Baking normal maps in blender: "Error: No objects or images found to bake to"

This happens pretty much every time I try to bake normal maps. It's quite a broad error message and I still don't know exactly what the problems I'm having are, only that if I keep clicking things for half an hour eventually it sometimes just works.  My understanding of the things needed:   A "Generated" blender Image that the normals are written to (In UV/Image Editor, click Image->New)   Tell blender that this is the bake output, below (this is the really confusing bit which blender seems to try to guess and fails)  A UV Map for the low poly model (you only need the geometry of the high poly and it doesn't need a UV map) Under Bake, in the rendering tab:   Bake Mode = Normals Normal Space = Tangent Selected to Active = ✓ (for the next bit)  Select the high rez object first, then the low poly object With the two objects selected, click Bake (you may have to move the mouse to see the error pops up)   Now, from what I can tell the only  (with regard to the setup and apart from the internals of baking) is how blender finds the output image:   Cycles  Have a material using an ImageTexture node which points to your normal map output. Then  says the node must be selected, but  doesn't mention selecting. Blender Render  Have a texture attached to the material that uses the image.  is pretty vague on assigning the output image. Sometimes I've found hitting tab to go to edit mode and selecting the normal map image in the UV editor to help, or at least it seemed to.   I would like to know the exact details of what blender goes looking for when you hit Bake, rather than have to guess by following tutorials. For example, it seems to look for the high and low poly objects in your selection and based off the order you select them. How does it find the normal map/image to write to for both cycles and blender render? Does the Texture need to Influence Normals or does it just need to reference the Image? etc...


Ability to Use Formatting Hotkeys for Comments

In the questions/answers you can markup text easily using hotkeys like Ctrl+B for bolding text, Ctrl+K for code, etc. Why isn't this done for comments since comments use 'mini-Markdown' (just not via hotkey)? It would surely save time commenting.


BibLaTex, Biber and Lyx: how to resolve \bibliographystyle error?

I want to learn to use biper and biblatex in Lyx. This is how I would do it in LaTeX traditionally with biblatex and biber  \documentclass[12pt,a4paper,oneside,pdftex]{report} \usepackage[backend=biber]{biblatex} \addbibresource{minCuts.bib} ... \printbibliography \end{document}   The error is apparently originating from the \bibliographystyle command and biblatex package getting mixed, by . But I have no \bibliographystyle command in Preamble so they should not be mixed unless Lyx is somehow importing the \bibliographystyle.   How to resolve the biblioraphystyle error in Lyx with Biber and Biblatex?    Settings by the instructions  and Error        Document > Settings > Bibliography > Biber                  In Document > Settings > LaTeX Preamble                   Insert > List / TOC > BibTeX Bibliography...                        Package biblatex Error : '\bibliographystyle' invalid.


How does Google determine important links on a website to display in search results?

Sometimes when I search for something on Google it shows some results (website links), but it also shows some important links on that website.  Is it a feature of the website or does Google use something to find those main links of the website? Is it related to search engine optimization?


Generics, arrays, and the ClassCastException

I think there must be something subtle going on here that I don't know about. Consider the following:  public class Foo<T> {   private T[] a = (T[]) new Object[5];    public Foo() {     // Add some elements to a   }    public T[] getA() {     return a;   } }   Suppose that your main method contains the following:  Foo<Double> f = new Foo<Double>(); Double[] d = f.getA();   You will get a CastClassException with the message java.lang.Object cannot be cast to java.lang.Double.  Can anyone tell me why? My understanding of ClassCastException is that it is thrown when you try to cast an object to a type that cannot be casted. That is, to a subclass of which it is not an instance (to quote the documentation). e.g.:  Object o = new Double(3.); Double d = (Double) o; // Working cast String s = (String) o; // ClassCastException   And it seems I can do this. If a was just a T instead of an array T[], we can get a and cast it without a problem. Why do arrays break this?  Thanks.


From what little I know about general relativity, energy (and equivalently mass) distorts and curves spacetime due to the Einstien Field Equations. I also know "wormholes" are theoretically solutions to the field equations, that connect two points in spacetime.  However, how do these two definitions work with eachother? Energy distorts space into a fourth dimension, I understand that, but using that description, how could a wormhole "connect" those two points? The way I've seen it describes it folding over a piece of paper and poking a pencil through it - but that seems like a cop out. What's the equivalent of "folding" in physics, and does a theoretical wormhole actually fold the space?   How can two distortions in a uniform 3D space possibly connect to eachother?


Is it possible to remove some of the default Google apps from Gmail? I'm only using the Drive and the Calendar apps, and would like to remove the other apps (YouTube, Google+, Photos, etc). By remove, I mean either hide from view or delete them entirely.  I have followed the guide provided on the , and the answer provided . However, these are about removing external apps. I would like to remove the ones by Google.  My reason for this is that the app view is too cluttered for me. More options is fine, but the way it's set up now is just... Annoying  to me.  The following image shows what I'd like to remove (or hide, if removal is impossible).


Windows, prevent file access even to admin

I mostly work on Mac but have a Windows problem:  I need to prevent access to specific files to all (even administrator). I'm running a local nodeJs server app, and need to prevent access to the main script. In short I need to prevent tempering with the program.  I know IIS has 'special' users for example, preventing access from any 'standard user', but not sure that prevents access from an admin.   Is there any way to prevent access to a file even to an administrator?  Special User permissions?  My guess is that an admin would always be able to change user permissions, so I'm not sure it's possible but there may be 'special' accounts that can be used?  Any hints / direction as to where to look would be appreciated.  Thanks


Shortcut to save screenshot both to desktop and clipboard

The screenshot shortcuts save either to the desktop or to the clipboard, but not to both at once. Is it possible to copy to clipboard, and to save in desktop, the same screenshot preferred in a single shortcut? If a single shortcut is not available, the only way is to save to desktop and then copy the saved image to clipboard manually?


I am trying to get the GMT in unix time. I use the following code:            public static long GetGMTInMS()         {             var unixTime = DateTime.Now.ToUniversalTime() -                 new DateTime(1970, 1, 1, 0, 0, 0, DateTimeKind.Utc);              return (long)unixTime.TotalMilliseconds;         }    To then convert the unix time back to a DatTime object, I use this:            public static DateTime UnixTimeStampToDateTime(double unixTimeStamp)         {             System.DateTime dtDateTime = new DateTime(1970, 1, 1, 0, 0, 0, 0);             dtDateTime = dtDateTime.AddMilliseconds(unixTimeStamp).ToLocalTime();             return dtDateTime;         }    When I run it, the GetGMTInMS() 1320249196267. When I pass it to UnixTimeStampToDateTime() I get {11/2/2011 11:53:16 AM}  Which is fine. That is the correct time fro when I ran my code. The issue I have is when I try and put 1320249196267 into an unix time converter, such as , it returns the totally wrong time.  The other issue, is i am in the eastern time zone. This returned the time in my time zone. Is this something that the DateTime object handles or am I not getting the GMT.


I'm trying to take numbers (integers) from a website and put them into an array for further manipulation. Here is what I have so far  import java.io.IOException; import java.net.URL; import java.util.Scanner; public class Scores {     public static void main(String[] args) throws IOException{         URL url = new URL("http://cs.armstrong.edu/liang/data/Scores.txt");         Scanner input = new Scanner(url.openStream());         int []score = new int [100];         int i = 0;         while (input.hasNextInt()) {             score[i++] = input.nextInt();             System.out.println(score);         }     } }   The problem is all of the numbers in the array come back as [I@6bc7c054, any help would be appreciated.


Algebra-sum of entries in each column of a sqaure matrix = constant

This is a question from an algebra homework and I am just looking for some tips.  The question is:                   We have:   $M$: an $n\times n$ matrix with real entries $c$: a real constant the sum of the entries of each column of $M$ is equal to $c$   We have to prove that $c$ is an eigenvalue of $M$.  I started out by writing out the form of the matrix and see if anything was popping up without much success. I found a similar question except that they were working with a $2\times 2$ matrix and that the sum of entries in each column $= c$ as well as the sum of entries in each row. Also, in this question they are looking for eigenvectors. In this case the question is pretty easy as we can notice that each column or row is composed of the same entries (in different order or not).  link (p4):   Hence I looked at the sum in the columns to find some kind of pattern or hint that could help me solve this question without any success. It is obvious that the entries in each column might not be the same.  Anyhow I am stuck there.  Again I am not asking for the answer, just a hint.  Thank you for your time and good luck.


Live Agent Pre Chat Form - popup window size

We're about to go live with Live Agent (the version that built into your Salesforce instance).  We're using some a prechat form which appears as a popup window when the user clicks the "Chat" button.  When the window pops up, our form doesn't fit fully inside. I'm trying to find where to define the size of that pop-up window.  I can't find it in any setting, and changing the Visualforce page that represents the Pre Chat form doesn't make a difference.  Does anyone know where the Size of the pop up window is referenced?   Update**  ***Per the comment below - I also thought it would be in the code for the button. Nearest I can tell it calls a method onclick called "Liveagent.startChat()" but I don't see that javascript anywhere.


Let $a, b, c, d > 0 \in \mathbb{R}$ such that $a^2 + b^2 + c^2 + d^2 = 4$. Show that:  $S = \frac{a^2}{b} + \frac{b^2}{c} + \frac{c^2}{d} + \frac{d^2}{a} \geq 4$  My approach: I used the Cauchy-Schwarz inequality to show that $S \geq a + b + c + d$ but that is useless as $a + b + c + d \leq 4$. How would you approach this problem? (Only hints desired)


How do I search for connecting point-to-point flights?

There are often situations where buying two separate one-way tickets from A to C via B is cheaper than buying a normal multi-leg ticket. This can be especially useful with airlines such as Ryanair, which specifically avoids selling multi-leg tickets.  Is there a search engine which allows one to search for such flights?


Wifi module stops connect to any access points

After an update wifi stops connecting to any network (excluding router at work). It just tries to connect and after that asks for the password again and again.  I tried to reinstall the driver but that doesn't help.  12:00.0 Network controller: Broadcom Corporation BCM4313 802.11b/g/n Wireless LAN Controller (rev 01) Ubuntu 12.04.2 LTS \n \l   It's strange because this is a Dell Vostro 1440 which is in certified Ubuntu laptop list.


I can't shrink my OS X Yosemite partition

I recently reformatted my machine and am trying to shrink my OS X partiton to make room for a linux partition, following instructions at  . I am at the Resize Partitions step, and when I opened up Disk Utility, there was no way for me to drag the existing partition to shrink its size and create free space.  When looking at the GUI, the normal resize handle is missing, and the help text sounds much more restrictive than it has in the past.


I used a juicer to juice vegetables. Then, I used the juice in making bread. Some of my friends said that something in vegetables affects the fermentation, namely the enzymes. They said it can kill the yeast. Is it true? Can you briefly explain?


