What is the convention for showing toggle icons to a user? This question is specific to password unmasking, but it can easily be used in &quot;on / off&quot; icons et al. In our situation, we have an unmask button at the end of a password field. The password is masked by default, and the icon is an open eye indicating &quot;if you click me, you will see what's behind the curtain&quot; Then the inverse is true when the password is unmasked. The eye is closed, indicating &quot;if you click me, we will hide your password&quot;. see the following two images.   for the user's experience, is this the right approach for this situation, or should it be the opposite? Example:  password masked == eye closed icon password shown == eye open icon  Note: we're additionally using a title attribute on the button that says &quot;show password / hide password&quot;
I have a quick question about buttons that toggle between two states. (Think Play/Pause, or Shuffle/Regular Play.) As the title says, should the toggle show it's current state or the state to which it will transition?  I think people are used to the Play/Pause convention. But the Shuffle/Regular play might be more confusing if you show the transition state instead of current. For example, the built-in music player on the Xbox 360 does it this way: when it's in shuffle mode, it shows the icon for direct play and vice versa and it always confuses me (am I in shuffle mode or straight play).  I see it this way: Play/Pause is more like action as in begin playing or pause playing. Yes behind the scenes it is a state transition but to the user, there is an action. Whereas Shuffle/Straight Play is an option and it's best to show the current state (and possibly have only one icon and change button to show that the option is enabled/disabled). Thoughts?
Showing that the roots of a polynomial with descending positive coefficients lie in the unit disc. database disk image is malformed with dnf on Fedora 29 How to prove that $\hat\sigma^2$ has $\chi^2_{n-p}$ distribution (linear regression) Consider the linear regression model:   $$Y_i=r(x_i)+\varepsilon_i\equiv\sum_{j = 1}^p x_{ij} \beta _j + \varepsilon _i,\quad i=1,\ldots,n.$$  where $x_1,\ldots,x_n\in \mathbb{R}^p$ are fixed, $E(\varepsilon_i)=0$,  $\operatorname{Var}(\varepsilon_i)=\sigma^2$. Denote $Y=(Y_1,\ldots,Y_n)^T$, $\beta=(\beta_1,\ldots,\beta_p)^T$, $X=(x_{ij})_{n\times p}$. As is known, $\hat \beta  = \arg\min\limits_{\beta  \in \mathbb{R}^p} (Y - X\beta)^T (Y - X\beta)=(X^TX)^{-1}X^TY$ if the matrix $X^TX$ is invertible, and so an estimator of $r(x)$ at $x=(x_1,\ldots,x_p)\in\mathbb{R}^p$ is given by $\hat r_n(x)=x^T\hat\beta$.  Let $$\hat{\sigma}^2 = \frac{1}{\sigma^2}\sum_{i = 1}^n (Y_i - {\hat r}_n (x_i))^2.$$ I am stucking the problem: $\hat\sigma^2$ has $\chi^2_{n-p}$ distribution. How to prove the statement? Which is correct: "drive safe" or "drive safely"? chemformula: No auto-completion in TeXstudio? I have trouble getting auto-completion to work with chemformula in TeXstudio. I have other packages working just fine.   The .cwl-file is showing up in "Options > Configure TeXstudio > Completion", and I have it ticked. However, it doesn't work when typing.  I have contacted Clemens Niederberger (who maintains the package), however he recommended I ask here instead.  It is mainly the \ch command I would like to have auto-complete, but all commands would be ideal.  N.B. I'm running TeXStudio 2.9.4 TeXLive 2015 (both newest, at the time of writing) Note: this is intended to be a canonical question about summoning sickness.  "Summoning sickness", broadly, is the rule that stops you from attacking or paying {T} costs with a creature that you just played. But how exactly does it work? How does it interact with other rules and effects?  For example, if I'm trying to figure out how a creature is affected:   Does the status matter (tapped/untapped, face down/face up, etc.)? What if it came into play, but I didn't cast it? What if it's a token? What if it was on the battlefield when my turn started, but it wasn't a creature? What if it stops being a creature? What if it's a creature and also another card type? What if it's a double-faced card that just transformed? What if it changes control? What if it's a copy of another creature? Which of the creature's activated abilities can I use? Are any of its other abilities affected? Can I tap the creature to pay a cost that is not a {T} cost?   (These examples are primarily taken from questions about summoning sickness that have already been asked on the site) Proof that the Euler characteristic is additive I'm reading through a set of notes which assumes that the Euler characteristic is additive, but doesn't give a proof, so I would like to understand why this is.  Let $A_n$ be a finitely generated Abelian group, non-zero for $0&lt;n&lt;k$. Consider the long exact sequence  $ \cdots \rightarrow A_n \rightarrow B_n \rightarrow C_n \rightarrow A_{n-1} \rightarrow B_{n-1} \rightarrow C_{n-1} \rightarrow \cdots $  where $B_n$, $C_n$ defined similarly to $A_n$.   I know that the Euler characteristic of $A$ is given by $\chi(A) = \sum_0^k (-1)^n \text{rank}(A_n)$, with similar definitions for $B$ and $C$. I want to prove that $\chi(B) = \chi(A) + \chi(C)$.  The notes say that for an exact sequence  $0 \rightarrow X \rightarrow Y \rightarrow Z \rightarrow 0$  of finitely generated Abelian groups $X,Y,Z$, we have the result rank($Y$) $=$ rank($X$) +  rank($Z$), and that the additivity of the Euler characteristic follows from this fact, but I can't see how. Did they decide to destroy it simply because they were Wise and knew it was dangerous to wield? Did they create the Fellowship simply because they were heroic; and decided to face Sauron after the Ring was destroyed?  Or did they know that destroying the ring would defeat Sauron, and they wouldn't actually have to do anything once that is taken care of? class and private variables Here is an interesting piece of code that my fellow team members were just having a slightly heated discussion about...    Dim fred As Integer    If True Then fred = 5 : fred = 3 : fred = 6 Else fred = 4 : fred = 2 : fred = 1   After executing the above code snippet, what is the value of fred?  Try not to cheat and debug the code.  This is a highly contrived code example that started out as an example of using the colon with an If statement, but then someone decided to take it upon themselves to proffer a result for fred.  UPDATE: I would not normally write code like this and this snippet only serves as an example. As it so happens, this question originated from a discussion involving the creation of a coding standards document for our team. Is there a way to configure pdflatex to make all but the .tex and .pdf files hidden files? I have asked a  about how to manage all the files generated when my LaTeX files are compiled but the approach in the answer I accepted is still unsatisfactory for the many small documents I generate.    I realize the LaTeX  all the files it generates so I can't prevent their creation.    However is there a way to configure pdflatex to make all but the .tex and .pdf files hidden files (i.e., preceded by .)?   (Edit: The two main systems that I use are tex live on Ubuntu Linux and BasicTeX on OS X) This is from page 3 of  ().  Copying the relevant segment:     Stirling’s approximation tells us $\sqrt{2\pi n} (n/e)^n \leq n! \leq e^{1/12n} \sqrt{2\pi n} (n/e)^n$. In particular we can use this to say that   $$ {n \choose k} \leq \left(\frac{en}{ k}\right)^k$$   I tried the tactic of combining bounds from $n!$, $k!$ and $(n-k)!$ and it didn't work. How does this bound follow from stirling's approximation? By definition a matrix representing a Lorentz transformation is orthogonal, so that its inverse is equal to its transpose.   Consider a pure boost in the t-x plane; $$\Lambda_x=\begin{pmatrix} \cosh(\gamma) &amp;&amp; \sinh(\gamma) &amp;&amp; 0 &amp;&amp; 0\\ \sinh(\gamma) &amp;&amp; \cosh(\gamma) &amp;&amp; 0 &amp;&amp; 0\\ 0 &amp;&amp; 0 &amp;&amp; 1 &amp;&amp; 0\\ 0&amp;&amp;0&amp;&amp;0&amp;&amp;1 \end{pmatrix}.