction', in general is extended to the specific meaning of 'self-attraction' of the gravitational field.


jQuery accordion on Wiki page only works in edit mode?

I have an SP2013 wiki page that I want to use a jQuery accordion on.  Just with some static content, not pulling any information from anywhere in SharePoint.  I created the page, inserted a script editor web part at the top, and inserted this snippet:       Then, I put the cursor under the script editor web part, and clicked on "Edit Source".  Then underneath the HTML that represents the script editor, I put this HTML (basically the jQuery accordion demo HTML):

       Section 1

Mauris mauris ante, blandit et, ultrices a, suscipit eget, quam. Integer ut neque. Vivamus nisi metus, molestie vel, gravida in, condimentum sit amet, nunc. Nam a nibh. Donec suscipit eros. Nam mi. Proin viverra leo ut odio. Curabitur malesuada. Vestibulum a velit eu ante scelerisque vulputate.

       Section 2

Sed non urna. Donec et ante. Phasellus eu ligula. Vestibulum sit amet purus. Vivamus hendrerit, dolor at aliquet laoreet, mauris turpis porttitor velit, faucibus interdum tellus libero ac justo. Vivamus non quam. In suscipit faucibus urna.

       Section 3

Nam enim risus, molestie et, porta ac, aliquam ac, risus. Quisque lobortis. Phasellus pellentesque purus in massa. Aenean in pede. Phasellus ac libero ac tellus pellentesque semper. Sed ac felis. Sed commodo, magna quis lacinia ornare, quam ante aliquam nisi, eu iaculis leo purus venenatis dui.

       Section 4

Cras dictum. Pellentesque habitant morbi tristique senectus et netus et malesuada fames ac turpis egestas. Vestibulum ante ipsum primis in faucibus orci luctus et ultrices posuere cubilia Curae; Aenean lacinia mauris vel est.

Suspendisse eu nisl. Nullam ut libero. Integer dignissim consequat lectus. Class aptent taciti sociosqu ad litora torquent per conubia nostra, per inceptos himenaeos.

   After I saved the page, the accordion collapsed initially (as it is supposed to), but clicking on any of the headers does not expand the section.  If I go back into edit mode for the page, it works as expected - clicking a header expands the section.  Save it again, and it stops working.  What am I missing?  I don't think what I'm trying to do is all that complicated...  EDIT 12/8: Ok, so I put the jQuery and jQuery UI scripts in the site's Site Assets folder, and the behavior is the same -- the scripts do not get loaded in IE or Firefox unless the page is in Edit mode.  Incidentally I think the other script snippet, where I hook up the accordion, is also not getting loaded unless the page is in edit mode.  The reason I think this is that I changed the way I referenced the main jQuery script (to something that didn't work), and the debugger halted on $(function () { ...., saying $ was undefined.  So if jQuery is not loaded, and the debugger thinks $ is undefined, at least it's hitting that section of code.  Which makes me think that in non-edit mode, not only is jQuery not getting loaded, but that section of script is not getting loaded either, because the debugger is not choking on $.  Can anyone provide any insight as to why the Script Editor web part seems to be not working in IE and Firefox?  (Because apparently in Chrome it works fine.)


Why this proof $0=1$ is wrong?(breakfast joke)

We have $$e^{2\pi i n}=1$$  So we have $$e^{2\pi in+1}=e$$  which implies $$(e^{2\pi in+1})^{2\pi in+1}=e^{2\pi in+1}=e$$ Thus we have $$e^{-4\pi^{2}n^{2}+4\pi in+1}=e$$  This implies $$e^{-4\pi^{2}n^{2}}=1$$  Taking the limit when $n\rightarrow \infty$ gives $0=1$.


Safari can load internet but none of the other apps cannot!

This is by far the weirdest problem I've come across,  My mac can perfectly access internet through safari web browser, but when I tried to do   ping www.google.com   through the terminal, it's requests is being timed out.  None of the other apps are able to reach internet either. Dropbox, Skype, Spotify all showing offline, except the browser itself  I'm guessing something bad with the DNS, but spend 2 hours trying to fix this with no luck


To find when $6$ is a square I divided $6$ in to $2$ and $3$ by The Legendre symbol.  $$\frac{6}{p} = \frac{2}{p} \times \frac{3}{p}$$  I know that we can multiply the cases of when $2$ and $$ are squares because then it is (1)(1) by Legendre.   $2$ is a square when $p \equiv 1 \pmod{8}$   $3$ is a square when $p \equiv 1 \pmod{12}$  so $6$ is a square when $p \equiv 1 \pmod {24}$ ($96$, but the $lcm(8,12)= 24$)   but how do I find the cases when $2$ and $3$ are both NOT squares? because then $6$ would be a square then as well, $(-1)(-1) = 1$ by Legendre.


Lets say I want to build iOS quiz with guessing images, and want to guess pokemons. If I edit image like :   is it violating copyrights?


Möbius Tranformation: Map two non intersecting circles to concentric circles

Show that two non intersecting circles can always be mapped by a suitable Möbius transformation to two concentric circles.  I wanted to map the center of the first circle to the center of the second circle then using scaling the radius would give me the concentric circles. But having problem to execute.  Suggestions please,


Wifi doesn't work on Lenovo ideapad-130-15IKB

After installing ubuntu 18.08 LTS along side with windows 10 , i encountered some problems using ubuntu the first is the touchpad but thanks to askubuntu i corrected the problem. Now i'm searching solutions to another problem that is with my wifi wireless connection it doesn't work and more over when entering to wifi settings i see an No Wifi Adapter Found' i already tried some stuff but unluckily not working. when typingsudo lshw -C network` i get this :     *-network                         description: Ethernet interface        product: RTL8101/2/6E PCI Express Fast/Gigabit Ethernet controller        vendor: Realtek Semiconductor Co., Ltd.        physical id: 0        bus info: pci@0000:01:00.0        logical name: enp1s0        version: 07        serial: 98:29:a6:67:23:2b        capacity: 100Mbit/s        width: 64 bits        clock: 33MHz        capabilities: pm msi pciexpress msix vpd bus_master cap_list ethernet physical tp aui bnc mii fibre 10bt 10bt-fd 100bt 100bt-fd autonegotiation        configuration: autonegotiation=on broadcast=yes driver=r8169 firmware=rtl8106e-1_0.0.1 06/29/12 latency=0 link=no multicast=yes port=MII        resources: irq:16 ioport:4000(size=256) memory:b1200000-b1200fff memory:b1000000-b1003fff   *-network UNCLAIMED        description: Network controller        product: Realtek Semiconductor Co., Ltd.        vendor: Realtek Semiconductor Co., Ltd.        physical id: 0        bus info: pci@0000:02:00.0        version: 00        width: 64 bits        clock: 33MHz        capabilities: pm msi pciexpress bus_master cap_list        configuration: latency=0        resources: ioport:3000(size=256) memory:b1100000-b110ffff   *-network        description: Ethernet interface        physical id: 3        logical name: enp0s20f0u2        serial: 22:2e:f7:46:24:ff        capabilities: ethernet physical        configuration: broadcast=yes driver=rndis_host driverversion=22-Aug-2005 firmware=RNDIS device ip=192.168.42.91 link=yes multicast=yes   When typing `lspci -knn | grep Net -A02:00.0  i get :  02:00.0 Network controller [0280]: Realtek Semiconductor Co., Ltd. RTL8821CE 802.11ac PCIe Wireless Network Adapter [10ec:c821]     Subsystem: Lenovo RTL8821CE 802.11ac PCIe Wireless Network Adapter [17aa:c024]     Kernel modules: wl   When trying rfkill list i get :   0: ideapad_wlan: Wireless LAN     Soft blocked: no     Hard blocked: no 1: ideapad_bluetooth: Bluetooth     Soft blocked: no     Hard blocked: no 3: hci0: Bluetooth     Soft blocked: no     Hard blocked: no   Help please i want back my wireless connection


I have dataframe scrapped from the web with features that come from user inputed data. However, some of my columns which include features about cars have different capitalizations for the same feature i.e. 'Heated Seats' and 'heated seats'. These are dummy variables, so a car with heated seats will have a zero for one column and a 1 for the other. The end goal is to add all columns with the same feature, just different capitalization. Does anyone know of any libraries that can help with looping through hundreds of features to check for pairs in mismatched capitalization like this?  Thanks


Why are heavily-downvoted accepted answers still listed first?

The answer that sparked the question is  where the answerer provided a completely wrong answer to the question and was consequently heavily downvoted. However, the answer seems to have appealed to the OP's preconceived notions so it was accepted. Of course, the system is designed to allow the asker to choose an answer that was helpful to them; however, it's well accepted that the most important posts are those that are helpful to the far more numerous readers who come across the question from Google or somewhere else rather than the original asker. They should be shown the answer that the community deems best. In this case there's a perfectly good answer with a score of +5. That's what readers should see first. Not the post that the OP decided (against the judgement of everybody else) was best.


The code below throws an  AttributeError: 'bpy_prop_collection' object has no attribute 'link'  How does context.scene.objects.link(loxodrome) look in Blender 2.8? import bpy  from mathutils import Vector from math import radians, sin, cos, tan, sqrt, floor  context = bpy.context  def loxodrome_points(spirals, revs, angle_step=10):     a = 1 / spirals     degs = floor(360 * revs / 2)     segs = [radians(d) for d in range(-degs, degs, angle_step)]     points = []     for t in segs:         den = sqrt(1 + a * a * t * t)         x = cos(t) / den         y = sin(t) / den         z = - a * t / den         l = Vector((x, y, z))         points.append(l)          return points   points = loxodrome_points(10, 10) #loxodrome = bpy.data.objects.get("Loxodrome") #if loxodrome is None: if True:     loxocurve = bpy.data.curves.new("loxo", 'CURVE')     loxocurve.dimensions = '3D'     loxocurve.resolution_u = 2     spline = loxocurve.splines.new('NURBS')     spline.points.add(count=len(points) - 1)      for i, bp in enumerate(spline.points):         x, y, z = points[i]         bp.co = (x, y, z, 1)      loxodrome = bpy.data.objects.new("Loxodrome", loxocurve)         context.scene.objects.link(loxodrome)


How can I determine the OS within .bash_profile?

