The spell  states:  A beam of yellow light flashes from your pointing finger, then condenses to linger at a chosen point within range as a glowing bead for the duration. When the spell ends, either because your concentration is broken or because you decide to end it, the bead blossoms with a low roar into an explosion of flame that spreads around corners. Each creature in a 20-foot-radius sphere centered on that point must make a Dexterity saving throw. A creature takes fire damage equal to the total accumulated damage on a failed save, or half as much damage on a successful one. The spell's base damage is 12d6. If at the end of your turn the bead has not yet detonated, the damage increases by 1d6.  According to the  rules of The Rules of Magic (emphasis mine):  You can end concentration at any time (no action required).  Is it possible for a caster to cast Delayed Blast Fireball on their turn, end their turn (increasing the damage by a d6 by doing so), and immediately end the spell during the start of the next creature in the initiative order's turn?

From the :  Some spells require you to maintain concentration in order to keep their magic active. If you lose concentration, such a spell ends. If a spell must be maintained with concentration, that fact appears in its Duration entry, and the spell specifies how long you can concentrate on it. You can end concentration at any time (no action required).  The rule is very short and only says "at any time (no action required)". How is this "any time" defined? An example scenario:  I cast levitate on an enemy to remove them from the battle. Later, on his turn, he raises a crossbow. The DM declares the attack, but then I interrupt him and say that I end my concentration, so he will fall down and become prone.  Another example scenario:  I cast levitate on myself and fly 30 ft. The enemy then flies and spends all his movement to fly to me, to attack me in melee. After he reaches me, I declare I am ending my concentration, so I can fall back to the ground, preventing him from attacking me.  Is this allowed? Can I end concentration conveniently any time, interrupting any currently declared action/event?


On the  we can read about \K:     Keep the stuff left of the \K, don't include it in $&   Here is the practical example using GNU grep (which actually keeps stuff right of the \K):  $ echo "foo bar buzz" | grep -Po "foo \Kbar buzz" bar buzz   Is there any opposite sequence of \K?  For example to print just bar, like:  $ echo "foo bar buzz" | grep -Po "foo \Kbar\X buzz" bar

Say I have a file:  # file: 'test.txt' foobar bash 1 bash foobar happy foobar   I only want to know what words appear after "foobar", so I can use this regex:  "foobar \(\w\+\)"   The parenthesis indicate that I have a special interest in the word right after foobar.  But when I do a grep "foobar \(\w\+\)" test.txt, I get the entire lines that match the entire regex, rather than just "the word after foobar":  foobar bash 1 foobar happy   I would much prefer that the output of that command looked like this:  bash happy   Is there a way to tell grep to only output the items that match the grouping (or a specific grouping) in a regular expression?


this is basically the same thing i got to compare numbers from user input, with "int", but for some reason it doesnt work for words in an array of strings even when it is correct. its unfinished, i just want to make it compare properly.              case 2:              cell = (int)((Math.random() * 59) + 1);             System.out.println(englishNumbers[cell]);             System.out.println("what is the number? >");             String w = in.nextLine();             if(w != frenchNumbers[cell])             {                 System.out.println("That is incorrect");                 numChoice(2);             }             else             {                 System.out.println("That's correct");                 numChoice(2);             }             break;

I've been using the == operator in my program to compare all my strings so far. However, I ran into a bug, changed one of them into .equals() instead, and it fixed the bug.  Is == bad? When should it and should it not be used? What's the difference?


I'd like to use array function to get conditional sum based on two columns. Given the example, for each ID I want to calculate the sum of value column if column B is -1  ID | B | value | ________________ A1   1     2 A2   1     3 A3   1     4 A3  -1     5 A3  -1     1 A2   1     5 A1   1     1 A2  -1     2   The outcome should be  ID | value_total | __________________ A1  1      0 A2  1      2 A3  1      6

I have a spreadsheet of my bank account transaction history in this format:    | A          | B        | C        | D 1 | Date       | Amount   | Balance  | Category 2 | 2013-03-10 | $ -10.59 | $3700.76 | Food shopping 3 | 2013-03-11 | $ - 5.10 | $3695.66 | Car parking 4 | 2013-03-11 | $ 100.00 | $4695.66 | Salary   In my spreadsheet the Balance column is hidden because I recalculate it myself.  I want to have a summary for each month with data looking like this:    | A       | B        | C           | D 1 | Month   | Income   | Expenditure | Net 2 | 2013-03 | $ 100.00 |     $ 15.69 | $ 84.31 3 | 2013-04 | $  00.00 |     $ 00.00 | $ 00.00   These are the formulas I have right now, so I can compute Net fine, but I don't know how to compute Income or Expenditure on a monthly basis because SUMIF only lets me do criteria on a single column (in this case, the Date column, but I want to only sum rows >0.0 for Income and <0.0 for Expenditure):  Net = =SUMIF( MonthAndYear( Txn!$A:$A ) , $A$2, Txn!$B:$B )


I have a controller class  @RestController public class Controller {      @GetMapping("endpoint")     public void endpoint() {     } }   and need the reference to the method handling the request i.e. Controller#endpoint().   I'm not looking for obtaining a reference to the current method but rather assume I'm in a filter or service for example and I need a reference to the endpoint method.   (The ultimate goal is to then assess wheter @SomeRelevantAnnotation is present or not deep inside my custom spring security stack but that's out of scope for this question.)  I think I could use the RequestContextHolder instance which embedds the request instance that I can then use in HandlerMapping#getHandler(request) to get a reference to the method.  Is there an easier way?

Is there a way to get the name of the currently executing method in Java?


I have defined a floating environment. It defines a framed box using \mdframe. Here is the code I used.  \documentclass{article}  \usepackage{mdframed} \usepackage{lipsum} \usepackage{caption} \usepackage{newfloat}  \usepackage{float} \DeclareFloatingEnvironment[fileext=frm,placement={!ht},name=Frame]{myfloat}  \begin{document} \begin{myfloat}[tb] \begin{mdframed} \caption{Lipsum Frame}  \lipsum \end{mdframed} \end{myfloat}   \end{document}   The text content in the mdframed box is too large to fit in a single page. But on executing this code, I miss the text content which exceeds the first page's limit. The framed box abruptly stops at the end of first page. How to continue my framed box on the next page?

I'm using new float enviroment to show some examples in my document. This  enviroment contains tcolorbox which provides a gray background. The main text in the enviroment is a mixture of plain text and code blocks (in lstlisting env). Each float should have it's own caption and label.  In style file:  \usepackage{newfloat} \DeclareFloatingEnvironment[name={Example}]{suppfigure}   In the main document:  \begin{suppfigure}[!h] \caption{Some code example}\label{suppfigure1} \begin{tcolorbox}[arc=0mm, left=1pt, right = 1pt, boxrule=0mm,colback = {shadow-gray}]   Text  \begin{lstlisting}  int i = 0;  \end{lstlisting}  Some more text  \begin{lstlisting}  String.Format("{0,10:0.0}", -123.4567);   \end{lstlisting}  \end{tcolorbox}  \end{suppfigure}   How can I allow page break inside the suppfigure to extend my example to multiple pages?


Let $f: (M,d) \rightarrow (N,\rho)$ be continuous and let $A$ be a separable subset of M. Prove that $f(A)$ is separable.  My idea is to take countable dense subset of A and then construct an open ball for its points and use the definition of continuity in a metric space to conclude that $f(A)$ is separable.   Kindly help me to provide a rigorous proof.  Thanks!

Prove that every continuous image of a separable space is separable.   Let $(X, \mathcal T)$ be a separable space. Then there exists some countable subset $A \subseteq X$ such that $\overline{A}=X$. Let $f:X\to Y$ be a continuous mapping. Notice that $f:X \to f(X)\subseteq Y$ is clearly surjective.  Since $A\subseteq X$, and functions preserve set inclusion, we have that $$f(A) \subseteq f(X)= f(\overline{A}).$$ Also, it is clear that $f(A)$ is itself also countable.  What (I think) I need to show, however, is that $\overline{f(A)}=f(\overline{A})$ (which I am not sure if it's true). This will thus show that $f(A)$ is a countable, dense subset of $f(X).$  Is this the correct approach, or do I have a mistake in my method?  Can anyone please help show me how I can go about finishing this proof?


I have a Windows user profile all setup with all settings the way I want them. I want to copy the entire configured profile to a new user account.  How can I do that on Windows?

I need to connect my machine to a new domain soon. When I do so a new user profile will be created and I would like to copy all the settings/data from the old profile to the new one. This is a local profile only (no roaming). Running Windows 7 Enterprise 64 bit.   I found  previous question on the same topic, it however only seems to address Windows XP and the solutions do not seem to apply to Win7.


Peace, mercy and blessings of God  How to delete an image from an array  Example  int[] images = {R.drawable.ic_basket, R.drawable.ic_basket, R.drawable.ic_basket, R.drawable.ic_basket, R.drawable.ic_basket, R.drawable.ic_basket, R.drawable.ic_basket, R.drawable.ic_basket, R.drawable.ic_basket, R.drawable.ic_basket, R.drawable.ic_basket, R.drawable.ic_basket, R.drawable.ic_basket, R.drawable.ic_basket};   null method did not succeed and sends a mistake  images[x] = null; images[x] = Integer.parseInt(null);

Given an array of n Objects, let's say it is an array of strings, and it has the following values:  foo[0] = "a"; foo[1] = "cc"; foo[2] = "a"; foo[3] = "dd";   What do I have to do to delete/remove all the strings/objects equal to "a" in the array?


I have 8A 6port usb charger. It has two ports marked as fast charing, and the phone here actually charges faster than in the two other ports. When I dismantled it, all the USBs were on the same power line, so the charger is definitely somehow telling the phone how much current can it use.  There are bunch of resistors around the ports, looks like connected to the data pins, but I will have to desolder the USB's to see how they are connected, as most of the paths are on the PCB covered by the ports. I would like to be able to make the third port also fast charge (don't worry, I know there are current limitations and the other ports are used for handsfree and smartwatch cahrging which takes ~500mA, and as the phones draws ~2A, it will still be in the power source's limits). I tried to find a schematics for the resistors connections, but only thing I was able to find is about how it's done for Apple and tons of articles about quickcharge with no tech specs.  Only thing I need is to tell Android phone it could draw more than 1A from the USB. I'm also going to build charging station from PSU (5V 30A) and here I would also want to tell the phones that they could draw more power. Thanks for any help.

I have found that many USB wall chargers use a resistive voltage divider to set the D+ and D- pins to a specific voltage, usually between 2 and 3 volts.  Other USB wall chargers short the D+ and D- pins together with no connection to anything else.  From my experience some devices will not accept a charge rate above 500mA on the chargers using the voltage dividers, but will charge up to their max input on a charger with the data pins shorted. I have read things that suggest the opposite may be true as well, but have been unable to verify this. I am hoping to figure out which method provides the best compatibility with all USB devices.


