I could create a page like this:  using the following code:  \documentclass{article}   \usepackage{tikz} \usetikzlibrary{fit, calc}  \usepackage{fontspec} \newfontfamily{\myfont}{Arial} \usepackage{marginnote} \newcommand\commentary[2]{% \tikz[remember picture, baseline={(here.base)}] \node (here) {#1};% \marginpar{ \begin{tikzpicture}[remember picture, overlay]  \begin{scope}[rotate=(rand*10),shift={(1.8,0)}]     \node [text width=3cm, align=center, transform shape] (text) at (0, 0)   {\footnotesize \myfont #2};     \draw [transform shape, thick] plot [smooth, tension=0.8] coordinates {       ($(text.south) + (-10pt, -5pt) + (rand * 2pt, rand * 2pt)$)        ($(text.south east) + (-5pt, 5pt)$)       ($(text.north east) + (rand * 2pt - 5pt, rand * 2pt)$)       ($(text.north west) + (rand * 2pt + 5pt, rand * 2pt)$)       ($(text.south west) + (rand * 2pt + 5pt, rand * 2pt)$)       ($(text.south) + (10pt, -3pt) + (rand * 2pt, rand * 2pt)$)     }; \end{scope} \draw[-&gt;, thick] ($(text.south west) - (-10pt, 5pt)$)  to [bend left=20] ($(here.south east) - (3pt, 2pt)$); \end{tikzpicture}  }  }  \begin{document}  The equation of a plane through $(x_0,y_0,z_0)$ \commentary{is:}{The tangent   plane: $\nabla f(\mathbf{x})\cdot (\mathbf{x}-\mathbf{x}_0)=0$.} $$a(x-x_0)+b(y-y_0)+c(z-z_0)=0$$  The vector $(a,b,c)$ is normal to the plane.     \end{document}   1) How can put the head of the arrow to the equation (for example to + sign in the display question) instead of a word in the text (intead of "is :" in this example)?  (2) How can I move the text bubble 1 cm to up or down?
I just read a book "Linear Algebra and Its Applications 4E" by David C. Lay. The book is (should be) LaTeX typeset. The matrix and equations are so nice, please see the following 3 examples:        It's so beautiful, so I want get the same effect inside my paper. Here is my code:   \usepackage{amsmath} \usepackage{colortbl} \newcommand\y{\cellcolor{clight2}} \definecolor{clight2}{RGB}{212, 237, 244}%  %%% \[A=\left[ \begin{array}{ccccc} \y 0 &amp; -3 &amp; -6 &amp; 4 &amp; 9 \\    -1 &amp; \y -2 &amp; -1 &amp; 3 &amp; 1 \\ -2 &amp; -3 &amp; 0 &amp; \y 3 &amp; -1 \\ 1 &amp; 4 &amp; 5 &amp; -9 &amp; -7      \end{array} \right]\]  \[A=\left[\begin{array}{cccccc} \rowcolor{clight2} 3 &amp; -9 &amp; 12 &amp; -9 &amp; 6 &amp; 15\\ 0 &amp; 2 &amp; -4 &amp; 4 &amp; 2 &amp; -6 \\ 0 &amp; 3 &amp; -6 &amp; 6 &amp; 4 &amp; -5 \end{array} \right]\]   And the result:     But how to add these arrows??
