I am using my Google Spreadsheet to keep tabs of my incoming and outgoing money. I've made a row with ~19 cells in it, in those 19 cells I have the monthly what comes in and what goes out. At the end I add this all up and then subtract a different cell that adds up random costs.  But my problem here is that the calculation =SUM(C4:C17) counts everything, even the money that has not come in or that was spend. But I don't want to fiddle around with that calculation all the time.  Is it possible to make every cell in row C red and when it's red it does not count (so it will be ignored) but if I make the cell green it gets added in the grand total?

I have seen  and altough I face the same problem, the answer to that question is not helpful to my case.   I have large spreadsheets which are changed frequently. So, according to the solution accepted to that question, it is hard to duplicate all populated columns and it is cumbersome to edit one more cell everytime I wish to make a change on cells background colors.  Isn't there a way to sum data based on a condition regarding cell background color in Google Spreadsheets?


I've just stumbled across  poorly worded question - if you look through the comments it appears that the user previously asked an identical question that was deleted - it occurred to me that this question may well have been deleted before the poster had a chance to read any of the comments / feedback on that question, and may not have even realised that his question was deleted (hence the identical repost).  I'm not sure if this feature already exists or not (being that I've never had any of my questions deleted), but it strikes me it might be a good idea to allow users to see their deleted questions, and hence maybe learn why their question was deleted.

I would really like to see all of my questions and answers on the profile page, even if some of them were deleted, and I don't have enough rep to see them on the site. (Note that some questions are  after 30 days or 1 year, and the author might be oblivious about what happened.)   , the "deleted recent [questions/answers]" links in one's own user profile now list all respective posts that were deleted in the past 60 days, rather than just those that were originally posted in the last 60 days. , users with the "access to moderator tools" privilege (10k+ on designed sites, 2k+ on beta and non-designed sites) can use the search operator deleted:1 to see all their own deleted posts. , deleted questions and answers that were posted in the past 60 days, can be seen using the "deleted recent questions" and "deleted recent answers" links on the questions and answers tabs (at the bottom of the tab) in your user profile. For older posts: as of 2013-04-23 you can  if you already have a link to them, but they still aren't linked from the user profiles (not even just for you). Nor do you see inbox notifications for comments on them if you come back a few hours later. You have to have thought to bookmark your question, or you have to go digging for it in your browser history.


I tried to install massif-visualizer. After adding the kubuntu-ppa/backports PPA and running apt-get update,  apt-get install massif-visualizer   still gives me an error:  E: Unable to locate package massif-visualizer

When I try to install any package through the command line, I get an error.   $ sudo apt-get install <package> Reading package lists... Done Building dependency tree        Reading state information... Done E: Unable to locate package <package>   Can anyone help me on this?


After taking part in the Presidential Inaugural ceremony, all online articles refer to  as a poet. ,  meaning a female poet, is a well established term of the English language, so why do they call her poet? PS: I don’t think that the suggested duplicate question has much to do with what I am asking. My concern is specific about the usage of the term poetess.

Often I come across the term "female author" rather than "authoress". Which is the correct usage? "Female author" sounds wrong to me as other words that end in "-or" take a sex.


I'm wondering what * mean in this context. I've looked in the documentation too, but I'm still not too sure what it means. I've attached some code below for context.  (As an aside, I've also seen this used PyTorch tensors' .view() or .reshape_() method. Wondering if this is the same meaning.)  documentation:   def one_hot_encode(arr, n_labels):      one_hot = np.zeros((np.multiply(*arr.shape), n_labels), dtype=np.float32)      one_hot[np.arange(one_hot.shape[0]), arr.flatten()] = 1.      one_hot = one_hot.reshape((*arr.shape, n_labels))      return one_hot

In the following method definitions, what does the * and ** do for param2?  def foo(param1, *param2): def bar(param1, **param2):


If $a,b ,c>0$ . Then least value of $$\bigg\lfloor \frac{a+b}{c}\bigg\rfloor+\bigg\lfloor \frac{c+b}{a}\bigg\rfloor+\bigg\lfloor \frac{a+c}{b}\bigg\rfloor$$   Where $\lfloor x\rfloor$ is floor function of $x$  Plan  Using $$x-1< \lfloor x\rfloor\leq x$$  $$\frac{a+b}{c}-1< \bigg\lfloor \frac{a+b}{c}\bigg\rfloor \leq   \frac{a+b}{c}$$  $$\frac{b+c}{a}-1< \bigg\lfloor \frac{b+c}{a}\bigg\rfloor \leq\frac{b+c}{a}$$  $$\frac{c+a}{b}-1< \bigg\lfloor\frac{c+a}{b}\bigg\rfloor \leq \frac{c+a}{b}$$  How do i solve it Help me please

If we know that for every $a,b,c>0$ ,how we can find  the least possible value for :  $$ \lfloor \frac{a+b}{c}\rfloor +\lfloor \frac{b+c}{a} \rfloor+\lfloor \frac{c+a}{b} \rfloor $$


I have downloaded wubi as wubi.exe. when installing it in my windows 7, it shows an error. Please let me know the reason to solve this. even if i try to install it in my separate USB or DVD, it shows error as "global name 'sig' is not defined. How shall i proceed further?

Is there any Windows installer (wubi) for Ubuntu 14.04 LTS?  When I mount the .iso file with Daemon Tools and run wubi.exe, it just asks me if I want to reboot (I think that's useful only when the .iso  is burned on CD), so is there no "real" installation?


We define random variables as functions on a sample space $X(ω), ω ∈ Ω$. Here I do not see time being involved.  A stochastic process is a family of random variables, but they also are functions of two variables $X(ω, t)$ where $ω ∈ Ω$ and $t$ denotes time.  When I see a plot of a random process, I notice that the family of random variables is used as X-axis (or is it just only one random variable in diferent $t$ times?). The Y-axis is the range of this variables assuming they all are $i.i.d.$  I struggle in having a moderately clear concept of what a stochastic process is!

I'm trying to understand the basic concept of random processes.I already understood that a continuous-time random process is defined by X(¥,t) where ¥ is each element in the Sample Space and t is the time index.     By this definition, we can see the random process as an ensemble of sample realizations ( time-functions defined for each outcome in the Sample Space) or as a set of random variables ( each one defined for a specific time t ). In my mind, the value of the time-function ( sample realizations ) X(¥1,t) reflects the changing value of the probability of outcome ¥1 being choosen in the sample space, is that correct ?    For example, we have a boy B in the sample space representing outcome ¥1.Having this outcome ¥1 at time t=0 equals 30%.As the time passes, the sample spaces gets more crowded and at time t=5, the probabily of choosing boy B equals 20%.   Can i think that the time-function X(¥1,t) will equal 0,3 for t=0 and 0,2 for t=5 ? Does X(¥1,0)=0,3      and     X(¥1,5)=0,2         ?  Thanks in advance


I´ve read this fantastic book   and I have a question about the lasso equation for the Lasso problem in its Lagrangian form:  $\hat{\beta}_{lasso} = argmin \{ \frac{1}{2} \sum_{i=1}^{N}(y_i -\beta_0 -\sum_{j=1}^{p} x_{ij}\beta_{j})^2 + \lambda \sum_{j=1}^{p} |\beta_j| \}$  I don´t know why $\frac{1}{2}$ is necessary for lasso, however for ridge it doesn't.  $\hat{\beta}_{ridge} = argmin \{\sum_{i=1}^{N}(y_i -\beta_0 -\sum_{j=1}^{p} x_{ij}\beta_{j})^2 + \lambda \sum_{j=1}^{p} \beta_j^2 \}$  References   Friedman, J., Hastie, T., & Tibshirani, R. (2001). The elements of statistical learning (Vol. 1, pp. 241-249). New York: Springer series in statistics.

This question might be dumb, but I noticed that there are two different formulations of the Lasso regression. We know that the Lasso problem is to minimize the objective consisting of the square loss plus the $L$-1 penalty term, expressed as follows, $$ \min_\beta \|y - X \beta\|_2^2 + \lambda \|\beta\|_1 \; $$  But often time I saw the Lasso estimator can be written as $$ \hat{\beta}_n(\lambda) = \displaystyle\arg \min_{\beta} \{\frac {1}{2n} \|y - X \beta\|_2^2 + \lambda \|\beta\|_1 \} $$  My question is, are the equivalent? Where does the term $\frac {1}{2n}$ come in? The connections between the two formulations is not obvious to me.   [Update] I guess anther question I should ask is,  Why is there the second formulation? What's the advantage, theoretically or computationally, of formulating the problem that way?


I am using an old 4S and the Power Button is kind of half stuck down. Are there any hints or tricks out there to un-stuck it?

The volume controls on my iPhone 3G S are pretty hard lately. It works, but I need to press very hard on them to change volume. I am afraid that some sand went inside, but I am not sure about that.   Any hint to fix it?   Thanks!


Yesterday I played a game in a new group.  The Fighter (F) goes in and attacks the monster (M). Then it's my turn and I place my Rogue (R) opposite to the Fighter in regards to the monster. I was looking for the advantage in order to make a Sneak Attack, as I recall very vividly that such positioning gives advantage. So in the end our position looked like this:  +---+---+---+   F = Fighter |   | F |   |   M = Monster +---+---+---+   R = Rogue |   | M |   | +---+---+---+ |   | R |   | +---+---+---+   My DM ruled that I didn't have advantage because such rule doesn't exist in D&D 5th Edition. He however granted me my Sneak Attack because the Sneak Attack itself allows me to make such a hit in that situation.  I was a bit troubled because in every other group I played with, such a rule was accepted, and intensively used, even in groups without any Rogue. I checked the PHB and couldn't see any reference to this. So maybe such rule exist in the DMG?  So my question is: does such a rule for advantage exist? If yes, where is it defined? If not, does that idea of a rule come from any previous versions?

The rules packet does not provide any specific rules about flanking.  However the rule does say that the DM has lots of leeway in deciding when to give advantage or disadvantage in combat.  Should it be understood that flanking always gives advantage, or is the DM supposed to only give advantage when there is "clever flanking"?  What is the best way to handle "flanking" in D&D 5e?


Please provide an alternate statement too(if any).

Is there a pronoun I can use as a gender-neutral pronoun when referring back to a singular noun phrase?  Each student should save his questions until the end. Each student should save her questions until the end.


I will be teaching an introductory class, in which attendance is important, with approximately 60 students in 3 sections.  I'd like to have a system that:   Enables me to quickly mark whether a student is present. Allows students to see their own attendance record but not other students'. Lets students provide information about their absences.   For small classes, students email me (or I email them) for information about absences, but it would be overwhelming with this many students.  A single Google spreadsheet would be great for data entry, and students could use comments to annotate their absences, but it wouldn't protect students' privacy.  Any suggestions (besides not tracking attendance)?  My school provides Google Apps and Blackboard, although I'm willing to use other solutions.  UPDATE: I know a hack that would work in Blackboard would be to create a fake assignment for each day (attending class) and enter attendance information (0 or 1) there.  This is not ideal because (1) entering data into Blackboard is slower than putting it into a spreadsheet, (2) it would bloat the grade listings seen by the students, and (3) I don't think students could add a comment to the "grade" (the excuse).  There is a , but it does not address how to incorporate excuses/explanations, which, to me, is the tricky part.