I want to import some data from excel which is in table form (raw from that it not formatted) and I want to import into a longtable with the appropriate formatting (if indeed it can be done in one step) what is the easiest way to do this?

Manually hacking tables in LaTeX is one of the less funny things when preparing a document. Naturally, there are quite a few tools that promise to simplify this. In fact, I have somewhat lost track of all the tools available, and I'd like to gather your valuable experience into one big post. Some of the tools are mentioned in , but I feel there's much more around.  I'd suggest that somebody starts an overview with an alphabetic list (so that I can accept this answer and it stays on top), and that everyone replies with a "community wiki" entry, one reply per tool, and inserts the tool into the list.  Personally, I use Excel2LaTeX, but I'm unhappy with having to fire up Windows in order to generate the LaTeX code. I'm thinking of a rewrite as a standalone Python tool using the xlrd library, but I'm not too inclined to reinvent the wheel.


I've read tons of threads like this one, but I haven't come to a solution yet. I have a PC that I bought back in 2012, which has been having issues over the last few years. Lately I've just resorted to using my laptop instead. At any one point it just freezes and I have to hard-restart it. Usually I run Windows 10 on it, but today I tried Ubuntu, which also froze after a few minutes after just exploring the UI.  Details on the hardware:   Is there any hope for my computer, or should I just scrap it and buy another? Thanks, /Nils

A machine is described as being "really slow" or "freezing". How can I troubleshoot/resolve this issue? What should be the first steps to take?


how to prove that $\#\mathcal{P}(\mathbb{N}) = \#\mathbb{R}$? I'm thinking in associate a subset of $\mathbb{N}$ in a real number by the decimal representation, but i'm failed.

I have learnt that the cardinality of the power set of the natural numbers is equal to the cardinality of the real numbers. What is the function that gives the one-to-one correspondence between these two sets?  I have also learnt that there exists no set whose cardinality is strictly between the natural numbers and the real numbers. Is there a proof of this or at least some intuitiveness behind it?


I read the following statement in a book on Calculus, as part of my mathematics course:  Technically this separation of $\frac{dy}{dx}$ is not mathematically valid. However, the resulting integration leads to correct answer.  The book also contains the following:  To solve a differential equation by separation of variables:  get all the $x$ values on one side and all the $y$ values on the other side by multiplication and division. separate $\frac{dy}{dx}$ as if it were a fraction. integrate both sides.   Note: This box doesn't refer to a particular problem. It refers to a class of problems of differential equations which can be solved using the Method of Separation of Variables. My high school mathematics teacher told me that this is the most fundamental way to solve differential equations but the textbook says it is not mathematically valid. I am not able to understand why are certain methods being followed without having a mathematical proof. Or am I wrong?

I see an equation like this:  $$y\frac{\textrm{d}y}{\textrm{d}x} = e^x$$  and solve it by "separating variables" like this:  $$y\textrm{d}y = e^x\textrm{d}x$$ $$\int y\textrm{d}y = \int e^x\textrm{d}x$$ $$y^2/2  = e^x + c$$  What am I doing when I solve an equation this way?  Because $\textrm{d}y/\textrm{d}x$ actually means  $$\lim_{\Delta x \to 0} \frac{\Delta y}{\Delta x}$$  they are not really separate entities I can multiply around algebraically.    I can check the solution when I'm done this procedure, and I've never run into problems with it.  Nonetheless, what is the justification behind it?  What I thought of to do in this particular case is write  $$\int y \frac{\textrm{d}y}{\textrm{d}x}\textrm{d}x = \int e^x\textrm{d}x$$ $$\int \frac{\textrm{d}}{\textrm{d}x}(y^2/2)\textrm{d}x = e^x + c$$  then by the fundamental theorem of calculus  $$y^2/2 = e^x + c$$  Is this correct?  Will such a procedure work every time I can find a way to separate variables?


If I were to mix yellow paint (which reflects yellow light) and blue paint (which reflects blue light), I would get a mixture of paints that I would perceive as green.   Is that because the mixture is now reflecting green light (and absorbing blue/yellow)?  OR  Is it because both blue and yellow light is being reflected simultaneously and my visual cortex is interpreting that as "green?"   In other words, are humans capable of perceiving both green frequency light as well as mixtures of colors that our brains interpret as one color/shade? How much of color perception is physics (blue = 450 nm) vs subjective brain interpretation (450 nm + 570 nm = GREEN)?  Experimental example of my question: Man A and Man B both describe a laser emitting 525 nm light as "green." Is it possible for Man A to perceive a mixture of two different wavelength lasers to be a different color than Man B?

Our eyes contain 3 photoreceptor cells (cones) to perceive three wavelength ranges of light. Here is a visual representation of the wavelengths by these receptors (S, M and L).    So if we have light of 440 nm, it results in the color blue. If we have light of 540 nm, it results in the color green. If we see light of 650 nm, it results in the color red.  I think I understand our ability of the brain to mix the results of the signals of these receptors, producing colors like yellow. However, what I do not understand is how the color spectrum is displayed like this:    Given that spectrum, I would suggest that the color 'blue' is actually a mix between the receptors S and M. And the pure result of activating the S-receptor would result in the color 'purple' (I would describe the color in the left of the image as purple, right). Therefore, the receptor colors should instead be RGP (red, green, purple) instead of RGB (red, green, blue).  However, there is one problem with this which I cannot explain. How come that mixing red light with blue light also results in purple light? How is it possible that purple light can be achieved through mixing (additively) blue and red light, just as going to the shortest wavelength boundary of what we can see (from blue to ultraviolet via purple)?  So the actual problem here is:   Purple is the color at the very shortest wavelength we can see. Purple is an additive mix between what we see as red light and blue light.   That just doesn't make any sense. I don't see how our brain can possibly perceive this as being the same color. Shouldn't both purple colors actually be different colors (thus we would have a new different color for that)?  UPDATE: Pure activation of the S-cone (blue) may actually give violet instead of blue. That means that the color blue contains also a bit activation from the M- and L-cones (green and red). So then the "blue-est blue" is actually violet, not blue. This confusion originates from the RGB-system (and other sources) that assume blue as being a primary color, whereas violet would perhaps be more accurate! Further details can be found in the accepted answer.  The  may further help to understand what purple/magenta/violet really is.


I have links on my webpage like this:   So whenever I put a ' after 88, I get the following error: Warning: mysql_fetch_row() expects parameter 1 to be resource, boolean given in ... line 588  So I read about mysql_real_escape_string(), but I'm getting the ID not posting and I have no clue how should I prevent getting this error.   function news() { $query = mysql_query("SELECT * FROM news WHERE id=".$_GET['id'].""); while($news = mysql_fetch_row($query))  {     ... } }

If user input is inserted without modification into an SQL query, then the application becomes vulnerable to , like in the following example:  $unsafe_variable = $_POST['user_input'];   mysql_query("INSERT INTO `table` (`column`) VALUES ('$unsafe_variable')");   That's because the user can input something like value'); DROP TABLE table;--, and the query becomes:  INSERT INTO `table` (`column`) VALUES('value'); DROP TABLE table;--')   What can be done to prevent this from happening?


Each photon of light bulb carries momentum. Why does the light bulb not recoil from conservation of momentum?

Photons have no mass but they can push things, as evidenced by .   Can photons push the source which is emitting them? If yes, will a more intense flashlight accelerate me more? Does the wavelength of the light matter? Is this practical for space propulsion? Doesn't it defy the law of momentum conservation?  Note: As John Rennie mentioned, all in all the wavelength doesn't matter, but for a more accurate answer regarding that, see the comments in  .  Related Wikipedia articles: ,


Can the ARRAY MODIFIER make a mesh multiply along a side of a round object? Instead of it duplicating vertically or horizontally?

Is it possible to create a turret like mesh like this using the bottom mesh and an array modifier? I want to be able to easily change the height of the shown shingle siding pattern. What I am basically looking for is some way to offset the mesh in a similar way to an array modifier, but with a small rotation value.    This is similar to  but has some differences. That question wasn't exactly what I wanted.


In The Hobbit by JRR Tolkien, Rivendell, a city of elves, is ruled by Elrond. The party of adventurers are waylaid there until Midsummers Eve, but I noticed a small passage about Elrond.     The master of the house was an elf-friend - one of those people whose fathers came into the strange stories before the beginning of History, the wars of the evil goblins and the elves and the first men in the North. In those days of our tale there were still some people who had both elves and heroes of the North for ancestors, and Elrond the master of the house was their chief.   I know Elrond was sometimes called the 'half-elven'(as was pointed out in , and normally that would be that, but he appears fully elvish. For example, he appears to have an incredibly long life, as is evidenced by the above passage, and he noted his inability to act as the Elvish emissary in the Fellowship, because of his age and inability to leave, rather than because he was not fully Elvish. So, is he fully Elvish?

This passage in The Hobbit puzzled me:     The master of [Rivendell] was an elf-friend... He was as noble and as fair as an elf-lord, as strong as a warrior, as wise as a wizard, as venerable as a king of dwarves, and as kind as summer.   -The Hobbit, Chapter 3: "A Short Rest"   The person being described is none other than Elrond.  All of this suggests that Elrond isn't an elf, let alone an elf lord.     "Elf-friend" is a title bestowed upon individuals from other races who are friendly with Elves;  it makes no sense to call an elf "elf-friend".   Elrond is compared to an elf-lord, but clearly isn't one, in Tolkien's opinion (at the time he was writing The Hobbit): notice that he isn't any of the other things he is compared to - he isn't a dwarven King; he isn't a wizard; he isn't summer; and although he was once a warrior, according to LotR, he isn't one in The Hobbit.    Did Tolkien originally consider Elrond to be something other than an Elf, and an Elf-lord?


This really caught my attention. As you can below this photo, there's user (Maybe a  person or maybe bot) answered the question but it is not answer the question.     So is this person just a pure troll or a bot want to test us if we have really watch carefully those question and answer?