On my main machine, a MacBook Pro, I have a .bash_profile file that I'd like to use unaltered on my Dreamhost linux machine. However, there's a few lines that are only applicable to macOS, such as alias mvim="/Applications/MacVim.app/Contents/MacOS/MacVim".  Is there a way in bash to test for whether it's running under macOS or Debian (or just not macOS) and only execute that above line, and a few others, when running under macOS? Whereas other questions here address how to find out which Linux distro is being used, here I only need to know if I'm running on macOS or Linux, and the solutions for knowing the Linux distro aren't available on macOS.


I understand that showing function completeness is to use the symbols to generate the same truth values as if the other symbol would allow.  Out of the symbols {∧,∨,→,↔}, how would you generate the negation symbol '¬'


I know that if $F[x]$ is a PID then $F$ is a field. Now $F[x]$ being a field implies that $F[x]$ is a PID, so $F$ is a field.  Anyway, I tried to prove that $F$ is a field right away and the following argument came to mind:  Let $A[x]$ be a field, and let $p(x)= a + bx$, then there exists $q(x) = d x^n + ... + r$ where $b$ and $d$ are nonzero, such that $p(x)q(x) = 1.$ Carrying out the multiplication and equating the coefficient of $x^{n+1}$ to zero yields $bd = 0.$ Hence b and d are zero divisors and A is not even an integral domain.  What is wrong with this argument? And is $R[x]$ never a field?


Problem while using \href the "%" sign creates problem

I am using   \href{http://abcd/x/y%z/abcd.html}  but % creates problem. It is getting commented after % but I have % in my address, and \% did not work.


typing a special letter in the bibliography

In bibliography of a manuscript, I wish to point out an author whose name is written in the form    How can I type the last letter of his/her name?


When does Ax +b = 0 not have a solution?

And does that tell us anything about the properties of matrix A?


Are there examples of more informative PCA plots?

I am often disappointed with PCA plots in the scientific literature. Typically PCA plots do not provide a breakdown of the variables and their weights, just something like PCA1 (70% variance explained), PCA2 (10% variance explained). How could one tell which variables are strongly loaded into a component?  Are there PCA visualizations that can provide more insight into the data?


Prove that $ \int_0^\infty (\frac{\sin x}{x})^2 = \frac{\pi}{2}$.

I need to prove that  $ \int_0^\infty (\frac{\sin x}{x})^2 = \frac{\pi}{2}$.  I have proved that $\sum_1^\infty \frac {\sin^2(n \delta)}{n^2 \delta}=\frac{\pi-\delta}{2}$ for $0<\delta<\pi$ and I'm supposed to use this identity.


Let $x_{0} = 2$ and $x_{n+1} = x_{n} + \ln(x_{n})$, how can I find an asymptotic equivalent of this sequence say, to the third term? (This is not homework, it was a problem in the Oral Examination 2010 of Ecole Centrale).


What use are constructors in abstract classes?

Since we can't instantiate an abstract class, then what is the necessity of having constructors in abstract class?


I would like to draw a circle with a border containing two colors. One color should be the base color and the second color should fill up the border up to a certain percentage. For now I am only having this piece of code:  \documentclass{article} \usepackage{tikz} \usetikzlibrary{shapes} \newcommand*\circled[1]{\tikz[baseline=(char.base)]{         \node[shape=circle,draw,inner sep=2pt, thick] (char) {#1};}} \begin{document} \circled{85\%} \end{document}   Which draws a circle around the text:    What I want to achieve is this:


If $x^3$ is a multiple of 2, then that $x$ is a multiple of 2.

How can I prove that if the cube of a number is a multiple of 2, then that number is a multiple of 2


Is there any simple method to calculate $\sqrt x$ without using logarithm

Suppose that we don't know logarithm, then how we would able to calculate $\sqrt x$, where $x$ is a real number? More generally, is there any algorithm to calculate $\sqrt [ n ]{ x } $ without using logarithm? More simple techniques would be nice.  Here is a simple technique used to approximate square roots by :  For example: $\sqrt {78}\approx 8\frac { 14 }{ 17 } $ , where $8$ is the nearest integer root of $78$, $14 = 78 - 8^2$, $17 = 2 \times 8 + 1$.  if $n=2^k$ we can use the method above.   For example, for $k=2$ Lets calculate $\sqrt [ 4 ]{ 136 } $: $$\sqrt [ 4 ]{ 136 } =\sqrt { \sqrt { 136 }  } \approx \sqrt { 11\frac { 136-{ 11 }^{ 2 } }{ 11\times 2+1 }  } =\sqrt { 11\frac { 15 }{ 23 }  } \\ \sqrt { 11\frac { 15 }{ 23 }  } \approx 3\frac { 11\frac { 15 }{ 23 } -{ 3 }^{ 2 } }{ 3\times 2+1 } =\frac { 544 }{ 161 } =3.38\\$$ The exact result is$$ \sqrt [ 4 ]{ 136 } =3.4149\cdots$$ The method approximates well, but it is working for only $n=2^k$ as I know.


Why my program is failing with null pointer exception

I am working on a test assignment where i have to take name and phone number from the user ans save them to the arraylist. I created three classes    Contacts: to store contact details.  MobilePhone: to store the contacts objects.  Mobilemain : begins program execution.   Following is the content of the classes:   Contacts.java      package mobilephone;      public class Contacts {     private int number;     private String name;      public Contacts(String name,int number ) {         this.name = name;         this.number = number;     }      public int getNumber() {         return number;     }      public void setNumber(int number) {         this.number = number;     }      public String getName() {         return name;     }      public void setName(String name) {         this.name = name;     }  }   MobilePhone.java  package mobilephone;  import java.util.ArrayList;  public class MobilePhone {     private ArrayList<Contacts> phonebook = new ArrayList<Contacts>();      public void addPhone(Contacts contact) {         phonebook.add(contact);     }      public void showContacts(){         for(int i=0 ;i< phonebook.size();i++){         System.out.println(phonebook.get(i).getName()+" => "+phonebook.get(i).getNumber());         }     }   }   Mobilemain.java  package mobilephone;  import java.util.Scanner;  public class Mobilemain {     static Scanner scanner = new Scanner(System.in);     static Contacts contacts;     static MobilePhone mobilephone;     public static void main(String[] args){         addContact();                mobilephone.showContacts();     }      static void addContact(){         System.out.print("Enter name: ");         String name= scanner.nextLine();         System.out.println("Enter phone number");         int number= scanner.nextInt();         mobilephone.addPhone(new Contacts(name,number));      }   }   But on executing the  main class i am getting below error.  Enter name: fgsdg Enter phone number 234234 Exception in thread "main" java.lang.NullPointerException     at mobilephone.Mobilemain.addContact(Mobilemain.java:19)     at mobilephone.Mobilemain.main(Mobilemain.java:10)   I verified that the object i am passing at line 19 in Mobilemain.java is not null


What is the best editor for HTML, CSS etc?

in Windows I'm using Komodo & Notepad++ for coding HTML, CSS etc. In Ubuntu, what's the best editor I can use? Thanks :)


if __name__ == main PHP to protect my code

I am somehow a noobie in PHP and I want to learn. I am making a proyect, in which I use require('parts/header.php') statements to include functions and templates. My pages look like this:  <?php  include('core/checklogin.php'); //This will check if the user is logged in and can see this page or not include('parts/top.php'); //This loads the  tags and the header, including the navbar ?>

Hello <?php echo getUserNickname()?>

Some stuff

  <?php  include('parts/bottom.php'); //This loads the  tags and the header, including the navbar ?>   The problem is if someone enters myproyect.com/parts/top.php he would see the top part, and that file is going to be executed. I don't want that. I was thinking doing some stuff in a .htaccess file like:   #.htaccess inside parts directory  dont_serve_anything_inside_this_directory_and_return_forbidden();   But I don't know how without affecting the server side code. Another alternative is to use the equivalent of if __name__ == 'main':  of python, and do like:   //parts/top.php  if(__name__ == 'main'){      header('Location: /index.php');      exit();  }   What could I do?


Is there a way to order a collection by two properties? For example:  I have a PriorityProcess class, and I want to order a collection of these instances by priority (descending) and then arrival time (ascending), but I want this last sort not to overwrite the previous one, more like a sub-sort.  Suppose I have this array of processes:   P0 -> Priority = 1, Arrival Time = 0 P1 -> Priority = 2, Arrival Time = 3 P2 -> Priority = 1, Arrival Time = 8 P3 -> Priority = 3, Arrival Time = 16   I would like to sort it, so I end up with this:   P3 -> Priority = 3, Arrival Time = 16 P1 -> Priority = 2, Arrival Time = 3 P0 -> Priority = 1, Arrival Time = 0 P2 -> Priority = 1, Arrival Time = 8   Is there a way to accomplish this in a single LINQ instruction?  Thanks for your time


How do I prove that the function  $$f(x) = \frac{-2x+1}{(2x-1)^2-1}$$  is one-to-one from the interval (0,1)? I have simplified the function $f(x)=f(y)$ and have a multivariable quadratic equation equal to zero. How do I conclude that the function is one to one?


Which one is correct:  "A popular approach is the so-called immersed interface methods."  "A popular approach are the so-called immersed interface methods."  In Portuguese, the second one would be correct, because the verb "to be" sometimes agrees with the object instead of the subject. I was wondering if in English such exception also exists, of if the verb "to be" always agrees with the subject no matter what.