I work in the Computing and Mathematics School at my university (UK). This year the School has adopted a fairly aggressive policy regarding student attendance. If a student has a poor – or zero – attendance rate, the student is contacted and a dialogue opened. This has many benefits including identifying those students who have possible  undiscovered or undeclared learning difficulties.   If a student’s attendance rate remains poor following a first intervention, a process of issuing formal warnings commences, culminating with the withdrawal of the student if the student does not start to engage with their course.  Attendance is presently monitored at all laboratory and tutorial sessions. Attendance is not presently monitored for lectures.   Our current system comprises a series of shared Google spreadsheets which contains the details of all students for all classes. Staff members enter attendance manually into the spreadsheet for their class.  The difficulty with this system is that there is presently no automatic link between the existing official university student record database and the attendance register spreadsheets. This means if students change groups, enrol late, withdraw, change course or units, all this information must be dealt with in a robust manner. Currently, such changes are implemented manually. This means errors are likely to be introduced into the attendance register.  I notice that there are a number of commercial attendance monitoring solutions available which are based on hardware, e.g. . I would be interested in anyone’s experience with such systems, however I don’t forsee these to be ultimately workable in my case owing to the large cost.   I am interested in software solutions. If your institution monitors student attendance, do you use any specialist software? If so, what do you use?  Another option – a preferable one – is to work within the existing university data systems. All the necessary information regarding student details and activities is available. The problem arises when we try to ensure our ad hoc attendance register contains up to date student information. Ideally we’d use our Virtual Learning Environment to enter attendance data. Our VLE is Moodle. Are there any Moodle users out there who use Moodle to record attendance?


I tried to save some data to a csv file and i got this error:  i:\Games\Pokemon GO\pokeminer-0.2>python worker.py -st 10 Traceback (most recent call last):   File "worker.py", line 25, in <module>     import db   File "i:\Games\Pokemon GO\pokeminer-0.2\db.py", line 64     f = open('i:\Games\Pokemon GO\pokeminer-0.2\spawn_location.csv','w')                                                                        ^ IndentationError: unindent does not match any outer indentation level   And this is the code:  def add_sighting(session, spawn_id, pokemon):   obj = Sighting(       pokemon_id=pokemon['id'],       spawn_id=spawn_id,       expire_timestamp=pokemon['disappear_time'],       normalized_timestamp=normalize_timestamp(pokemon['disappear_time']),       lat=pokemon['lat'],       lon=pokemon['lng'],   )   # Check if there isn't the same entry already   existing = session.query(Sighting) \       .filter(Sighting.pokemon_id == obj.pokemon_id) \       .filter(Sighting.spawn_id == obj.spawn_id) \       .filter(Sighting.expire_timestamp > obj.expire_timestamp - 10) \       .filter(Sighting.expire_timestamp < obj.expire_timestamp + 10) \       .filter(Sighting.lat == obj.lat) \       .filter(Sighting.lon == obj.lon) \       .first()    if existing:       return   session.add(obj)   f = open('i:\Games\Pokemon GO\pokeminer-0.2\spawn_location.csv','w')     f.write(pokemon_id+lon+lat+expire_timestamp)     f.close()       This code is not mine, i'm just trying to make it write some details to a csv file. Can you please help me out with this, to make it work?

When I compile the Python code below, I get      IndentationError: unindent does not match any outer indentation level     import sys  def Factorial(n): # Return factorial     result = 1     for i in range (1,n):         result = result * i     print "factorial is ",result     return result   Why?


For my following code, the frame is not working. Latex gives a lot of errors, such as      Undefined control sequence \end{frame},    Illegal unit of measure (pt> inserted) \end{frame}   I cannot find any error with my code. Can any one suggest where is the bug?  \documentclass{beamer} \usepackage{listings} %used for source code \begin{frame}     \frametitle{Matlab Generated Plot}      \begin{columns}[onlytextwidth]         \begin{column}{0.45\textwidth}             \begin{block}{Code}                 \begin{lstlisting}                     for i:=maxint to 0 do                     begin                     { do nothing }                     end;                     Write('Case insensitive ');                     Write('Pascal keywords.');                 \end{lstlisting}             \end{block}         \end{column}         \begin{column}{0.45\textwidth}         Test         %\input{fig_x2}         \end{column}     \end{columns} \end{frame} \end{document}

I am trying to to put an lstlisting environment in the left column, but I'm getting errors. Are lstlisting and the columns environment in beamer incompatible? Or is it something else?  \documentclass{beamer}  \usepackage{remreset} \usepackage{comment} % end and begin comment \usepackage{dtklogos} % for \BibTeX  \usepackage{listings} % display code on slides; don't forget [fragile] option after \begin{frame} \usepackage{bera} % pause in listing \usepackage{color} \definecolor{lightgrey}{rgb}{0.92,0.92,0.92} % defining color for listing \definecolor{darkgreen}{rgb}{0,0.6,0} % defining color for listing  \usepackage{graphicx} % importing figure  \usepackage{verbatim} % writing code   \makeatletter \@removefromreset{subsection}{section} % creates navigation circles for every slide not section \makeatother \setcounter{subsection}{1} % creates navigation circles for every slide not section  \usetheme{Frankfurt}  \lstset{language=[LaTeX]TeX, basicstyle=\small\ttfamily, texcsstyle=*\bf\color{blue}, numbers=left, breaklines=true, keywordstyle=\color{darkgreen}, commentstyle=\color{red}, otherkeywords={$}, frame=leftline, tabsize=2, backgroundcolor=\color{lightgrey}, escapeinside=|| }  %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% \begin{document} %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%  \begin{frame} \begin{columns}  \begin{column}{5cm} \begin{lstlisting}[float=*] \pause \end{lstlisting} \end{column}  \begin{column}{5cm} text \end{column}  \end{columns}  \end{frame}  %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% \end{document} %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%


For two numbers $a$ and $b$ with $0 \leq a\leq b $ we have that: $a_{n+1} =\sqrt{a_nb_n} \quad$ , $\qquad b_{n+1} = \frac {a_n+b_n}2 \quad,$ $\qquad a_0 = a, \quad b_0=b $ And I have to prove for $n\ge1$ that $b_n-a_n < (\frac {1}2)^n(b-a) \quad $ if $a\neq b$ In previous exercises I've proved that: (i) $\sqrt{ab} \leq \frac{a+b}2$ $\quad$ for $\; 0\leq a \leq b \;$ with equality if and only if $a=b$ (ii) $ a <\sqrt{ab} \; $ and $\frac{a+b}2 <b \; $ for $0 \leq a<b$ By using (i) and (ii) I have done this so far: $b_n-a_n =\frac{a_{n-1}+b_{n-1}}2 - \sqrt{a_{n-1}b_{n-1}} $ $\qquad \quad < \frac{a_{n-1}+b_{n-1}}2-a_{n-1}=\frac{1}2(b_{n-1}-a_{n-1}) \quad$ for $n\ge1$ I'm stuck from here. (Edited)

I am given this problem: let $a\ge0$,$b\ge0$, and the sequences $a_n$ and $b_n$ are defined in this way: $a_0:=a$, $b_0:=b$ and $a_{n+1}:= \sqrt{a_nb_n}$ and $b_{n+1}:=\frac{1}{2}(a_n+b_n)$ for all $n\in\Bbb{N}$    To prove is that both sequences converge and that they have the same limit. I don't know how to show this. I have spent 2 hours on this, no sign of success


I just found another post where a user is using single line break to create separate lines / paragraphs. This of course won't do anything in Markdown; two line breaks or a <p> tag are required. So I wanted to point out how to add paragraphs / sections by forwarding the user to . However, to my surprise nothing is said about this, while creating sections in a post is one of the best tips to enhance readability.  Could somebody please put this somewhere on top of the Stack Exchange and Stack Overflow formatting pages? Maybe put the trick to insert line breaks [space][space][enter] right below it so they are grouped together (and code blocks / comments below that). That way new users don't need to wonder what happened to their line breaks... at least if they took the time to read the formatting hints.

Like balpha once , a
 line break (newline) should be used in very few cases, and surely is not the same as a new
 paragraph. Still  only explains line breaks, not paragraphs:      Some sites  an additional "New paragraphs only occur when there is a blank line. A single carriage does not create a new paragraph.", but I feel that's not very clear*, and the emphasis is still on line breaks while it should be on paragraphs:      So: As a minimum, please add (rephrase) a note about the blank line, and maybe use "Only when really needed [...] force":  Paragraphs and line breaks Simply use a blank line between two paragraphs to start a new
 paragraph. Only when really needed, end a line with two spaces to force a
 line break: How do I love thee?__     Let me count the ways   I'd even prefer an explicit example, simply as I think
 should be favoured over
 in most situations:  Paragraphs and line breaks Simply use a blank line to start a new
 paragraph: First sentence in the first paragraph. Another sentence. And a third. Maybe making this multiple consecutive lines of text, but still one paragraph.  The second paragraph.  Only when really needed, end a line with two spaces to force a
 line break: How do I love thee?__     Let me count the ways   Alternatively, slightly change the existing "Linebreaks"† part, and above that add a standalone section, :  Paragraphs A paragraph is simply one or more consecutive lines of text, separated by one or more blank lines: A blank line is any line that looks like a blank line. A line containing nothing but spaces or tabs is considered blank.  Normal paragraphs should not be indented with spaces or tabs.  Line breaks Only when really needed, end a line with two spaces to force a
 line break: How do I love thee?__     Let me count the ways   And: maybe even add a section "Paragraphs" to the inline post help on top of the editor? I'm not sure which help tab should then be shown  though.  * Also note how not all sites highlight the two spaces with a different background color. † Yes, I think "line break" likes a space too...


I lost the reputation just 10-15 minutes ago and not 5hrs ago as it shows. And moreover I remember I only edited the question long back(Do not remember the date). Now it shows the question was removed, and I surprisingly I lost rep. What are the reasons for which I lost the rep?

Do you lose the +2 edit rep if the edited post is subsequently deleted?  It seems a little unfair if this is true, but reputation can evaporate in this way in similar circumstances.