Spam gets fairly heavily punished - 100 reputation penalty, if I recall correctly, and the content itself gets hidden in the revision history.  Now if we just have some rubbish:     dfajiojaifojadiofjadhigaowkokaomdiovnuiyhioqejgioqejgio   I'm not talking about someone posting a question or comment as an answer (i.e. possibly just not knowing the rules or being frustrated with not having the required privileges), or someone making some really horrible attempt at answering the question, I'm talking about an answer that clearly shows absolutely no observation of any content on the page.  This, in my opinion, causes a similar amount of harm to the site - I'm inclined to say the fact that someone posts spam isn't as important as the fact that they're posting something that needs to be deleted, since we're likely going to delete it pretty quickly, and they're (likely) behaving maliciously, or am I wrong?  Why don't we treat this equally harshly, or why do we treat spam as harshly as we do?    Side notes:  I'm sure I've seen a few times where users get punished for posting spam when their link is likely actually relevant to the question and useful (should I flag these? They are still link-only answers, so they shouldn't really come back, and often I'm just not sure enough). While false positives are bad, it seems worse that we're treating worse behaviour better.  I'm assuming that's not what "abusive" in this reason is referring to: (I'm also not sure, off the top of my head, how this one gets treated)     It is offensive, abusive, or hate speech


if $f:[0,1] \to \mathbb{R}$ is increasing, show that $f$ is the pointwise limit of a sequence of continuous  functions over $[0,1]$  Intuitively this makes sense but I am having trouble with showing why there would be a sequence of continuous functions converging pointwise to $f$.  Clearly there is a sequence converging pointwise to $f$, I can set: $\forall n \in \mathbb{N}, f_n = f$.  How to prove there is at least one which is made up of continuous functions $f_n, \forall n \in \mathbb{N}$ over $[0,1]$ I can't quite figure out the argument.

$\newcommand{\R}{\mathbb R}$  Let $f: \R \to \R$ be an increasing function. $(a \leq b \Rightarrow f(a) \leq f(b))$. I want to prove that $f \in \mathcal B$, the Baire one functions.  I first tried to prove that $g(x) := \lfloor f(x)+x \rfloor$ is in $\mathcal B$. The points of discontinuity of $g$ are countable since $g$ is increasing. Now, let $\mathcal D$ be the points in $\R$ where $g$ is not continuous. If $z \in \mathcal D$ then I want to prove that $\exists \delta > 0: (z-\delta,z+\delta) \cap \mathcal D = \{z\}$, i.e. $z$ is the only discontinuity in a certain neighborhood. Then it is not hard to prove that $g \in \mathcal B$ and that $f$ is the uniform limit of $\mathcal B$ functions and thus is also $\mathcal B$.  I already tried to prove this (existence of $\delta > 0$) by contradiction. However, I could not see a nice way to get here a contradiction.


On a math.stackechange this question was asked,     Does there exist a function $f: \mathbb{R} \rightarrow \mathbb{R}$ such that $f(x+y)=f(x)+f(y)$ for all $x,y \in\mathbb{R}$; $f(1)=1$; and $f(\sqrt 2)=3$?   I solved it as per this,  First of all we start by taking $x,y=0$ $$f(0+0)=f(0)+f(0)$$ $$f(0)=0\cdots (1)$$     Now   $$f'(x)=\lim_{h\to 0} \frac{f(x+h)-f(x)}{h}$$   $$f'(x)=\lim_{h\to 0} \frac{f(x)+f(h)-f(x)}{h}$$   $$f'(x)=\lim_{h\to 0} \frac{f(h)}{h}$$   Now as $f(0)=0$ we can apply the L'Hospital rule,   $$f'(x)=f'(0)$$   Now as f'(0) is const, Integrating both the sides, $$\int_{0}^{x} f'(x)dx=\int_{0}^{x} f'(0)dx$$ $$f(x)-f(0)=f'(0)x$$ $$f(x)=f'(0)x$$     Now if,   $$f(1)=f'(0)=1$$    It cannot be that,   $$f(\sqrt{2})=f'(0)\sqrt{2}=3$$   $$f'(0)=\frac{3}{\sqrt{2}}$$      But one of the answer says such function does exist, where did I go wrong?   Link:$\ref{https://math.stackexchange.com/questions/2428719/does-there-exist-a-function-f-mathbbr→-mathbbr-such-that-fxy-fxfy/2428750#2428750}{ here}$     And if f is non-differentiable, how do we solve these equations?   And can someone name a function if $f$ is non-úmgcos table and satisfies the above conditions?

Does there exist a function $f: \mathbb{R} \rightarrow \mathbb{R}$ such that $f(x+y)=f(x)+f(y)$ for all $x,y \in\mathbb{R}$; $f(1)=1$; and $f(\sqrt 2)=3$?  Intuitively, I believe the answer is no. However, I'm having a hard time proving this. My initial thought was a proof by contradiction. Somehow using  $f(1)=1$ and $f(\sqrt 2)=3$ to show that $f(x+y)\neq(x)+f(y)$ for some choice in $x$ and $y$. This didn't prove fruitful. My next thought was to use properties of functions satisfying the addition property of homomorphisms to prove that $f(\sqrt 2)\neq3$. For example, one such property is $f(nx)=nf(x)$ for all $n \in \mathbb{Z}, x \in \mathbb{R}$. With this, one could theoretically construct a proof by induction that $f(x)=x$ for all $x \in \mathbb{R}$. Once again, this didn't prove fruitful. After these failed attempts at showing such a function doesn't exist, I considered how to show that one does exist. For reference, this question was asked in the context of a Field Theory course. As such, the thought for how to construct a proof is to satisfy the addition property with some linear transformation and show that a correct selection of basis spans all of $\mathbb{R}$. This idea seems feasible, however I am not sure where to begin. Any advice on how to approach this problem is greatly appreciated.


First of all, I don't think this is the smartest question and I feel quite ashamed about it, but here goes nothing:  I wanted to prove that in the polynomial ring $k[x_1, \ldots, x_n]$ the ideal $I = (x_1 - a_1, \ldots, x_n - a_n)$ is maximal and tried as follows: I have defined a map   $$\varphi: k[x_1, \ldots, x_n] \to k: f(x_1, \ldots, x_n) \mapsto f(a_1, \ldots, a_n)$$ for which I was able to prove that it is a surjective ring homomorphism. Hence I know from the first isomorphism theorem that   $$k[x_1, \ldots, x_n]/ \ker(\varphi) \cong k$$ showing that $\ker(\varphi)$ is maximal. I see that the ideal $I \subset \ker(\varphi)$ but I am stuck on the other direction: suppose $f \in \ker(\varphi)$, then $f(a_1, \ldots, a_n) = 0$. How do I show that it must be of the form $(x_1-a_1)g_1 + \ldots (x_n - a_n)g_n$ for $g_i \in k[x_1, \ldots, x_n]$?   $\textbf{Remark: }$ I know the question on how to prove this is a maximal ideal has been asked many times before, e.g.  and , but they do not seem to adress my particular question.

Let $R$ be a commutative ring, $a_1, ..., a_n$ its elements and  $\phi: R[x_1, ..., x_n] \to R$  defined by  $ \phi(f(x_1, ..., x_n)) = f(a_1, ... ,a_n)$  a ring homomorphism.  Prove: $\ker \phi = (x_1-a_1, ..., x_n-a_n)$  It is obvious that $(x_1 - a_1, ..., x_n -a_n) \subseteq \ker \phi$. I'm not sure how to prove the converse.  At this point I don't know any division algorithms for multivariable polynomials, only for the ones in $R[x]$(and the book from where I taken the exercise doesn't assume the reader to know something beyond basics of rings and ideals, and the division algorithm for $R[x]$). Though I know this could be solved for $i = 1$ by dividing by $x-a$:   Let $f(x) \in \ker \phi$, divide by $x-a: f(x) = q(x)(x-a) + r, f(a) = r = 0$, so $f(x) = q(x)(x-a) \in (x-a)$.


Hi In C# windows application. I need to know by using .NET Reflector  all source code is viewed by anyone. But I want hide some code(Important secure code) in c# from .Net Reflector.   Anyone help me to hide managed code(C# code) from Reflector. Thanks...

Obfuscation is one way, but it can't protect from breaking the piracy protection security of the application. How do I make sure that the application is not tampered with, and how do I make sure that the registration mechanism can't be reverse engineered?  Also it is possible to convert a C# application to native code, and  is too costly.  C# provides lot of features, and is the ideal language for my code, so writing the whole codebase again in C++ is out of the question.  Secure certificates can be easily removed from the signed assemblies in .NET.


I'm trying to create a startup disk for ubuntu 15.04. I already have installed 15.04, but I need another copy.  It states that the disk has 2kb of storage size and it has none of that left, but I can burn files onto it and it states in other programs it has 4.7 GB of data space and none of it is used, what do I do?

I'm using ubuntu 14.04 (x86). I was trying to create a bootable dvd disk for Ubuntu 13.04. I have downloaded the image file (.iso) and successfully created a bootable USB using Startup Disk Creator. But when I tried to do the same with a 4.7 GB DVD, the Startup Disk Creator is showing DVD's capacity as 2KB and Free Space as 0.0B. It also shows a message "The device is not large enough to hold this image".


I installed several GFCI’s throughout the house to bring things up to code.    After installation I tested each one per the instructions and indications are they’re all working properly.  I then decided to use my Commercial Electric brand plug-in circuit tester as a final check and all but one GFCI tested as it should.  The one at the kitchen counter, however, trips as soon as the tester is plugged in, but it doesn’t trip when appliances are plugged in, they all work properly.  That particular GFCI loads two (2) other outlets downstream so I disconnected them and ran the test at the GFCI by itself and sure enough, it tripped again.  I can plug things into the outlet and they all work fine but plugging the tester in trips it every time.  It seems strange that the tester works in all other outlets throughout the house but that one.  I even switched GFCI’s thinking maybe it’s a faulty unit but the same thing happens with either GFCI.   I verified that the incoming power source (white-black-ground) are properly connected to the LINE terminals on the GFCI.  Right now I’m continuing to use the outlet as I have for the 30 years that I’ve lived here (home built in 1986).  It’s just perplexing as to why my tester works properly in all outlets of the house except that one.

I replaced a non-protected receptacle with a GFCI type and now my circuit tester trips the GFCI as soon as it is plugged in.  The receptacle tested fine before replacement, ground, neutral, hot, etc.  I've double checked the hot/neutral/ground connections.  I've also tried it with the downstream load disconnected.   The GFCI trips the moment I plug in my circuit tester (before pushing the test button).  Otherwise things check out OK.  I can plug in a power tool without it tripping.  Also, the integrated test/reset button work correctly.   I've read that the integrated test button is the only one that truly matters. Is this correct or should I be concerned? I'm sure a home inspector will red flag this if their tester has the same result.  Update  My tester is by "Commercial Electric".  The tester is one of the palm sized three prong type with three leds to indicate the condition of the circuit and a button on top to test GFCI. It's new from the local box store.


I'm struggling to understand what the purpose of the empty slicing operator is in python string_example = 'foo blah blah' string_without_operator = string_example string_with_operator = string_example[:]  print(string_without_operator) print(string_with_operator)  In this example the results seem to be identical - are they functionally equivalent or am I missing something and this operator useful in a different application?