If $[E:F] = p$, with $p$ a prime. There are no intermediate fields between $E$ and $F$

Let $E$ be an extension field of the field $F$. If $[E:F]$ is prime, then there are no intermediate fields between $E$ and $F$


Removing admin bar from wordpress dashboard

I'm using wordpress multiste 3.3.1 I'm not gonna update it in the future. So I disabled all upgrade functions.  I want to remove the wordpress admin bar from both frontend as well as dashboard.  I can remove it from frontend using this code.  add_action( 'init', 'disable_admin_bar', 1 ); function disable_admin_bar() {     add_filter( 'show_admin_bar', '__return_false' ); }   But i couldn't find any solution to remove it from dashboard.   I don't want to use css solution to hide admin bar and I'm ready to edit the core files to remove it  Can anyone help me to remove it completely?. Thanks


'Obvious' theorems that are actually false

It's one of my real analysis professor's favourite sayings that "being obvious does not imply that it's true".  Now, I know a fair few examples of things that are obviously true and that can be proved to be true (like the Jordan curve theorem).  But what are some theorems (preferably short ones) which, when put into layman's terms, the average person would claim to be true, but, which, actually, are false (i.e. counter-intuitively-false theorems)?  The only ones that spring to my mind are the Monty Hall problem and the divergence of $\sum\limits_{n=1}^{\infty}\frac{1}{n}$ (counter-intuitive for me, at least, since $\frac{1}{n} \to 0$ ).  I suppose, also, that $$\lim\limits_{n \to \infty}\left(1+\frac{1}{n}\right)^n = e=\sum\limits_{n=0}^{\infty}\frac{1}{n!}$$ is not obvious, since one 'expects' that $\left(1+\frac{1}{n}\right)^n \to (1+0)^n=1$.  I'm looking just for theorems and not their (dis)proof -- I'm happy to research that myself.  Thanks!


How do I get prompted for a hostname in a preseed?

I want my automated install to ask me for a hostname.  This is my  and this is my pxe startup conf  LABEL auto64-1110         MENU LABEL ^C Ubuntu 11.10 64-bit auto install met proxy         KERNEL ubuntu-installer-1110/amd64/linux         APPEND vga=normal initrd=ubuntu-installer-1110/amd64/initrd.gz ramdisk_size=16417 root=/dev/ram rw preseed/url=http://pxe-int.hobby.nl/auto-install-ubuntu-hobbynet.txt locale=en_US setup/layoutcode=en_US console-setup/layoutcode=en interface=eth1 netcfg/dhcp_timeout=60 netcfg/get_hostname=install keyboard-configuration/layoutcode=us --   What am I doing wrong?


Finding the Derivative of |x| using the Limit Definition

Please Help me derive the derivative of the absolute value of x using the following limit definition. $$\lim_{\Delta x\rightarrow 0}\frac{f(x+\Delta x)-f(x)}{\Delta x} $$ I have no idea as to how to get started.Please Help.  Thank You


USB WiFi dongle device that can emulate a virtual mass storage device for a home video player

Is there a USB WiFi dongle device that can:   Emulate a virtual mass storage device for a home video player But in fact shows the files from a network-shared folder?


Is there a term for this word play where a song intentionally avoids completing a rhyme?

Take this for example:  In this , at 1:04 to 1:10, the person goes on rapping with a rhyming word at the end of each line, but he pauses before the end of the last word and, being humans, we predict the next word (due to the hint from the rhyme) that he is going to say but he avoids it intentionally. Is there a word or phrase for this word play?     ...and the beat still knocks when I sort my socks   I'm five foot eleven of sex   from the tip of my head to my gorgeous...   knees    Not the best example I could find but I think it sums up my point quite well.


Wifi Adapter Not Found on SONY VAIO with UBUNTU 18.04 RTL8111

My SONY VAIO Laptop with a fresh UBUNTU 18.04 install cant seem to find the Wi-fi Adapter, found this info on the Adapter:  *-network        descripción: Ethernet interface        producto: RTL8111/8168/8411 PCI Express Gigabit Ethernet Controller        fabricante: Realtek Semiconductor Co., Ltd.        id físico: 0        información del bus: pci@0000:0e:00.0        nombre lógico: enp14s0        versión: 0c        serie: 3c:07:71:53:c2:03        tamaño: 100Mbit/s        capacidad: 1Gbit/s        anchura: 64 bits        reloj: 33MHz        capacidades: bus_master cap_list ethernet physical tp mii 10bt 10bt-fd 100bt 100bt-fd 1000bt-fd autonegotiation        configuración: autonegotiation=on broadcast=yes driver=r8169 duplex=full firmware=rtl8168g-2_0.0.1 02/06/13 ip=192.168.0.167 latency=0 link=yes multicast=yes port=MII speed=100Mbit/s        recursos: irq:18 ioport:2000(size=256) memoria:c0500000-c0500fff memoria:c0400000-c0403fff AVISO: la salida puede ser incompleta o imprecisa, debería ejecutar este programa como superusuario.


Database connection PrepareStatement with unknown NULL Pointer

I'm new to the use of Java with database connections, but am getting a NullPointerException using the following code:   import java.sql.Connection; import java.sql.PreparedStatement; import java.sql.ResultSet; import java.util.ArrayList;   public ArrayList<UserVO> getAllUsers(Connection connection) throws Exception {             ArrayList<UserVO> userList = new ArrayList<UserVO>();             try {                 PreparedStatement ps = connection.prepareStatement("SELECT * FROM user");                 ResultSet rs = ps.executeQuery();                 while (rs.next()) {                     UserVO uservo = new UserVO();                     uservo.setUsername(rs.getString("username"));                     uservo.setPassword(rs.getString("password"));                     userList.add(uservo);                 }                 return userList;             } catch (Exception e) {             throw e;             }         }      }   At  PreparedStatement ps = connection.prepareStatement("SELECT * FROM user");   the code throws an exception for java.lang.NullPointerException.I don't know why this is happening, as a   System.out.println("isClosed = " + connection.isClosed());   before the PreparedStatement declaration returns false, and I can print out the connection info.   Any idea of the cause or how to properly compose a statement before query execution? Thanks!  EDIT: Full(ish) stack trace - it's very long  java.lang.NullPointerException     at com.mysql.jdbc.PreparedStatement.asSql(PreparedStatement.java:649)     at com.mysql.jdbc.PreparedStatement.asSql(PreparedStatement.java:587)     at com.mysql.jdbc.PreparedStatement.toString(PreparedStatement.java:4068)     at java.lang.String.valueOf(String.java:2994)     at java.lang.StringBuffer.append(StringBuffer.java:263)     at com.mysql.jdbc.trace.Tracer.printParameters(Tracer.aj:240)     at com.mysql.jdbc.trace.Tracer.printEntering(Tracer.aj:167)     at com.mysql.jdbc.trace.Tracer.entry(Tracer.aj:126)     at com.mysql.jdbc.trace.Tracer.ajc$before$com_mysql_jdbc_trace_Tracer$1$f51c62b8(Tracer.aj:45)     at com.mysql.jdbc.Connection.registerStatement(Connection.java)     at com.mysql.jdbc.Statement.<init>(Statement.java:270)     at com.mysql.jdbc.PreparedStatement.<init>


How do we respond to live website help questions? ("My website is broken, here's the link")

There's a certain class of problematic questions which appears regularly in Stack Overflow: live website help questions. They generally go like this:   The asker has a problem with their website. The CSS isn't working, their JavaScript isn't broken, or their HTML isn't cooperating. They link their website directly, and provide no code samples in the question - often because the code concerned would be most of the webpage and its enormous quantity of HTML, CSS and JS, and there's no way to provide some simple code extracts.   This is the latest example:   The problem is these questions are useless to all future visitors  Code questions generally need code examples. That way, future visitors can look at the problem, understand it, and recognise whether it's their issue or not.  In the case of questions where the only example is a live website, the problematic code will probably be fixed within days, and the webpage may be entirely replaced or cease to exist within months.  Essentially: within a few days, nobody will be able to understand and recognise the problem, or learn from the questions. I would go as far as to say these questions only help the asker.  How do we respond to these questions?  Do we downvote them? Do we close them with the close reason of "Questions concerning problems with code you've written must describe the specific problem — and include valid code to reproduce it — in the question itself"? Do we need a specific close reason, or do we need to specifically mention somewhere that a live website is not a sufficient code example?


java.lang.NullPointerException error in java

I am trying to build a garage in java. I have got a NullPointerException when I call the method addOption on my object Lagouna in my Main "Test". It is strange because it works when I call my method setMoteur. My object Lagouna is not null. My object GPS is not null as well.  Main  public class Test {      public static void main(String[] args) {         // TODO Auto-generated method stub      Garage garage = new Garage();         System.out.println(garage);       Vehicule lag1 = new Lagouna();      lag1.setMoteur(new MoteurEssence("150 Chevaux", 10256d));      lag1.addOption(new GPS()); // here is my error      } }   Class Vehicule  public abstract class Vehicule {  protected double prix; protected String nom; protected Marque nomMarque; protected List<Option> options; protected Moteur moteur;   Vehicule(double prix,String nom,Marque nomMarque){     this.prix=prix;     this.nom=nom;     this.nomMarque=nomMarque; } Vehicule(){     prix=0d;     nom="";     nomMarque=null;     options=null;     moteur=null; } public String toString() {     String str="Je suis une voiture "+ nom + " de la marque "+ nomMarque;     return str;     }  public void addOption(Option opt) {     options.add(opt);         } public Marque getMarque() {     return nomMarque;     } public List<Option> getOptions() {     return options;     } public double getPrix() {     return prix;     } public void setMoteur(Moteur mot) {     this.moteur=mot;     } }   Class Lagouna  public class Lagouna extends Vehicule {      Lagouna(){         super();     } }   Class GPS  public class GPS implements Option{  static double prix=113.5d;     public double getPrix() {         return prix;     } }   Class Option  public interface Option {  public double getPrix(); }


How many squares of size a×a can be packed into a circle of radius R?  like this examples :


Numerically stable algorithm for solving the quadratic equation when $a$ is very small or $0$

Solving $a x^2 + bx +c=0$ for $x$ gives  $$x = \frac{-b \pm \sqrt{b^2-4ac}}{2a} \text{, for } a \ne 0$$  But for $a = 0$ we get   $$x=-\frac{c}{b}$$  How to implement a numerically stable algorithm for computing $x$ from $a,b,c$ that allows $a$ to be close to zero or zero?