After reading about the , I decided to update to 1.8.28 manually. I downloaded deb file from sudo.ws and used dpkg to install it, and it failed due to lack of dependencies. sudo dpkg -i debs/sudo_1.8.28-1_ubu1804_i386.deb  (Reading database ... 232031 files and directories currently installed.) Preparing to unpack .../sudo_1.8.28-1_ubu1804_i386.deb ... Unpacking sudo:i386 (1.8.28-1) over (1.8.27-1ubuntu1.1) ... dpkg: dependency problems prevent configuration of sudo:i386: sudo:i386 depends on libc6. sudo:i386 depends on libpam0g. sudo:i386 depends on libpam-modules. sudo:i386 depends on zlib1g. sudo:i386 depends on libselinux1. sudo:i386 depends on libaudit1.  dpkg: error processing package sudo:i386 (--install): dependency problems - leaving unconfigured Processing triggers for man-db (2.8.5-2) ... Errors were encountered while processing: sudo:i386  After that I can't call sudo any more and it seems to be damaged cause I can locate it in /usr/bin/sudo: l /usr/bin/sudo -rwsr-xr-x 1 root root 479K Oct 10 20:15 /usr/bin/sudo  Since there is no Root user available on Ubuntu I was wondering if there is any  solution other than rebooting as root in recovery mode? Update Here is the output of type on sudo: type -a sudo  sudo is /usr/bin/sudo sudo is /bin/sudo  And pkexecdoesn't seem to be working for me (no action. Only sitting there gazing at me) The only option left is recovery mode which I have to postpone till end of the day and I'll let you know the result.

This seems to be a chicken-egg problem. The most common task using sudo is installing and removing software.  sudo apt-get purge <appname>   But sudo itself can be removed.  sudo apt-get purge sudo # Do not run this command on production computers!   This is where the fun comes  ubuntu@ubuntu:~$ sudo bash: /usr/bin/sudo: No such file or directory   Although it's obvious that no person in his right mind will purge sudo (other than me), someone can be fooled to run this command (not directly, in its hex mode, or whatever it's called) or a person could SSH in disguised as tech guru and do the mess.  So is there a way of reinstalling sudo?


I was following the backpropagation tutorial by Michael Nielsen on , one of the very few places where the backprop algorithm is nicely explained both in theory and practice with an actual implementation in python.  Now, something is not clear when he explains how to calculate the error on a specific layer in terms of error in the next layer (I will provide a screenshot because I don't want to mess with notation):    Here, $\delta^l$ is the error in layer l, $\odot$ is the elementwise product betweeen vectors, $w$ is a weight matrix, and $\sigma'$ indicates the derivative of an activation function.  Now, observe he points out that by applying the transpose of $w$ to the next-layer-error vector (which is the previous layer during backprop), one is "sending back" the error across the network, and then, multiplying by the derivative of sigma, one applies (I presume) the chain rule which completes the backprop step.  I have troubles understanding what does he really mean by saying that the traspose "sends back" the error. Why should it? Perhaps he wants to apply the inverse trasformation? But unless the matrix happens to be orthogonal, which is not the case AFAIK, the transpose does NOT equal the inverse.. What is the algebraic significance of the transpose operator in this specific context?  In any case, I would have thought, reasoning about the chain rule, of applying some kind of differential operator to matrix $w$, instead of transposing it.  Before asking that question, I researched the topic for a long time, but I was unable to find whatever information about that particular point.  Opinions?

I was following the backpropagation tutorial by Michael Nielsen on , one of the very few places where the backprop algorithm is nicely explained both in theory and practice with an actual implementation in python.  Now, something is not clear when he explains how to calculate the error on a specific layer in terms of error in the next layer (I will provide a screenshot because I don't want to mess with notation):    Here, delta^l is the error in layer l, the circled dot is the elementwise product betweeen vectors, w is a weight matrix, and sigma primed indicates the derivative of an activation function.  Now, observe he points out that by applying the transpose operator to the next-layer-error vector (which is the previous layer during backprop), one is "sending back" the error across the network, and then, multiplying by the derivative of sigma, one applies the chain rule which completes the backprop step.  I have troubles understanding what does he really mean by saying that the traspose operator "sends back".  Perhaps he wants to apply the inverse trasformation? But unless the matrix happens to be orthogonal, which is not the case AFAIK, the transpose does NOT equal the inverse..  In any case, I would have thought of applying some kind of differential operator to matrix w, and not the transpose one.  Opinions?  NOTE: Please let me know whether this post is correctly suited for stackoverflow, or should it be posted on stats or math stackexchange.


When I insert my Promoted Links into my Team Site, a number in square brackets appears to the right of the list name.  What causes this and how can I get rid of it? I have a promoted links list called 'Quick links' I've gone to my Team Wiki and added this list, but the title shows as 'Quick links [3]'

I'm sure this is a really simple setting I'm having trouble finding. If I delete a web part then add it again, there is a number in brackets after the title that goes up by 1 each time. How do I get rid of this?


How long are you supposed to stay out of Israel after your 3 month tourist visa has expired in order to get another tourist visa? I am Chilean citizen and I tried to get a meeting for extending my visa at the ministry but unfortunately they don't have any dates until October and my visa will end in September.

How long are you supposed to stay out of Israel after your 3 month tourist visa has expired in order to get another tourist visa?  I'm a U.S. citizen, if it matters.


Unfortunately i tried to log in using my Facebook account, it created a duplicate stack overflow account because i have an account using yahoo, please delete the duplicate account this is my original account   this is the account created beacuse i have wrongly logged using facebook

I accidentally posted a question without being logged in. Is there a way to associate that question with my account?   For more information, visit "" in the .   a.k.a. How can you link a registered account to a cookie-based account? a.k.a. How do I merge an unregistered account with a registered account a.k.a. Merging users a.k.a. How do I associate anonymous questions I’ve asked with my registered account? a.k.a. Is there a way to claim an unregistered user? (in case anyone searches with those terms)


is my profile page on Stack Overflow. I have accounts on all 104 Stack Exchange sites including the newest ones. But the profile page is showing only 101 accounts instead of 104. Is this a possible bug? I must also add that all those accounts are quite old. EDIT  page on Stack Exchange shows all the 104 accounts, so I believe none of the accounts were deleted.

My profile main page ():  My SE websites ()  "Software Recommendations" is missing on my profile main page. I think it's related to the repeatedly dismissed bug


So I have Android app with Tabs and RecyclerView. When I run my app, it crashes.  logcat:  java.lang.NullPointerException: Attempt to invoke virtual method 'int java.lang.String.length()' on a null object reference         at java.io.StringReader.<init>(StringReader.java:47)         at android.text.HtmlToSpannedConverter.convert(Html.java:442)         at android.text.Html.fromHtml(Html.java:136)         at android.text.Html.fromHtml(Html.java:99)         at com.example.app.MyRecyclerViewAdapter2.onBindViewHolder(MyRecyclerViewAdapter2.java:80)         at com.example.app.MyRecyclerViewAdapter2.onBindViewHolder(MyRecyclerViewAdapter2.java:17)        ...      at com.example.app.MyRecyclerViewAdapter2.onBindViewHolder(MyRecyclerViewAdapter2.java:80)   It points to this line of the code  listRowViewHolder.postId.setText(Html.fromHtml(listItems.getPostId())); // This line of code leads to crashing of app   If I delete this line, my app will work fine.  MyRecyclerViewAdapter2.java:      package com.example.app;   import android.content.Context; import android.content.Intent; import android.support.v7.widget.RecyclerView; import android.text.Html; import android.view.LayoutInflater; import android.view.View; import android.view.ViewGroup; import android.widget.TextView;  import com.android.volley.toolbox.ImageLoader;  import java.util.List;  public class MyRecyclerViewAdapter2 extends RecyclerView.Adapter<ListRowViewHolder> {     private List<ListItems> listItemsList;     private Context mContext;     private ImageLoader mImageLoader;     private int focusedItem = 0;  public MyRecyclerViewAdapter2(Context context, List<ListItems> listItemsList) {     this.mContext = context;     this.listItemsList = listItemsList; }  @Override public ListRowViewHolder onCreateViewHolder(final ViewGroup viewGroup, int position) {     View v = LayoutInflater.from(viewGroup.getContext()).inflate(R.layout.card_view_row2, null);      ListRowViewHolder holder = new ListRowViewHolder(v);      holder.itemView.setOnClickListener(new View.OnClickListener() {         @Override         public void onClick(View v) {             TextView postUrl =  (TextView) v.findViewById(R.id.postId);             String post_Id = postUrl.getText().toString();              Intent intent = new Intent(mContext, ViewPostActivity.class);             intent.putExtra("id", post_Id);             mContext.startActivity(intent);          }     });      return holder; }  @Override public void onBindViewHolder(ListRowViewHolder listRowViewHolder, int position) {     ListItems listItems = listItemsList.get(position);     listRowViewHolder.itemView.setSelected(focusedItem == position);      listRowViewHolder.getLayoutPosition();      mImageLoader = MySingleton.getInstance(mContext).getImageLoader();     listRowViewHolder.thumbnail.setImageUrl(listItems.getThumbnail(), mImageLoader);     listRowViewHolder.thumbnail.setDefaultImageResId(R.drawable.website_placeholder);      listRowViewHolder.title.setText(Html.fromHtml(listItems.getTitle()));     listRowViewHolder.date.setText(Html.fromHtml(listItems.getDate()));     listRowViewHolder.content.setText(Html.fromHtml(listItems.getContent()));     listRowViewHolder.postId.setText(Html.fromHtml(listItems.getPostId())); // This line of code leads to crashing of app }  public void clearAdapter () {     listItemsList.clear();     notifyDataSetChanged(); }   @Override public int getItemCount() {     return (null != listItemsList ? listItemsList.size() : 0); }}

What are Null Pointer Exceptions (java.lang.NullPointerException) and what causes them?  What methods/tools can be used to determine the cause so that you stop the exception from causing the program to terminate prematurely?


I think the title is self-explanatory but should I make the connection on PCB or they are already connected? If so, should I still connect them externally? Why? I'm working on ATMEGA328p-pu if it matters.  (source: )

Take a look at this example schematic:  The chip in question is the  and as you can see power is provided on both sides (with a 100nF cap to smooth noise I guess). Is this strictly required or could you put power into one side and just ignore the other? I know that I have just put power in one side and everything still seems to work fine but I feel uneasy with doing that. I feel that they would not waste pins that could be doing something useful by having an extra pair of power in/out pins. For what purpose does this PIC MCU (and others like it) have multiple power pins?


I have server and there is one 1TB drive in it and I guess it's not running any raid, I'm thinking if it's possible to add another 1TB HDD and setup RAID1 somehow?(software raid1)  Server is running CentOS 6.4  Is it possible to do that? Would it occur any downtime, perhaps data loss? How simple is it?

I have a computer with two WD 1TB drives and I want to configure disk mirroring on it.  I tried setting up RAID during the installation by creating RAID partitions but that does not work for me.  Is there a convenient software that I can install to do the job for me? If no, what shell commands can be used?  Once it is set up how should I verify that it is working?