In this program, I am attempting to read in a line from a file, and tokenize the line and store the values into an array. I have created a struct called "Course" which stores information about courses that I read in from the file, and has an array storing the number of courses that depend on this particular course as a prerequisite. I am having difficulty tokenizing the line and storing it into the "dependencies" array.   The file I am trying to read in with tokenizing looks like this  2    6     7    8    9    11    15 etc...   Here is the code:  #include <iostream> #include <fstream> #include <cstdlib> #include <string> #include <cstdio>  using namespace std;   typedef struct Course {     int numDependencies;     int numPrerequisites;     string name;     //stores number of courses this course depends on     int dependencies[6]; } Course;  int main() {  int N;  //Number of courses ifstream infile("CSCCourses.txt"); if (infile.fail()){     cout << "File not found." << endl;     //exit(0); } //read in number of courses infile >> N; //dynamically allocate array of courses Course* courseArray = new Course[N]; string line; //loop N times to read course names for (int i = 0; i < N; i++){     infile >> line;     cout << line << endl;     courseArray[i].name = line; } //loop again to read course information for (int j = 0; j < N; j++) {     //Course dependencies[6];     getline(infile,line);     cout << line << endl;     string::size_type lastPos = line.find_first_of(" ", 0);     string::size_type pos = line.find_first_of(" ", lastPos);     while (string::npos != pos || string::npos != lastPos) {         //found token, add to array.          dependencies[].push_back(line.substr(lastPos, pos - lastPos));         //skip delimiters         lastPos = line.find_first_not_of(" ", pos);         //find next non delimiter         pos = line.find_first_of(" ", lastPos);     } }  infile.close();   }


I heard this phrase or the variants (rooted phone, rooting, etc.) in android forums but I don't know what it means. Can you explain it in simple terms?


How can I add an icon to my custom context menu item in Windows 7?

Related:    I've created my custom context menu item, and it seems to work on all file types - even through shortcut links.  (Selecting my custom option performs the operation on the shortcut target, not the .lnk file.)  Now, I'd like to create an icon to make it stand out.  My antivirus program and Notepad++ seem to have been able to do this, so I know it's possible.  The only question is, how?


How to find out if USB flash drives are USB 2.0 or 3.0

I inherited a lot of USB flash drives and would like to find out what USB version they are (i.e. 2.0, 3.0 or maybe even older). How can I do that on Ubuntu?


How is the statement $\bot \to \top$ true? If, for example, I take the statement  $P = 2$ is an odd number $Q = 5$ is an odd number Then $P$ is false and $Q$ is true.  Clearly, false implies true translates to  if $2$ is an odd number then 5 is an odd number  which means that  if $2$ is not an odd number (i.e. even) then $5$ is not an odd number  which is clearly false as $2$ is indeed an even number. Please help me to find what I’m missing out in this. Thanks for your help!


Find all paths from start node to the end node in a graph

Here is my question.  I am trying to resolve this problem.      Given the start point and the end point, find all paths from start   corner to the end corner. Include only routes which do not pass   through any corner more than once.   For example: 1 is the start node, 6 is the end point. I have the the data as  1 2 1 3 3 4 3 5 4 6 5 6 2 3 2 4   The pairs of positive integers separated by blanks which are connected. So the output should be.  1 2 3 4 6 1 2 3 5 6 1 2 4 3 5 6 1 2 4 6 1 3 2 4 6 1 3 4 6 1 3 5 6   There are 7 routes from 1 to 6.  Now I use the graph search algorithm, I can only find one. And also I can't find the one given the final destination. I mean that I can only traversal the graph.  What I did was that I created the adjacency matrix of the graph then did a depth first search.   First I defined a class Node.  public class Node {     public string NodeId;     public bool IsVisited;     public Node(string nodeId)     {         NodeId = nodeId;     } }   Then the Graph class,   public class Graph {     private Node[] _nodes;     private int[][] _adjacencyMatrix;     public int _numberOfTotalNodes;     public Graph(int[][] adjacencyMatrix, int numberOfTotalNodes)     {         _adjacencyMatrix = adjacencyMatrix;         _numberOfTotalNodes = numberOfTotalNodes;         _nodes = new Node[_numberOfTotalNodes];         for (int i = 0; i < _numberOfTotalNodes; i++)         {             _nodes[i] = new Node((i + 1).ToString());         }     }      public void DepthFirstSearch()     {         Stack s = new Stack();         _nodes[0].IsVisited = true;         DisplayNodeId(0);         s.Push(0);         int v;         while (s.Count > 0)         {             v = GetAdjUnvisitedNode((int)s.Peek());             if (v == -1 || _nodes[v].IsVisited)             {                 s.Pop();             }             else             {                 _nodes[v].IsVisited = true;                 DisplayNodeId(v);                 s.Push(v);             }         }         for (int u = 0; u < _numberOfTotalNodes; u++)         {             _nodes[u].IsVisited = false;         }     }      public void DisplayNodeId(int nodePosition)     {         Console.Write(_nodes[nodePosition].NodeId + " ");     }      public int GetAdjUnvisitedNode(int v)     {         for (int j = 0; j < _numberOfTotalNodes; j++)         {             if (_adjacencyMatrix[v][j] == 1 && _nodes[j].IsVisited == false)             {                 return j;             }         }         return -1;     } }   To call it, just use the code.  var graph = new Graph(adjacenyMatrix, adjacenyMatrix.GetLength(0)); graph.DepthFirstSearch();   Please point it out the flaws of my algorithm.   Base on the comment, there is a  there, I would like C# code. However it is not completed. It lacks of the method AdjacentNodes(T current).


I am trying to make a gold ore material on my object but I cannot seem to make it look right with different nodes. Can anybody help me?!! I am just learning about nodes so I am fairly new to how they work and it needs to be explained in detail what to do. This is what I have that is slightly close to what I am looking for...


How can I stop brew prune and brew upgrade from fighting?

I am running Homebrew on 10.13.6, with the prefix /usr/local.    When I run brew upgrade, two directories are created in /usr/local/share.  These are: /usr/local/share/man/man2, and /usr/local/share/man/man6.  There are no files in these directories.  Meanwhile, whenever I run brew prune --verbose, I get the output:  rmdir /usr/local/share/man/man6 rmdir /usr/local/share/man/man2 Pruned 0 symbolic links and 2 directories from /usr/local   Whenever brew upgrade, these two troublesome directories are then re-created! The cycle continues, on and on and on.  I have repeatedly run brew update, brew cleanup, and brew doctor.  I have even reinstalled Homebrew and all my packages.  Yet, the eternal battle between brew upgrade and brew prune continues.  How can I get them to stop fighting?


Old book about a child who found a box containing aliens that could alter gravity and time

When I was about 12 (c. 2002), I read a fiction book, but today I can't remember its title or who wrote it. May have been a two part series, and I'm not sure how old the book was at the time.  Protagonist was a child, found a box that could not be opened normally.  I remember they had to put their head on the lid, with their hands on the sides and rotate their hands in opposite directions.  The box lid would then disappear and inside was a species of sentient insectoid aliens.  I remember they said "Have you eaten well?" as a formal greeting.  The box also contained a smaller box with a dial on it.  The dial would alter gravity, which would affect how the holder perceived time, as well as the weight of the containment box.  Increasing the gravity made the box heavier while time sped up around the holder.  Decreasing gravity would make the box lighter while slowing time around the holder.  I don't remember much about the plot, but at one point the box containing the aliens was taken by a group of people (possibly a government agency), and the protagonist had to use the dial to get the box back.  There was also something dealing with the protagonist's uncle.  I believe he had gone missing, but later on it's found that he had a working replica of the dial, and was using it to slow time for himself, allowing him to live a great deal of time without aging.


Options for generating travel time isochrones in QGIS 3.4: what do you use?

I'm currently using the updated OSM tools to generate isochrones in QGIS 3.4, which works well (example below).  My question is just what methods other people use and whether there is something better (e.g. live traffic information - I can dream). I have seen a variety of methods online, but I am specifically interested in methods with QGIS 3.4 - I know it can be done other ways of course but I want to make sure I'm not missing anything.


Non-isomorphic groups with same number of homomorphisms

What would be an example of two non-isomorphic groups $G$ and $G'$ such that for all groups $H$, there are as many homomorphisms $H\to G$ as homomorphisms $H\to G'$? By the Yoneda lemma, if $\hom(-,G)$ is naturally isomorphic to $\hom(-,G')$, then $G$ is isomorphic to $G'$. My question aims at finding an example that shows that it doesn't suffice to just assume that $\hom(H,G)$ and $\hom(H,G')$ are isomorphic for all $H$.


I have seen “data” used with “show” and with “shows” in the newspaper. For example,         Data show that domestic violence increases when there is a greater unemployment.   Data shows that domestic violence increases when there is a greater unemployment.      Which one is correct?  Please clarify is it grammatically correct to use shows  in above sentence.


Problem in sharing clipboard with VirtualBox guest machine

I use Ubuntu 16.04 and have installed VirtualBox-5.1.38_Ubuntu r122592 and also VBoxGuestAdditions.iso by this command:  $ sudo apt-get install virtualbox-guest-additions-iso   Previously I created some virtual machines and shared clipboard between Host and Guests (bidirectional). Yesterday I created another guest and did these:   mounting VBoxGuestAdditions.iso into the guest running sudo sh ./VBoxLinuxAdditions.run in mounted iso (in guest):  Verifying archive integrity ... All good. Uncompressing VirtualBox 5.1.38 Guest Additions for Linux........... VirtualBox Guest Additions installer Removing installed version 5.1.38 of VirtualBox Guest Additions... Copying additional installer modules ... Installing additional modules ... vboxadd.sh: Starting the VirtualBox Guest Additions.  Devices -> Share Clipboard -> Bidirectional rebooting guest   But "clipboard sharing" is not enabled, however I can do copy/paste between older created guests and host. How I can solve this problem?


Radius of convergence of the series $\displaystyle\sum_{n=0}^{\infty}n!z^{2n+1}$

We have the result, $\displaystyle{\frac{1}{R}=lim_{n\to\infty}|\frac{a_{n+1}}{a_n}|}$, where $R$ is the radius of the convergence, where $\displaystyle{a_n}$ is  the coefficient of the series $\displaystyle{\sum_{n=0}^{\infty}}a_nz^n$,   Here we redefine the   series as$\displaystyle{\sum_{n=0}^{\infty}}a_nz^n$, where $a_n=(0,1,0,1,0,2,0,6,0,24,0,.....)$,  so we can not use this method? or can we?,  We have other result as $\displaystyle{\frac{1}{R}=\lim \inf} |a_n|^{-1/n}=\lim\inf{\frac{1}{|a_n|^{1/n}}}$  My question is  1)Is it valid to take $a_n=0$ for infinitely many $n\in \mathbb{N}$  2) $\displaystyle{\frac{1}{R}=\lim\inf{\frac{1}{|n!|^{1/n}}}}????$   Can someone help how to move further


Geoserver WMS Circle SLD style return incomplete Circle with higher zoom levels

I'm using  v2.6   I created a SLD style for a points layer and create 2 rules:   Rule to draw a graphics icon from png file. Rule to draw a circle with radius(size) from db table using (OGC Attribute) value in meters.   I use the following code to load the layer in OL3:      var wmsSource = new ol.source.TileWMS ({     url: 'http://localhost:8080/geoserver/wms',     params: {'TILED': true, VERSION:'1.3.0',        'LAYERS': 'myds:antenna',     },     serverType: 'geoserver' });  new ol.layer.Tile({          id:'Message',          title: 'Antennas',          visible: true ,          source:wmsSource      });   The layer loaded correctly on the map in some lower zoom levels (0-10) if i zoomed in to more levels down (11-17) the circle shape is trimmed by the tiles like the image below:    The strange thing when i set the 2nd rule in the SLD that to get a fixed radius value like (2000) meters - Not from db table -, it draw a complete circle in all zoom levels, but i need to set a different radius for each circle.  I tried many solutions to avoid this error by changing the metatiling factors to be 100x100 instead of 4x4 and change the Gutter to be 100px, it solve the problem but affect the loading speed badly.  So kindly help me solve this problem.