Images as Planes in Eevee having weird transparency

I have a weird problem with my viewport. As the images show, there are some very basic objects. But some textured objects are shown through other objects, although they should be hidden. It's obvious with the gravel – the object with grass texture should conceal a part of the object with gravel texture. On the other hand, the gravel goes some way under the plain white object, and is hidden by it, as expected.    I'm anything but a noob with Blender, but switched recently to 2.82. This problem happens with different objects and different materials, even with Cycles or Eevee. Could this be a graphical glitch? My PC isn't anything but bleeding edge, more kind of usable ol' buddy. Never had this behavior with 2.79b.  Thanks in advance.


Cannot find NullPointerException in lottery application

I am making a program that makes a randomized lotto ticket and compares it to a user's set of numbers. My problem is I cannot locate the error of NullPointerException. I also feel like my method for comparing numbers is sub-optimal but I can't think of better way to write it.  package lotteryapplication;  import java.util.Random; import java.util.Scanner;  public class LotteryApplication {      public static int lotteryNumbers[];     public static int usersNumbers[] = new int[5];      /**      * @param args the command line arguments      */     public static void main(String[] args) {          System.out.println(                 " This is the lottery. Numbers in my lottery range from 1 through 60.");         System.out.println(" See if you can win\n");         getUserPicks();         getRandomNumbers();         checkLotteryMatch();     }      public static void getUserPicks() {         Scanner keyboard = new Scanner(System.in);         for (int i = 0; i < 5; i++) {             System.out.print(String.format(                     "Enter a Number from 1 through 60 for spot :" + (i + 1))                     + "\n");             usersNumbers[i] = keyboard.nextInt();             keyboard.nextLine();         }     }      public static void getRandomNumbers() {         int lotteryNumbers[] = new int[5];         Random r = new Random();         for (int i = 0; i < 5; i++) {             lotteryNumbers[i] = r.nextInt(60) + 1;         }     }      public static void checkLotteryMatch() {         int matchedNums = 0;         if (usersNumbers.length == lotteryNumbers.length) {              for (int i = 0; i < lotteryNumbers.length; i++) {                 if (usersNumbers[0] == lotteryNumbers[i]) {                     matchedNums++;                 }             }             for (int i = 0; i < lotteryNumbers.length; i++) {                 if (usersNumbers[1] == lotteryNumbers[i]) {                     matchedNums++;                 }             }             for (int i = 0; i < lotteryNumbers.length; i++) {                 if (usersNumbers[2] == lotteryNumbers[i]) {                     matchedNums++;                 }             }             for (int i = 0; i < lotteryNumbers.length; i++) {                 if (usersNumbers[3] == lotteryNumbers[i]) {                     matchedNums++;                 }             }             for (int i = 0; i < lotteryNumbers.length; i++) {                 if (usersNumbers[4] == lotteryNumbers[i]) {                     matchedNums++;                 }             }             for (int i = 0; i < lotteryNumbers.length; i++) {                 if (usersNumbers[5] == lotteryNumbers[i]) {                     matchedNums++;                 }             }         }         if (matchedNums == 1) {             System.out.println("You only got one match sorry you win nothing.");         }         if (matchedNums == 2) {             System.out.println("You only got two matched sorry you win nothing");         }         if (matchedNums == 3) {             System.out.println(                     "you will recieve a free Lottery ticket as the prize");         }         if (matchedNums == 4) {             System.out.println("You will recieve a $2,000 prize");         }         if (matchedNums == 5) {             System.out.println("You will recieve a 500,000 prize");         }         if (matchedNums == 6) {             System.out.println("You will recieve a grand prize of $1,000,000");         }     } }


I have a visa type D (multiple) for Italy. My flight has a stop in Barcelona. Would it cause any problem for me that my first time entry to Schengen is not to Italy? My stop there is for 4 hours and I am not going to leave the airport.


Integral elements form a ring. What can we say about polynomials of sum and product?

Let $B$ be a ring (commutative and with identity). It is a standard fact in Algebraic Number Theory that the sum $b_{1}+b_{2}$ and the product $b_{1}b_{2}$ of integral elements $b_{1},b_{2}\in B$ over a ring $A$ are again integral over the ring $A$. The proof of this fact is due to the module-theoretic interpretation of integrality: an element $b\in B$ is integral over $A$ iff the $A$-module $A[b]$ is finitely-generated.  I don't know much about module theory, so I'm not sure if this is an obvious question:  If $f_{1}(x)$ and $f_{2}(x)$ are "integral polynomials" for $b_{1}$ and $b_{2}$ integral elements $\in B$ over $A$, (i.e. monic polynomials in $A[x]$ with $f_{1}(b_{1})=0$ and $f_{2}(b_{2})=0$) can we say something (even if the proof is not elementary) about "integral polynomials" for the sum $b_{1}+b_{2}$ or product $b_{1}b_{2}$ in terms of $f_{1}$ and $f_{2}$? Do we know how to produce such polynomials?


Is it possible to enable usb debug without touch screen?

I have a samsung i9100 phone. The screen is broken. Usb debug mode is not enabled. So is it possible to enable usb debug in such situation? I don't want to replace the screen now.


Best way to prevent default server? (for HTTPS)

In Nginx (https server), how can I reject all requests for my server's IP address that don't contain the real domain name? (I would like to stop script kiddies who scan every single IP address that Digital Ocean owns!)  I'm looking for the proper HTTPS way of answering  question which only works on pure HTTP.  Thank you!


Find the determinant of the following matrix: $$A = \begin{bmatrix} 1+x_1^2 &x_1x_2  & ... & x_1x_n \\   x_2x_1&1+x_2^2  &...  & x_2x_n\\   ...& ... & ... &... \\   x_nx_1& x_nx_2  &...  & 1+x_n^2 \end{bmatrix}$$  I computed for the case $n=2$, and $n=3$ and guessed that $\det(A)$ should be $ 1+\sum_{i=1}^n x_i^2 $  but not sure how to proceed for any $n$.


Android JAVA - NullPointerException while using and Interface Field

I'm coding an Android App. At a certain point, the App is asked to retrieve data from a Web Service that I have on Heroku. The class that contains the methods that retreive data and the class with the methods that use those data are different. I'm trying to pass the data from an AsyncTask's onPostExecute() to my other class using an interface; however I'm getting an annoying NullPointerException and I'm not understanding the reason of this!  My "main" class:   public class Details extends AppCompatActivity implements ResponseFromWebService.AsyncResponse {  @Override     public void processFinish(String output){         System.out.println(output);     } //Other Stuff }   My ResponseFromWebService class:  public class ResponseFromWebService {  public void getData (String Name) {     new JSONTask().execute("censored-URL"); }  public interface AsyncResponse {     void processFinish(String output); }  public class JSONTask extends AsyncTask<String, String, String> {      AsyncResponse delegate = null;      @Override     protected String doInBackground(String... params) {         HttpURLConnection connection = null;         BufferedReader reader = null;         StringBuffer buffer = new StringBuffer();          try {             URL url = new URL(params[0]);             connection = (HttpURLConnection) url.openConnection();             connection.connect();              InputStream stream = connection.getInputStream();              reader = new BufferedReader(new InputStreamReader(stream));              String line = "";             while ((line = reader.readLine()) != null) {                 buffer.append(line);             }              String finalJson = buffer.toString();              JSONObject finalObject = new JSONObject(finalJson);              String Desc = finalObject.getString("desc");              return Desc;          } catch (MalformedURLException e) {             e.printStackTrace();         } catch (IOException e) {             e.printStackTrace();         } catch (JSONException e) {             e.printStackTrace();         } finally {             if (connection != null)                 connection.disconnect();             try {                 if (reader != null)                     reader.close();             } catch (IOException e) {                 e.printStackTrace();             }         }         return null;     }      @Override     protected void onPostExecute(String s) {         super.onPostExecute(s);         delegate.processFinish(s);     } } }   The NPE occurs at the last line, when there is a call to delegate.processFinish(s);  Really need help!


When I ran a command, I got the following error:     You need to be root to perform this command.   What is root and how can I become it?


So hard "that" I can't tell the difference

I have always been doubtful about whether  I have to put " THAT"  when I want to give an explanation or reason for something happening or not.  " I'm so tired I can't even stand up"  or "I'm so tired THat I can't even stand up"  His  biggest problem at the interview was he didn't know to read.  His  biggest problem at the interview was THAT he didn't know to read.  My only problem was I needed money I didn't have   My only problem was THAT I needed money I didn't have.  This is so disappointing I don't even wan to say a word about it.  This is so disappointing THAT I don't even want to say a word about it.  I know I can leave out "That" when another  subject goes immediately after the first verb, but when I'm trying to explain the reason for something happening, I find THAT useful. Is that correct grammar?


Can't select vertices of different meshes in edit mode

why can't i select two objects in edit mode?     I am trying to make a face from two different meshes but can't perform the action


I'm looking for a sequence of functions that is continuous and absolutely integrable, but pointwise divergent for every $z$ $\in [0,1]$.  In other words,   $ \int_0^1 |f_n(z)| dz \rightarrow 0$ as $n \rightarrow \infty$, but $(f_n(z))_n$ pointwise diverges for every $z$ $\in [0,1]$.  I'm having no luck coming up with an example, and would appreciate any sort of insight on how to go about constructing such a sequence.


How to obtain basic golden cards that are not class-specific?