I have a WD My Passport P/N ends with BBK-01 1TB. I had it for couple of years and it was functioning smoothly on Windows 7 and Win 8.1, before upgrading to Windows 10 it stopped working, the Windows recognize it when connected to USB 3 or 2, it also shows up in "Devices and Printers" but with missing details, the properties windows shows that it is working properly and the HardwareID have some attributes to it, but I can't access it from neither my computer nor the "diskmgmt.msc", the external HDD anyhow, spin then beeps twice with clicks prior to each beep and stop spinning but keep on flashing repeatedly, until disconnected of course.  Is it time for me get a new HDD? And is there a way to get to the HDD? I have more than 800GB of essential data on it.

What steps can I take to try to recover lost or inaccessible data from any storage device?  Answers:   This applies to any computer storage device, e.g. internal/external hard drives, USB sticks, flash memory. The most important thing is to STOP using it, any type of I/O can ruin your chances of a recovery.     We have separate questions covering common problems with USB flash drives in greater detail:


I was wondering what algorithm would compute    S(n, k {occurences of each element})     Where  S(6, 3, {1, 2, 3} )   would give the total number of ways a set with 6 elements in which 3 are the same element and a different 2 are another element (and 1 is its unique element) could be split into 3 non-empty sets, ignoring permutations.    This is basically the extension of Stirling numbers of the second kind to deal with multisets.

$S(n, k)$ count the number of ways to partition a set of $n$ elements into $k$ nonempty subsets. What if there were duplicate elements in the set? That is, the set is a ?


So I'm trying to derive the covariance between $z_t$ and $z_{t-1}$ in the $AR(1)$ model: $z_t =\phi z_{t-1} + a_t$. Can anyone give me some advice on where to start?

Is the ar1 coefficient from an AR(1) model the "first order correlation of the noise" of a time series?  I'm using R's aws package and one of the arguments of the aws function allows you to "specify a first order correlation of the noise". Instinctively, I did  arima (foo, c(1, 0, 0))   and used the ar1 coefficient as this correlation value. Plugging it into aws makes the results look more like what I'd expect, so I was quite happy…  Until it struck me that AR coefficients can fall outside of the range [-1, 1], while the correlation cannot. So maybe I just got lucky. Then it struck me that if the ar1 coefficient of an AR(1) model falls outside of [-1, 1], the model's not stationary, so perhaps a well-fitting AR(1) model's ar1 coefficient is essentially restricted to [-1, 1].  But then I thought: just because they share the same range doesn't mean they are the same. I did some searching and didn't find anything saying this is a correlation. I did some simulations and it appears that it is close to a correlation.  Anyone have an authoritative statement on the matter?  I've also looked at arima (foo, c(1, 0, 0), xreg=theDate) to account for a trend. I've thought that if the AR coefficient is a correlation: what if an AR(2) model is a better fit than an AR(1) model -- is the ar1 coefficient still what I'm looking for or do I have to combine it with the ar2 coefficient, or do I still go with the AR(1) model?


float c = 0.0f; private void FixedUpdate() {     if (startRotatingBack)     {         var p = transform.eulerAngles;          if (p.y != -40)         {             p.y -= 1;             transform.eulerAngles = p;         }          c = c + 0.1f;         playerAnimator.SetFloat("Forward", c);     } }  The problem is that the transform keeps rotating nonstop. Maybe the problem is with this chick? if (p.y != -40)  I want to make that the player will rotate backward. -40 or -45 is good enough but the player the transform is keep rotating nonstop so it's making circles instead of rotating once to -40 or to -45. I tried also this way but it's not working either : if (!Mathf.Approximately(p.y, -40))

I use the following code to rotate a transform towards another. And it's working fine. However, I want to lerp it over time period. public void RotateToward(Transform target) {    Vector3 from = transform.up;    Vector3 to = target.position - transform.position;    float angle = Vector3.SignedAngle(from, to, transform.forward);   transform.Rotate(0.0f, 0.0f, angle);  }  An example would greatly help.


I want to ask you if there's some special rule about pronouncing foreign names with or without accent. For example, can I say Fedor or Andrey in native russian manner and with russian accent or should I say it with english accent? Is it appropriate?

When reading to an audience, or speaking in conversation, when is it appropriate to use the original pronunciation of a foreign word versus the English pronunciation (assuming you know the appropriate pronunciation for it)? Is it considered rude, or condescending? Or is it considered a mark of being knowledgeable?  One of the things to consider are place names. When referring to Paris, France, should it be pronounced with the silent 'S' as the French would say it, or with the 'S'? Should Hiroshima be pronounced as a Japanese speaker would pronounce it slightly more emphasis on RO, rather than the SHI? Should Mount Pinatubo be pronounced as a Filipino speaker would pronounce it with shorter stronger vowels, or the longer vowels? (e.g. Pi as is 'pick' rather than 'pea'.) Should Wichita be pronounces as the original "shi" rather than the modern "chi"?  Pronounce pesos or sombrero as a Spanish speaker 'eh' or the English 'ay'?  (I can't think of other common words right now that aren't words taken from other languages like hurricane, boondocks, tornado, etc. which I think have (correctly) changed to English pronunciations.)


The Socratic badge is a gold, and we get it when 100 questions with score > 0 and maintain a positive question record, obtainable multiple times   When someone does not have it, then we can see how we're doing.  When someone already has it, then how can we see our progress towards the next one?

Just got the  on StackOverflow and, since it can be awarded multiple times, wanted to start tracking progress to the next one, but, the badge is not shown in Available badges to track anymore:    Is it possible to track already awarded badges that can be awarded multiple times?


I've travelled by plane many times, and I often experience strong pain in my ears when landing. It is caused by the rising cabin pressure, which creates a force on the eardrum. Apparently, my inner ear does not let any air in to compensate the pressure.  What can I do to prevent or mitigate this pain (and potential injuries)? Can I prepare myself, or do something during or after the flight?

I always feel a pain in my ears when flying. Specially when descending. The last time I had extreme pain, feeling it inclusive around my eye balls. It felt like someone was touching the eye and pulling it from the inside. I really had to focus, close my eyes and hold to avoid screaming. I am not sure but I think both things might be related. Such a severe situation only happened once.  I just heard that with a cold the ear pain gets worse. I am bit worried that I might go through that situation again. I have a cold and I am going to fly soon.  What can I do to improve this?  I see that some consider this a duplicate of the question "best way to make my ears pop" but after reading the answers I think my question goes a bit beyond that since my pain is more extreme and I think it goes beyond just popping the ears. I also want to know if other methods, like using earplugs, might be effective.


Can I cause an xhr request to interrupt/terminate clientside? I have a number of long running requests, and I want to abandon them once they're no longer relevant.

Is it possible that using jQuery, I cancel/abort an Ajax request that I have not yet received the response from?


In few months we are going to visit Japan to cycle the 88 Temples pilgrimage there, and therefore we want to take our bikes with us.   Neglecting the transport from home to the airport, I will need to carry the bikes first on the plane, and then from the airport to the starting point, either via train or bus, with the constraints that the bikes must be covered and shall not exceed certain dimensions, else they won't be ammitted on the transport (and the train/bus crew is very strict on the size fitting).  I booked a direct flight to minimize handling at airport, but still I am not able to decide among the various options for packing them (taking for granted that the bikes will have the wheels removed and tightened to the frame before packing):   Use two hard bags:   Plus: good protection of the bike during the flight  Minus: hard to store for the flight back, rather expensive, won't allow usage in-between in case we decide to take train or bus Use two soft bags covered with Fragile labels  Plus: lightweight and easy to carry along, less expensive than hard bags, can be used also for taking the bikes on the train or bus no matter when it happens during the trip  Minus: do airport operators care about "fragile" bags? Use cardboard boxes  Plus: they come for free, good protection  Minus: likely single use only, where to find a new pair of boxes in Japan (both bikes are XL, not really the common Japanese size),  won't allow usage inbetween in case we decide to take train or bus.   Talking with a friend who is often travelling on airplanes with his bike along, he always used a simple home-made soft bag with no labels, which led only to a bent derailleur gears after several trips. In my case the derailleur gears will be protected by the dissasmbled rear wheel, but I am still concerned about the carbon fork, which is not really keen to take strange impacts. Another one told me he found a kind local who accepted to keep his cardboard box at his place for the entire lenght of the trip, but I'd rather not count on lucky meetings to plan this trip.

I am doing a cycle tour of Japan starting from Fukuoka and ending in Tokyo. I will be flying with the bike and as my start and end points differ I will not have the opportunity to use a box (unless anyone has any ideas?). I will most likely use one of  bags and I have been told by the airline that nothing is necessary by way of packing the bike but I would naturally like to see my bike in one piece at the other end. The bike is a Specialized Tricross with disc brakes. Does anyone have any pointers as to the safest way to package something like this. I think I will definitely take the rear dérailleur off and wrap bubble wrap along the length of the bike to protect the wheels, pedals etc but other than that I'm not sure what lengths to go to. Does anybody have any experience or ideas?


I realize this a difficult issue to solve but still, maybe someone can suggest a good compromise. When designing a website on my system the colors look the way I want but when checking them on the customer displays they look horrible (in some cases). Is there a way to solve this issue? What would be the best approach? Thank you.

This question has to do with color in the context of web pages.  Computer monitors and mobile screens can vary a lot in their color rendering, meaning that a given color on one monitor can look much different on another monitor.  For example, some greens and teals may look pleasant on one monitor but look sickly yellowish on others.  Are there certain web colors that are "safer" than others (NOT to be confused with the outdated practice of using "web-safe color palette")?  Or do you just create the web design on a calibrated monitor and know that's all you can do?


There is a portrait document in which only the second page have to be made landscape (the document has header and footer made with fancyhdr). To accomplish the portrait to landscape turn I'm using the following:  \pdfpageheight=\paperwidth \pdfpagewidth=\paperheight \paperwidth=\pdfpagewidth \paperheight=\pdfpageheight    Also, I'm using geometry to adjust layout in both modes (portrait and landscape). I'm going fine in maintaining the top and left margins across the modes. But I'm not seeing how to manage right and bottom.  To exemplify: I've tried \geometry{bottom=5cm} but in the landscape mode the footer goes beyond the page. It seems that the 4 lines of code above just cut the paper accordingly but foot stays in the same position (as in portrait mode).  What's the proper way to switch from portrait to landscape maintaining margins?  The following demonstrates what happens, foot disappear in landscape.  \documentclass[10pt,a4paper]{article} \usepackage[left=3cm, top=5cm, headheight=2cm, height=20cm]{geometry} \usepackage{lipsum} \usepackage{fancyhdr}  \renewcommand{\footrulewidth}{0.4pt}  \begin{document}  \thispagestyle{fancy} \pagestyle{fancy}  \lipsum[1]  \newpage  \pdfpageheight=\paperwidth \pdfpagewidth=\paperheight \paperwidth=\pdfpagewidth \paperheight=\pdfpageheight   \newgeometry{left=3cm, top=5cm, headheight=2cm}  \fancyhfoffset[L]{0pt}  \lipsum[1]  \restoregeometry  \paperwidth=\pdfpageheight \paperheight=\pdfpagewidth \pdfpageheight=\paperheight \pdfpagewidth=\paperwidth  \lipsum[1]  \end{document}

Objective  How to change the heading of landscaped pages from    to    ?  Minimal Code  \documentclass{book} \usepackage[a5paper,hmargin=3cm,vmargin=5cm]{geometry} \usepackage{lscape,lipsum}  \begin{document} \chapter{One} \lipsum[1]  \section{One One} \lipsum[2]  \newgeometry{hmargin=5cm,vmargin=3cm}  \begin{landscape} \lipsum[3-5] \end{landscape}  \restoregeometry \lipsum[6]  \end{document}   Edit 1 (my real scenario layout)  In my real scenario, the left-right margins should not be occupied by headings.