I need a good explanation (references are a plus) on Python's slice notation.   To me, this notation needs a bit of picking up.   It looks extremely powerful, but I haven't quite got my head around it.


How can I prevent the user from writing a new line with the enter key in a contenteditable div?  So far I have tried (the id of my editable div is editable:  $('#editable').on('keyup', function(e) {     if (e.which == 13) {         event.preventDefault();     } });   However this does not work.   Is this possible using JS and jQuery?     Edit   I have been informed that pressing enter does not insert a new line so I have put a picture showing when happens when I press enter inside the editable div.  I would like code to remain on one line basically, even if the user presses enter.

When using contentEditable in Firefox, is there a way to prevent the user from inserting paragraph or line breaks by pressing enter or shift+enter?


I'm trying to get an intuition as to why degrees of freedom is n - 1 when calculating sample covariance. This is what I found:  1) Start with 2n degrees of freedom from the bivariate data 2) Lose 2 degrees of freedom from calculating the means 3) Lose n-1 degrees of freedom from computing product derivations  In step 3, are the degrees of freedom being halved, or is n-1 being subtracted? What is the intuition of step 3?

The denominator of the (unbiased) variance estimator is $n-1$ as there are $n$ observations and only one parameter is being estimated.  $$ \mathbb{V}\left(X\right)=\frac{\sum_{i=1}^{n}\left(X_{i}-\overline{X}\right)^{2}}{n-1} $$  By the same token I wonder why shouldn't the denominator of covariance be $n-2$ when two parameters are being estimated?  $$ \mathbb{Cov}\left(X, Y\right)=\frac{\sum_{i=1}^{n}\left(X_{i}-\overline{X}\right)\left(Y_{i}-\overline{Y}\right)}{n-1} $$


I need to add a support for my site for both Hebrew and English Languages. At the first page, there will be a selection of the desired language: Now, by this selection am I supposed to hold some parameter in the config file and the fill my whole application with  if (LanParam == English) --> Return Info In English else --> Return Info In Hebrew  Sounds like a lot of code replication. What is the common way to this Nowdays?  I've read different threads here and other forums and I know about the resource file: I'm going to use it for Labels and static texts in my site.   The point is that Hebrew is a language written from right to left while English written from left to right. Am I supposed to prepare different CSS files?  Moreover, I also work with WCF services in my web site (which are also developed within our oragnization).  We have 2 options of design:  1. Change the services to accept input of Language and then the correct info is returned by the service as a single output parameter.  2. The service will return 2 properties: info in English and info in Hebrew, and I will manipulate it (on the client side) again using the if (LanParam == English) mentioned above or another way you might suggest me.  I've never done something similar to that, so I would love to hear about how it is done, about popular approaches for multiple language support in web sites and any other useful advice. Thanks in advance.

What would be best practice to localize your ASP.NET MVC application?  I would like to cover two situations:   one application deployment in IIS which would handle multiple languages one language/application deployment.   In first situation should you go with some kind of view based thing like, ~/View/EN, ~/View/FI, ~/View/SWE or something different?  What about second case, just application based config via Web.config and point these different languages to different URLs?


This might sound a like a silly question to most people, but it is my first day learning shell scripting, so. #! /bin/bash str=""  if [ -n $str ] then     echo "True" else     echo "False" fi  if [ -n "$str" ] then     echo "True" else     echo "False" fi  When I ran it on bash, the first test gave "True" and the second one gave "False." Why? Is it because in the first one bash doesn't treat $str as a string? GNU bash, version 5.0.17(1)-release (x86_64-pc-linux-gnu)

Any idea why echo statement is being executed in both scenarios?  Outputs it worked:  #!/bin/bash  rizwan='' if [ -n $rizwan ]; then   echo "it worked" fi   Replace -n with -z, and it outputs it worked when expecting no output:  #!/bin/bash  rizwan='' if [ -z $rizwan ]; then   echo "it worked" fi


I need to prove that a radical ideal in the coordinate ring $\mathbb{C}[V]$ (where V is an algebraic variety) is the intersection of all maximal ideals containing it.    The hint I was given was to consider the correspondence between ideals in a quotient ring $R/I$ and the ideals of $R$ containing $I$.  Any suggestions for where to begin? I don't even know where to start.

Let $I$ be a proper ideal in $k[x_1,....,x_n]$, where $k$ is an algebraically closed field. Show that $\sqrt{I}= \cap M$, where $M$ runs through all maximal ideals containing $I$.    I am confused by what we can say is in the intersection of all maximal ideals.   For the proof, since k is algebraically closed, I think I would want to use Nullstellensatz, but once I have that $\sqrt{I}=I(V(I))$, I am not sure what to do next.


I have read somewhere that the covariant derivative of the stress-energy-momentum tensor is zero and this is one of the key features in formulating the field equations. Is there a proof for this assumption? Could you explain?

Einstein assumed in the derivation of his field equations that the covariant derivative (defined through the metric) of the energy momentum tensor of matter is zero, i.e. $$\nabla_{\mu}T^{\mu\nu}=0,$$  no matter how distorted the spacetime is.  It seems such a conclusion cannot be reached at via Nöther's theorem (since the metric is itself changing over spacetime). So my question is how did he have this insight then, and how would one justify the correctness of this assumption in retrospect from a Lagrangian point of view now?   If it's based on the existence of infinitesimal coordinate transformations that fix the boundary of some volume in spacetime, then would this also imply that the energy momentum tensor of any field will always have zero covariant derivative with or without gravity?    Edit: Previous form of the question had an abuse of language, viz., that I referred to the "vanishing of the covariant derivative of the energy-momentum tensor" as "energy momentum tensor is covariantly conserved". This was rightly pointed out by Ben Crowell in his answer and, I've edited the question and made it mathematically precise for the sake of clarity.


I know a couple of people who have determined that they, for whatever reason, need to help guide other people through their lives. They always do things or suggest things to multiple people, usually disingenuously, in order to reach a desired outcome. This isn't necessarily to their benefit, but usually a mutual benefit or to the benefit of the "victim".  Looking for something other then overseer, if possible.

I've experienced this way too many times, and the best example I can give is a person who treats you like you have no idea how to do X and who keeps teaching you how to do it. I feel handicapped. Take for example how to play a card game. You know how to play the game because you've played it 5 times. However, there is a person always insists on explaining the game to you - like you are always new to the game - when you don't actually need any help and you just want to think for yourself. Another example situation is doing a repetitive task which you already have experience with, and yet the person continually tries to 'teach' you when you don't need help/already know how to do it. It almost makes you mad because you really don't need help. As an example which recently happened to me:  "Hey, do you remember how to start the wood chipper?" "Yes I do" "Okay, well, let me show you one more time"  Again, is there a term for someone who does this?


What is the order and cofactor of a base point? Is it possible to deduct the order and cofactor, given just the basepoint. What about the other way around from order and cofactor to basepoint?

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?


I was just wondering what computers do when an usb is detected(plugged in). Im assuming theres some sort of scanning but i dont know any of the details :/

I'm curious how USB device recognition works in Windows. I imagine it's something like this:   When you plug in a device, it tells Windows "here's my device ID to tell you what I am" Windows looks to see if any drivers have been installed that match that device ID. The driver probably tells Windows what the device should be called - like "BlackBerry Curve" or "Canon Printer" If so, it somehow associates that device with that driver Otherwise, it looks for a matching driver online (if you let it)   Am I right? If so, that still leaves some questions.   When you install drivers, where do they go? Are they files in a folder, or do they get added to the registry? What is Windows doing when it first recognizes the device, thinks, and finally says "your new device is installed and ready to use?" Where does Windows look for missing drivers? Is it in their own database? Do device manufacturers submit drivers to Microsoft for inclusion there?   Can anybody explain how this process really works? Also, do other OSes do this differently?


I am a little unsure about the semantics in this regard, and was hoping someone could cast some light on this.  As far as I understand, multivariable is basically one dependent variable and several independent variables, whereas multivariate is when several dependent variables are included. However, in the examples I've seen this is often related to repeated measures.  Instead, let's say I have some data (independent variables), and then three dependent variables. However, they are not repeated measures. Maybe I wanted to "measure" the health of a person, e.g. this could include: weight, lung capacity, and resting heart rate - just to pick some arbitrary ones.  So basically these dependent variables might give me some insight to a persons health. If one of the independent variables are smoking for example, then this might affect all three dependent variables, but maybe other independent variables will only influence one of each.  In this case, what am I performing ? Multivariable regression, multivariate regression, a mix, or...?

Are multiple and multivariate regression really different? What is a variate anyways?


When a DC-universe human runs/exercises in general, much like our earth's humans they get out of breath and tire. Does this happen to the Flash? If so does he just have an insanely high fitness level?  In both the comics and the tv-shows/cartoons there have been instances where the Flash has not been able to push himself any more or stopped running and then had to have a sit down/rest.  Does the Flash get tired by performing "regular" exercise, as he does with running fast (not to be confused with time/dimension-travel, because then he isn't even a thing anymore, he's just energy using "running" as a vehicle so his mind can perceive and control what's happening).  If the Flash ran around the world perpetually, would he get tired like a regular athlete hitting their upper bound or not? If the Flash swam perpetually would he get tired as mentioned, or not?  An ideal answer would then show if there is a relationship between the two!

I mean a average human can run at his full speed for 15 to 20 mins before getting tired. Trained athletes can go on running for much more time without tiring out.  Do Superheroes like Quicksilver or Flash ever get tired due to excessive running?


Is it possible to download a file using the download link URL using C# WPF Application without opening the browser?  For example: The link -  when typed into the address bar of the browser automatically downloads a file. How can i download this file upon a button click in WPF application (C#) without opening the browser?   TIA.

Is it possible to download a file from a website in Windows Application form and put it into a certain directory?


I'm trying to import a large 70GB+ database (all InnoDB) using mysqlimport. This is a development system on Windows using WAMP server. MySQL 5.6.17.  I'm getting the following error:  mysqlimport: Error: 1064 You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near '* WRITE' at line 1   Here's the command I'm trying to use:  mysqlimport -u root -p --lock-tables --debug-info --use-threads=4 testdb "C:\Users\Test User\Documents\Dump20140620_1642\*.sql"   I usually use MySQL Workbench to do the import but I wanted to use the use-threads parameter and I don't think MySQL Workbench does this. What's wrong with this syntax?  I also tried:  mysqlimport -u root -p --lock-tables --debug-info --use-threads=4 testdb "C:/Users/Test User/Documents/Dump20140620_1642/*.sql"  mysqlimport -u root -p --lock-tables --debug-info --use-threads=4 testdb 'C:\Users\Test User\Documents\Dump20140620_1642\*.sql'  mysqlimport -u root -p --lock-tables --debug-info --use-threads=4 testdb "C:\\Users\\Test User\\Documents\\Dump20140620_1642\\*.sql"   All gave the same error message.