$$ $\Lambda_x$ has inverse  $$\Lambda_x^{-1}=\begin{pmatrix} \cosh(\gamma) &amp;&amp; -\sinh(\gamma) &amp;&amp; 0&amp;&amp;0\\ -\sinh(\gamma) &amp;&amp; \cosh(\gamma) &amp;&amp; 0&amp;&amp;0\\ 0 &amp;&amp; 0 &amp;&amp; 1 &amp;&amp;0\\ 0&amp;&amp;0&amp;&amp;0&amp;&amp;1 \end{pmatrix}$$ but tranpose  $$\Lambda_x^T=\begin{pmatrix} \cosh(\gamma) &amp;&amp; \sinh(\gamma) &amp;&amp; 0&amp;&amp;0\\ \sinh(\gamma) &amp;&amp; \cosh(\gamma) &amp;&amp; 0&amp;&amp;0\\ 0 &amp;&amp; 0 &amp;&amp; 1&amp;&amp;0\\ 0&amp;&amp;0&amp;&amp;0&amp;&amp;1 \end{pmatrix}.$$ These are not equal. Where have I gone wrong? I'm a bit annoyed with the typesetting of citations that biblatex deems "ambiguous". In the following example, I have two papers with the same first author, but a different second author in two different years. When citing in the main text, the second author is included before "et al", since biblatex deems these references to be ambiguous. However, the references were published in different years, so I cannot see why these are ambiguous. Is it possible to get these citations referenced using only the first author?  MWE  \documentclass{article}  \usepackage{filecontents} \usepackage[hyperref,style=authoryear,natbib=true,maxbibnames=10,maxcitenames=2,useeditor=false,url=false,useprefix,giveninits=false]{biblatex} \addbibresource{ref.bib}  \begin{filecontents}{jobname.bib} @book{author_book, title = {Book's title}, author = {Author, Some and Better, Some and Cetter, Some}, location = {The City}, publisher = {Publisher}, date = {2005}, } @book{author_book2, title = {Book's title}, author = {Author, Some and Getter, Some and Cetter, Some}, location = {The City}, publisher = {Publisher}, date = {2006}, } \end{filecontents}  \bibliography{jobname} % \bibliography{ref}  \begin{document} Hello world \citet{author_book} \citet{author_book2} \printbibliography \end{document} Printing reverse of any String without using any predefined function? I have created 50 spreadsheets for 50 students. Each spreadsheet contains 33 sheets, numbered 1 to 33, along with a couple of other sheets.  Within each of these 33 sheets, there are many protected ranges.  I accidentally protected a range that ought not to have been protected. So, with 50 students each having 33 sheets, I have over 1800 sheets to unprotected.  I want to loop through each sheet, 1 to 33, and remove protection from cell F15. Right now, I (the owner) am the only editor.  Since I'm not an actual programmer, I've clearly not done this properly.  Can someone offer a suggestion of how I can change my Google Script to make this work?  var ss = SpreadsheetApp.getActiveSpreadsheet(); var sheets = ss.getSheets();  for (var i=2; i  &lt;sheets.length; i++) {   var sheet = ss.getSheets()[i];   sheet.activate();   SpreadsheetApp.flush();   var range = sheet.getRange('F15');        var protection = range.protect().setDescription('Protected range');        var me = Session.getEffectiveUser();        protection.addEditor(me);        protection.removeEditors(protection.getEditors());        if (protection.canDomainEdit()) {          protection.remove();          } //end of if statement  } Is Multiplying the Inverse Better or Worse? When dealing with double data types is multiplying by the inverse better or worse? Which way is faster? Which way uses less memory? Which way is preferred? How does MSIL handle this? SquareInches = MMSquared / 645.16  SquareInches = MMSquared * 0.0015500031000062000124000248000496    NB: 10K users will note that this is a duplicate of , which was deleted because the original question asker decided to berate everyone in the 'comments' section of the question.  This question was reposted because it is a 'good' question. Please 'uncheck' Community Wiki for your answer, as I'm only posting this as CW so that it's not seen as a 'reputation' grab. Related Question: How can I add custom '.desktop' application launchers to Ubuntu Dock? How can a question banned user fix their questions if they're deleted? If a user is question banned  and the , how can the user fix this on their own?  Until recently, advice has been to improve their questions, but since they can't see the questions on their question screen, they can't improve them:     Feature request: Allow a question banned user to see their own deleted questions, or warn them that deleting questions could lead to a question ban. how can I add an overlapped anchor in both overlapped paths automatically