Let $G$ be a graph of order $n$ with $\kappa (G) \geq 1$. Prove that $n> \kappa(G)[\operatorname{diam}(G)-1]+2$   I know $\kappa(G) \leq n-1$. I do not know if do we have to prove it by induction or there is another way.

Question I found in "Introduction to Graph Theory" by Douglas B. West:     Let $G$ graph on $n$ vertices with connectivity $\kappa(G)=k \geq 1$. Prove that $$n \geq k(\operatorname{diam}(G)-1)+2$$ where $\operatorname{diam}(G)$ is the the maximal (edge) distance between a pair of vertices in $G$   Seems easy and I've seen the answer, too, which goes the same as thought: by taking the vertices the end vertices of the path of length $\operatorname{diam}(G)$, and applying Menger's Theorem. I'm having a hard time understanding one part - it seems like all the paths need to be of the same length for the $n \geq k(\operatorname{diam}(G)-1)+2$ to apply. Am I missing some part here?


With my previous installation I just had  /usr/bin/udisks --mount /dev/sda2 && /usr/bin/udisks --mount /dev/sda3   among the startup applications, but on my new installation (also 12.04.4) it has no effect.  The command works fine in the terminal.  Autostarting firefox using the startup applications tool works also.  How do I automount those partitions?  (No, update does not help!)

Sometimes when I restart my computer, my drives will mount but sometimes they won't (like right now when I'm typing this question out).   Is there an easy way, like a program that can mount them for me? Going in the console, making folders, etc, is NOT what I want. I like how Windows does it where they always mount the drives no matter what.   If there isn't a program how else can I easily mount all drives?


I created a chat system using php. For the chat box I used Input text box. wheneve I try to send a message, previous msg that I sent start to show on top of the box. as you can see that previous 2  messages are showing on top of the input box. I don't want this. I have used thia code for input     <input style="padding:4px;" id="msgCont" type="text" placeholder="Message..." class="inputText w95" />  please help me to remove this recommend data.

How do you disable autocomplete in the major browsers for a specific input (or form field)?


Let $X_1,X_2,\dots, X_n$ be rvs with pdf: $$f(x\mid \theta)=\frac{1}{2\theta}I(-\theta<x<\theta)$$  I know that $Y=\max|X_{i}|$ is a sufficient statistics for $\theta$ and I found an unbiased estimator $\hat\theta$ of $\theta$,  $\hat\theta = c_n(X_{(n)}-X_{(1)})$, where $X_{(n)}$ is the largest sample,  $X_{(1)}$ is the smallest sample and $c_n = (n+1)/(2n-2)$ is a constant which makes $\hat\theta$ unbiased estimator of $\theta$!  So, by Rao-Blackwell theorem, I should calculate conditional expectation $E(\hat\theta | Y)$ to improve  $\hat\theta$!!  I tried to calculate this by using that  $$\max|X_i| = \max(X_{(n)},-X_{(1)})$$  However, since $X_{(n)},-X_{(1)}$ are not independent, I am having a trouble with calculating this conditional expectation!

Suppose $X_1,\ldots,X_n$ are a random sample of $U(-\theta,\theta)$ with $\theta>0$. How can find $$ E\left(|X_1|\ \big|\max |X_i| \right) $$ that $1\leq i\leq n$?


In the story people see a speck on the moon which keeps getting bigger day by day and eventually the creature lands on earth. I don't know if this is in the beginning or middle of the story. I read this excerpt about the landing in one of my old English Textbooks. The speck growing and landing is described in detail along with perception and thoughts of people.  (This is not "Heresies of the Huge God", I read it to confirm that.)  Update: As per accepted answer, this and its possible duplicate question have same answer. But both questions are referring to different excerpts of same story. The excerpt I am referring to doesn't mention the robot. It is all about the appearance and arrival of the dragon.

I'm hoping someone recognizes this short story I read as a boy. The story was about a robotic eyeball that rolled around on a beach until it found a hand. The two parts joined up and wiggled around until they found a leg. They joined the leg and hopped around. That is all I can remember. I would like to know the ending. Does anyone remember this short story or know where it came from?


When I try to install a new app (a code editor in this case, brackets) I click on install but it doesn't work. When I want to install new updates available from Ubuntu Software it does this: I click on install, then it asks me for the admin password, I write it, the install bar gets full and stays like this for ever. No installation.  Please what could the problem be? I read other topics about this same problem but it doesn't seem to go away

I get this error whenever I try to install programs using the terminal:  home@ubuntu:~$ apt-get install myunity E: Could not open lock file /var/lib/dpkg/lock - open (13: Permission denied) E: Unable to lock the administration directory (/var/lib/dpkg/), are you root?   Also I'm unable to install updates using the terminal.


I am using outlook.com for my own email "mydomain.info" but I can not add an account in Apple Mail. I have searched in Ask Different for similar questions. I got this:    I have exact the same problem but the accepted answer doesn't work for me. My domain is "domain.info". I never configured an account successfully in Apple Mail from Maverick to Yosemite and now El Capitan.

I use Outlook.com as my email provider but have my own personal domain name instead of the one provided by Microsoft. So, instead of "mail@outlook.com", my email address looks like "mail@personaldomain.com".  I have been trying to somehow configure this email on my Apple Mail client but so far been unsuccessful. I have read several how-to's and tutorials that explain how to configure an outlook.com email on Apple Mail; however, none have explained what to do when you have a private domain running on Outlook.com. Could someone with a similar experience please help me out?  Also, though I will be more than happy to just have my email configured, it would be really great if IMAP were a possibility instead of POP3.


Is there any general proof that a  of a fluid always guarantees an equivalent  and vice versa?

I'm having trouble understanding the motivation between wanting to transition between the two descriptions.  I figure that switching from  is useful if we want to recover a particle's trajectory maybe? Is there any other reason to do so? and then what are we measuring by switching from Lagrangian to Eulerian?


I have downloaded the app "Pokemon Go" but it seems to be in Japanese I don't speak Japanese and do not know how to solve this problem !! Can somebody pls help me I am dying to play the game

My game is currently in French, probably because my phone is in French.   I would like to change the language of Pokémon GO because I always played Pokémon in English and, as a result, I don't know the names of the Pokémon in French.  Is it possible for me to change the language of Pokemon GO to English? How can I achieve this?


$ sudo apt-get install cgroups-lite [sudo] password for neethu:  Reading package lists... Done Building dependency tree  Reading state information... Done E: Unable to locate package cgroups-lite

When I try to install any package through the command line, I get an error.   $ sudo apt-get install <package> Reading package lists... Done Building dependency tree        Reading state information... Done E: Unable to locate package <package>   Can anyone help me on this?


i am unable to install Ubuntu restricted extras and VLC and many. when i use sudo apt-get install Ubuntu restricted extras in terminal it is showing unable to locate  ubuntu restricted extras. how can i make it possible

For the command   sudo apt-get update   I get following error:  W: Failed to fetch http://ch.archive.ubuntu.com/ubuntu/dists/maverick-updates/multiverse/binary-i386/Packages.gz   407  Proxy Authentication Required (The ISA Server requires authorization to fulfill the request. Access to the Web Proxy filter is denied. )   I am running Ubuntu 10.10 installed on Windows XP using VirtualBox. For Internet connections I am using proxy server with an authentication. I tried to use gnome-network-proxy tool to set proxy settings system-wide.   After that /etc/environment has been updated by http_proxy variable with the format http://my_proxy:port/, there were no authentication data.  I checked this with Firefox. Browser asked my for login and password and everything was working fine. It was unfortunately not the case for apt-get. I have also tried to do as described . Unfortunately it does not work.  May it be somehow related to the fact that a proxy is in a Windows domain, any ideas?  My proxy name is http-proxy. Is '-' a special character here?


A comment saying something short like "I did." or "It is." in response to another comment is perfectly legitimate. What's the point in requiring users to fill it up with pointless "..." or other characters?

I understand that there is an upper limit. But why do you have to type at least 15 characters to post a comment? It is easy to work around it anyway (like adding dots or other useless things).


I've read this in  on Pottermore, and the answers in: .   We know that a member of Hogwarts' staff goes and explains to the Muggle-born that they're wizards or witches. But how do they track them? For wizards families they simply send an owl, but for Muggle-borns, how exactly do they find a specific location that a Muggle-born resides.

In the seventh book, Harry wonders if 'the trace' is still on him after his seventeenth birthday, as the Ministry of Magic/Death Eaters keep managing to track him, Hermione and Ron down. It is later revealed that Voldemort's name has been "tabooed", so that the location of anyone speaking it will be revealed, and the However, in the first book, 'the trace' would only have worked if Harry was using magic- which, aside from setting a Boa Constrictor on Dudley, does not happen. The address(es) on the Hogwarts acceptance letter(s) sent to Harry are very specific:  "Mr H. Potter, The Cupboard under the Stairs, 4 Privet Drive, Little Whinging, Surrey"   "Mr H. Potter, The Smallest bedroom, 4 Privet Drive, Little Whinging, Surrey"   "Mr H. Potter, Room 17, Railview Hotel, Cokeworth"  At first I thought that the Anthony Horowitz book "Groosham Grange" (which was published a decade before Harry Potter and ) might help provide an answer, as in the book a black crow is sent by the school to watch David. However, there are no mentions of Owls/other birds except for the ones delivering the (already addressed) mail. It's possible that professor Trelawney used a crystal ball or her prophecy powers to watch Harry's movements, however, in 'The Prisoner of Azkaban', Dumbledore comments:  'Do you know, Harry, I think she might have been,' he said thoughtfully. 'Who'd have thought it? That brings her total of real predictions up to two. I should offer her a pay rise…' (PA22)"  As her first real prediction was the prophecy "neither shall live while the other survives", and the second was the one about "the servant returning to his master". Crystal-ball-gazing doesn't seem to extend to present events as such, and in any case, Dumbledore admitted in the quote that she wasn't a great seer, so what I'm wondering is: How did the Hogwarts professors know (and in such great detail) where Harry was, and; Why couldn't this method be replicated in later books (such as when the Death Eaters wanted to track Harry)? Additionally, does anyone have any idea how (Wizarding-world) Owls can manage to track people with no addresses written on them? E.g, in book 4, (aside from being a super-smart bird) how is it that Hedwig can easily find where Sirius is?