This is a  about  the use of a *AMPP's stack.    I recently had a talk with some experienced people and they suggested to me not to use a WAMP stack, and instead install apache, mysql and php separately.  I don't understand why they have suggested this, though, so can anyone tell me?  Is there a particular disadvantage of WAMP, or a particular advantage to installing all of them separately?  Since a WAMP stack itself is composed of apache, mysql and php, then what's the difference between using the WAMP stack and installing them all separately?


I'm having some trouble wrapping my head around this.  I would like to have a solid red bar (about 200px wide) running the entire length of the page. I have this already using a small 200x1px image repeated on the Y.  I'd then like another image to sit on top of this red bar, that will be fixed to a specific position on the page at all times.  I'm not sure how to go about's creating this "Second" wallpaper.  I hope this makes sense. Thanks.

Is it possible to have two background images?  For instance, I'd like to have one image repeat across the top (repeat-x), and another repeat across the entire page (repeat), where the one across the entire page is behind the one which repeats across the top.  I've found that I can achieve the desired effect for two background images by setting the background of html and body:  html {     background: url(images/bg.png); }  body {     background: url(images/bgtop.png) repeat-x; }   Is this "good" CSS?  Is there a better method?  And what if I wanted three or more background images?


I have such a class:  public class Cycle {           public List<int> Edges         {             get;             private set;         }          public override bool Equals(object obj)         {             Cycle cycle = (Cycle)obj;              var list1 = cycle.Edges;             var list2 = Edges;             var same = list1.Except(list2).Count() == 0 &&                        list2.Except(list1).Count() == 0;             return same;          }          public override int GetHashCode()         {          //   return Edges.GetHashCode();         } }    As you can see, if two Edge Lists are the same, then I deem the Cycles as the same.   The issue now is how to implement the GetHashCode()?  I tried Edges.GetHashCode(), but the problem is that two List<Cycle>, with the same Cycle object but different orders, will be deemed different, even though they should be the same.

I would like to write a function GetHashCodeOfList() which returns a hash-code of a list of strings regardless of order. Given 2 lists with the same strings should return the same hash-code.   ArrayList list1 = new ArrayList()     list1.Add("String1"); list1.Add("String2"); list1.Add("String3");      ArrayList list2 = new ArrayList()     list2.Add("String3");     list2.Add("String2");  list2.Add("String1");  GetHashCodeOfList(list1) = GetHashCodeOfList(list2) //this should be equal.   I had a few thoughts:    I can first sort the list, then combine the sorted list into 1 long string and then call GetHashCode(). However sorting is a slow operation. I can get the hash of each individual string (by calling string.GetHashCode()) in the list, then multiplying all hashes and calling Mod UInt32.MaxValue.  For example: "String1".GetHashCode() * "String2".GetHashCode * … MOD UInt32.MaxValue. But this results in a number overflow.   Does anyone have any thoughts?  Thanks in advance for your help.


I am trying to write this text value to the XML tag like this    <Parameter name="name"><![CDATA[xyzvalue]]></Parameter>   Whenever, i am setting this value as text to this tag. It generates it like this   <Parameter name="name">&lt;![CDATA[xyzvalue]]&gt;</Parameter>   I need have tried to avoid unescape characters in the code   ET.SubElement(parameters, "Parameter", name="id").text = unescape("&lt;![CDATA[xyzvalue]]>")   How can i avoid it writing like this to the xml file ? I need to avoid escaping characters in the XML.  This is my complete code:  map = ET.Element("Map")  parameters = ET.SubElement(map, "Parameters") ET.SubElement(parameters, "Parameter", name="bounds").text = "-180,-85.05112877980659,180,85.05112877980659" ET.SubElement(parameters, "Parameter", name="center").text = "0,0,2" ET.SubElement(parameters, "Parameter", name="format").text = "png" ET.SubElement(parameters, "Parameter", name="minzoom").text = "0" ET.SubElement(parameters, "Parameter", name="maxzoom").text = "22" ET.SubElement(parameters, "Parameter", name="scale").text = "1" ET.SubElement(parameters, "Parameter", name="metatile").text = "2" ET.SubElement(parameters, "Parameter", name="id").text = unescape("&lt;![CDATA[xyzvalue]]>") ET.SubElement(parameters, "Parameter", name="_updated").text = "1552288036000" ET.SubElement(parameters, "Parameter", name="name").text = "<![CDATA[xyzvalue]]>" ET.SubElement(parameters, "Parameter", name="tilejson").text = "<![CDATA[2.0.0]]>" ET.SubElement(parameters, "Parameter", name="scheme").text = "<![CDATA[xyz]]>"  indent(map) tree = ET.ElementTree(map) tree.write("plotfinder_tiles.xml", xml_declaration=True, encoding='utf-8', method="xml")     This is different to , in a way, that i have this issue at the Element creation not to prettify/ remove after xml has been created.

I've discovered that cElementTree is about 30 times faster than xml.dom.minidom and I'm rewriting my XML encoding/decoding code. However, I need to output XML that contains CDATA sections and there doesn't seem to be a way to do that with ElementTree.  Can it be done?


let's consider the following code snippet: class Vehicle:     pass  class Car(Vehicle):     pass  my_car = Car()  print(issubclass(type(my_car), Car)) print(issubclass(type(my_car), Vehicle))  Output: True True  Now if my task was to tell if my_car is of type Vehicle but not of type Car, how would I do that? Is there a smart, short, elegant way for this?

What is the best way to check whether a given object is of a given type? How about checking whether the object inherits from a given type?  Let's say I have an object o. How do I check whether it's a str?


For e. g., less has option --squeeze-blank-lines (or -s in short) and it squeezes multiple blank lines into single blank line, buuut, less wouldn't do this being used as filter (i. e., having its output sent not to a tty).  Similar option can be found in cat too, it's also called -s usually, and it also makes single blank line instead of several.  What about removing empty/blank lines all together? One approach I can think of is using grep, but may be I've overlooked something more simple?

I want to remove all empty lines from a file. Even if the line contains spaces or tabs it should also be removed.


I have an entity (using entity API) for which I would like a fixed number of fields (and would prefer to use fields and the API rather than just creating properties) - it makes no sense to make a bundle - but do I need to create a bundle nonetheless to allow fields to be attached?  I'm thinking this is the case since field_attach_instance takes a 'bundle' value in the array to pass in (and field_config_instance contains the bundle column).

I'm learning about the Entity API. I have a simple extra table that I'd like to "drupalize" so that I can use it in Views, for example.  I've read quite a bit, watched a few videos, looked at quite a few examples. I'm stuck on the concept of bundles. I understand what bundles are (e.g. node types are bundles of the node entity).  But for my use there will only ever be one bundle. In the examples I've seen the bundle is stored in the database table; this is not necessary for me as it would be the same value stored against every record. So I was thinking I could somehow skip this, or have my entity always return a standard string for bundle.  Have I misunderstood? Do bundles always have to be implemented, and implemented at database table level?


I need to print a webpage. I use this javascript function to print it.  function myFunction() {     window.print(); }   I see html title and date at the top and the page url at the bottom. I don't want these to see on my print and tried to find a fix for that but no luck. Any advice is highly appreciated.

I want to remove the URL that gets printed on the bottom of the page.   like:  yomari.com/.../main.php?sen_n   How can it be omitted or prevent from getting printed?  To be more specific, is there any way I can prevent the page URL, date and the page title being printed along, while printing the web page?


If my dad and grandma were both born in Canada but my grandfather was born in the US, does that mean I am part Canadian?    They are all US citizens and all my ancestors after my grandma came from other places.    If so how much would the percentage be?

My sister, cousins, and other relatives speculate that my mom's grandmother was Jewish (for various reasons). I've heard people say at times things like, for example, "I'm 50% German" or "I'm 25% Swedish." This has to do with their ancestry. But, how exactly is this calculated? Say for example that my mother's paternal grandmother was indeed 100% Jewish, what would that make me and my siblings, and how is it calculated?


I have a need to create an SSH key management system. In our environment, we use OpenSSH on the server side, and we use PuTTY on the client side. I know how to use the PuTTYgen GUI to convert OpenSSH keys to PuTTY keys and vice versa. However, this is not practical when dealing with a large number of keys.  Does anybody know of command-line utilities that will perform these conversions and which I could call in a script or in some other way automate?

I have generated a key pair with ssh-keygen. I now want to use the same key pair with PuTTY-based applications.  Because I'm working in a CLI environment, I want to convert the key to the .ppk format from within this environment.  Apparently, you can use puttygen openssh_private_key -o output_filename.ppk on UNIX-like environments. But the Windows version of puttygen will just load the key and prompt you to use the GUI to export the key.   suggests that this simply is not currently possible, at least with puttygen. I'd gladly accept and option that uses other means though.  How can I convert the key from the command line?


Is it somehow possible to reformulate the following exuation into something easier to calculate: $$(A^{-1}+ B^{-1})^{-1}$$ A and B are both square real matrices: $A, B \in \mathbb{R}^{n \times n}$, and are positive definite and therefore invertible.

If $A, B$ and $A + B$ are all $n × n$ invertible matrices. Prove that $A^{−1} + B^{−1}$ is invertible and the inverse is $A(A + B) ^{−1}B$.  I am afraid I am really stuck on this one, and I haven't really tried much because I don't know what to try.  Thanks for all the help guys, I understand now.


I find the issue very hard to explain  and  i also have no clue where it came from, but it is making me anxious on the progress of my model. New meshes added to the scene don't seem to have the same problem. Below is a picture  of before and after activaing wireframe and also a picture of how it looks in shading

I don't know why but now, when i go in material preview or rendered (in solid mode it works fine), my object is entirely gray, or invisible idk, because it has the same color of the background. I've been working for days on this project without having this issue, it suddenly showed up. I tried opening other old projects and suddenly they all do the same so i guess it is some blender program setting that applies for all the projects, but idk how it happened cuz i didn't change anything :/, anyone got any tips?


I'm developing a WPF application(scheduler), that would announce the start of some events. For that, I need to show my window and make it cover all other windows in the system, which do not belong to my application. Is it possible in WPF application?

How can I bring my WPF application to the front of the desktop? So far I've tried:  SwitchToThisWindow(new WindowInteropHelper(Application.Current.MainWindow).Handle, true);  SetWindowPos(new WindowInteropHelper(Application.Current.MainWindow).Handle, IntPtr.Zero, 0, 0, 0, 0, SWP_NOMOVE | SWP_NOSIZE);  SetForegroundWindow(new WindowInteropHelper(Application.Current.MainWindow).Handle);   None of which are doing the job (Marshal.GetLastWin32Error() is saying these operations completed successfully, and the P/Invoke attributes for each definition do have SetLastError=true).  If I create a new blank WPF application, and call SwitchToThisWindow with a timer, it works exactly as expected, so I'm not sure why it's not working in my original case.  Edit: I'm doing this in conjunction with a global hotkey.