To obtain the golden basic cards for a specific class I need to level the class, but what do I have to do to obtain golden versions of basic cards that are not class specific, since they cannot be crafted with dust?


What is $\sum_{k=1}^n{{n}\choose{k}}k^{3}$ equal to?

Find a compact form for the sum $$\sum_{k=1}^n{{n}\choose{k}}k^{3}$$  I have been trying to solve this question for some time now. My guess is that I am supposed to write this in terms of something simpler (like a power of a simple sum) but I just can't come up with anything. I would appreciate it if you could give me a hint before providing the full answer so I can think about it on my own.


How to expose opportunity object in a community

We are creating a new community for our grantees.  We are managing the grantee information in the opportunity object.  So each grantee has an opportunity record and we want him to be able to manage his opportunity through the community.  We want to use the Customer Community Logins user licenses for our grantees, because they are reasonably priced.  But the opportunity object is not viable with that license .  So our question is:  What is the best way to expose the opportunity to the community?  I can think of 2 ways:   Buy the very expensive "Partner Community Logins" user license (this is too expensive to my company so not a real viable solution). Develop a lightning component / VF page to show and manage the opportunity.   Is there another way?  What is the best way to implement that?  What are the pros / cons?  Any info would be highly appreciated!  Thanks, Itai  EDIT  This question is not a duplicate of  question because they are not the same - I am asking for a workaround and what is the best approach for a solution and I know the opportunity is not accessible for the customer community license, while the other question asks if this is true...  Also the answer there is not good enough as I am searching for a better workaround.


Redirect anonymous users to the register page

Is it possible to redirect anonymous user to user/register page? How can I do that?


How do I view files that start with a period?

I have Ubuntu 15.04 and for whatever reason, folders that start with a "." won't display in the file explorer. Is there a way to display these folders? Example: my app doomseeker has a folder in home that it says it has created (.doomseeker) and it won't display in the file explorer. Thank you very much.


Will my photographer be able to sell me better prints than I can get from the 2400×3600 JPEG files I hav?

I just got my senior pictures back and want to print them professionally. They were shot with a Canon EOS Rebel T5 and specs are 2400 x 3600, 240 dpi. My photographer uploaded them to her website and I saved them as JPGs, then did some mild teeth whitening in Photoshop and saved them as TIFs. I know nothing about photography, but would I be able to get a nice quality 16x20 print with these specifications? Keep in mind it will hang on the wall and people likely won't go up close to view them, however I still want them to look relatively nice at a close distance.   Also, if I order straight from my photographer will the quality be better because she has the original files?  My question has been marked as a duplicate but I've already viewed that question and it didn't help me enough. Plus I want to know if printing online vs with my photographer will make a difference.


Expected Double value to display two zeros after precision value

I have a scenario where we need to display two zeros i.e 00 after the precision for double value. But unfortunately Java is not returning the second zero.  I have tried the below way but it is returning only one zero after decimal.  double inputvalue = 12345.00; double d = ((BigDecimal.valueOf(inputvalue)).setScale(2,RoundingMode.UP)).doubleValue();   Expected output: 12345.00 but it is returning 1234.0.


I am wondering how i can center my image upload form.
Your browser doesn't support upload.
   All the other elements like buttons are centered with:  .jumbotron { margin: 60px 0; text-align: center; }


What are these "[verb]-ing" forms called?

How would you describe the bolded words here? They don't intuitively seem like  to me, but I might be wrong.       List X can be created by appending the contents of List B to List A.         List Y is the result of sorting List X.


To backup my document root (/var/www/html/ I can execute):  zip -r ~/backups/all_zipped-$(date +\%F-\%T).zip /var/www/html/   The problem is that inside the created zip file, I get 3 base directories instead of 1:   var. www. html.   The desired end state is to have only 1 base directory (the last one). In this case, of course, html (and its inodes).  Using zip -r ~/backups/all_zipped-$(date +\%F-\%T).zip /var/www/html/* (note the *), didn't help.  How to zip current directory without its entire path?


I would like that for files with .vm extension vim would:   colour in red all the words between two back-ticks like `this`, colour in yellow what is between two dollars like $this is in yellow$, and colour in green all words between # and the end of the line.


I just got a brand new dell XPS 13 and I went to set it up. I typed in the wifi password and realized I got it wrong. So I ended up hitting a button in the bottom right corner. For some reason it reset the computer and when it booted back up, it didn't save any of my info and I'm stuck with the guest account.   I don't have any internet connection in the guest account and can't set it up. What can I do to create an account and have full control of my laptop? The guest account won't allow me to create a new account.


If I have Extra Attacks, when can I decide which one is a sneak attack?

So, if a character multiclasses to a point where they have multiple attacks in a round, I assume you can decide once the hit has been confirmed by the DM, but before you roll damage, whether you make the hit a sneak attack?  I ask because you may know an enemy is weak, and don't want to waste the damage to finish it. I also want to confirm that you cannot declare sneak attack damage after you have already rolled your base damage, to finish off a still standing opponent for example. The "Is it dead? No? Oh! Then sneak attack!" seems dumb and nonsensical to me. I expect it to be like smite, decided on hit, but before damage is rolled.


Which of these sentences is correct?     You mentioned having been in a hospital last year.      You mentioned being in a hospital last year.


Manage abbreviations before parantheses at the end of a sentence

There are already topics very close to my question, but not quite there. Does anyone know what to do about this:     We review our accounts p.a. (at the end of the year).   Normally, without the text in parentheses, the "." after "a" would suffice to end the sentence, but then the parentheses come into play.  Should there be another period after the parentheses like in my example, or no?


I have mistakenly deleted my movies using root rm -rf /home/username/Videos/movies. How can i recover it, I have already installed extundelete and am using ext4 and its mounted at /dev/sda


Ubuntu 18.04: Boot Freeze / Purple Screen Hangs

Just today when I started Ubuntu 18.04 (Linux Kernel 4.15.0-51) in VMware Workstation Player 14 (14.1.7) the boot freezes just before the login prompt. The mouse cursor is visible and the Ubuntu logo at the bottom center is just being rendered as is visible in the attached screenshot. (Depending on the exact moment of the freeze the Ubuntu logo appears more or less bright.)  I am able to boot if I enter recovery mode and simply resume the boot. However, I am not able to set the display resolution to the hosts' nor is the host's display device detected.  To resolve the issue I reinstalled the VMware tools as well as the open-vm-tools. I also tried to extend the "Unit" section of /etc/systemd/system/multi-user.target.wants/open-vm-tools.service with Requires/After=graphical.target to no effect. Lastly, I attempted to check the filesystem which failed:   /lib/recovery-mode/recovery-menu: line 80: /etc/default/rcS: No such file or directory fsck from util-linux 2.31.1 /dev/sda1 mounted. e2fsck: Cannot continue, aborting.  Finished, please press ENTER   Boot freeze on purple screen before login prompt:


How to normalize a value from a range to another

I have a set of value with range 0 to 1. I have to change the dataset from 0 to x. Which formula i have to use?


Should I do someone else's peer-review work?

My secondary advisor approached me; he is on the program committee of a conference and asked if I were willing to review a research paper that is in my avenue of research. The review is part of the peer-review process, to determine acceptance.  I accepted, but it turns out it he is planning to submit the review himself, just asking me to write it for him.   Should I protest? If they are my words, my name should be on the review. But I don't want to raise a ruckus if it materially doesn't matter anyway.   Do I gain any benefit if it is me who submits the review instead of him?


Modify parents dict() argument in child definition

Say I have a class A:  class A:     list_attribute = ['foo', 'bar']     dict_attribute = {'foo': 'bar'}   A is extended by B, and in B I want to add elements to list_attribute in the declaration of the class, it is pretty easy   class B(A):     list_attribute = A.list_attribute + ['foobar', 'barfoo']   My question is, how can I add elements to the dict_attribute the same way I did for the list_attribute (in the attribute definition, and not in the __init__), since dicts don't support the + operator ?  Thanks in advance and have a great day!


Read a line-oriented file which may not end with a newline

I have a file named /tmp/urlFile where each line represents a url. I am trying to read from the file as follows:  cat "/tmp/urlFile" | while read url do     echo $url done   If the last line doesn't end with a newline character, that line won't be read. I was wondering why?   Is it possible to read all the lines, regardless if they are ended with a new line or not?


What are some good books with the help of which I can self-study Bayesian from the basics to advanced, mentioning why do we need Bayesian and also which contains numericals, which can boost my concept. I know the basics of Bayes theorem and conditional, but when it comes to Bayesian my knowledge is very abstract. So it would be very helpful if I am suggested a good book which I can download online. Thank You.


How to export model with custom material?

this seems like such a simple "just google it" thing, but nothing I've found has worked for me. I have a model with a custom material that I want to export into Unity.  I've applied an image onto the model using the Diffuse BSDF shader and setting the Image Texture under color, and it looks fine in Blender (fine for my horrible standards), but when I export to fbx it's just a gray colorless model, even if I follow the advice of setting 'Path Mode' to 'Copy' and checking 'Embed Textures'. Some people say to bake but I haven't been able to figure out how to make that work either. Thank you


convergence to infinity of$ (2^n + 3^n)^{\frac{1}{n}}$ (as $n \to \infty$)

Just checking. $2^n$ ($n \to \infty$) tends to $\infty$. + $3^n$ also ($n \to \infty$) tends to $\infty$  so the sum gets me $\infty$.  Now $(\infty)^{1/\infty}$ : $(\infty)^0 = 1$  I see no other way.  Theorem: $n^{\frac{1}{n}} = 1$ as $n \to \infty$.  Analogous:  $(2^n - 3^n)^\frac{1}{n}$ = $(\infty  - \infty)^0$ = 1 ???  Is it ok to suppose infinity on any integer $k^n$ as $n$ goes to infinity ?