Can someone explain in simple words and with many good down-to-earth examples what is the p-value and how do we find it?   Is it true that it shows what is the probability that the sample we have tested is true not simply by chance? Isn't that the point of the alpha level to guarantee that for an instance, for 95% of the time, it is not a chance that our hypothesis is true? For the rest of the 5% if it is true, it is by chance?  I will greatly appreciate if you can explain the difference between p-value and alpha level(significance level), how are they connected, what do they tell me for the "real world" and give me examples! (Because any mathematical explanation seems to confuse me more)   Thanks in advance!  PS: I am aware that there are questions about p-value with good explanations out there, would then just like to have answers for the other questions.

After taking a statistics course and then trying to help fellow students, I noticed one subject that inspires much head-desk banging is interpreting the results of statistical hypothesis tests.  It seems that students easily learn how to perform the calculations required by a given test but get hung up on interpreting the results.  Many computerized tools report test results in terms of "p values" or "t values".  How would you explain the following points to college students taking their first course in statistics:   What does a "p-value" mean in relation to the hypothesis being tested?  Are there cases when one should be looking for a high p-value or a low p-value? What is the relationship between a p-value and a t-value?


My daughter has bought a return ticket to Hawaii which exceeds the 90 day limit by one day.  She intends to travel for the first month and do voluntary work on an organic farm for two months before she flies home.  Is outstaying the 90 day limit by one day going to be a problem?

I recently discovered that I will be over-staying my 90 day visa waiver by 2 days. My question is about leaving the country as I fly from NYC to LA before flying home to Australia and I'm wondering that if because the Visa has technically expired will I be allowed to fly from one US state to another or will I be forced to fly directly out of the US from NYC?


I am asked to find all $f : \mathbb{R} \to \mathbb{R}$ such that $f(x - f(y)) = f(f(y)) + 2 x f(y) + f(x) - 1$, which I solved and got that $f(x) = 1 - x^2$ -- a correct solution and everything.  What puzzles me is how do I find all solutions. I wrote that all functions $g : \mathbb{R} \to \mathbb{R}$ which map in the same way as $f$ are solutions, but is there something I'm missing here?  Have an awesome day, all of you.

I came across the functional equation $$ f \big( x - f ( y ) \big) = f \big( f ( y ) \big) + x f ( y ) + f ( x ) - 1 \text . $$ So far I tried plugging $ x = f ( y ) $ and got $ f ( x ) = \frac { f ( 0 ) - x ^ 2 + 1 } 2 $ which holds for every $ x $ that is equal to $ f ( y ) $ for some $ y $. I suppose that $ f ( 0 ) = 1 $ and $ f ( x ) = 1 - \frac { x ^ 2 } 2 $, which would be true if I prove that $ f $ is surjective, which I still haven't proven. Could anybody help me?


Can there be a lottery of the natural numbers, so that every natural number is chosen equally likely?   The standard answer would be "No" because: If we define a measure $\mathbf{P}$ on $\mathbb{N}$ so that $\mathbf{P}(n) = r \in (0,1] \; \forall \, \mathbb{N}$, then $\mathbf{P}(\mathbb{N}) = \infty$. If we define a measure so that $\mathbf{P}(n) = 0$, then $\mathbf{P}(\mathbb{N}) = 0$.  But why can we conclude from that, that a lottery of the natural numbers (with every natural number equally likely) is impossible?  Note: the question is not if there can be a uniform probability distribution (satisfying all axioms of probability, including countable additivity) over the natural numbers but if there can be a lottery of the natural numbers so that every number is chosen equally likely!

Apparently, the solution to the  is that a uniform probability distribution over the positive real numbers doesn't exist. Can anyone explain why this is the case and what probability distributions can exist over the positive real numbers (it seems that this would be quite limited, given that such a simple distribution is impossible)?


We host a domain on the internet that is accessible outside of our internal network using domain.com or www.domain.com, but is our actual internal network domain as well, but the external website is only accessible from our computers using www.domain.com - using domain.com gives "connection refused" in Chrome, and does a Bing search in IE.  I've asked our DNS guy about it, and he says internally domain.com goes to the internal network domain controller, and can't be rerouted/directed to the www version.  I've only done config on websites, not internal networks, so is there no way for domain.com from our internal network computers to resolve to www.domain.com?

The MSP for a law firm office that has just joined our company is using a FQDN as an internal AD Domain and has been doing so for sometime apparently. They have this issue in that they have a website of the same FQDN which is hosted offsite, so when they try to browse  they get the IIS7 page of their DC rather than the website which we (outside of their local network) see.   works fine internally because they have a forward lookup on their DC, but I've asked them to do the same for the hostless A record of the website and the MSP said that would need to be researched first and might have to be dealt with as a project because of the implications on the local domain and RDS environment. Is this the case? Isn't all AD domain lookups done via UNC and IP rather than DNS lookups?


We are developing a new product/website and one of our product managers said we should never use the word "please" either on our website or in our transactional emails.   Personally, I disagree. We are trying to make our site casual and friendly and I think using the word "please" is just polite.  What do you think?

Often I'll see a website, especially when registering or filling out a form that says something like "Please only use letters and numbers in this field" or "Please try again."  Please is a pleasantry and I suppose it could make wording sound more "natural" but in this context I don't find it helpful at all. In fact often when I see "please" in a validation message it's not an optional requirement. In that case even in spoken English the "please" is misleading and incorrect as it indicates that you should do something, while omitting the please turns the same phrase ("Use only letters and numbers in this field") turns it into a command, which is correct.  Is there a reason to use statements like these? Are some situations more appropriate than others? It seems fairly prevalent but strikes me as inappropriate interaction.


Let $\mathfrak{sl}(n,\mathbb{R})=\{X\in\mathfrak{gl}(n,\mathbb{R}): \mathrm{tr}(X)=0\}$ the Lie algebra of $\mathrm{SL}(n,\mathbb{R})$, i want show that, if $X\in\mathfrak{sl}(n,\mathbb{R})$ is such that: $[X,Y]=0$, for all $Y\in\mathfrak{sl}(n,\mathbb{R})$, then: $X=0$. Where, for all $A,B\in\mathfrak{sl}(n,\mathbb{R})$: $$[A,B]=AB-BA.$$ I have no idea how to proceed. Any help would be appreciated!

For $L=sl_2(\mathbb{F})$ i.e. matrices with trace zero,  what is the centre i.e. $Z(L)$= {$x\in L : [x,y]=[y,x] \ \forall\ y \in L$}.  I will have to find matrices $A \in L$ such that $AB=BA$ for all $B \in L$. But how to appoach this considering trace is zero here.


If  $u(x) \in C([a, b]), u(a) = 0,\; u(x) = \int_{a}^{x}u^{'}(t)dt$  then  $\int_{a}^{b} |u|^{2} dx \le \frac{1}{2}(b - a)^{2}\int_{a}^{b}|u^{'}(t)|^{2}dt$  The book said it can be proved using cauchy-schwarz-inequality, but I cannot make it.

Let $f:[0;1]\to\mathbb R$ be continiously differentiable  and $ f(0)=0$.   Prove that $\int\limits_0^1 |f(x)|^2\, dx\leq \dfrac{1}{2}\int\limits_0^1 |f'(x)|^2\, dx.$


What is the difference between $('.abc') and $(".abc") in jQuery?  Example:  var main = function() {  $('.btn').click(function(event) {    $('.container').hide();  }); };   vs  var main = function() {  $(".btn").click(function(event) {    $(".container").hide();  }); };   Both of the code snippets work well. So what is different?

console.log("double"); vs. console.log('single'); I see more and more JavaScript libraries out there using single quotes when handling strings. What are the reasons to use one over the other? I thought they're pretty much interchangeable.


Mathematicians define real numbers in an abstract way - as an 'ordered field' with 'the least upper bound property'.  In physics, we use real numbers to represent distances. For us to be able to do this, we need to establish the following:   With every distance a real number can be associated. With every real number, a distance can be associated.   In other words, a one to one correspondence.  Is there any proof of this?

Why is physical space equivalent to $\mathbb{R}^3$, as opposed to e.g.  $\mathbb{Q}^3$?  I am trying to understand what would be the logical reasons behind our assumption that our physical space is equivalent to $\mathbb{R}^3$ or 'physical straight line' is equivalent to $\mathbb{R}$ .   The set of reals $\mathbb{R}$  is a basically an algebraically constructed set, which is nothing but the completion of $\mathbb{Q}$, the set of rationals. For reference see here . Now my question is what is the reason behind our approximation of the physical space by this abstract set. Why is this approximation assumed to be most suitable or good approximation?


Is there a software from the official repositories that can cut GIFs? For example, if given a GIF that runs for 20s, the software should be able to extract the last 5s from it.  I prefer GUIs, but if there are none, command line tools are fine too.

I have an animated gif and I'd like to cut off the last 5 seconds. Does anyone know how to do that in Linux/Ubuntu?


The following nice riddle is a quote from the excellent, free-to-download book: , written by .     How can you use a (fair) coin to draw straws among 3 people?

When flipping a coin to make important decisions in life you can flip once to choose between 2 possible outcomes. (Heads I eat cake, Tails I eat chocolate!)  You can also flip twice to choose between 4 outcomes. (Heads-Heads, Tails-Tails, Heads-Tails, Tails-Heads)  Can you use a coin to choose evenly between three possible choices? If so how?  (Ignoring slight abnormalities in weight)


When an object is immersed in a fluid, say or example water, then the force exerted by the fluid is always perpendicular to the surface. I'm unable to understand why is this so?  My books writes :- (NCERT Class 11 th Physics Part 2)     When an object is submerged in a fluid at rest, the fluid exerts a force on its surface. This force always normal to the object's surface. This is because if there were a component of force parallel to the surface, then the object will also exert force on the fluid parallel to it as a consequence of Newton's third law. This will cause the fluid to flow parallel to the surface. Since the fluid is at rest therefore it cannot happen. Hence, the force exerted by the fluid has to be perpendicular to the surface.      I have some counter-arguments for this explanation.   As you can see from the picture that if the fluid exerts a force F1 then the block would exert a reactionary force -F1 and this should cause the fluid to move upward in a beaker but why don't we observe it in real life?   F3 on block would compel the block to exert -F3 on the fluid which should cause the fluid to flow in the beaker.   I tried to satisfy myself that reactions of F3 and F4 would cancel each other but we also know that pressure i.e. force (if area is constant) varies with depth and therefore I couldn't account for the absence of this upward motion. For sideway motion it is satisfactory that reactions of F3 and F4 would cancel each other out (although I'm not sure over here too).   So, I request to please solve my misconception. Books like these tend to be logical but always ends up being illogical.   At last I want to make another request: Please give a plausible explanation why the fluid force is always normal to the surface?    My question is addressing Newton's third law in explaining the "normal" nature of the fluid pressure.