Have we seen this object that Rey has at the end of TRoS before?

At the end of The Rise of Skywalker, Rey      holds a fairly gnarly lightsaber. It doesn't look new.   Have we seen it before?


Let $\{x_n\}$ be a sequence defined by $x_1 = 3, x_{n+1} = \frac{1}{4-x_n}$, for n $\geq 1$. prove it converges  (a) Prove that $\{x_n\}$ is decreasing and bounded (below by $0$ and above by $4$), i.e., prove that $0 < x_{n+1} < x_n < 4$, for all $n \in \mathbb N$.  (b) Does $\{x_n\}$ converge or diverge? Justify    My attempt: (Could someone check)  Claim: $\{x_n\}$ is bounded below 0 and bounded above by 4 (1), $\{x_n\}$ is strictly decreasing (2), for all $n \in \mathbb N$  Proof of (1)  WTS: $0 < x_n < 4, \forall n \in \mathbb N$  Since the function is not continuous at x = 4 I will find its limit for a better bound  $$x_n = \frac{1}{4-x_n} \leftrightarrow \left(x_{n} - \frac{4-\sqrt{12}}{2}\right)\left(x_n - \frac{4+\sqrt{12}}{2}\right)$$  Since the function is decreasing this will be the new bound $$0 < x_n < \frac{4-\sqrt{12}}{2}$$  I will prove this by induction:  Base case (n=1)   0 < 3 < $\frac{4-\sqrt{12}}{2} < 4$ holds  Inductive hypothesis: Let $k \in \mathbb N$ be arbitrary. Assume $0 < a_k < \frac{4-\sqrt{12}}{2}$  Inductive step: $\forall k \in \mathbb N$, $0 < a_k < \frac{4-\sqrt{12}}{2} \to 0 < a_{k+1} < \frac{4-\sqrt{12}}{2}$  $$a_{k+1} = \frac{1}{4-x_n} \text{ By definition}$$  $$< \frac{1}{4-\frac{4-\sqrt{12}}{2}} \text{ By I.H.}$$  $$= \frac{2}{4-\sqrt{12}}$$  $$= \frac{2(4+\sqrt{12})}{16-12}$$  $$= \frac{4+\sqrt{12}}{2} < 4$$  Now for bounded below  $$a_{k+1} = \frac{1}{4-x_n} \text{ By def}$$  $$> \frac{1}{4-0} \text{ By I.H.}$$  $$> 0$$  Therefore by induction $0 < x_n < \frac{4-\sqrt{12}}{2} < 4, \forall n \in \mathbb N$  Proof of (2)  WTS: $x_{n} > x_{n+1}, \forall n \in \mathbb N$  $$x_n > x_{n+1}$$  $$\leftrightarrow x_n > \frac{1}{4-x_n} \text{ By definition}$$  $$\leftrightarrow 0 > \left(x_{n} - \frac{4-\sqrt{12}}{2}\right)\left(x_n - \frac{4+\sqrt{12}}{2}\right)$$  By 1 we know that the first one is > 0 and the second < 0. Then (+)(-) = - < 0  Therefore it is decreasing. For (b) by the bounded monotone convergence theorem we know that this converges since it is bounded below and strictly decreasing.   Is this right?  I think I did the choosing the limit part wrong. If its decreasing I choose the smaller one as the upperbound right?


What is back-focusing? Is it something I need to be worried about, or can I just live with it? How can I tell if my camera/lens is sufferring from it?


How to copy all files from a directory to a remote directory using scp?

My goal is copy only all files from ~/local_dir to user@host.com /var/www/html/target_dir using scp and do not create local_dir category in local_dir.   /var/www/html/target_dir/files..   but not   /var/www/html/target_dir/local_dir/files.. when use -r parameter


Creating a Live USB with Ubuntu Startup Disk Creator that has persistent storage mounted on boot?

A friend of mine is constantly switching between different laptops that he's working on and he would like to have a Live USB with persistent storage (For Firefox bookmarks, email, etc.) that he can save to the live USB drive so that it all transfers as he's moving between machines.  Is there a way to do this with Ubuntu Startup Disk Creator so that USB drive has a partition that is mounted to a user home directory on startup?


I am planning to install IBM websphere community edition in Ubuntu.  Could you please suggest how can I extract the wasce_ibm60sdk_setup-3.0.0.4-ppc64linux.tar.bz2 file?


Developing and/or designing iOS apps on Windows

After developing an app for Android we want to step forward a bit and do it for iOS. We have no prior experience with developing for iOS(the code is not the problem, but the tehnique is). With a bit of research, i found that you need Apple Computers or VM's or Apple Mirroring for this job, because it is "imposible" to develop in Xcode(meaning that i try to keep it as native as i can). I also found Xamarin and other tools but finaly decided with my team upon a Mirrored Mac ( inCloud). The problem is that, with little financial backup we do not afford to buy a Mac or to Buy more than 1 subscription(30-35$ for a month is a lot for starters). Now i want to know if there is a safe way to work for iOS on Windows(maybe without installing anotherOS on PC), or at least to Design( visual)- storyboards, views and others..for the app.. Maybe one can work on the Cloud Machine and the others can work from their home computers..and than kind of merge the projects.. thank you.


How to call parent class member function from an overloaded function?

I created one new class which is publicly inherited from the string class. I wish to overload the  < (less than) operator in the derived class. But from the overloaded function I need to call the parent class < operator. What is the syntax for calling this function? I would like to implement the operator as a member function if possible.  In Java there is super keyword for this.  My code is given below.  #include<iostream> #include<string> using namespace std;     class mystring:public string     {      bool operator<(const mystring ms)      {       //some stmt;       //some stmt;       //call the overloaded <( less than )operator in the string class and return the value       }      };


My daughter asked me to cosign on a car loan.  Somehow I ended up as the borrower and she a the cosigner.  Is that legal?


Suppose I have two parallel hyperplanes: $\{x \in \mathbb{R}^n|a^Tx=b_1\}$ and $\{x \in \mathbb{R}^n|a^Tx=b_2\}$. How would I find the distance between these two hyperplanes?


Are there any advantages to stunning an alien besides being able to interrogate it?

Aside from being able to interrogate an alien in the Alien Containment chamber, are there any particular advantages to risk trying to stun an alien instead of just killing it outright?


Lightning web components issue with SFDX push and pull

I Create an sfdx scratch org using . I also created a sample hello world lightning web component and pushed it to the scratch org and everything works fine as I was able to preview my hello world lwc in the app builder. I also created an aura component from dev console and was able to pull it to vscode.  Now here comes the issue, Later I created couple of more lwc from the vscode  and used push command after saving them, then It shows me what was pushed to the scratch org and everything was fine, but when I actually went to the app builder page of the scratch org that the code was pushed I don't see the newly pushed Lightning web components. Also every time I try to push some deltas I can see the deltas getting pushed.  How do I verify this issue? At least for aura components I can look into lightning resources to see the components but for lwc Im not sure of a way to verify whether they are pushed or not.  Below are the commands used:  sfdx force:source:push // for push  sfdx force:source:pull // for pull   Note: I was able to see the actual lightning web components in the force-app folder in my local host.  PS: From your scratch org   setup Lightning component opens a list view where you can see aura components and lwc and I can see all the lwc      Even though all the lightning web components are available in the org,   I was not able to see them in the app builder except for the first   one!


How to calculate elliptic curve parameters?

I'm having a rough time understanding the math behind elliptic curves. I want to implement ECDH where user can define a, b, and p parameters of elliptic curve.  How can I calculate generator base point G? Is it any point that satisfies elliptic curve equation $ y^2 \equiv x^3 + ax + b \pmod p$?  Also, how can I calculate order n and cofactor h given the base point?


Accessing the Id parameter in VF page passing it to Javascript function

How to access the Id from URL in visualforce, i want to pass that Id to javascript function to load my page, please help.


Losing precision after parsing an integer

I countered this issue in my program, I have a string numStr and I want to parse it as an integer.  I tried both on node and spider-monkey environments.  What is the problem and how I fix it?  const numStr = '12360600901222567'; console.log(+numStr); console.log(parseInt(numStr)); console.log(parseFloat(numStr)); console.log(Number(numStr));   Output:  12360600901222568 12360600901222568 12360600901222568 12360600901222568   Expected:  12360600901222567


How to render an ASP.NET MVC view as a string?

I want to output two different views (one as a string that will be sent as an email), and the other the page displayed to a user.  Is this possible in ASP.NET MVC beta?  I've tried multiple examples:  1.      If I use this example, I receive the "Cannot redirect after HTTP   headers have been sent.".   2.      If I use this, I seem to be unable to do a redirectToAction, as it   tries to render a view that may not exist. If I do return the view, it   is completely messed up and doesn't look right at all.   Does anyone have any ideas/solutions to these issues i have, or have any suggestions for better ones?  Many thanks!  Below is an example. What I'm trying to do is create the GetViewForEmail method:  public ActionResult OrderResult(string ref) {     //Get the order     Order order = OrderService.GetOrder(ref);      //The email helper would do the meat and veg by getting the view as a string     //Pass the control name (OrderResultEmail) and the model (order)     string emailView = GetViewForEmail("OrderResultEmail", order);      //Email the order out     EmailHelper(order, emailView);     return View("OrderResult", order); }   Accepted answer from Tim Scott (changed and formatted a little by me):  public virtual string RenderViewToString(     ControllerContext controllerContext,     string viewPath,     string masterPath,     ViewDataDictionary viewData,     TempDataDictionary tempData) {     Stream filter = null;     ViewPage viewPage = new ViewPage();      //Right, create our view     viewPage.ViewContext = new ViewContext(controllerContext, new WebFormView(viewPath, masterPath), viewData, tempData);      //Get the response context, flush it and get the response filter.     var response = viewPage.ViewContext.HttpContext.Response;     response.Flush();     var oldFilter = response.Filter;      try     {         //Put a new filter into the response         filter = new MemoryStream();         response.Filter = filter;          //Now render the view into the memorystream and flush the response         viewPage.ViewContext.View.Render(viewPage.ViewContext, viewPage.ViewContext.HttpContext.Response.Output);         response.Flush();          //Now read the rendered view.         filter.Position = 0;         var reader = new StreamReader(filter, response.ContentEncoding);         return reader.ReadToEnd();     }     finally     {         //Clean up.         if (filter != null)         {             filter.Dispose();         }          //Now replace the response filter         response.Filter = oldFilter;     } }   Example usage  Assuming a call from the controller to get the order confirmation email, passing the Site.Master location.  string myString = RenderViewToString(this.ControllerContext, "~/Views/Order/OrderResultEmail.aspx", "~/Views/Shared/Site.Master", this.ViewData, this.TempData);


How do I split one row into multiple rows with Excel?