I know how formula of buoyant force come (upthrust=$V\rho g$).I also know its derivation. I can understand why buoyant force equals weight of fluid displaced according to this equation but that understanding is mathematically. I want a intuitive understanding why buoyant force equals weight of fluid displaced.

For a submerged object, buoyant force ($F_b$) is defined as:  $$F_b = V_{\text{submerged}} \times \rho \text{ (density)} \times g \text{ (gravitational constant)}$$   Conceptually, the buoyant force equation says that buoyant force exerted is equal to the weight of the volume of water a given object displaced. Why? I went online to   and found the following explanation, but it seems like non-sequitur to me:      Explanation: When an object is removed, the volume that the object occupied will fill with fluid. This volume of fluid must be supported by the pressure of the surrounding liquid since a fluid can not support itself. When no object is present, the net upward force on this volume of fluid must equal to its weight, i.e. the weight of the fluid displaced. When the object is present, this same upward force will act on the object.


I'm trying to set my Script Tool Editor in the Geoprocessing Options dialog so that I can edit a script tool within ArcMap. Currently, whenever I right-click on my script and select "Edit..." from the resulting menu, nothing happens. I've set my editor to what I think is the correct .exe file (C:\Python27\ArcGIS10.1\Lib\idlelib\idle.pyw), but selecting "Edit..." on the script tool menu still has no effect.   My issue seems to be similar to  which was never answered but I am using ArcMap 10.1 SP for Desktop Basic and Python 2.7 (I think).

I am unable to edit scripts in ArcMap or ArcCatalog.  I navigate to the script, right-click on it and select "Edit", then nothing happens. I am using notepad++ as my editor (set in geoprocessing options). I have looked into this issue () and have attempted the steps therein. However I am still getting the same result, nothing happens.  I am using ArcGIS for Desktop Basic Version 10.3.1 and Python 2.6  What steps should I attempt to solve this issue?


we need to add a limit for pasting to SMB Folder from Windows Server 2012. Is any way, users within MS Server to have quota/limiter once pasting files to SMB share? The share is mounted at Windows Server.  Thank you

There is any way to limit usage on folders with quota on Windows 2003 Server?  I know it's possible for volumes, but it's possible for folders?


The Issue:  The issue I have is that I have several hard drives ALL 250GB, however, they vary ever so slightly on the amount of sectors. When cloning with CloneZilla on Parted Magic, I get the volume size error. The drive I am using as the master just happens to be the one with the most sectors.  What I need to do:  I installed Vista and ran all the updates which took a couple of days to do in total, and I don't want to have to reinstall everything again. I now need to copy this to the other drives.  I tried:  Resizing the partition of the OS to around 200GB, and doing a partition copy, however this will not boot.  I also tried other software but all give the same error. I did try to set the option to ignore the size difference but it gave other errors.

I have a image which was taken with Clonezilla as SAVEDISK on a 160GB harddrive. Now a newer version of the PC released with a 120GB harddrive, the space in use is just 20GB  Is there a way I can force Clonezilla (or any other program) to manipulate the images 'original size' to 120GB or lower, so Clonezilla can write it to the new PC?


Can one give an example showing that it is not a field? I think the essential problem is to show that there exists some element in the ring without an inverse?

Let $G$ be a group. Let $K$ be any field and consider its group algebra $K[G]$. It is known that if $G$ is a finite group then $K[G]$ is never a field. Or even if $G$ is not finite: if $G$ has at least one non-trivial torsion element, then $K[G]$ is not a field.  Question: Do there exist infinite groups $G$ such that $K[G]$ is a field or a division ring?


Please see below output. After creating a file, and doing a grep for the fist time --> the file access time is getting updated. But on subsequent greps the file access time is not getting updated. $ echo first line > b.txt  ~/wtmp/ttime$ stat b.txt    File: b.txt   Size: 11          Blocks: 8          IO Block: 4096   regular file Device: 804h/2052d  Inode: 1969341     Links: 1 Access: (0664/-rw-rw-r--)  Uid: ( 1000/       w)   Gid: ( 1000/       w) Access: 2020-09-06 17:36:01.091962795 +0530 Modify: 2020-09-06 17:36:01.091962795 +0530 Change: 2020-09-06 17:36:01.091962795 +0530  Birth: -  ~/wtmp/ttime$ date Sunday 06 September 2020 05:37:06 PM IST  ~/wtmp/ttime$ grep f b.txt  first line  ~/wtmp/ttime$ stat b.txt    File: b.txt   Size: 11          Blocks: 8          IO Block: 4096   regular file Device: 804h/2052d  Inode: 1969341     Links: 1 Access: (0664/-rw-rw-r--)  Uid: ( 1000/       w)   Gid: ( 1000/       w) Access: 2020-09-06 17:37:21.049046050 +0530 Modify: 2020-09-06 17:36:01.091962795 +0530 Change: 2020-09-06 17:36:01.091962795 +0530  Birth: -  ~/wtmp/ttime$ date Sunday 06 September 2020 05:38:23 PM IST    ## Second attempt searching for different letter  ~/wtmp/ttime$ grep l b.txt  first line    ~/wtmp/ttime$ stat b.txt    File: b.txt   Size: 11          Blocks: 8          IO Block: 4096   regular file Device: 804h/2052d  Inode: 1969341     Links: 1 Access: (0664/-rw-rw-r--)  Uid: ( 1000/       w)   Gid: ( 1000/       w) **Access: 2020-09-06 17:37:21.049046050 +0530** Modify: 2020-09-06 17:36:01.091962795 +0530 Change: 2020-09-06 17:36:01.091962795 +0530  Birth: -  Is this because the file is cached in memory and the access is done from memory. If that is the case is there a way to tell grep or any command to not use cached version but access it from file system.

After using the cat command to read a file, I used the stat command to view it's changed access time, but it's not getting updated.  I checked /etc/fstab file and there is no noatime on any of my drives, so why is the access time not getting updated?  I'm using Ubuntu 12.04 Precise Pangolin.


Let $H$ be a Hilbert space and $u,v \in H$. I need to prove:     If $\|u+\lambda v\| \ge \|u\|$ $\forall \lambda \in K = \mathbb{C},\mathbb{R}$ then $u \perp v$.   I need this to close a triple equivalence and I'm not sure if this way is evident or I should follow another way.

Prove that $\langle u,v\rangle=0\Longleftrightarrow \|u\|\leq \|u+av\|$.  So far I can get the $\Longrightarrow$ very easily, but I need some help with the $\Longleftarrow$ implication, any hints would be greatly appreciated.  Please no answers, I just want a small nudge to get me in the right direction, I've been stumped on this for a little bit.  Here's what I have so far:  ($\Longleftarrow$)  Assume $\|u\| \leq \|u+av\|$  $\|u+av\|^2=\langle u+av,u+av\rangle=\langle u,u\rangle+ \langle u,av\rangle+\langle av,u\rangle+\langle v,v\rangle=\|u\|^2+\bar{a} \langle u,v\rangle+a\langle v,u\rangle+\|v\|^2=\|u\|^2+ \bar{a}\bar{\langle v,u\rangle}+a\langle v,u\rangle+\|v\|^2$  Thoughts/ideas?


I have a Python list of tuples:  vals = [(40.69, array([1.34, 1.516, 0.000135,....])), (213.69, array([0.34, 1.51256, 0.0110135,....])...] vals.sort()   The first element in the tuple is a float and the second element is a numpy ndarray. There are 784 elements in the array.   I get ValueError: The truth value of an array with more than one element is ambiguous. Use a.any() or a.all() at vals.sort. I am trying to sort on the first element in the tuple itself. This code works when I use a smaller dataset that produces only 13 elements in the ndarray. I can't figure out why it should throw this particular error if the number of elements is more.  Can anyone please help me out?

I've got a list of Python objects that I'd like to sort by an attribute of the objects themselves.  The list looks like:  >>> ut [<Tag: 128>, <Tag: 2008>, <Tag: <>, <Tag: actionscript>, <Tag: addresses>,  <Tag: aes>, <Tag: ajax> ...]   Each object has a count:  >>> ut[1].count 1L   I need to sort the list by number of counts descending.  I've seen several methods for this, but I'm looking for best practice in Python.


I've tried to cook an egg with some oil underneath on low fire, trying to make an omelette, but the egg still got stuck and when I turned it over a plate it collapsed apart. It was just some egg and hard cheese bits. Anyone know what went wrong?  Maybe it's because the small pot was not nonstick. I thought it would turn out ok anyways.  Thanks.

I recently purchased a stainless steel pan from AllClad, but I'm struggling to use it. Food, and in particular eggs, seem to stick readily to the pan, making it hard to use. There is a question on Seasoned Advice that pertains to cooking an omelette on a stainless steel pan, but I think the challenges of frying an egg are different and more challenging. I've been able to cook an omelette in this pan, but have yet to succeed with a fried egg.  Looking online, I learned that stainless steel pans, like cast-iron, need to be seasoned in order to be non-stick. The process that I followed to season my pan was as follows:   Pour in 1/4 cup walnut oil.  Heat pan on medium heat until the oil begins to smoke. Turn heat off and let the pan cool completely. Remove the oil and wipe the pan dry.   I tried this process, but when I try to fry an egg in the pan, it still sticks readily. There is some improvement, but it is still not possible to cook an egg without sticking that destroys the egg in the end.  I'm not sure what I may be doing wrong, or is a stainless steel pan just not something that one can use for frying eggs? Should I just expect that there will be some stick whenever I use this pan?  Update  After watching , I tried to pre-heat my pan, using the water-test as a guide, and adding just a bit of oil to the pan before dropping the egg in. The results were the same. The egg stuck to the pan thoroughly. So again I'm not sure what I'm doing incorrectly. Maybe the oil I'm using isn't right? I've been using ghee.  Update 2:  I've yet to succeed in frying a egg on this pan, but a few additional questions/issues have surfaced:   Some answers here have suggested that despite the presence on the web of tutorials for "seasoning" stainless steel pan this is not necessary and may not be advisable. The trick may be to fry the egg starting at a much lower heat then you might with something like a piece of meat. For meat, you often encounter the suggestion to use the "water test", but as at least one answer has suggested here that may not work with a fried egg.    These are the possibly insights I've gleaned so far, but I've also yet to succeed, so these may turn out to be wrong as well.  Satisfying Answer (May be others)  The solution that I have settled on here -- i.e. what finally worked for me -- was to work with lower heat than I thought was needed, and not to season the pan. There is definitely a lot of conflicting information out there about stainless steel pans. There are a great number of blog posts and YouTube videos that talk about how to season a pan. Seasoning may still be a useful thing to do, but I was able to fry an egg on an unseasoned pan finally.  The method I used is more or less as follows:   Clean pan thoroughly. Take egg out of refrigerator and let it sit in warm water for five minutes or so. (This may not be necessary.) Put pan on stove on medium flame/heat. (I only tried this on a gas stove.) Let pan pre-heat until it is warm when you hold your hands over the pan. Warm, not hot! This might take 20-30 seconds, maybe less.  Add the oil (1-2 tbsp), and lower the flame to low. Let the oil heat a bit, perhaps another 10-15 seconds, or less. Crack the egg into the pan. The whites should stay clear, only slowly whitening. If the egg begins to turn white immediately, the pan is too hot. And the egg should also not stick at this point. There may be a bit of sticking, especially around the edges. You can dislodge the sticking gently by hand, but don't mess with the egg too much. Cook until done or ready to flip. Make sure heat stays low. If you see some sticking it may be (I'm not sure about this) because the pan has become too hot.   So that's the best I've been able to do with help from the selected answer.