What what I understand, hydrostatic pressure is the "weight" of the water pushing against objects. But if this is true, why is hydrostatic pressure perpendicular to the surface it acts on instead of always going down?  For example, if you placed a book on a desk, the book's weight would push against the desk, but gravity is pulling it "down". But if you put another book beside this book the first book wouldn't apply any force on it. The weight exerted from the book always goes down.  Similarly, why doesn't hydrostatic pressure always go down? I understand that if you put a plate on the seabed, the weight of the water would push down on it, but if you just had a vertical plate standing on the bed, why would force push it from the sides?  To sum up, why does hydrostatic pressure act perpendicular to the object instead of always down?


I was looking for a simple way to find the number of samples $n$ needed to get a decent approximation to the covariance matrix $\boldsymbol{\Sigma}$. Given a random sample $\{ \mathbf{X}_1,\mathbf{X}_2, \dots ,\mathbf{X}_n\}$, the sample covariance matrix is   $$ \boldsymbol{\Sigma}_{n} = \frac{1}{n-1} \sum^{n}_{k=1}  \left( \boldsymbol{\mathbf{X}}_k -  \overline{\boldsymbol{\mathbf{X}}}  \right)\left(\boldsymbol{\mathbf{X}}_k -  \overline{\boldsymbol{\mathbf{X}}} \right)^T  $$  I want to plot the number of samples $n$ (on the x-axis) vs some scalar value computed from the estimate $\boldsymbol{\Sigma}_{n}$ (on the y-axis). What quantity can I compute in a simple way to plot such a convergence graph?. What about the matrix norm $\left \| \cdot \right \|_2$, i.e. the maximum singular value of $\boldsymbol{\Sigma}_{n}$?.

Gaussian data distributed in a single dimension requires two parameters to characterise it (mean, variance), and rumour has it that around 30 randomly-selected samples is usually sufficient to estimate these parameters with reasonably high confidence. But what happens as the number of dimensions increases?  In two dimensions (e.g. height, weight) it takes 5 parameters to specifiy a "best-fit" ellipse. In three dimensions, this rises to 9 parameters to describe an ellipsoid, and in 4-D it takes 14 parameters. I am interested to know if the number of samples required to estimate these parameters also rises at a comparable rate, at a slower rate or (please no!) at a higher rate. Better still, if there was a broadly accepted rule of thumb that suggests how many samples are required to characterise a gaussian distribution in a given number of dimensions, that would be good to know.  To be more precise, suppose we want to define a symmetrical "best-fit" boundary centred at the mean point inside which we can be confident that 95% of all samples will fall. I want to know how many samples it might take to find the parameters to approximate this boundary (interval in 1-D, ellipse in 2-D, etc) with suitably high (>95%) confidence, and how that number varies as the number of dimensions increases.


I just stumbled upon the Area51 Stack Exchange sites and happen to see few proposals based entirely on language. For example:         I think there will be many more. I did not go through all the language-specific proposals. Here is my concern:  The criteria required to make a site live (Proposals -> Commits -> Beta -> Live) will get easily matched for such proposals considering there will be a lot of SO users who speak a particular language and are likely to communicate/involve on SO in their native language only.  So there will be quite high chances that a person who is currently quite active on Stack Overflow and speaks (say Russian and English) will be more active on stackoverflow.com/russian_version and will likely to stop involve on English version in the longer run.   Same questions will be asked again and again in multiple languages It will not make sense to share a link to an answer from Spanish version to English version of SO even if the answer is already present in Spanish version. A famous question in English can be asked again in different language to gain more upvotes.   I believe this is really a big problem and should be well thought before making such sites live.  PS: Please do not take my question personally as I am not opposed to any country/language. I am just concerned about the quality of Stack Overflow in the future along with the existence of language-specific sites.

I recently visited area51 for the first time and was disturbed to see proposals for Stack Overflow variants in other languages dominating the site.       I'll admit that seeing these worries me greatly. What is the reasoning behind allowing international variants of Stack Overflow? I understand it might be easier for non-native speakers, but it risks fragmenting our knowledgebase over multiple languages and segregating our users. Is this really the proper approach when English is, essentially, programming's lingua franca? There has been discussion in the past relating to non-English Stack Exchange sites:     And many outstanding points have been made on the subject:       But I'm still rather curious. Why are we suddenly forgoing Stack Exchange's Non-English Policy in favor of fracturing our userbase? As an afterthought: A great comment was posted by Emrakul (Actually that entire comment thread is lovely. Read it.) on the answer found just above.  We need to see charts of activity by country to gauge how many people this would bleed away from the main site. My guess is, it's a lot more than you'd expect.  Does this information actually exist anywhere? It would be amazingly useful/interesting if it has been made available to Stack Exchange users. A Note: I've tried to cite as many great discussion items as I can on the subject. Quite a bit of information exists on alternate language variants, but, to my knowledge, this question has never been directly asked. In summary, the question asks "Why should language variants be allowed?" and "Does the reward really outweigh the risk of dividing our user and knowledge bases?". NOT "Is it okay to be proposing these sites?", "Should these questions be closed?", or "Does Stack Exchange support sites in languages other than English?" (all things which have already been asked).


There are a couples of questions about upgrading to Ubuntu 20.04 and keeping data/customizations etc. I want to do the exact opposite of that. That is, achieving the same result as in overwriting my current partition via booting and installing from a live cd. I am just wondering if, for convenience, it is possible to do so within my current installation(18.04). Thanks. EDIT: Just to clarify, my endgoal is to have clean Ubuntu 20.04.

How do I format the hard drive on my machine before installing?


How can i campare a textfield.settext with a string for example:  if(textField_1.setText != ("Hello"))   I can't do !=, how can i do it?

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?


Whenever I create a new event in my calendar and start typing a description, e.g. Hairddresser, a list of previously used descriptions appears.  This is useful but after a while I just want to delete those descriptions I no longer want to appear. How do I access the list where they are stored to delete them?  Anyone have any idea?

This is not about system autocomplete, it's about an autocomplete internal to Calendar (autocompletion of the name of the event when you create one) - and is there any way to turn it off.  I have many hundreds of events in ical as I've been using it for about the past five years.     Problem is whenever I create a new event, then start typing in the event name field, as I work out what I want to call the event (or reminder), a giant list of similar past events that I've entered pops up and is annoyingly distracting. I'm simply not interested in those past events anymore and I don't want to know about them. I use ical as a reminders system for tasks, i.e. as a todo list as well as calendar. I find that better than using a separate task app in addition.  I'd love to find a way to turn these suggestions off, without having to delete all past events from my calendar history (which it looks like I might have to resort to).  Haven't found a way to do this but would be very grateful if someone knows how.


I mean we can represent plane waves using just sine and cosine functions. Why do we need to use Euler's formula to represents plane waves as complex exponentials? What is the intuition behind using $i=\sqrt{-1}$. Of course, the plane waves are solution of Maxwell's electromagnetic equations. Please clarify my doubt!

We have a complex electric field. Is there any definition for absolute and imaginary part of a complex electric field? What do they stand for?


I was trying to install a hard drive by following the , but I accidentally formatted my 2 TB external hard drive instead of my 1 TB internal hard drive.  I'm running Ubuntu 14.04 and I have 3 hard drives:   80gb Intel SSDSC2BW080A4 (DC22) master boot record ST1000DM003-1ER162 (CC43) GUID Partition Table (the one i wanted to install and mount) My 2 TB Segate external Hard Drive that now is inaccessible and formatted.   When i go to my disks tool and choose this hard drive it tells me that its 1.6% full, which sounds like good news to me.  I read a couple of different post look into some programs but I'm not really sure how to proceed.  results of the deep analysis with testdisk  Disk /dev/sdc - 2000 GB / 1863 GiB - CHS 243201 255 63  The harddisk (2000 GB / 1863 GiB) seems too small! (< 17833196 TB / 16219197 TiB Check the harddisk size: HD jumpers settings, BIOS detection...  The following partitions can't be recovered:  Partition               Start        End    Size in sectors     VMFS                 38417 201 39 3789016855  14 45 3924794316768135   SysV 4               49694 147  2 7723719 218 31 123283216128 [^\%^DK]  VMFS                 138906 191 51 3432453218  29 16 34830459532972999  XFS 4                179830 196 24 1053386502  20 50 17956568663837018 [~[JR4  NTFS                 243201   0 63 486402   0 62 3907024065  i probably should have mentioned that im very new to this. so cant really make sense of any of that.

About two weeks ago I had a problem with my PC that my brother wrote a question about at .  I still haven't solved the problem, so my PC is unusable now.  Now I think that it would be simpler to re-install both Win7 & Ubuntu than repair them, but there're some data on their partitions. I want to recover this data.  These partitions are not mountable for some reason. I don't know why.  sudo fdisk -l about the problematic partitions:     Device    Boot      Start         End      Blocks   Id  System /dev/sda1            2048     147912703    73955328   83 Linux /dev/sdb2            206848   174079999    86936576    7  HPFS/NTFS/exFAT   And in GParted:      And the error of the mount command:  Failed to mount '/dev/sdb2': Invalid argument The device '/dev/sdb2' doesn't seem to have a valid NTFS. Maybe the wrong device is used? Or the whole disk instead of a partition (e.g. /dev/sda, not /dev/sda1)? Or the other way around?   And the exact same message for /dev/sda1  How can I recover my data from those HDDs?  EDIT     I have tried to specify the type of the drive:  $ sudo mount -t ext4 /dev/sda1 /olddisk mount: wrong fs type, bad option, bad superblock on /dev/sda1,        missing codepage or helper program, or other error        In some cases useful info is found in syslog - try        dmesg | tail  or so $ sudo mount -t ntfs /dev/sdb2 /olddisk NTFS signature is missing. Failed to mount '/dev/sdb2': Invalid argument The device '/dev/sdb2' doesn't seem to have a valid NTFS. Maybe the wrong device is used? Or the whole disk instead of a partition (e.g. /dev/sda, not /dev/sda1)? Or the other way around?   EDIT     sudo ntfsfix /dev/sdb2 returns:  Mounting volume... NTFS signature is missing. FAILED Attempting to correct errors... NTFS signature is missing. FAILED Failed to startup volume: Invalid argument NTFS signature is missing. Trying the alternate boot sector Unrecoverable error Volume is corrupt. You should run chkdsk.