Moved .mov to wrong directory and now it is a Unix Executable File

Was moving a movie file using mv but I typed the directory wrong. It turned my movie file into a Unix Executable File.   mv /path/to/folder/1/this.mov /path/to/folder2  /folder2 did not exist  Can I undo this action or return this file to a .mov?  I fear that this is not an undo thing. Any help or guidance will be a great thing.  Thank you


What do the parentheses and number after a Unix command or C function mean?

I keep seeing parentheses and a number after a command in Unix or Linux or C function.   For example: man(8), ftok(2), mount(8), etc.  What do these mean? I see them in man too.


Compact convergence $\sum_{n = 1}^{\infty} f(z^n)$

Let $f \colon \mathbb{E} \to \mathbb{C}$ holomorphic with $f(0) = 0$. Ist there a way to prove the compact convergence of the series $$\sum_{n = 1}^{\infty} f(z^n)$$ without using the Taylor series and then applying some theorem for double serieses?


Which email was the verification email sent to? pokemon Go

I started my app today and it said that I needed to verify my email. But I don't know the email I chose. I logged on every email in but there was never a verify email. Is there a way to know your email on Pokemon Go?


Any idea whats going on with these back legs?

I tried removing doubles and nothing happened. Not sure what else to try


A word(?) on giving something a different name on media to make it more acceptable?

Is there a word or a phrase that has to do with renaming an act (that is deemed morally questionable) so that it may seem more neutral and therefore acceptable to the general public? It has nothing to do with understating the horrors of what is done, rather it is more on giving it a different label so that the there is more distance between the public and whatever reprehensible act was done, making it an easier pill to swallow.   The only example I could find online is renaming 'acts of torture' with 'abuse' in the Abu Ghraib scandal to make it seem more neutral.


Is there a statistical test to compare two samples of size 1 and 3?

For an ecology project, my lab group added vinegar to 4 tanks containing equal volumes of pond water, 1 control with no elodea (an aquatic plant) and 3 treatments with the same amount of elodea in each. The purpose of adding the vinegar was to reduce the pH. The hypothesis was that the tanks with elodea would go back to their normal pH quicker. This was indeed the case. We measured the pH of each tank daily for about two weeks. All the tanks eventually returned to their natural pH, but the length of time that this took was much shorter for the tanks with elodea.  When we told our professor about our experimental design, he said that there exists no statistical test that can be performed on the data to compare the control to the treatment. That because there was no replicate for the control (we only used one control tank) we cannot calculate variance and so we can't compare the sample means of the control and the treatment. So my question is, is this true? I definitely understand what he means. For example, if you took the height of one man and one woman, you can't draw conclusions about their respective populations. But we did 3 treatments, and the variance was small. It seems reasonable to assume that the variance would be similar in the control?  Update:  Thank you for the excellent answer. We got more water and elodea from the wetland and decided we would run the experiment again with smaller tanks but this time with 5 controls and 5 treatments. We were going to combine this with our original data but the starting pH of the tanks was different enough that it doesn't seem valid to consider the new experiment to be sampled from the same population as the original experiment.  We considered adding different amounts of elodea and trying to correlate speed of pH remediation (measured as time elapsed until pH returned to its original value) with amount of elodea, but we decided that wasn't necessary. Our objective is only to show that the elodea makes a positive difference, not to construct some kind of predictive model for exactly how the pH responds to differing amounts of elodea. It would be interesting to determine the optimal amount of elodea, but that's probably just the maximum amount that can survive. Trying to fit a regression curve to the data wouldn't be especially illuminating because of the various complicated changes that occur to the community when adding a large amount. The elodea dies, decomposes, new organisms start to dominate, and so on.


How do I approach existing questions to which I believe the answers are inadequate?

I've come across this problem recently when trying to find a solution to a problem on Stack Overflow. It was a common question to which there were already literally dozens of highly rated answers.  In my view, these answers were not good, or did not address the question (in this case the solutions simply didn't work for me).  I have gone about this by posting my own question, outlining why the answers didn't work, and hoping for a response. Is this how things should be done? For anyone interested, here is my new question:


Let $(x-1)^3$ divides $p(x)+1$ and $(x+1)^3$ divides $p(x)-1$. Find a polynomial $p(x)$ of degree 5. Here's what I have tried:—  As $(x-1)^3$ divides $p(x)+1$, $p(1)+1=0$, $p(1)=-1$ $p(-1)=1$ Letting $p(x)=a_5x^{5} + a_4x^{4} + a_3x^{3} + a_2x^{2} + a_1x + a_0$  I don't know how to proceed any further. I think the divisibility rule is gonna be used somewhere.


Is it possible to find out what apps created a given file/folder?

I want to keep track of the application that created the folder. I use an Android phone. And some apps automatically creates unnecessary folders in the root directory of my phone. I want to know where they come from.(The photo below is an example.) I can delete that folder but it will be recreated within few minutes. Are there any apps or adb commands that can monitor whether a folder or file is being edited? Or, is there a way to block the creation of a folder with the same name?  I have read all of the guides but may still be wrong. Please tell me if this is a duplicate question. I apologize if this is a bad question. I want to catch the culprit!


What is the 'ctr' variable in a parallel C# loop?

I recently used a Parallel.For loop (see code below) in a small C# program and I'm a little perplexed by the ctr variable. Every example I've seen so far has the name of this variable set to ctr, but I cant seem to find any good resource on what it means or why exactly this name is used. If anyone knows more about it, I would be happy to hear it! public static int[] calcArray(int[] arrName, int arrSize, int seed) {     Parallel.For(0, arrSize, ctr =>    {        arrName[ctr] = AllfunctionsClass.Random(seed);        seed++;    });     return arrName; }


Can anyone help me out? I've searched here on Superuser, I've searched Google, I've searched everywhere, and I cannot for the life of me find out how to shut down Cortana. Mind you, I have a new laptop, so maybe information hasn't caught up yet. She's everywhere. She's there when I Alt+Tab. She's there in the corner. I've shut down permissions everywhere I can find. But she's still there. Can anyone tell me once and for all how to shut down Cortana? I shouldn't have to fight with Microsoft just to get Cortana to leave me alone. In case it matters, I have Windows 10 build 19041.630.


When is the message "Have you considered accepting an answer or starting a bounty for this question?" displayed?

Sometimes, I notice the following message on the Questions tab in my profile on Stack Exchange site:  Have you considered accepting an answer or starting a bounty for this question?  When does this message get displayed? Is it based on time of non-availability of answers or inactivity period?


Exercise 6.V - The Elements of Integration and Lebesgue Measure by Bartle

6.V The space $L_{\infty}(X,X,\mu)$ is contained in $L_{1}(X,X,\mu)$ if and only if $\mu(X)<\infty$. If $\mu(X)=1$ and $f\in L_{\infty}$ ,then $$||f||_{\infty}=\lim_{p\to \infty}{||f||_{p}}$$   For the first part, if containment is true then $$\because f=1$$ a constant function, is contained in $L_{\infty}$. From our assumption it will also be contained in $L_{1}$.  $$\therefore \int|f|d\mu<\infty$$ $$\int d\mu <\infty$$ $$\mu(X)<\infty$$   Conversly, if $\mu (X)<\infty$.  Let $f\in L_{\infty}$ be an arbitrary element,$$\therefore ||f||_{\infty}<\infty$$ Also, there exists a measurable set $E$ with $\mu(E^{\complement}) =0$ such that for every $$\forall x\in E$$ $$|f(x)|\leq||f||_{\infty}$$ Consider, $$\int|f|d\mu = \int_{E}|f|d\mu + \int_{E^{\complement}}|f|d\mu$$ $$\int|f|d\mu = \int_{E}|f|d\mu + 0$$ $$\int|f|d\mu < \int_{E}||f||_{\infty}d\mu$$ $$\int|f|d\mu < ||f||_{\infty}\int_{E}d\mu$$ $$\int|f|d\mu < ||f||_{\infty}\mu(E)$$ $$\because \mu(E)<\mu(X)<\infty$$ $$\int|f|d\mu < \infty $$ $$\therefore f \in L_{1}$$ Hence,$$L_{\infty}\subset L_{1}$$ For the second part of the question, I was able to show that $$||f||_{p}<||f||_{\infty},$$ using similar steps as used to prove that $||f||_{1} < \infty$, for first part of the question. I think that it might come handy for solving the second part.  But i do not know, how to show that it is a convergent sequence and it converges to $||f||_{\infty}$.


Shift between OpenLayers and vector layer QGIS 2.20

Can you please help me solve this issue with OpenLayers Plugin. I see some shift with a vector layer of Laos water boundaries when the background is Google Physical Layer.  I am using CRS EPSG:32647 (UTM 47N). QGIS version is 2.2.0.   Please see the picture attached.


Is there a way to make a conditional where the test is the definition of a counter with a specific name, i.e. "if there exists a counter named foo, then do [bar], otherwise do [baz]"? If so, how do I do that?


I'm attempting to build an LED bed lamp that will be powered by 240V mains. The LEDs are  which if I use with a 12V supply and have calculated correctly will draw 0.24W each. I plan to use 5 or 6 of them in the lamp so will consume a maximum of 1.5W.  Initially I thought I'd use a transformer and bridge rectifier to get the required 12V DC but the transformer weighs a ton and is too bulky. The next option was to use a  but I'm wondering is there is a better way?  I think it would be possible to power the LEDs directly from mains using only a rectifier without mains and stepping down the voltage but then it's not safe. Are there any smallish components that can both isolate the mains and supply a DC voltage?


Looking for name of a book-series - Spaceship crashed, Civilization based on Magic rebuilt

I'm trying to figure out the title of a series I read when I was younger. As far as I can remember, it started with a spaceship crashing on a planet in book 1. Some plants on that planet had weird effects on the people of the ship, not sure what kind though.  All of the books afterwards are set centuries or even millennia later, about the rebuilt civilization where "magic" or some kind of powers were around.  I'll update if I remember anything more specific.