I'd like to know how to create 700m x 700m grid array in ArcGIS.   I am a beginner at GIS.   I'd like to develop the insect distribution map.

I have a map of small remnants of forest along creeks for an entire county in California. I need to divide the whole map into equal sections so I can print it so you can actually see the sections of forest. I'd like a map with a grid which I can look at, and then look at a zoomed in map of (for example) section A1.  I've tried the Grids and Graticules wizard, which gives me a grid for the map, but when I zoom, the grid remains the same. I want the grid sections to be georeferenced with the map, so when I zoom in, the grid zooms also.   I'm using ArcMap 10.1.


I am running a vanilla Minecraft server on my Azure account and have an idea for it that I'm not sure is possible or not. Essentially I want to set up an area, something like 8x8 chunks that is designated as a creative area.  In order to achieve this I'm thinking that I will need at least one command block running constantly checking for players entering or exiting the area and adjusting their game mode accordingly. The problem I'm having is that I can't think of or find a way to reliably detect the threshold crossing, specifically for any height.  One potential solution I've come up with is to surround the creative chunks with barrier blocks to limit the ways in which the player can leave the area, but this is not ideal.  Bonus #1: If the player attempts to fly out of the creative zone it would be nice to also teleport them to the ground so they don't die when the game mode is switched.  Bonus #2: Can I have another set of command blocks that will store/restore a players inventory when crossing the threshold.

Is there a way to set an "Adventure Mode Boundary" in Minecraft?  I am trying to create this village where players can spawn in, and then set out to explore the world and build and do normal minecraft stuff. I don't want them to destroy this village, so I want them to be in adventure mode when they are in the village and then switch them to survival when they leave, and vice-versa. When they return to the village, they get switched back to adventure mode.  In other words, I want to set an "Adventure Mode Boundary" to protect buildings. I am working without mods. I am hoping there is an simple way using command blocks.


I would like to know if i can reject, using a linear regression and a t-distribution, the following Null hypothesis:  b=1  where b is the slope of my linear regression. My hypothesis is that b>1.  I am using R, and i know how to test whether my slope is significantly different than 0 but not if it is significantly different than 1!  Thank you for your time.

Brief caveat- I haven't dusted off my stats knowledge since some university courses a few years ago, and I'm struggling with cobwebs.  I have a model where a linear 1 to 1 relationship has been assumed in the past. The model assumes that revenue from Product A will translate to Product B- it's not perfect, but it's what we've been using for now. I was given the task of doing some exploratory work on this relationship.   I modelled the relationship between revenue B and revenue A, and was able to work out a rough coeffecient. This coeffecient seems to be significant (t test within bounds), but I know the t test is testing whether the slope of this regression line is significantly different than zero. I would like to know if this slope is significantly different than 1, the previous relationship we assumed. How can I adjust a hypothesis test for this? I know I'm going to see the answer and hate myself for asking, thanks for helping me shake this out of my brain.


For a registration page, what's the best way to verify a user's email address? Some websites ask you for the username, password and email address all on the registration form and then email you a link which when clicked simply displays "you are now verified". However, I came across a site which had a registration system where they asked for only your email address; they then sent an email with a link to a page where you can then choose your username and password.  The benefits of the first method is that there's just one form that the user has to fill in and once they've done that, all they have to do is click a link.  The benefits of the second method is that the form appears less daunting since there's only one field. Also, it rules out the chance of a user entering a username with an incorrect email address, so they have to choose a different username because the original username is now taken.  What's the best way to ensure that a user's email address is valid?

I have a registration form, name, email, password. I also offer the Facebook connection and in the future all other Open ID ways but for now I would focus on the regular process:  Currently, I require the password confirmation and then I send an email to confirm the email address.  But I really also like the Tumblr way which grants full functionality even without email confirmation, and so with your email+password entered you are into the site in literally 30 seconds...  So my question is: what are the best practices and in terms of metrics/stats if it is better to allow an easy process but with the risk of high volume of fake, wrong, incomplete accounts OR ask more initially so those users who complete the process are "quality users"?  (I hope my question was clear, sorry for my English.)


Why is the derivative of the volume of a sphere the surface area? And why is the derivative of the area of a circle the circumference? Too much of a coincidence, there has to be a reason!  Also, why is the sum of the cubes the square of the sum of the integers?

When differentiated with respect to $r$, the derivative of $\pi r^2$ is $2 \pi r$, which is the circumference of a circle.  Similarly, when the formula for a sphere's volume $\frac{4}{3} \pi r^3$ is differentiated with respect to $r$, we get $4 \pi r^2$.  Is this just a coincidence, or is there some deep explanation for why we should expect this?


How is current independent of the voltage drop in a diode?

This image from wikipedia, explains that there occurs a potential drop across a , and an electric field confined to the depletion region.  I already know the reason for the existence of this drop and the calculation of the difference but I have two questions regarding this drop.    1) If the  regions are externally connected using a perfectly conducting wire, why will not any current flow? Connecting the two regions should equalize their potentials (since wire is a resistance less) conductor, and therefore the gradient at the junction is destroyed resulting in a  which is obviously against conservation of energy as the semiconductor has non-zero resistivity. Where will extra potential drops will be created so that Kirchoff's voltage rule holds without any current and the built-in potential difference $V_o$ of the juction persists?    2) (probably naive) If an external Bias is applied, of say $|V|<|V_o|$, then the pn potential difference across the junction will just reduce by that amount ($|V|$). Assuming that the external voltage source is ideal without any resistance, what will be the potential drops which would sum to zero in this case? Will drop due to the resistance of semiconductor play a par in it? If yes, then there cannot be any ideal resistance-less semiconductor junction, can there?


I need to install R 3.0.2 because a needed library isn't compatible with 3.0.3 yet (the latest).   I can install the older version of R like so:  sudo apt-get install r-base=3.0.2-1precise0   However all the dependencies of r-base try and install with 3.0.3  root@foo:~# apt-get install r-base=3.0.2-1precise0 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:  r-base : Depends: r-recommended (= 3.0.2-1precise0) but 3.0.3-1precise0 is to be installed E: Unable to correct problems, you have held broken packages.   How can I install r-base 3.0.2 and all the dependencies as 3.0.2 ?

Occasionally, when I'm installing stuff, I get an error like the following:  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:  package1 : Depends: package2 (>= 1.8) but 1.7.5-1ubuntu1 is to be installed E: Unable to correct problems, you have held broken packages.   How can I resolve this?


Recently I casted a Close vote on this post  as a dupe of this post .  Later the moderator Cody Gray closed the other one as a dupe of this post.  If it's confusing, let me explain.  I casted a Close vote on A as dupe of B. Then a mod closed B as a dupe of A.  Now I can't retract my close vote.  I tried it after the mod closed the question.    But the close vote count changed from 1 to 0. Also The retract button is not there.  I checked it today and saw the same message. I can't retract my Close Vote.    Since the working of Close is same for all SE sites, I don't think this is an issue pertains only to Stack Overflow.

I just happened across , which has one close vote suggesting that it be closed as an exact duplicate of .  This suggestion is perfectly correct: these are exactly identical questions asked by the same user.  However, there's not much point in closing question A as a duplicate of B, since question B has already been closed as a duplicate of A.  Yet the close vote remains, doing nothing but wasting reviewers' time.  This is not the first time I've seen this happen, so I'd like to suggest that the Stack Exchange software should do something about it.  In particular, I'd like to suggest the following feature:     When a question Y is closed as an exact duplicate of another question X, any votes or flags to close X as a duplicate of Y should be automatically discarded.   Actually, I'm kind of surprised that the SE software doesn't do that already.  If anyone else thinks that this constitutes an actual bug, feel free to retag it.


I have developed a shell script, which calls main method of a java program RHEL environment.    Shell script ( say app.sh) have multiple options on the lines of tomcat.sh   start: It will start a java program by calling main method  stop: It will get running process id and kill the process   I have already implemented start and stop command and looking forward to implement pause command.   pause: This option should get the pid of running java application and call a non-Main method.  I don't have issues to get the process id. But can I invoke non-Main method of java program from running process id?  EDIT:    question offer solutions in different technologies but I can't move to different technology except using shell script.

I have a really simple Java class that effectively decorates a Map with input validation, with the obvious void set() and String get() methods.  I'd like to be able to effectively call those methods and handle return values and exceptions from outside the JVM, but still on the same machine Update: the caller I have in mind is not another JVM; thanks @Dave Ray  My implementation considerations are typical    performance ease of implementation and maintenance (simplicity?) reliability flexibility (i.e. can I call from a remote machine, etc.)   Is there a 'right way?' If not, what are my options, and what are the pro/cons for each?  (Stuff people have actually done and can provide real-life feedback on would be great!)


When I try to add this line of code :  onclick="document.getElementById('part3').style.display='';return false;"   Into a link it disables the other function for some reason.. This is the code in which i would like to add the above code:  a href="javascript:DecreaseQuantity('PROD_VK_1.4')">   Works fine until i add the code, then only the onclick function works not the javascript part.  How can I fix this?

Many times I've seen links like these in HTML pages:  Click here !   What's the effect of the return false in there?  Also, I don't usually see that in buttons.  Is this specified anywhere? In some spec in w3.org?