I'm updating a drupal 6 site and getting hit with alot of notice errors. how can i silence these non vital errors. Usually just get undefined index and warning/notice messages

Is there a way to silence all PHP errors, warnings and notices in Drupal? They are usefull on the devel site but they are a big security risk, and make the site look bad on live.  I know on Drupal 6 the page at admin/settings/error-reporting can stop Drupal from writing errors to the screen, but where can I find this in Drupal 7? It seems it is missing.


How can I left align the text "Mi" inside the node? I assumed that align=left would work however the text is still centered.  \documentclass[fontsize=6pt]{article} \usepackage{tikz} \usepackage[right]{showlabels} \usetikzlibrary{positioning}  \begin{document}   \begin{tikzpicture}[x=23mm,y=6mm,%     mybox/.style={rectangle,rounded corners,minimum width=23mm, minimum height=6mm, align=left},%     workday/.style={mybox,draw=black,align=left}]%  \node at (0,-1) [workday] {Mi};  \end{tikzpicture} \end{document}

I'm not able to align the text left.  \documentclass{article} \usepackage{tikz} \usetikzlibrary{positioning} \newcommand{\altura}{.45cm} \begin{document}  \begin{tikzpicture}[x=1cm, y=-\altura, node distance=0,outer sep=0,inner sep=0] \tikzstyle{nome}=[draw, rectangle,anchor=west, minimum height=\altura,minimum width=9cm,fill=yellow!30]  \node[nome,right] (p1) {text}; \node[nome,right] (p2) [below = of p1] {text text}; \node[nome,right] (p3) [below  = of p2] {text text text};  \end{tikzpicture} \end{document}   The left or anchor=west not work. I need the text align left.


My girlfriend wants $1500 to prove to customs that she had money to look after herself when she arrives in Australia. True or false. I'm questioning it. I do believe it's for real. She seems very genuine.

On Travel.SE we often see questions about a person (usually a love interest) asking for money to pay for airfare, visas, permits and other expenses. For example        What general advice can be given in such situations to the person asking the question? Is it all a scam or can there be legitimate situations in which an online friend could be asking for money?


I've a data which has multiple time series. I want to find the seasonality in the data based on a number as it won't be feasible to check the seasonality by checking the plot. There are around 2505 time series.  I explored, but was unable to find any good solution/ approach?  Can any expert help me out with this!

This post is the continuation of another post related to a . Basically, at this point I'm interested in a robust way to discover the periodicity/seasonality of a generic time series affected by a lot of noise. From a developer point of view, I would like a simple interface such as:  unsigned int discover_period(vector<double> v);  Where v is the array containing the samples, and the return value is the period of the signal. The main point is that, again, I can't make any assumption regarding the analyzed signal. I already tried an approach based on the signal autocorrelation (detecting the peaks of a correlogram), but it's not robust as I would like.


I can't figure out how to find all left ideals of the ring $$M_2(\mathbb R)= \left\{\begin{bmatrix}a&b\\c&d\end{bmatrix}\quad |\quad a,b,c,d \in \mathbb{R} \right\}.$$    Thanks in advance.

Let $K$ be a field and $n \in \mathbb N$. Show the following: (i) Let $V \subset K^n$ be a subspace and $I_V$ the subset of $M_n(K)$ consisting of all the matrices whose rows belong to $V$. Prove that $I_V$ is a left ideal of $M_n(K)$. (ii) Show that every left ideal of $M_n(K)$ is of the form defined in (i).  I think I could show (i). I am having problems with (ii) For (i), take $M \in M_n(K)$ and $N \in I_V$. Let $P=MN$, I want to show that $P \in I_V$. Let $P_i=(P_{i1} ... P_{in})$ be the i-th row of $P$. Then, by definition of matrix multiplication, $$P_i=(\sum_{k=1}^n M_{ik}N_{k1} ... \sum_{k=1}^n M_{ik}N_{kn})$$ $$=\sum_{k=1}^n M_{ik} (N_{k1} ... N_{kn})$$ $$=M_{i1}(N_{11} ... N_{1n})+...+M_{in}(N_{n1} ... N_{nn})$$ This means that the $i-th$ row  of $P$ is a linear combination of the rows of $N$. From here it follows $P=MN \in I_V$. This proves $I_V$ is a left ideal of $M_n(K)$. I don't know how to show (ii), I would appreciate some help with that part.


What is the proper possessive form for a surname that ends with “z”? Is it z’ or z’s?

I know that if a word ends with an s then it should be made plural or possessive by use of an apostrophe with no extra s (e.g. "Thomas Harris' book was a riveting read." as opposed to "Gary Barlow's voice is so distracting.")  What about if the word ends with a z. For example, would it be Gomez' album or Gomez's album?


I was seeing some Javascript code and I stumbled upon something like this:   function() {     if(true) {         var a = 5;     }     alert(a); }   I was pretty sure this would output undefined but it didn't ? Can someone tell me why?

How would you explain JavaScript closures to someone with a knowledge of the concepts they consist of (for example functions, variables and the like), but does not understand closures themselves?  I have seen  given on Wikipedia, but unfortunately it did not help.


I have a list that will always be of even length.  mylist = ['a', 'b', 'c', 'd', 'e', 'f']   What's the best way I can turn it into this:  mylist = ['ab', 'cd', 'ef']   I have this, and it works, but it seems hugely verbose:  myotherlist = [] for x in xrange(0, len(mylist), 2):     myotherlist.append(mylist[x] + mylist[x + 1])   Which returns this:  >>> myotherlist ['ab', 'cd', 'ef']

I have a list of arbitrary length, and I need to split it up into equal size chunks and operate on it. There are some obvious ways to do this, like keeping a counter and two lists, and when the second list fills up, add it to the first list and empty the second list for the next round of data, but this is potentially extremely expensive.  I was wondering if anyone had a good solution to this for lists of any length, e.g. using generators.  I was looking for something useful in itertools but I couldn't find anything obviously useful. Might've missed it, though.  Related question:


I was working on this :     Using only 1k resistors, synthesize a  resistor of 3/5k and a    resistor of 5/3k. Use no more than four 1k resistors in each case.   I found how to do it but I'm not sure I used the efficient method. Indeed, I listed all the different ways to combine four resistors and computed the total resistance of each of them.  Does it exist a fastest method to find the good combination? Or does it exist some tables where the work is already done?

In the 70's I had a stack of old Amateur Radio magazines (50s-60s), and for a long time I saved an article about using the  to combine a number of resistors to achieve a specific value. Does anyone recall and have a copy of this article, or know how the Euclidean algorithm is applied to solve this problem?


I have seen many explanations for why the net electric field inside of a conductor is zero (assuming only electrical forces are acting on the particles inside of it). These explanations typically say that the charges in the conductor will move the outside and, to ensure that they remain stationary, there must be a net electric field of zero everywhere inside of the conductor. There seems to me to be a very large disconnect in this logic. If all of the charges are on the surface, then yes, I understand that the electric field near the surface of the conductor must be zero, but why does it have to be zero at, say, the center of the conductor (where there are presumably no charges).

In electromagnetism books, such as Griffiths or the like, when they talk about the properties of conductors in case of electrostatics they say that the electric field inside a conductor is zero.  I have 2 questions:    We know that conductors (metallic) have free electrons which randomly moves in all directions, so how come we can talk about electrostatics which by definition means stationary charges? When the textbooks try to show why the electric field inside a conductor is zero they say let us put our conductor in an electric field. What happens then is that there will be an induced surface charge density which consequently induces an electric field within the conductor such that the total electric field within the conductor will be zero. That is perfectly understood, but my problem is the following: the original claim was that the electric field within a conductor is 0, not the electric field after putting the conductor in an external electric field it became zero. I do not understand the logic!


Lufthansa charges me almost double the price for departing and returning flights, if they are only one day apart, than if I would stay yet another day or two. Why is this? I find this extremely annoying, because now I need to balance additional hotel costs for a longer stay with this silly pricing system.

Based on the question , I got curious. Is there a guide or resource that describes how the price of a ticket is determined?  When you search you often see curious effects like cheaper tickets for a flight from A to B with a layover compared to a direct flight. This seems counter-intuitive from an outsider's perspective since you fly twice. Also one way tickets more expensive than 2 ways.  It can be a short set of rules. Something that helps someone to get started with finding good prices. I know these can be very complex and they probably change over time and over airline interests but there is probably a simplified set of rules that can be enunciated.


I heard that Ken Wilson had an explanation of the level-spacing of the harmonic oscillator spectrum directly from the symmetry of $H$ under interchange of $p$ and $x$, without ladder operators or direct computation.   After some thought, I don't know what such an explanation may be.

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


I had a Chase MileagePlus Explorer card, which I cancelled due to numerous issues with United.  I called up and told them I wanted to cancel the card.  They confirmed, and that was that.  However, I can still log on to the website.  I can still see that I have a "$0.00 balance".  Did they really cancel (i.e. do they have a legal obligation to, and one they usually follow), or should I double-check?

I would like . In the online portal, there are no links that permit me to cancel the card online and receive an instant verification that it was closed successfully.   Due to this, I assume that I will have to call the number on the back of my credit card, be directed to Customer Retention after I inform them I wish to cancel the card, and hassle for some time period before they give up and initiate the process to cancel my account.  I don't like this option because I won't get any kind of verification aside from the call center employee's word that he canceled my card.  What is the standard operating procedure for canceling a credit card and verifying it was successfully closed as quickly as possible?


I always thought the verb "to prove" was irregular (prove, proved, proven). Recently, I've heard quite a few times people saying "I was proved wrong" or "It has been proved that he did it" rather than "I was proven wrong".  Are both forms correct?

Searching The New York Times, I found 22,100 results for "is it proved" and, therefore, I argue that that phrase is likely correct English.  But on History Stack Exchange a user edited the following sentence, written by me, "Is it proved that the United States didn't have a third atomic bomb to drop over Japan?" transforming it into this other sentence, "Has it been proven that the United States didn't have a third atomic bomb to drop over Japan?"  The user has left this comment "... corrected minor errors with spelling and grammar."  In reference to the context where those sentences had been written, can anybody explain why the sentence I wrote is wrong and, particularly, why the proofread version is correct or more appropriate in comparison with mine?


What is the process of finding the expected value of $X$ in a normal distribution between a certain interval?  In particular I want to find: $E(X | a \le X \le b)$.  For example, if $X$ has $\mu=0$ and $\sigma=0.5$,  I want to calculate  $E(X | 0.2 \le X \le0.3)$.  I have read  but it refers to the truncation of the upper tail only.

Just wondering if it is possible to find the Expected value of x if it is normally distributed, given that  is below a certain value (for example, below the mean value).