I have a product database in Excel with several hundred entries, each of which has from 1 to 3 "tiers" of pricing: Standard, Deluxe, and Premium. Each tier has its own SKU (A, B, or C added on to the end of the base SKU) and price. My data is like this:  Name, Description, Price A, Price B, Price C, SKU A, SKU B, SKU C name1,      desc1,   14.95,   19.95,        , sku1A, sku1B,  name2,      desc2,    4.95,    9.95,   12.95, sku2A, sku2B, sku2C name3,      desc3,   49.95,        ,        , sku3A,      ,   How would I go about getting the data to look like this:  Name, Description,   SKU, Price name1,      desc1, sku1A, 14.95 name1,      desc1, sku1B, 19.95 name2,      desc2, sku2A,  4.95 name2,      desc2, sku2B,  9.95 name2,      desc2, sku2C, 12.95 name3,      desc3, sku3A, 49.95   If it helps, I'm going to be importing these products into a Magento installation.  Thank you in advanced.


Why Ubuntu does not release his OS for Intel Processor (ubuntu-20.04-desktop-amd64) i have problem with installing Ubuntu on intel processo?

Since the downloaded file from Ubuntu website always consist of AMD64 such as ubuntu-20.04-desktop-amd64. I think my Acer Predator Helio 300 which has Intel i7 7th gen processor does not fit well. Because i try to install 3 to 4 times of Ubuntu 18.04 with Proper installation and proper installation of NVIDIA 1060 Graphics card.But there is always problem of Overheating and unexpected shut down of the laptop.  My Question is there is another OS Build for Intel processors laptop?  My mainly work of building ML and Neural Net model. And Sometime for fun i am building Android and ISO Apps. Could you please suggest what is the problem with my laptop with Ubuntu and could i need to switch some other distro then what is the best distro for my work.  "I will be grateful for any help you can provide with this situation."


Example of a group where $o(a)$ and $o(b)$ are finite but $o(ab)$ is infinite

Let G be a group and $a,b \in G$. It is given that $o(a)$ and $o(b)$ are finite. Can you give an example of a group where $o(ab)$ is infinite?


What is the blood status of someone born to two muggle-borns?

We know that if you can trace wizarding blood in your ancestry three generations, you are pureblood. If you can only trace that back three generations, you are a half blood. If you have Muggle parents, you are a Muggle-born. But what if you have Muggle-born parents? Than what is your blood status?


JavaScript function var in function scope

I thought that  function foo() { return 42; }   is mostly equivalent to  var foo = function() { return 42; }   except that foo.name differs in both cases. But regarding the scope, I thought it would be the same.  However, then I stumbled upon this code:  function demo() {     return foo;      function foo() { return 42; } }   And demo() actually returns the foo function, i.e. demo()() == 42.  So, it seems that function evaluation is probably already done earlier, probably at compile stage.  Is my guess correct? Is that standard? (I'm using V8.)  (I just found  - it might be a duplicate.)


Does a 55-minute layover suffice at Chicago O'Hare International Airport?

My grandparents bought a flight on United Airlines, as the one and same ticket, from Toronto, to ORD with one 55-minute layover, then to Maui. :     You won’t need to pay extra for airfare if you miss the flight, but on the other hand, you will most likely not be compensated by the airline for the incurred delay. It always depends on the amount of time, the reason for the delay and the airline’s policies. As soon as it’s weather-related, you won’t be getting a penny (and that’s normal: airlines can’t control the weather).    Yet they obviously prefer to avoid such charges from missing the 2nd flight.   Please see the titled question? Would they need to hotfoot or scamper from one gate to another, to not miss the 2nd flight? If yes to 2, can they request an airport electric shuttle cart now, before the flight?


Creating a terminal command to run a file

When I am in a specific directory, I can run a file in the terminal using the command ./file.  How can I make it so that I can run that file from anywhere using a custom terminal command?


How do I remove a PPA added via command-line?

I added a PPA for updating my kernel for ubuntu-12.04. Later, I found that the kernel doesnot exist on the link within PPA.  I used this command. sudo add-apt-repository ppa:kernel-ppa/ppa  Now if I try sudo apt-get update, I get an error 404, because  , does not exist.  Trouble is I am unable to do an update. Even not able to do sudo ppa-purge ppa:kernel-ppa/ppa  Suggest a solution.


I've been upgrading my ssh keys on all my machines, and came across a bit of weirdness with ssh-add.  If I create an ed25519 key and then try to ssh-add it fails. If I take the original rsa key, and convert it with ssh-keygen then ssh-add it works.  reproduce the problem  # ssh-keygen -t ed25519 -a 256 Generating public/private ed25519 key pair. Enter file in which to save the key (/home/trevor/.ssh/id_ed25519):  Enter passphrase (empty for no passphrase):  Enter same passphrase again:  Your identification has been saved in /home/trevor/.ssh/id_ed25519. Your public key has been saved in /home/trevor/.ssh/id_ed25519.pub.   Now lets try to add it.  $ ssh-add Enter passphrase for /home/trevor/.ssh/id_ed25519:  Could not add identity "/home/trevor/.ssh/id_ed25519": communication with agent failed   If I try to add a normal rsa key it works  # ssh-add Enter passphrase for /home/trevor/.ssh/id_rsa:  Identity added: /home/trevor/.ssh/id_rsa (/home/trevor/.ssh/id_rsa)   Have I found a bug with ssh-add or is it a problem with Ubuntu.  Running all the above on Ubuntu 16.04LTS  apt list --installed | grep ssh libssh-4/xenial,now 0.6.3-4.3 amd64 [installed,automatic] libssh-gcrypt-4/xenial,now 0.6.3-4.3 amd64 [installed,automatic] libssh2-1/xenial-updates,xenial-security,now 1.5.0-2ubuntu0.1 amd64 [installed,automatic] openssh-client/xenial-security,now 1:7.2p2-4ubuntu2.1 amd64 [installed,upgradable to: 1:7.2p2-4ubuntu2.2] openssh-server/xenial-security,now 1:7.2p2-4ubuntu2.1 amd64 [installed,upgradable to: 1:7.2p2-4ubuntu2.2] openssh-sftp-server/xenial-security,now 1:7.2p2-4ubuntu2.1 amd64 [installed,upgradable to: 1:7.2p2-4ubuntu2.2] ssh-askpass/xenial,now 1:1.2.4.1-9 amd64 [installed] ssh-import-id/xenial,xenial,now 5.5-0ubuntu1 all [installed,automatic] sshpass/xenial,now 1.05-1 amd64 [installed,automatic]   Doing this on RHEL v7 has no issues.


Display Media Uploader in Own Plugin on Wordpress 3.5

I have little problem with Media Uploader in new WordPress 3.5. I created own plugin which is upload the picture. I'm using this code JS:  <script type="text/javascript">     var file_frame;      jQuery('.button-secondary').live('click', function( event ){          event.preventDefault();          if ( file_frame ) {             file_frame.open();             return;         }          file_frame = wp.media.frames.file_frame = wp.media(             {                 title: 'Select File',                 button: {                     text: jQuery( this ).data( 'uploader_button_text' )                 },                 multiple: false             }         );          file_frame.on('select', function() {             attachment = file_frame.state().get('selection').first().toJSON();             jQuery('#IMGsrc').val(attachment.url);         });          file_frame.open();     }); </script>   The code works fine, but unfortunately forms appears incomplete. When I select any picture doesn't show me 'Attachment Display Settings' on right side. I don't know why. I try add options to media:  displaySettings: true, displayUserSettings: true   But it also doesn't work.


How to limit the number of users who can connect to an Windows-based access point using netsh?

I have a Wi-Fi dongle with the RTL8188EUS chipset. I'm using it to make a access point from a computer that has Windows 7. However, I have noticed that the dongle shuts off when 12 or more people are connected to it and I have to restart the hostednetwork.  When I do      netsh wlan show hostednetwork   it shows that the maximum amount of clients is 100.  Mode                   : Allowed SSID name              : "name" Max number of clients  : 100 Authentication         : WPA2-Personal Cipher                 : CCMP   Is there any way to reduce this number with the netsh command, does it require some additional work?  Thanks for answering.


I am running Ubuntu 14 LTS as a virtual machine with VMware player 6.07. The machine is currently using 24.7 GB but the maximum size available to the disk is 230 GB. The disk space is not preallocated, however, my host operating system (windows 7) sees this maximum 230 GB file for the VMWare guest OS and thinks my disk is full. I can't find any good instructions for how to reduce the file size. I have run   sudo vmware-toolbox-cmd disk shrink /   within the Ubuntu Guest operating system, however, I don't know how to reduce the maximum size allocated to the guest OS. This command merely shrinks the used space (in my case from 32GB to 24.7 GB), but doesn't change how windows sees the guest os.


Prove $x^4 + 131 = 3y^4$ has no integer solutions

I tried proving that $\dfrac{\Delta}{4}$ isn't a perfect square, but reducing it modulo 4 doesn't lead anywhere. Any help is greatly appreciated.


I've been fiddling around with different desktop environments lately. I started with Gnome Fallback, then Gnome 3 then XFCE and now I decided to use Unity.  I installed ubuntu-desktop and launched "Ubuntu" in Lightdm but no panel or launcher appears. To make them appear I need to do CTRL+ALT+F1, login and execute:  export DISPLAY=:0 setsid unity   It then appears after I execute that but every time I login I need to do that. In addition, there are no indicators in the top right corner.  Does anyone know how I can make the indicators appear and make the launcher and panel appear when I log in?  Thanks,


When voting to close a question, can the automatically added comment be made immediately visible to the voter?

When you vote to close a question, certain reasons generate a comment, e.g. closing as a duplicate generates a comment "possible duplicate of ...".  This comment doesn't show up on the question straight away after the popup with closing reasons is closed. This sometimes confuses me as I forget that a comment was to be added automatically and add a manual one too.  Can the comments section be refreshed automatically so that I can see the comment added straight away?


Sorting an array of an array of objects in PHP by key value

Basically I have a setup like the following:  Array (  [0] => Array ( [0] => stdClass Object ( [nid] => 1 [title] => title1 [uid] => 1 [parent] => 0 [weight] => -15 [name] => name1 [value] => 0 )                [1] => stdClass Object ( [nid] => 2 [title] => title2 [uid] => 1 [parent] => 0 [weight] => -7 [name] => name2 [value] => 100 )                [2] => stdClass Object ( [nid] => 3 [title] => title3 [uid] => 2 [parent] => 0 [weight] => -1 [name] => name3 [value] => 0 )                [3] => stdClass Object ( [nid] => 4 [title] => title4 [uid] => 2 [parent] => 0 [weight] => 1 [name] => name4 [value] => 80 )               )   )   What I need is a way to sort all the arrays inside the parent array by the [value] key in the Object. I've been trying for about 2 days now with usort and different methods but I just can't seem to get my head around it. The [value] key will range anywhere from 0 to 100 and I need all of the arrays sorted in decreasing order (IE: 100 down to 0).