I'm having a problem when rendering my Latex code to PDF when using PDFLatex. My problem is that, when I render the code, some math symbols like the parentheses appear bitmapped, with bad quality and I don't see where the problem is. These are some examples of what I see:     These are the packages that i'm using:  \documentclass[12pt]{article}  \usepackage[utf8]{inputenc} \usepackage[T1]{fontenc} \usepackage{amsmath} \usepackage{siunitx} \usepackage[catalan]{babel} \usepackage{graphicx} \usepackage{tabularx} \usepackage{array} \usepackage{subcaption} \usepackage{mathabx} \usepackage{float} \usepackage[margin=1in]{geometry} \usepackage{longtable} \usepackage{lmodern} \usepackage{physics}   \title{Determinació de la constant de gravitació universal G} \author{Carlos Gómez Cayuela}  \begin{document} \end{document}   I would appreciate some help with this. Thanks in advanced!

I've just noticed, that after rendering if I zoom the text then it look like a low quality text (look at the screen). I've heard that I can install cm-super package. I put \usepackage{cm-super} to the preamble but get an error "cm-super.sty not found". Before If I didn't have any package latex suggested me to install it right in the latex so I didn't have to visit any websites or something. Am I supposed to install it manually?  Anyway, how can I solve the problem?  I have two files in my project: latex file and .sty file. Here's how the preambles look:    In the main file:   \documentclass[10pt, a4paper]{article} \usepackage[utf8]{inputenc} \usepackage[T2A]{fontenc} \usepackage[english, russian]{babel} \usepackage{Lections_style}    In the lections style:     \RequirePackage{amsfonts}   \RequirePackage{amsmath}   \RequirePackage{amssymb}   \RequirePackage{graphicx}   \RequirePackage{babel,blindtext}   \RequirePackage{subfigure}   \RequirePackage{hyperref}   \RequirePackage{fancyhdr}   \RequirePackage{cite}   \RequirePackage{amsthm}   \RequirePackage{xparse}   \RequirePackage{mathabx}   \RequirePackage{array}   \RequirePackage{tabularx}   \RequirePackage{multirow}   \RequirePackage{makecell}     There're already 55 pages typed so I would be very glad if there's any solution without a lot of pain. Thank you and sorry for my English.   I've been asked to give a MWE, so here it is:      \documentclass[10pt, a4paper]{article}     \usepackage[utf8]{inputenc}      \usepackage[T2A]{fontenc}      \usepackage[english, russian]{babel}      \begin{document} Проверка текста.      \end{document}


I want to modify environment variable by user given value. For example, user will give the variable to be modified and a value to put in the variable.  I tried the command:  set[variable[=val]]   Its working fine but I don't know if its right way to modify or i have to use export command for that purpose?  My code is :  modify_env(){ echo "Environmental variable:" read var echo "Environmental value" read value set [var[=value]] }

I'm trying to set up Apache Tomcat on my pc, and it wants me to set up an environment variable for CATALINA_HOME.  Does any know how to do this?


Let $f: \mathbb R \to \mathbb R$ be a real function, which is continuous in 0. There exists one $a \in \mathbb R \backslash\{-1, 1\}$ with $f(x) = f(ax)$   $~~~~(x \in \mathbb R)$. Prove that $f$ is constant.

Let $f:\mathbb{R}\to\mathbb{R}$ , there is $k \in \mathbb{R}$, $|k|\ne 1$, so that for every $x\in \mathbb{R} , f(kx)=f(x).$ Show that if $f$ continuous at $0$ then $f$ is a constant function.   I tried to find something to show it from the definition of continuous function but I didn't know how to continue. We have that $f$ continuous at $0$ if for every $\epsilon>0$ there is $\delta>0$ such that $|x-0|<\delta \implies |f(x)-f(0)|<\epsilon$ And if $f$ not continuous on $0$ is $f$ still a constant function?


GE brand new front load washer trips breaker every single time within 5 mins (model GFW850SSNWW). Connected to a GFCI protected outlet (does not have TEST/ RESET buttons on it) and GFCI breaker (SWD brand) since it's in the utility room. Washer works when plugged to a standard  Can you please suggest what could we do?

I have a Kenmore 80 Series (Model No. 110.24872300) washing machine which up to this point has been working fine. Since it is near a sink, the outlet it is plugged into is a GFCI outlet. On the last load I came back after letting it run for some time to find that it had tripped the GFCI in the middle of the wash cycle - the washer was still full of soapy water. I reset the outlet and let it run again, only to come down the next morning and find it full of water still (it had tripped during the rinse cycle this time). I reset the outlet again and this time it finished the rest of the cycle.  My guess is that water is somehow getting onto the internal components of the washer and causing it to short - is there any way I can test this theory or fix the problem myself?


I'm looking to take a spontaneous trip for a long weekend. The date is flexible and the destination can be anywhere in the world. Is there a site that would allow me to search airfares within a date range, while keeping the destination parameters open?

Several airline and trip planning sites will allow you to check "I am flexible with my dates" or a similar option.  Is there any way to also search more broadly for location?  For example, if you wanted to leave from YYZ or YKF and arrive at any airport in California, can a search for such flights be done somehow?  I ask because when I plan plane trips, I want the lowest price.  I'm OK with leaving a day or two later if I save $200 (same with the return trip).  There are 3 airports within 80 km of me, I'll leave from the one with the cheapest flight. And I'm also OK with changing the trip to spend time exploring San Francisco instead of lying on the beach near San Diego, and that sort of thing.  Normally this would take dozens of searches, but I'd like to see it all at once.


I know that we aren't supposed to use Illustrator for text, but I needed to use the Type on a Path feature and that's why I did it.    Above is the text in Illustator. When I export the text from Illustrator to InDesign, the text becomes blurry.     I'm assuming because it becomes an image file when it goes into InDesign.  Thus, I was wondering if there was a way to increase the image quality or directly copy the text boxes from Illustrator so that when they appear in InDesign, they are text boxes rather than image boxes.  Thanks in advance!

I'm creating a magazine in Indesign and have pdf ads that I imported and placed all throughout the magazine. The pdf ads are crisp and clear in their original format, but when I place them in Indesign, they're super blurry. I tried converting the pdf ads to a bunch of different formats (jpeg's, png's, etc), then placed them in Indesign. This reduces some of the blurriness, but when printed, they are still unreadable.   Just to show you what I mean, here's an ss of a pdf in Adobe Reader:    and here's how it appears in InDesign:    Both are at 100%.   Do you have any idea why I'm having this problem, and how I might be able to fix it?


I was trying to prove some equation and reached this summation $\sum \limits_{j=0}^{m} {2j\choose{j}} {2m-2j \choose {m-j}} = 4^m $  I tried pascal identity and other known binomial identities but with no succes   Is there any simple proof (preferably algebraic one).  Thanks

It's not difficult to show that  $$(1-z^2)^{-1/2}=\sum_{n=0}^\infty \binom{2n}{n}2^{-2n}z^{2n}$$  On the other hand, we have $(1-z^2)^{-1}=\sum z^{2n}$.  Squaring the first power series and comparing terms gives us  $$\sum_{k=0}^n \binom{2k}{k}\binom{2(n-k)}{n-k}2^{-2n}=1$$  that is,  $$\sum_{k=0}^n \binom{2k}{k}\binom{2(n-k)}{n-k}=2^{2n}$$  My question: is there a more direct, combinatorial proof of this identity?  I've been racking my brains trying to come up with one but I'm not having much success.


Say there is a convolutional layer that has 8 filters of size 3x3 and takes as input 28x28x1 images.  Then the output size will be 26x26x8.  So how are there 8 26x26 feature maps for that layer or just 1 26x26 feature map? If the answer is 1 feature map then how is it created since the output has 8 channels?

Intro Background Within a convolutional neural network, we usually have a general structure / flow that looks like this:  input image (i.e. a 2D vector x)   (1st Convolutional layer (Conv1) starts here...)  convolve a set of filters (w1) along the 2D image (i.e. do the z1 = w1*x + b1 dot product multiplications), where z1 is 3D, and b1 is biases. apply an activation function (e.g. ReLu) to make z1 non-linear (e.g. a1 = ReLu(z1)), where a1 is 3D.   (2nd Convolutional layer  (Conv2) starts here...)  convolve a set of filters along the newly computed activations (i.e. do the z2 = w2*a1 + b2 dot product multiplications), where z2 is 3D, and and b2 is biases. apply an activation function (e.g. ReLu) to make z2 non-linear (e.g. a2 = ReLu(z2)), where a2 is 3D.    The Question The definition of the term "feature map" seems to vary from literature to literature. Concretely:  For the 1st convolutional layer, does "feature map" corresponds to the input vector x, or the output dot product z1, or the output activations a1, or the "process" converting x to a1, or something else? Similarly, for the 2nd convolutional layer, does "feature map" corresponds to the input activations a1, or the output dot product z2, or the output activation a2, or the "process" converting a1 to a2, or something else?  In addition, is it true that the term "feature map" is exactly the same as "activation map"? (or do they actually mean two different thing?)  Additional references: Snippets from :  *The nomenclature is being used loosely here. In particular, I'm using "feature map" to mean not the function computed by the convolutional layer, but rather the activation of the hidden neurons output from the layer. This kind of mild abuse of nomenclature is pretty common in the research literature.   Snippets from :  In this paper we introduce a visualization technique that reveals the input stimuli that excite individual feature maps at any layer in the model. [...] Our approach, by contrast, provides a non-parametric view of invariance, showing which patterns from the training set activate the feature map. [...] a local contrast operation that normalizes the responses across feature maps. [...] To examine a given convnet activation, we set all other activations in the layer to zero and pass the feature maps as input to the attached deconvnet layer. [...] The convnet uses relu non-linearities, which rectify the feature maps thus ensuring the feature maps are always positive. [...] The convnet uses learned filters to convolve the feature maps from the previous layer. [...] Fig. 6, these visualizations are accurate representations of the input pattern that stimulates the given feature map in the model [...] when the parts of the original input image corresponding to the pattern are occluded, we see a distinct drop in activity within the feature map. [...]  Remarks: also introduces the term "feature map" and "rectified feature map" in Fig 1.  Snippets from :  [...] One dangerous pitfall that can be easily noticed with this visualization is that some activation maps may be all zero for many different inputs, which can indicate dead filters, and can be a symptom of high learning rates [...] Typical-looking activations on the first CONV layer (left), and the 5th CONV layer (right) of a trained AlexNet looking at a picture of a cat. Every box shows an activation map corresponding to some filter. Notice that the activations are sparse (most values are zero, in this visualization shown in black) and mostly local.   Snippets from   [...] Every unique location on the input volume produces a number. After sliding the filter over all the locations, you will find out that what you’re left with is a 28 x 28 x 1 array of numbers, which we call an activation map or feature map.


I know it might seem lame but i was just wondering why do we need a sudo command to use su cmd to switch to root user.

when I try using a command with sudo everything works fine, however, if I want to log in as the superuser using su it doesn't let me. Why?