How does the values of an array changes when we passed it as an argument to other function?

When i passed an array as an argument to the function, the original array gets changed, but the array should not get changed right? please correct me if am wrong.  below i passed an int x=10 as an argument to change(int a) function. the value of the original int x got changed.  So how does the same code affects an array and int in different way?  public  class Runy  {  public static void main(String [] args)  {     Runy p = new Runy();     p.start(); }  void start()  {     long [] a1 = {3,4,5};     long [] a2 = fix(a1);      int x=10;     int y= change(x);      System.out.println(y);     System.out.println(x);      System.out.print(a1[0] + a1[1] + a1[2] + " ");     System.out.println(a2[0] + a2[1] + a2[2]);  }  long [] fix(long [] a3)  {     a3[1] = 7;     return a3; } int change(int a) {     a=a+1;     return a; }   }


What is the best way to clone a disk between two Macs? I ask this every couple years or so and every time I get the same answer. "Use ", they say. But the unfortunate fact is that CCC is a file-level copy between disks. When I migrate to my new Mac, sure all the files are there but there are quirks here and there (including file dates being different etc).   So, really now, once again: how do you clone the disk over byte-for-byte?


Puzzle. Transfer maximal coal using a train

We need to transfer coal from point $A$ to point $B$ using a train. There is $9000$ tonne at point $A$. The distance between point $A$ and $B$ is $3000$ km. Train can carry only $3000$ tonne included its fuel. Also train consumes $1$ tonne coal per $1$ km. How much coal can be transferred from point $A$ to $B$?  I can do only $1500$. But can't prove it is optimal.


New feature proposal: move 'closed' questions to a "Recycle Bin"

Whenever a question is 'closed' in any of the Stack Exchange forums, for ANY reason, it instantly becomes locked: i.e., it is not answerable anymore. Now, some questions could be edited and then re-opened, some could be migrated, but in many cases, nobody knows how to make a question better; the only thing that they know is, "it doesn't belong here". Most users who post such questions are new and are not accustomed to the narrow, stringent on-topic guidelines, or read the guidelines, thought that it would be on-topic, but it turned out that it is not. (Okay, many people do not read or research anything, but they should not determine how the others get treated!) Not only this affects the asker's account, but also, more than that, it gives off a "you're not welcome here" vibe. As a result of this negative experience, it might discourage some to ask questions in the future, or drive them away forever. Given that how overworked Moderators are and how frustrating their tasks could be, plus, as a community-oriented set of forums, I think every question and every asker should, at least, have an oppurtunity to be judged by the community as a whole. I propose that there should be a "Recycle Bin" ("What's in a name?") in every Stack Exchange forum, to where a closed question automatically goes, and stays there for, say, 30, 60, or 90 days, or until re-opened, after which it gets deleted. While in the "Recycle Bin", it is answerable. The "Recycle Bin" link would be in the left side navigation panel. Optional: "Recycle Bin" up-votes give more positive reputation, and, possibly, special badge(s).  In its current form, it's just one or a few people who decides what the rest gets to see! (I admit that they have earned it, but we are all humans, and prone to errors and biases.) As Stack Exchange strives to be a democratic forum, I think that separating those questions from the mainstream (you'll see them if you choose to see them), and those still being answerable, would be a good idea. What if this is tried as a beta? If it turns out to be fruitless, it could be stopped anytime.  The suggested question (and the linked ones to that) is asking that the question stay in the "main area". I am asking that it be moved to a place of its own, eligible to get answers, and still be deleted after a time period if not clarified well enough to return to the "main area". As of now,  is the only way (for a kind-hearted) to answer a closed question, which is not very "Stack Exchange-y"! N.B.: As with any opinions, there always are people who think that a question is valid, or it makes sense to them, and/or would like to help. I am asking about giving everybody a chance before deleting forever.


How to concatenate a char * and a const char*?

I need to put "Hello World" in str3. How can I do this ?  const char *one = "Hello "; char *two = "World"; char *str3;


Secure Online Highscore Lists for Non-Web Games

I'm playing around with a native (non-web) single-player game I'm writing, and it occured to me that having a daily/weekly/all-time online highscore list (think Xbox Live Leaderboard) would make the game much more interesting, adding some (small) amount of community and competition. However, I'm afraid people would see such a feature as an invitation to hacking, which would discourage regular players due to impossibly high scores.  I thought about the obvious ways of preventing such attempts (public/private key encryption, for example), but I've figured out reasonably simple ways hackers could circumvent all of my ideas (extracting the public key from the binary and thus sending fake encrypted scores, for example).  Have you ever implemented an online highscore list or leaderboard? Did you find a reasonably hacker-proof way of implementing this? If so, how did you do it? What are your experiences with hacking attempts?


Why are there only two tangents to a hyperbola from a point, instead of four?

Why are only two tangents possible to a hyperbola from a point? If we treat the hyperbola as two individual parabolas, then a point should be able to create two tangents through it for both of them, hence a total of 4.


Passing apache2 digest authentication information to a wsgi script run by mod_wsgi

I've got the directive  <VirtualHost *>     <Location />         AuthType Digest         AuthName "global"         AuthDigestDomain /         AuthUserFile /root/apache_users         <Limit GET>             Require valid-user         </Limit>     </Location>     WSGIScriptAlias / /some/script.wsgi     WSGIDaemonProcess mywsgi user=someuser group=somegroup processes=2 threads=25     WSGIProcessGroup mywsgi     ServerName some.example.org </VirtualHost>   I'd like to know in the /some/script.wsgi  def application(environ, start_response):     start_response('200 OK', [         ('Content-Type', 'text/plain'),     ])     return ['Hello']   What user is logged in.  How do I do that?


Assigning Weights to An Averaged Forecast

So I've been learning how to forecast over this summer and I've been using Rob Hyndman's book Forecasting: principles and practice.  I've been using R, but my questions aren't about code.  For the data I've been using, I've found that an average forecast of multiple models has produced higher accuracy levels that any sole model by itself.    Recently I read an blog that talked about averaging forecasting methods and assigning weights to them.  So in my case, lets say I assign 11 different models to my set of data (Arima, ETS, Holt Winters, naive, snaive, and so forth) and I want to average a few of these to get a forecast.  Has anyone had any experience with this or can point me to an article that might give some insight on the best way of going about this?  As of right now, I'm using cross validation and Mean Absolute Error to figure out which models perform best and which perform worst. I can even use this to identify the top k # of models.  I guess my questions are  1) How many models would you suggest selecting? (2,3,4,5,6, etc)  2) Any ideas on weights?  (50% to the best, 25% to the second best, 15% third best, 10% to the 4th best, etc)  3) Are any of these forecasting models redundant and shouldn't be included?  (Arima, snaive, naive, HW's "additive", ETS, HoltWinters exponential smoothing, HoltWinters smoothing w/ trend, HoltWinters w/ trend/seasonality, multiple regression)


I ran across the following problem in my Advanced Calculus class:  For a fixed positive number $\beta$, find  $$\lim_{n\to \infty} \left[\frac {1^\beta + 2^\beta + \cdots + n^\beta} {n^{\beta + 1}}\right]$$  I tried manipulating the expression inside the limit but didn't come up with anything useful. I also noted that the numerator can be rewritten as  $$\sum_{i=1}^{n}i^\beta$$ which is a well-known formula with a closed form (Faulhaber's formula) but I don't fully understand that formula and we haven't talked about the Bernoulli numbers at all, so I think the author intended for the problem to be solved a different way. Any suggestions on how to tackle this would be much appreciated.


Statistics for ratio of questions to answers

It seems some people have a ton of questions on Stack Overflow, but relatively few answers, whereas some people have a ton of answers but relatively few questions; it seems like a smaller percentage of people fall in the "even" category.  I can't find a graph/grid of these ratios. Is this particular metric available somewhere?   I'm looking for a histogram of number of answers/number of questions.         |#     U|##     S|###     E|#####     R|#########     S|#############      |------------------             #A/#Q


How can preprocessing with PCA but keeping the same dimensionality improve random forest results?

I found these sentences:     PCA before random forest can be useful not for dimensionality   reduction but to give you data a shape where random forest can perform   better.      I am quiet sure that in general if you transform your data with PCA   keeping the same dimensionality of the original data you will have a   better classification with random forest   from this page:   In my case I found this is really true, for a regression problem with a database of ~1M records and 25 predictors. The error decreases by about 10% if I use the 25 PCA as predictors instead of the 25 original predictors.  Can anyone help me in understanding and clearly interpreting this result?


How can I increase the traffic to my site?

I don't want to do link exchanges or anything shady. I just want some legitimate ways that I can direct a little bit more traffic to my site. How do I do that?


How to use find command with wildcard when current directory contains a match?

Possible Duplicate:          I'm having some confusion with the find command.  If I type:  find . -name *.xml   or   find ./ -name *.xml   I receive a list of all the xml files in subdirectories of the current directory, UNLESS the current directory contains an xml file, in which case I get:  find: paths must precede expression: foo.xml Usage: find [-H] [-L] [-P] [-Olevel] [-D help|tree|search|stat|rates|opt|exec] [path...] [expression]   What is the correct way to search for files with wildcard when the current directory may contain a match?


"modified" link in the home page questions list does not contain "?lastactivity" parameter

I have just noticed that the "modified" link for  does not contain "?lastactivity" parameter in homepage questions list:        When , it's changing to https://meta.stackexchange.com/questions/253359/list-of-communities-with-base-css-updates-completed/286876#286876 as it should, and showing the deleted answer to those who can see it.  Other questions I checked are not affected. Possible way to reproduce might be question with zero answers, where the "modified" was caused by a now-deleted answer.


Why is the probability of having a *rare* disease super low even if the test is very accurate?