I was reading the Proof of Hölder's Inequality in Measure Theory, and i saw, that our professor used an inequality and didn't explain, why it is true, and the inequality is;  For $\alpha\in(0,1)$ and $x\in\mathbb R_+$ $x^\alpha-\alpha x\le 1-\alpha$  $\textbf{I tried ;}$ $x^\alpha-\alpha x\le 1-\alpha$ $\Leftrightarrow x^\alpha\le 1-\alpha+\alpha x=1+\alpha(x-1)$ and $x^\alpha\le 1+\alpha(x-1)$ looks similar to bernoulli inequality, if you take $x'=\alpha(x-1)$ and $r=\frac{1}{\alpha}$ $(1+x')^r\ge x$ Is my justification correct, and does Bernoulli hold also for rational exponents ?


$(x+y)^r \le x^r+y^r$ when $r \in (0,1)$ and $x,y$ are real positive numbers.

I'm sorry for the silly question, but I have a doubt. Given two positive real numbers $x,y$ and taking $0<r<1$, is it true that  $$ (x+y)^r \le x^r+y^r? $$  In all the examples I considered, this turns out to be true. Moreover, to try to give a proof, does it suffices to prove that the function $f(z)=(1+z)^r-1-z^r$ is non-positive when $z \in (0,1]$ (i.e. taking $x>y$ and dividing by $x$?


I want to advance in the ranks of Senator Lavigny-Duval. How can I get merit points? I know I can participate in expansion goals, but is there a better way than that?


Richard Stallman states that Ubuntu "has installed surveillance code". See:   Is this true?   I agree with him that "Any excuse Canonical offers is inadequate....".


If multiple hashing algorithms are chained together, is the compound hash function more collision resistant?

The , which is a Proof of Work hashing algorithm composed of 11 separate hash functions which are run as a sequence.   Example: $Digest = H_{11}...(H_3(H_2(H_1(Input))))$  Questions:   1) Is this algorithm's collision resistance that of the weakest function in the sequence?  2) Can this algorithm tolerate a hashing collision found in one of the constituent parts and still produce output that is considered safe?


Suppose I have to vectors $w$ and $x$, each of size $[512,1]$. Each element of $w$ and $x$ is an i.i.d sample from a Guassian Distibution with mean 0 and variance 1. So $x_i$ and $w_i$ follow  $N(0,1)$  Let $y=w^Tx$  be my vector of interest. Then the question is what is the variance of $y$?  So $y=\sum w_ix_i$  $Var(y)=\sum Var(w_ix_i)$  I do not know how to take it forward from here....


Direct and indirect object with "give" and "buy"

I have been studying Longman's English grammar book, and something is really confusing me:   We can put it and them after the verb: Give it to me. Buy them for me. Do it for me. With e.g. give and buy, we can say: Give me it. Buy me them. (But not *Do me it.) We say: Give it to John. Buy them for John. (Not *Give John it - *Buy John them.)   Why can't I say Buy John it or Give John them?  There is another post related to it that talks about the same topic: . However, the most voted answer was, indeed, useful for me, but didn't get everything clear.  What's the main rule for inverting the position and dropping the preposition?  As far as I managed to understand, if the direct object is it or them and the indirect object is a pronoun, the normal construction's placement is necessary, i.e.: Subject + Verb + Direct object + To/For + Indirect object  Is this right?


Compute the integral $\int\frac{dx}{(x^2-x+1)\sqrt{x^2+x+1}}$

Compute the indefinite integral   $$ \int\frac{dx}{(x^2-x+1)\sqrt{x^2+x+1}} $$   My Attempt:  $$ \int\frac{dx}{(x^2-x+1)\sqrt{x^2+x+1}}=\int\frac{1}{(x^2-x+1)^{3/2}.\sqrt{\dfrac{x^2+x+1}{x^2-x+1}}}\,dx $$  Now define $t$ such that $t^2=\dfrac{x^2+x+1}{x^2-x+1}$ to get  $$ \begin{align} 2t\,dt &= \frac{(x^2-x+1)(2x+1)-(x^2+x+1)\cdot (2x-1)}{(x^2-x+1)^2}\,dx\\ 2tdt &= \frac{-4x^2+2x+2}{(x^2-x+1)^2}dx \end{align} $$  I don't know how to proceed from here.


So I need to prove that if gcd(a,b) = 1, then gcd(a,a+b) = 1. How do I go about it? I tried going with the ax + by = 1 method but it didn't work out so well.


Could $\pi$, raised to some power can give rational result?

For example $\sqrt 7$ is irrational but $\sqrt 7$ raised to power $2$ is rational. Similarly, is it possible that $\pi$ raised to some power (say $n$) could be rational ?


As Griffiths says:  Suppose we have a piece of polarized material - that is, an object containing a lot of microscopic dipoles lined up. The dipole moment per unit volume P is given. What is the electric potential produced by this object (not the field that may have caused the polarization, but the field the polarization itself causes)? Well, we know what the field of an individual dipole looks like, so why not to chop the material up the infinitesimal dipoles and integrate to get the total? For a single dipole p $$ V ({\bf {r}})= { 1 \over 4 \pi \epsilon_0} {\textbf p  \cdot \hat r \over r^2  }$$ where $ \vec r$ is the vector from the dipole  to the point at which we are evaluating the potential. In the present context, we have a dipole moment $ \bf p = \bf P  \rm  d \tau ' $ in each volume element $ \rm d \tau '$, so the total potential (function) is $$ V ({\bf {r}})= {1 \over 4 \pi \epsilon_0} \int_{\tau} { {\bf{P}} ({\bf {r'}}) \cdot \hat r \over r^2} \rm d \tau '$$  After some maths, he shows that: $$ V ({\bf {r}})= { 1 \over 4 \pi \epsilon_0} \oint_{\partial \tau}{\sigma_p \over r  } d \sigma' + { 1 \over 4 \pi \epsilon_0} \int_{ \tau}{\rho_p \over r  } d \tau'$$ where the quantities $$ \sigma_p = \bf P \cdot \hat n$$ $$ \rho_p = - \nabla \cdot \bf P $$ are the surface charge and the volume charge densities respectively. As far as I understood, the last equation is very general (at least for perfect dielectrics) and it can be used to calculate the potential ANYWHERE you want, even INSIDE the dielectric. But the formula we started with is valid only if you are far away from the dipole... so how can we prove the universality of our result even if we used a (strong) condition at the beginning?


Electrons, Muons and Pauli Exclusion   Put in a possibly oversimplified way, lepton universality says that electrons, muons, and taus all behave in the same way except for mass effects.  The question is “Does this apply to Pauli exclusion?”  Due to the Pauli exclusion principle, only two electrons can be in the s orbital, and hence in the ground state of regular beryllium, two electrons are in the s orbital, and two electrons are in the p orbital.  My question is what happens in the ground state of dimuonic beryllium, with two muons and two electrons. Are all four particles in s orbitals, or are two in s orbitals and two in p orbitals?   A similar question can be asked about muonic lithium, which would be easier to create experimentally.  i.e., in muonic lithium, with one electron replaced by a muon, can all three leptons be in the s orbital?


I am trying to write up a proof for the convergence of this recursive function. I was wondering if there exists a closed form.  Given first term in sequence is $\sqrt{2}$ and second is $\sqrt{2\sqrt{2}}$, and so on.


Easier way to access Favorites in the Stack Exchange Android app

It would be great if there was an easier way to access the questions I marked as favorite. I didn't find a way to do this in the app.


Keyboard Shortcut to Maximize Current Window / Application in OSX

I am using OSX 10.9.1.  Is there a keyboard shortcut to simulate the maximize and minimize functions that you normally find on the top left hand corner of the screen?  I read some of the other questions asked on SuperUser about this, but they are all quite old.  Any updates to the latest versions of Mac that make this possible now without 3rd party add-ons?


Prove $\langle a^s \rangle=\langle a^t \rangle \iff \gcd(n,s)=\gcd(n,t)$

Problem Let $G$ be a cyclic group with $n$ elements and with $a$ as the generator let $b \in G$ and let $b=a^s$. Then $b$ generates a cyclic subgroup of $H$ of $G$ containing $\dfrac{n}{d}$ elements, where $d=\gcd(n,s)$. Also show that $\langle a^s \rangle=\langle a^t \rangle \iff \gcd(n,s)=\gcd(n,t)$  I could prove all the remaining parts of the problem but I can't figure out the way to prove the second part of the problem i.e. $\langle a^s \rangle=\langle a^t \rangle \impliedby \gcd(n,s)=\gcd(n,t)$ without using the concept of Isomorphism.  The only things that can be used are,  Definition of cyclic group  The theorem that every cyclic group is abelian.  The theorem that every subgroup of a cyclic group is cyclic.    Any help will be appreciated.


An inequality involving $n$ blue points and $n$ red points on a line.

Question : Let $n$ blue points $A_i$ and $n$ red points $B_i$ ($i=1,2,...,n$) be situated on a line. Prove that $$\sum_{i,j}A_iB_j\ge \sum_{i<j}A_iA_j+\sum_{i<j}B_iB_j$$  I tried inducting on $n$ but cant proceed in the inductive step ( as usual ). Please help, if there is a direct method of approach please give hints. Is this true if all the blue points were on a different line?


why ssh myLogin@localhost works but ssh root@localhost doesn't?

I know ssh root@localhost is a bad idea...I get it.  But why doesn't ssh root@localhost work?  I even changed my root password just in case:  > sudo -s > passwd   But still when I do ssh root@localhost I get  root@localhost's password: [I enter the password]  Permission denied, please try again.    I tried ssh -v not sure what to look for here are the final few lines:  ... debug1: Offering RSA public key: /home/myName/.ssh/id_rsa debug1: Authentications that can continue: publickey,password debug1: Trying private key: /home/myName/.ssh/id_dsa debug1: Trying private key: /home/myName/.ssh/id_abcde debug1: Trying private key: /home/myName/.ssh/id_ed123456 debug1: Next authentication method: password root@localhost's password:  debug1: Authentications that can continue: publickey,password                                                                                Permission denied, please try again.                                                                                root@localhost's password:                                                                                debug1: Authentications that can continue: publickey,password                                                                                Permission denied, please try again.                                                                                root@localhost's password:                                                                                debug1: Authentications that can continue: publickey,password                                                                                debug1: No more authentication methods to try.                                                                                Permission denied (publickey,password).      /etc/ssh/sshd_config  ChallengeResponseAuthentication no PermitRootLogin without-password


What does it mean when the connectivity icons in the status bar go white/gray?

The connectivity icons (Data, Mobile Signal, Wifi) in the status bar on my Nexus S are normally green, but sometimes they go white. I can't seem to figure out what this means, as I still have a signal and can receive phonecalls/texts.  They are always all the same, e.g. either all white or all green. I'm on Android 2.3.4.


I want to create a zip archive from all files which are in "my_folder". Here is how I do it:  zip -9 -y -r -q  name.zip /home/user/Stack_Exchange/my_folder/   The problem is that right now when I unpack the archive, the hierarchy of folders is fixed, so the result of unpacking is the home folder and inside is the user folder, etc.  How can I create a zip archive which has only "my_folder" in the directory? I mean I want to see the folder "my_folder" after unpacking the archive.


I have a log file being written by another process which I want to watch for changes. Each time a change occurs I'd like to read the new data in to do some processing on it.  What's the best way to do this? I was hoping there'd be some sort of hook from the PyWin32 library. I've found the win32file.FindNextChangeNotification function but have no idea how to ask it to watch a specific file.  If anyone's done anything like this I'd be really grateful to hear how...  [Edit] I should have mentioned that I was after a solution that doesn't require polling.  [Edit] Curses! It seems this doesn't work over a mapped network drive. I'm guessing windows doesn't 'hear' any updates to the file the way it does on a local disk.


"No such file or directory" on files that exist?

In the past day, I've found at least 4 binaries that say "bin-name: No such file or directory" when I try to run them. Even if I type part of the name and tab complete it, I get the same error. I'm on an x86_64 architecture.  Output of file:  fez-09152013-bin: ELF 32-bit LSB executable, Intel 80386, version 1 (SYSV), dynamically linked (uses shared libs), for GNU/Linux 2.6.24, BuildID[sha1]=0x78612e4aac547367548dcc7cc3067c3cfcf2f177, stripped   Output of strace:  execve("./fez-09152013-bin", ["./fez-09152013-bin"], [/* 23 vars */]) = -1 ENOENT (No such file or directory) dup(2)                                  = 3 fcntl(3, F_GETFL)                       = 0x8002 (flags O_RDWR|O_LARGEFILE) fstat(3, {st_mode=S_IFCHR|0620, st_rdev=makedev(136, 1), ...}) = 0 mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7f3fda17a000 lseek(3, 0, SEEK_CUR)                   = -1 ESPIPE (Illegal seek) write(3, "strace: exec: No such file or di"..., 40strace: exec: No such file or directory ) = 40 close(3)                                = 0 munmap(0x7f3fda17a000, 4096)            = 0 exit_group(1)                           = ?   Output of ldd:  Not a dynamic executable   Output of strings is way too long to indent, so here's a link:   apt-get error:  Reading package lists... Done Building dependency tree        Reading state information... Done Some packages could not be installed. This may mean that you have requested an impossible situation or if you are using the unstable distribution that some required packages have not yet been created or been moved out of Incoming. The following information may help to resolve the situation:  The following packages have unmet dependencies:  ia32-libs : Depends: ia32-libs-i386 but it is not installable E: Unable to correct problems, you have held broken packages.


In proof by induction, what does it mean when condition for inductive step is lesser than the propsition itself?

My question is regarding the question posed at the end of the proof.  My answer is that the result does not hold for all $m \ge 7$ because when $m=7$, the result is $343 \le 128$, which is false.  Is there another way to answer this sort of question besides directly trying different values until you get a false result?  EDIT:  Another question I have regarding this solution is:  In the proof for the inductive step, we start by assuming $k \ge 10$. But along the way, the author mentions $k \ge 1$ and $k \ge 7$ to justify the inequality.  Why do we bother to do this instead of just sticking with $k \ge 10$?


How can I get maximum DoF with no distance markers?

I am aware of what hyperfocal distance is and the general principles behind it. However, most of the tutorials I have seen and read regarding it make use of lenses with focus distance indicators. Unfortunately, neither of my lenses (Nikkor 18-55mm & 35mm f1.8) have indicators.  I have read that you can 'cheat' and simply focus a third of the way into the shot (which I have done previously simply by spot-focusing on the lowest focus point in my VF). I also assume you could pace out the distance and note an object to focus on when you get back to the camera (though that might be easier said than done).  Does anyone have any suggestions on how to achieve maximum sharpness from front to back without focus distance markers. A new lens is not an option; global economic crisis and all that!


Ran in to this deployment issue error "Cannot deploy InstalledPackage in Package Manifest with any other types!" the only solutions i can find is to roll back from v28 to v27... but i cant find a copy for mac or pc any suggestions on rolling back?    Thanks


in a for-loop, what does the (int i : tall) do, where tall is an array of int

As the header says, I was tipped by some people that if I wanted to print the sum of everything in an array of numbers, I should use the above-mentioned parameter for a for-loop (code will follow if further explanation is needed). But what is the exact definiton of what that does? The :-part I mean. Is it; for every number i in the array tall?  import java.util.*;  class Uke36{     public static void main(String[]args){      Scanner input=new Scanner(System.in);     int[] tall=new int[5];      for (int i=0; i<=4; i++){         System.out.println("Vennligst oppgi det " + (i+1) + ". tallet: ");         tall[i]=input.nextInt();     }     int sum = 0;     for(int i : tall){         sum+=;     }     } }


Proving that $f(z)=\sum\limits_{n=1}^{\infty}\frac{z}{n(1+n|z|^{2})}$ converges uniformly on $\mathbb{C}$

How can one prove that $$f(z)=\sum_{n=1}^{\infty}\dfrac{z}{n(1+n|z|^{2})}$$ converges uniformly on $\mathbb{C}$ ?     My attempt was to let $z=x+iy$, then consider $$|\dfrac{z}{n(1+n|z|^{2})}|=\dfrac{\sqrt{x^{2}+y^{2}}}{\sqrt{(n^{2}x^{2}+n)^{2}+(n^{2}y)^{2}}}.$$     which looks like a mess. The main idea was to try to find an upper bound, $M_{k}$ so that I can apply the Weierstrass M-test. If I can show that the upper bound, $M_{k}$ is convergent (which is often simple by using root test etc.), I will be able to conclude that $f(z)$ converges uniformly.    Is there a simpler or more elegant way I can approach this question and if my approach is correct, can someone kindly guide me to find the required upper bound?


What is the best salutation to use in cover letter when I don't have contact information?

I prepare to write a cover letter to several banks. The application is online and I need to submit it to each employer. So how could I write in the salutation of the cover letter. I don't have the contact of HR people. Could I write something like this:     To whom it may concern,   ...        Dear Citibank HR,   ...


Pass the generic type based on Type variable

I have a generic function:  T GetVal<T>()             where T : class;  I also have a function which gets a Type and based on it should return the type specified: func(Type type) { var classType = ? // get the class type from type to use it in the next line    return GetVal<classType>() }  Is it possible?


Is there a closed form solution to the series $\sum ^{\infty }_{n=0}\dfrac {1}{n^{n}}$ ? I ran a python program and tried to use ries to find a closed form with no luck. Thanks


Can't send mail from my localhost by using smtp with C#

I am working on a Web Project. I want to create "Forget my password" system and send a mail to user when it needed but when i try this, it gives errors like SmtpException : Failure Sending Message, SocketException: Party did not properly respond or connection failed because connected host failed to respond and fails to send mail. I tried 2525, 25 and 587 ports. I also checked if i can connect smtp.gmail.com by mxtoolbox:  This is SMTP Email Server Test    This is SMTP DNS Test     and here is my code:   protected void lblForPass_Click(object sender, EventArgs e)  {      SmtpClient client = new SmtpClient();      client.DeliveryMethod = SmtpDeliveryMethod.Network;      client.EnableSsl = true;      client.Host = "smtp.gmail.com";      client.UseDefaultCredentials = false;      client.Port = 25;      client.Timeout = 300000;      System.Net.NetworkCredential credentials = new System.Net.NetworkCredential("mytestmail@gmail.com", "1122334455");      client.Credentials = credentials;       MailMessage msg = new MailMessage();      msg.From = new MailAddress("mytestmail@gmail.com");      msg.To.Add(new MailAddress("mytestmail2@gmail.com"));       msg.Subject = "Subject Test";      msg.IsBodyHtml = true;      msg.Body = string.Format("Body Test");         try       {           client.Send(msg);           ScriptManager.RegisterClientScriptBlock(this, GetType(), "Mail Status", "alert('Sended Successfuly')", true);       }        catch(Exception ex)       {           Exception ex2 = ex;           string errorMessage = string.Empty;           while (ex2 != null)           {               errorMessage += ex2.ToString();               ex2 = ex2.InnerException;            }           string err = ex.Message;           ScriptManager.RegisterClientScriptBlock(this, GetType(), "Mail Error", "alert('" +err+"')", true);         }       }     Is there anything that i missed at this code block or do i need to check anything else? Thank you.


Why do I get "unresolved external symbol" errors when using templates?

When I write C++ code for a class using templates and split the code between a source (CPP) file and a header (H) file, I get a whole lot of "unresolved external symbol" errors when it comes to linking the final executible, despite the object file being correctly built and included in the linking.  What's happening here, and how can I fix it?


Java JDBC CachedRowSet creation results in NullPointerException

I'm working on creating a connection between a Java program and a MySQL database. The only thing not included in the code is the ConnectionValue class which pulls all the relevant connection data needed for each specific connection/query. This class does work. When I run the code, it creates a NullPointerException. import javax.sql.rowset.CachedRowSet; import java.sql.*;  public class SQLCommands {     private Connection connection;     private PreparedStatement preparedStatement;     private CachedRowSet cachedRowSet;      public void createConnection(ConnectionValues connectionValues) throws SQLException {         connection=DriverManager.getConnection(connectionValues.urlString,connectionValues.userName,connectionValues.password);     }      public void createCachedRowSet(ConnectionValues connectionValues, String query) throws SQLException {         cachedRowSet.setUsername(connectionValues.userName);         cachedRowSet.setPassword(connectionValues.password);         cachedRowSet.setUrl(connectionValues.urlString);         cachedRowSet.setCommand(query);     }      public void createPreparedStatement(CachedRowSet cachedRowSet) throws SQLException {         preparedStatement=connection.prepareStatement(cachedRowSet.getCommand());     }      public CachedRowSet readDataBase(int dbID, String query) throws Exception {         ConnectionValues connectionValues=new ConnectionValues(dbID);         createConnection(connectionValues);         System.out.println(connectionValues.urlString+"\n"+connectionValues.password+"\n"+connectionValues.userName);         createCachedRowSet(connectionValues,query);         createPreparedStatement(cachedRowSet);          try {             preparedStatement.execute();             return cachedRowSet;         }catch (Exception e){             System.err.print("ERROR!\nFunction: readDataBase\nClass: SQLCommands\n");             System.err.print(e);         }finally {             connection.close();         }         return cachedRowSet;     } }  The stack trace reports that the error is occurring at line 14. Which is the cachedRowSet.setUsername(connectionValues.userName); in the function createCachedRowSet. The data is correct, I have a test print method that prints the relevant information in the code and it not only pulls the same data without error but also prints the correct information. So I'm not sure what is wrong. Knowing me, it's probably obvious but I can't see it.


How to find the sum of the series $1+\frac{1}{2}+ \frac{1}{3}+\frac{1}{4}+\dots+\frac{1}{n}$?

How to find the sum of the following series? $$1 + \frac{1}{2} + \frac{1}{3} + \frac{1}{4} + \dots + \frac{1}{n}$$ This is a harmonic progression. So, is the following formula correct? $\frac{(number ~of ~terms)^2}{sum~ of~ all ~the~ denominators}$ $\Rightarrow $ if $\frac{1}{A} + \frac{1}{B} +\frac{1}{C}$ are in H.P. Therefore the sum of the series can be written as : $\Rightarrow \frac{(3)^3}{(A+B+C)}$ Is this correct? Please suggest.