Let's say someone wants to test the probability that the person has a disease:  the person gets tested for a test accuracy of 98% (P(B|A)), meaning that with 98% of the time (if a person has the rare disease, it'll correctly tell that the patient has it, and if the person don't have the disease, it'll correctly tell that it doesn't have it 98% of the time. ). So,   P(B|A) = 98% = 0.98 P(B|A^C) = 2% = 0.02   We know that the occurance of the disease in the population (P(A)) is:  1 of every 10000 people: 0.0001 P(A) = 0.0001 and P(A^C) = 0.9999   If the person has a positive test result, how likely is the person to actually have the disease? Let's define A: have the disease and B: test is positive.  So the question is what is P(A|B) (probability that the person has the disease GIVEN that the test is positive) Use Bayes' rule to get the result  $$P(A|B) =  \frac{P(B|A)P(A)}{P(B|A)P(A) + P(B|A^C)P(A^C)}$$ $$P(A|B) =  \frac{0.98*0.0001}{0.98*0.0001+0.02*0.9999}$$ $$= 0.004876592$$ so the chance that you have the disease is actually less than $1\%$ (or it is $0.49\%$)      So the probability is not even half a percent that you actually have the disease. How does this makes any sense?


I have the following data: group A: very bad 12, bad 20, quite good 11, good 29, very good 14 group B: very bad 20, bad 10, quite good 6, good 11, very good 34  which test is appropriate for this kind of data? I think the chi-square test is appropriate since it's nominal data.  could you apply the same test to these data in a different way? I built a 2x2 contingency table by grouping very bad and bad on the one hand, and  quite good, good and very good on the other hand.  if the chi square in 1. is significant an the chi square test in 2 is non significant, how would you intepret the results? I am not sure really.  Could you recode the data and apply a differnt test? I recoded the data as 5-point Likert scale and applied a Mann Whitney test.  If the Mann Whitney test is non significant how would you interpret this result compared to those of chi-square tests? I don't know.   I would be very grateful if anyone could help with this. I am not sure that the chi-square test is the right choice for 1 either. So if anyone had suggestions it would be helpful.


What is the most elementary proof that $\lim_{n \to \infty} (1+1/n)^n$ exists?

Here is my candidate for  the most elementary proof that $\lim_{n \to \infty}(1+1/n)^n $ exists. I would be interested in seeing others.  $***$ Added after some comments: I prove here by very elementary means that the limit exists. Calling the limit "$e$" names it. $***$  It only needs Bernoulli's inequality (BI) in the form $(1+x)^n \ge 1+nx$ for $x > -1$ and $n$ a positive integer, with equality only if $x = 0$ or $n = 1$. This is easily proved by induction: It is true for $n=1$, and $(1+x)^{n+1} = (1+x)(1+x)^n \ge (1+x)(1+nx) = 1+(n+1)x+nx^2 \ge 1+(n+1)x $. (If $-1 < x < 0$, if $1+nx \ge 0$, the above proof goes through, and if $1+nx < 0$, $1+mx < 0$ for all $m \ge n$ so certainly $(1+x)^m > 1+mx$.)  This proof originally appeared in N.S Mendelsohn, An application of a famous inequality, Amer. Math. Monthly 58 (1951), 563 and uses the arithmetic-geometric mean inequality (AGMI) in the form $\big(\sum_{i=1}^n v_i/n\big)^n \ge \prod_{i=1}^n v_i$  (all $v_i$ positive) with equality if and only if all the $v_i$ are equal.  Let $a_n = (1+1/n)^n$ and $b_n = (1+1/n)^{n+1}$.  We will prove that $a_n$ is an increasing sequence  and $b_n$ is an decreasing sequence.  Since $a_n < b_n$, this implies,  for any positive integers $n$ and $m$ with $m < n$  that $a_m < a_n < b_n < b_m$.  For $a_n$, consider n values of $1+1/n$ and $1$ value of $1$.  Since their sum is $n+2$ and their product is $(1+1/n)^n$, by the AGMI,  $((n+2)/(n+1))^{n+1} > (1+1/n)^n$,  or $(1+1/(n+1))^{n+1} > (1+1/n)^n$,  or $a_{n+1} > a_n$.  For $b_n$, consider $n$ values of $1-1/n$ and $1$ value of $1$.  Since their sum is $n$ and their product is $(1-1/n)^n$, by the AGMI,  $(n/(n+1))^{n+1} > (1-1/n)^n$  or $(1+1/n)^{n+1} < (1+1/(n-1))^n$,  or $b_n > b_{n+1}$.  Since $b_n-a_n  = (1+1/n)^{n+1} - (1+1/n)^n = (1+1/n)^n(1/n) =a_n/n $ and every $a_n$ is less than any $b_n$ and $b_3 = (1+1/3)^4 = 256/81 < 4$, $b_n-a_n < 4/n$, so $b_n$ and $a_n$ converge to a common limit.  These proofs do not seem to be really elementary,  since they use the AGMI.  However, they use a special form of the AGMI,  where all but one of the values are the same,  and this will now be shown to be implied by BI,  and thus be truly elementary.   Suppose we have $n-1$ values of $u$ and $1$ value of $v$ with $u$ and $v$ positive.  The AGMI for these values is  $(((n-1)u+v)/n)^n \ge u^{n-1}v$  with equality if and only if $u = v$.  We will now show that this is implied by BI: $(((n-1)u+v)/n)^n \ge u^{n-1}v$  is the same as  $(u+(v-u)/n)^n \ge u^n(v/u)$.  Dividing by $u^n$,  this is equivalent to  $(1+(v/u-1)/n)^n \ge v/u$.  By BI,  since $(v/u-1)/n > -1/n > -1$, $(1+(v/u-1)/n)^n \ge 1+n((v/u-1)/n) = v/u$  with equality only if $n=1$ or $v/u-1 = 0$. Thus BI implies this version of the AGMI.


I was trying to make a bootable usb stick but i accidently formatted my 1TB hard disk. Is there a way to recover my files. The command that i used for formatting my disk   sudo dd if=ubuntu-gnome-15.10-desktop-amd64.iso of=/dev/sdc bs=1M


Why does every single Pokemon run away? Or, what is a soft ban?

No matter what, every single Pokemon that I try to catch runs away from me! I can't spin any Pokestops, and I can't fight any gyms!  I've heard about something called a soft ban. Is that what's happening to me?


Hosting multiple distinct folders for distinct domains

I have a VPS that I've installed a Apache Web Server on. What I want to do is forward my own website domains to that server and host those websites' files inside my Apache Web Server. As far as I understand a DNS server is required to manage which domain is hosted where (IP-wise). But what I want to do is host my websites under the same IP address, the one that my web server has. How can I separate those websites' files inside my web server so I don't have to use http://host/foo for www.foo.com and http://host/bar for www.bar.com?


Every subspace of the dual of a finite-dimensional vector space is an annihilator

Exercise 26 page 115 of Linear Algebra Done Right by Sheldon Axler is the following:     Suppose $V$ is finite-dimensional and $\Gamma$ is a subspace of $V'$. Show that $$\Gamma=\{v\in V:\varphi(v)=0\text{ for every }\varphi\in\Gamma\}^0$$   where $V'$ is the dual space of $V$ and, for any $S\subset V$, $S^0$ is the annihilator of $S$.  Attempt:  Let $S=\{v\in V:\varphi(v)=0\text{ for every }\varphi\in\Gamma\}$. Clearly, $\Gamma\subset S^0$.I tried to show that $S^0\subset\Gamma$ using some bases of $V$ and $V'$, but I failed.  I also tried to show that $\dim{\Gamma}=\dim{V}-\dim{S}=\dim{S^°}$. If $s_1,\dots,s_n$ is a basis of $S$ and $s_1',\dots,s_n'$ its dual, and if $\psi_1,\dots,\psi_p$ is a basis of $\Gamma$, it's easy to see that $s_1',\dots,s_n',\psi_1,\dots,\psi_p$ is a linearly independent list of $V'$. Also, if you extend $s_1,\dots,s_n$ to a basis $s_1,\dots,s_n,v_1,\dots,v_m$ of $V$, then its dual $s_1',\dots,s_n',v_1',\dots,v_m'$ is a basis of $V'$; in fact $S^0=\text{span}\{v_1',\dots,v_m'\}$. Two remarkable facts:$$\forall i\in[1,m],\,\exists j\in[1,p],\,\psi_j(v_i)\neq0$$ because $v_j\notin S$, and $$\forall i\in[1,p],\,\exists j\in[1,m],\,\psi_i(v_j)\neq 0$$ because $\psi_i\neq 0$; in other words the matrix of the inclusion map from $\Gamma$ to $V'$ with respect to the basis of $\Gamma$ and the dual base of the chosen basis of $V$ has no $0$ row nor $0$ column. But this doesn't seem to provide a way to prove that any linear comination of the $(v_i')_{1\le i\le m}$ is a linear combination of the elements of the basis of $\Gamma$. I believe that $v_1,\dots, v_m$ should be chosen more carefuly but I fail to.  Could you please help me? Thank you in advance!


On Linux, the Compose key is a great way to enter many symbols. E.g.   em-dash — by pressing Compose then - - - ö by pressing Compose then : o Euro € by pressing Compose then C =   (The Compose key function can be assigned to various keyboard keys, such as right/left Alt, right/left Windows key.)  I really miss the Compose key when using Windows. I've looked but so far haven't found any way to get equivalent Compose key functionality on Windows. Does anyone know of how to do it?


How long does it take for a item to despawn?

I want to know this because I died really far away and I am stressing that the items will despawn. My world tick speed is 1.


newbie here. I'd like to know what are the best ways to invest ~10k euros here in Europe. I don't have any debt and I am able to save 1k euros every month moving forward. I can't buy property yet, because I can't get a loan in my home country (not employed there) and can't get a loan in my current country because I ain't a citizen. I was looking at savings accounts but earnings are really low. 0.4% a year isn't that fun.   If you folks could point me in the right direction so that I could learn more, I would appreciate it a lot.