I've looked a lot to find out where a user's account picture is stored in macOS. So exactly the path to be able to access it with the Finder. I haven't found a way to get the path anywhere. The only thing I've found is how to extract it as an address. But that is exactly the problem where is this address? dscl . -read /Users/$(stat -f %Su) JPEGPhoto  You can extract it like this: dscl . -read /Users/$(stat -f %Su) JPEGPhoto |xxd -r -p > ~/Kontobild.jpg  Any ideas where it could be stored? Thank you in advance


Why is the potential difference across a component not constant?

In the diagram above, the resistor has a constant resistance R.  We know that:  $$R=\frac{V}{I}$$ $$V\propto I$$  If the current increases, that means the rate of flow of charge (i.e. the speed at which the charge is flowing) has increased.  However, why should the potential difference across the resistor decrease to maintain the proportionality? The resistance of the resistor hasn't changed, so each coulomb of charge still needs to do the same amount of work on the resistor to flow through it.   In other words, the potential difference across a component is defined as the work each coulomb of charge needs to do on the component to flow through it. In that case, shouldn't the rate of flow of charge and the work done per unit charge be completely independent?


I used to use  MyClass.prototype.myMethod1 = function(value) {     this._current = this.getValue("key", function(value2){         return value2;     }); };   How do I access the value of this within the callback function like below?  MyClass.prototype.myMethod1 = function(value) {    this.getValue("key", function(value2){        //ooopss! this is not the same here!            this._current = value2;    }); };


Why do I keep getting told I posted less than 15 characters when I posted more than 15?

I tried to post the following comment and it claims it was less than 15 when it was more.  Based on Tim's comment and testing I believe it would not let me post because with @Shadow removed it is less than 15. However, the characters left message indicates I have passed the 15 character minimum thus it is wrong.  This is the bug I'm reporting:  The characters remaining message and the characters left message do not take into account striping out @name prefixes.


Seller and Purchaser each represents? Or Seller and Purchaser each represent?

Here is the pertinent part of the sentence:  "Seller and Purchaser each warrants and represents that it has not engaged the services of any agent, finder or broker in connection with the transaction which is the subject of this Agreement...."  While it is true that "each" is always singular, the question is whether the word "each" can render the plural "Seller and Purchaser" singular by its inclusion in the sentence.  I believe the answer is no, based on the fact that if you replace "Seller and Purchaser" with the pronoun "they," the sentence makes no sense:  "They each warrants and represents...."  But you can't simply remove the word "each" because then the sentence would imply that Seller and Purchaser warrant and represent on each other's behalf, which is clearly not the intent of the sentence either. So the answer, in my mind, is to break up the sentence into 2 separate sentences:  "Purchaser warrants and represents....Seller warrants and represents...."  Any other thoughts or suggestions?


Find the Remainder when $333^{333}$ is divided by $7$  I think I have to find $333^{333}\equiv r \pmod7$ where $r(\ge0)$ is the remainder but how do I get in that form


Knowing the gcd and lcm, how to find a, b

Find all positive pairs of integers a, b such that (a, b) = 12 and [a, b] = 360.  I used the formula [a, b] = ab/(a, b) and I got that ab = 4320.  From there I just listed all 48 factors of 4320 alongside the factor they correspond with. However, the pair 54 and 80 multiply to 4320 but their lcm is 2160, and not 360 as the problem asks. Is there a faster way to find out which pairs fit the criteria than testing them one by one?


How to fix issue with apt and sources.list.d to install Yandex browser?

I followed the instructions at  to install Yandex browser.   When I did apt-get update, I got this error:  root@aspire:~# apt-get update E: Malformed line 1 in source list /etc/apt/sources.list.d/yandex-browser.list (URI) E: The list of sources could not be read.   So apparently the  were not quite correct, because I entered the lines into yandex-browser.list as instructed  root@aspire:~# more /etc/apt/sources.list.d/yandex-browser.list deb [arch=amd64] http://repo.yandex.ru/yandex-browser/deb beta main   So, if the problem is the first line, how should I change this? I am guessing I need to remove the [arch=amd64] part, but then will I still get to the right package, as there are both a 32-bit and a 64-bit packate at the repository?


Is there a way to constraint a generic type to only integral type?  In example, if I have a method  T[] sort<T>(T[] data) where : T ... {}   what would I put as constraint if I wanted to ensure the parameter will be some sort of integral type?  I have tryed looking at  however it does not seem to mention anything about constraining and primitive types.  Thank you for your help.


Two developer licenses under the same Apple ID (same company)

We already have one developer license, but want to buy one more developer license.  Is it possible under the same Apple ID?  We want to buy one more license under same company name, same Apple ID.  Basically Apple ID (having agent role) is legal owner. So under the same Apple ID, we wanted to buy a 2nd license.  If no, what are the alternate ways?


In my org, I have an Address object that relates to the Account object (the relationship name is Address_vod__r). I'm trying to get a list of related Addresses in Apex, however, my subquery appears to be ignored. Executing this query in the query editor returns results as expected: SELECT Id, (     SELECT Zip_vod__c FROM Address_vod__r ) FROM Account LIMIT 10`   However, executing the exact same query in anonymous apex doesn't return any address results: System.debug([     SELECT Id, (         SELECT Zip_vod__c FROM Address_vod__r     ) FROM Account     LIMIT 10 ]);   Does anybody know what I'm doing wrong here?


Centre of gravity vs centre of mass for a pyramid mounted on a cube, all sides of length $l$

A uniform solid body is constructed using a square-based pyramid mounted on a cube. If each edge of the solid has length $l$ show that the centre of gravity of the body lies within the cube is, $\frac {11l}{(24 + 4√2)}$from the base of the pyramid.  Now Volume of cube = $l^3$, and of the pyramid = $\frac{l^3}{3√2}$, using the height of the pyramid as $\frac{l}{√2}$, from Pythagoras. If $O$ is at the base of the pyramid we can say that for the pyramid the height above $O$ is $\frac{l}{4√2}$, as the centre of gravity (centre of mass) is  $\frac{h}{4}$ above the base, and we are expecting the centre of gravity to be in the cube. The height below the base $O$ for the cube is $\frac{-l}{2}$.  Some texts equate the centre of gravity to the centre of mass. Can we do this in this particular problem?


Creating lines in procedural voronoi cell texture

I've been trying to figure out how to make a kind of crackle map similar to this:    Using this: the Voronoi cells texture in cycles:    My theory is that you could use the information in the texture (the places where the different colors meet) to create black lines, but I just cannot figure it out.  Any examples would be appreciated.


Can we start cleaning up [table] tag and burninate it ASAP

Related questions:     (This led to founding of )   The tag  has become cluttered with all kinds of questions ranging from sql tables (for all DBM systems, HTML tag <table>, outputting content in any language (PHP, C#, LaTeX to name a few) as a table and several plugins of various languages and/or IDEs (like jTable, tablesorters and the kind).  The current count stands at 18,315 questions having this ambiguous tag. A few of possible suggestions for cleaning process:    +  to  |   +  to  |   +  to  |   +  to  |   + other-specific-DBM systems to whatever_DBM_it_is-table  +  to  |    Since I've no idea about other languages and their specific features regarding table, I'd ask the community for their input on this (such as , ,  and ). The other questions are either tagged with arrays or sql and similar tags, and in my opinion, just removing  from such questions would be enough!


A word like ethereal that also means quickly vanishing

This is a question for English wordsmiths. Is there a word that "feels" like the word "ethereal" that means something ethereal that quickly disappears.  Or is "ethereal" the correct word choice for this? Ethereal was the first word that popped into my head for this.  From the various definitions that I've looked at for ethereal, it says delicate, beautiful, heavenly, etc. but not necessarily quickly vanishing, except for the secondary definitions related to ether that suggests it evaporates. I'm just wondering if there is a better word than this.  I'm using the term "ethereal skill" to describe a certain type of pilot skill (instrument flying) that requires tremendous practice to achieve proficiency, and once proficiency is achieved it is a beautiful thing, but if you don't practice it regularly, that skill vanishes after a few weeks.   USAGE: Instrument proficiency is an ethereal skill that once obtained must be maintained through constant and regular practice.


How to hide overflow characters of a div when resizing

I have a few div elements, I want to hide overflow characters when div resizing like this   to this  how to do this every time i resize page.  Can i do it from CSS?


Is there a rule for good usage as concerns applying a number word as "one", "two" and so on as opposed to Arabic numerals as "1342"? Is it, for instance, a rule that numbers less than 20 should be designated with number words and larger numbers with Arabic numerals?


Replace a power adapter 12V/1A DC with 15V/0.8A

I have a  that has an input of 12V/1A as specified in the .  Can I replace the adapter with a 15V/0.8A adapter ? I also have a 9V/0.85A  Will both work ? Which is more suitable and safer to replace with, or should I buy a 12V/1A ?  I was told 15V/0.8A and 12V/1A are practically the save since the have the same Power result in watts of 12W = 12*1 = 15*0.8 ? Is this correct ?


Why are the energy levels of a simple harmonic oscillator equally spaced?

The energy level of a simple harmonic oscillator is $E_n=(n+\frac{1}{2})\hbar\omega$. Is there any physical explanation why these levels are equally spaced ($= \hbar\omega$)?  Maybe this  can be helpful.


Getting List of Running processes and applications

How can I see which application and what processes are running recently after the login using terminal command.


When rubbing a ruler with my hair and get it closer to some pieces of papers , it'll attract them (they'll effect each other by an electric force). But why ? WhenI only charge the ruler not both of them ( I mean the pieces of papers too)


I have a directory variable and function as follows:  coding_dir="~/Documents/coding" function f() { cd $1 && ls -a ; }   And I want to create an alias as follows:  alias rnd="f $coding_dir/random"   But when I try using the alias, I get the following error:  f:cd: no such file or directory: /random   I am aware I could just use the entire directory in the alias, but this was working when I was using bash. How do I get this to work in zsh?


Colour status-completed, status-declined... and discussion, support... tags differently on the android app

In the website some Meta tags are coloured differently. I think this should be replicated on the android app.    Thinking about it I think the required meta tags, feature-request, support, discussion and bug should also be highlighted in some way, as they are on the desktop version.


Hopefully, someone can help me with my problem.  I have tried to implement the following code from an old post in my cv project:   Unfortunately, I failed :(  My code:   The design and colours should remain as they are, I just want the possibility to fill these circle half.  Looking forward to getting help form you :)  Best, Andreas


How do i transfer linux from usb to new hdd?

My old laptop stopped reading the hard drive. In bios it said there wasnt one. I replaced it. Now it shows the disk in bios.   I dowloaded linux cinnamon onto a usb. Now. I can get the laptop to run linux from the usb. Everything works great.  I thought i properly formatted the new drive and then copied linus to it . added the boot driver. Changed the boot order back to the hdd first . but it wont boot linux from the hdd. If i take the usb out it doesn't boot any OS.   Help?


If $A^2\succ B^2$, then necessarily $A\succ B$

I remember reading somewhere about the following properties of non-negative definite matrix. But I don't know how to prove it now.  Let $A$ and $B$ be two non-negative definite matrices. If $A^2\succ B^2$, then it necessarily follows that $A\succ B$, but $A\succ B$ doesn't necessarily leads to $A^2\succ B^2$.  How can you prove it? Thanks!


In the image below,    All the blocks are frictionless & identical with side of unit length, height $h$, weight $w$ & center of gravity at their geometric centers. The 2 lowest blocks are on solid ground. The distance from the corner of each block to the midpoint of the bottom side of the box above it is given (namely $a1,a2,b1,b2$). forces $F_{ac}$ and $F_{bc}$ are the resultant reaction forces exerted by blocks $A$ & $B$ on $C$.      I am interested in the behavior of these blocks immediately after setting them in this configuration and releasing them, or more specifically: For what relation between $a1,a2,b1$ & $b2$:    do $A,B$ and $C$ move?- case 1 do only $A$ and $C$ move?- case 2 do only $B$ and $C$ move?- case 3 is the configuration stable (does not change at all once set under this condition and then left.)?- case 4    For those interested, here's my approach & what (I think) I know already:  In an attempt to find the limiting conditions (the borderline conditions between equilibrium and non equilibrium), I assumed that initially $C$ will tend to be in equilibrium.(I have no rigorous justification for this assumption, just a hunch that "this isn't where the trouble is").Under this condition, $F_{ac}$ & $F_{bc}$ can be calculated, and the moments due to their "equal and opposites" ($F_{ca}$ & $F_{cb}$) about $P1$ and $P2$ can be obtained as: $$ M_{ca}(x,y)=w(.5+a1-a2-x)/(x/y+1)$$ $$ M_{cb}(y,x)=w(.5+b1-b2-y)/(y/x+1) $$ where $x$ & $y$ are the perpendicular distances of the respective forces from the center of $C$.   With some ad-hoc and shaky logic here's what I arrived at:   when $$w\cdot a_2 <M_{ca}(.5,.5)\quad \& \quad w\cdot b_2 <M_{cb}(.5,.5)$$ case-1 occurs with $A$ & $B$ touching $C$ only through it's vertices. when $$w\cdot a_2 =M_{ca}(x1,.5)\quad \& \quad w\cdot b_2 <M_{cb}(.5,x1)$$ where $a1\leqslant x1< .5$ case-1 occurs with $C$ rotating with $A$ maintaining a surface of contact with $A$ but only a point contact with $B$, but if $$\boldsymbol{w\cdot a_2 =M_{ca}(x1,.5)\quad \& \quad w\cdot b_2 \geqslant M_{cb}(.5,x1)}$$ the configuration is stable (case-4). when $$w\cdot a_2 >M_{ca}(a1,.5)\quad \& \quad w\cdot b_2 <M_{cb}(.5,a1)$$ case-3 occurs, but if $$\boldsymbol{w\cdot a_2 >M_{ca}(a1,.5)\quad \& \quad w\cdot b_2 <M_{cb}(.5,a1)}$$ the configuration is stable (case-4). The above conditions with $a$ & $b$ exchanged along with their corresponding variables.   But I have no way to check this or provide a satisfactory argument for these conditions, especially the parts written in bold (I arrived at it by putting various combinations of arguments for $M_{ca}$ & $M_{cb}$ & thinking about what would happen in each case). Is this set of conditions right?. What would be a good approach with a logical progression of steps to solve it?


US B1/B2 visa application refused without "strong" reasons and possible criteria applied

A 47-year-old relative applied for a US B1/B2 visa in Lima, Peru today and completed the DS-160 form specifying the following relevant information:  - That she was divorced for more than 10 years now.  - That she will travel with her 27-year-old son and that he will be mainly affording the trip costs. - That her sister is a LPR (Lawful Permanent Resident). - That her role at work is actually related to business tasks and being in charge of 3 people and also specified her salary (which is way more than the minimum wage for the country).   And, during the interview, the consular officer just asked the following questions (with a terrible attitude, not even saying “hello” and showing at least a bit of respect):  Q: What’s the purpose of the trip? A: Attend to my sister’s wedding with my son and stay for 5 days in FL.  Q: Who will afford the trip costs? A: I will, but my son will primarily do it (I have papers to demonstrate his funds and job if you want to take a look).  Q: Does your son have a US visa? A: Yes, he does.   Then, the consular officer just said “Ah, your son has a US visa" (she took note of something in the system) and told my relative that her application was refused under "Section 214(b) of the US immigration and Nationality Act" and gave her a paper “explaining the reasons” of the decision.   After that, my relative asked the consular officer what was the specific reason of the refusal and she just told her to read the paper - which actually says nothing and we all know it’s just a formalism and contains too abroad information - then my relative replied “but the paper says nothing” and the consular officer just stopped talking.    Being that said, I got the following questions:  1. What could be the criteria, in this particular case, for refusing my relative’s visa application (based on your experience, since I can't really understand) and how is it possible for a consular officer to determine whether or not you are eligible for a visa with such basic questions and without reviewing any document.  2. Based on the previous info, can I assume that my relative got a refusal because of the “attitude” of the consular officer and do you think it’s a good idea to re-apply soon?    Particularly I find all this a bit unfair and totally inaccurate to determine who is eligible for a US visa or not and compared to other embassies but this is just my personal opinion (at the end it feels as if the applicant is playing a roulette game).


Is dielectric capable of storing charge?  I mean if a dielectric is removed out of a charged capacitor will it still have charges stored into it??


when i type make in my terminal to build libraries and some tests in my machine ,i get this error:  g77 -O -fno-automatic -c lsame.f -o lsame.o make: g77: Command not found make: *** [lsame.o] Error 127   Please help me out.i am unable to install g77 too!


Which of the following sentences has correct use of prepositions? (A) I was angry at my results so I spoke with the teacher. (B) I was angry with my results so I spoke to the teacher.  here results are not a person so it is a different question


How to print AND redirect print content into a file?

I know how to redirect stdout into a file:  import sys sys.stdout = open('log.txt', 'w') print 'test'   This will create a log.txt where test will be written in it. However, test will not be print in stdout.  How can i print and redirect test in both terminal and file without changing every print statement in the program.  PS: I know that redirecting sys.stdout is bad (but i still need to do it)


Joining mirrored object causes half of it to disappear

Trying to join my meshes to create a single mesh so it is easier for exporting/ However when I click Ctrl+J to join them all of the mirrored meshes disappear and I am left with half a shape.  Any Suggestions?


I hold no strong opinions towards homosexuality one way or the other; I'll personally refrain, but don't apply my personal tastes to the rest of the world.  I remember seeing some articles a while back, and in some online debates, that there's been evidence in favour of a genetic component of homosexuality. I ignored it back then (before it became legalised), since it didn't affect me. However, after deep thinking, I started to seriously doubt those stories.  My gripe is this, based on my extremely limited understanding of Evolutionary Biology, organisms with genes which boost survivability, will tend to become more abundant. Genes that made organisms more fertile and reproduce more, will tend to become more abundant.  So, if say a particular gene, reduced effective fertility of organisms, that gene may be expected to be absent after a while. Fewer organisms with that gene would reproduce each successive new filial generation. There will be a diminishing marginal increase in the population of these gene bearers, before there eventually starts to become negative growth. I expect that population, may eventually find themselves in extinction, or on the brink of it.  In the few 100,000 years that Homo Sapiens have walked this planet, I guess there's been sufficient time for a population of genetically predisposed homosexuals to become extinct, or reach its brink. Certainly not the 5% - 10% estimated population we have today.  As such, I am unable to understand how homosexuality might be determined by genes in spite of natural selection.   My understanding of Evolutionary Biology may be severely lacking; especially as my teachers in the subject believed it was blatantly false, and were not really interested in making their students understand it. Some even going to the extent of making it seem as ridiculous as possible (I live in a country, where more than 90% of the population are genuinely religous (as in they truly believe in the existence of God) in one form or the other). I would appreciate answers to my question.  Of course, whether or not treatment of homosexuals should change, is another separate matter. It certainly does not follow from any conclusion of this inquiry; the answer to this question, is irrelevant as far as LGBT rights are concerned.


Is it acceptable to contract the phrase in the subject the way above (at least in a spoken English) without raising eyebrows?


Limit of a Sequence involving cubic root

I succeed in finding the following limit applying binomials and squeeze theorem: $$\lim(\sqrt{n+1} - \sqrt{n}) = \lim\frac{1}{\sqrt{n+1} + \sqrt{n}} = 0$$ because $0 \leq \frac{1}{\sqrt{n+1} + \sqrt{n}} \leq \frac{1}{\sqrt{n}}$  But I need help because I'm not finding any way to simplify and solve the following limit: $$\lim(\sqrt[3]{1-n^3} + n)$$


How do I prevent pages I visit from overriding selected Firefox shortcut keys?

In Firefox, how can I prevent pages from overriding Firefox built-in keyboard shortcuts through Javascript on a per-key basis? Preferably on a per-site basis, too? The most frustrating override is the forward slash ('/') that's linked to "Find in page". Sites like Google search results, Twitter timelines, some wikis, and other pages steal the slash key for their own search boxes, which is completely wrong.  Since my rep lets me ask, edit, and answer questions, but not add comments, this is basically a duplicate of these other two questions that weren't properly answered:


How do I delete a file whose name begins with "-" (hyphen a.k.a. dash or minus)?

How do you remove a file whose filename begins with a dash (hyphen or minus) -?  I'm ssh'd into a remote OSX server and I have this file in my directory:  tohru:~ $ ls -l total 8 -rw-r--r--    1 me  staff  1352 Aug 18 14:33 --help ...   How in the world can I delete --help from a CLI?  This issue is something that I come across in different forms on occasion, these files are easy to create, but hard to get rid of.  I have tried using backslash  rm \-\-help   I have tried quotes  rm "--help"   How do I prevent the minus (dash or hyphen) character to be interpreted as an option?


Set new heading for included multi-page document

In a large base document  \documentclass[10pt,onecolumn]{article}   I use   \pagestyle{myheadings} \markboth{ }{my main document heading text}   to set the headings.  I am also using the pdfpages package to include a multi-page document within my base document as follows:  \includepdf[pages={1-},scale=.95]{myMultiPageDocument.pdf}   I would like to set the heading within the base document showing the added document and tried  \markboth{ }{my new heading text here}  \includepdf[pages={1-},scale=.95]{myMultiPageDocument.pdf}   but no headings were rendered.  (I cannot set headings within myMultiPageDocument.pdf.)  How do I create new headings for the pages showing the included document?


Euclidean and induction with prime numbers

I have been given the following question in my homework:      Show that for every $n \in \mathbb{N}$ there are at least ${\log_2log_2 (n-1)}$ primes in $[1,n]$   I think it is related to euclidean and induction but I am having difficulties developing my solution.   Thanks for your help (:


Schengen visa to vist Italy with my husband who is from South Africa

I have dual citizenship South African and Italian.  My South African husband and I are planning to go to Italy in May 2017 for a visit.  We have already been on a two-week visit in October 2010 but were not married at the time and my brother in Italy sent an invitation letter.  Now that we are officially married, does the same invitation process applies or he can travel with a spouse visa?  Is a visa easier to obtain this time around as he has already obtained one Schengen Vvsa previously?