Evaluating $\int_{-\infty}^{\infty}\frac{1}{(x^2+b^2)^2}dx$ Find $$\int_{-\infty}^{\infty}\frac{1}{(x^2+b^2)^2}dx$$   We see that the only poles are at $x=\pm bi$.  Integrating over the semicircular contour implies that it is equal to $2\pi i*Res_{(+bi)}$ because the integral over the circular arc is $0$.  So now I just need to calculate the residue at $+bi$. Can anyone give hints on how to do this?  I was thinking about multiplying by $(x-bi)^2$ and then evaluating at $bi$ but I'm not sure why this even makes sense. Removing empty lines in Notepad++ I have the following sequences $(a_n)$, $(b_n)=(a_{2n})$, and $(c_n) = (a_{2n-1})$.  I have to show that:   if $(b_n)$ and $(c_n)$ both convergence to $a$, then $(a_n)$ also converges to $a$; if $(a_n)$ converges then $(b_n)$ and $(c_n)$ also converge; there exist $(a_n)$ not converging but with $(b_n)$ and $(c_n)$ converging.   I am not sure how to solve this since I only know that $(b_n)$ > $(c_n)$ > $(a_n)$ on the terms how the sequences are defined. So I know umask can restrict privileged users, using this format umask ugo.  I understand that the read = 4, write = 2, and exec = 1. However, when I type umask, it returns 4 digits which is 0022 or 0073. I have no understanding of how does this work now because there is an extra digit. What is that extra digit and what does 0022 mean? How does the coin limit work? How to populate UIList with all material slot in scene? 2.8 Is there a way to set app-specific volume? Time travel film: character with male and female reproductive organs is taken back in time by a barman who turns out to be themselves I have had a friend give me a rough description of a film and I'm curious to find out what it actually is. I don't know very much. I understand this will be difficult, especially since every time my friend explains the tale it's different so this description is likely to contain some inaccuracies.  The film's plot begins with a recounting given by the main character, who had both male and female reproductive organs but had one set removed (not sure which, think male ones were removed). The main character is narrating this tale to the barman in a bar. The barman then takes the main character back in time, where they make love to themselves and produce a child.  The child, once born, is abandoned by the mother in the past - but the barman takes the child to the orphanage and leaves them there, ensuring their survival. Eventually it is revealed that the child was the main character themselves, and so was the barman.  In other words every major character introduced up to that point was the same person who had severely messed with their own timeline. "big enough to do this" My question is what is the difference among these three sentences.   He is big enough to do such  heavy works. He is not big enough to do such heavy works. He is small enough to do such  heavy works.   I am so much confused between 2 and 3.Also, I don't get what the 3rd one means. Where is the itoa function in Linux? itoa() is a really handy function to convert a number to a string. Linux does not seem to have itoa(), is there an equivalent function or do I have to use sprintf(str, "%d", num)? How to number and cross-reference \subsubsection-level headers Assistive technology not found AWTError $ java -jar aprof-plot.jar Exception in thread "main" java.awt.AWTError: Assistive Technology not found: org.GNOME.Accessibility.AtkWrapper     at java.awt.Toolkit.loadAssistiveTechnologies(Toolkit.java:807)     at java.awt.Toolkit.getDefaultToolkit(Toolkit.java:886)     at java.awt.Toolkit.getEventQueue(Toolkit.java:1734)     at java.awt.EventQueue.invokeLater(EventQueue.java:1264)     at aprofplot.Main.newWindow(Main.java:33)     at aprofplot.Main.main(Main.java:359)   Possible explanations I saw here was to install Java-access-bridge. But I am unable to install libaccess-java-bridge. How to gracefully handle files that exceed PHP's `post_max_size`? Privacy leak in permalink? Update (Jan 8, 2019) This is now 8 years old, but still getting occasional upvotes/attention, so I thought it's worth giving a summary of the current state.  Despite originally being , over the last decade some changes have made the privacy implications much clearer.  You now click &quot;share&quot; instead of &quot;link&quot;, and the pop-up is very explicit that the link includes your user ID. There is a  asking that this user ID be anonymized or hashed, to allow users to earn publicity badges (the intention behind having the user ID present in the URL, as per ) while eliminating the privacy issue. Original Post It seems to me there is something of a privacy leak when permalinking to a question.  For what I would assume is the purposes of tracking which user is responsible for bringing traffic back to an SE site (for badges, etc.), the user ID of the user obtaining the permanent link . I wouldn't argue that this shouldn't be the case, but I find no warning or mention of this when I do these actions.  I'm sure I'm not the only one that doesn't desire anonymity on SO but would like at least pseudonymity on some places I might share a SO link, such as on a random blog.  As a user, I would not expect sharing a permanent link to leak my identity.   Unless you are familiar with Stack Exchange links or your own userID, it's certainly not obvious by looking at the link that it includes your personal info.  It'd be nice to have fair warning that using that feature will do so, and perhaps provide/describe the workaround: to simply remove the user-id segment from the URL.  Other features would be a preference that formats future permanent links to exclude the user id. Example (from this question)  Permalink:  Link to my user page: How can I select part of a mesh and make it seperate? I want to make the teeth a separate child object from the mouth. I want to know the best way to do this.   I have tried going into edit mode with Tab and trying to select all the vertices but that doesn't move the teeth. Is there an easy way to select just that part and make it a separate child mesh to the rest of the mouth? Show that $11^{10} \equiv 1 (\mod 100)$ $11^{10} \equiv 1 \pmod{100}$  I tried to solve by using euler's theorem, But I got stuck.  $\gcd(11, 100) = 1$  $11^{φ(100)} \equiv 1 \pmod{100}$  $11^{40} \equiv 1 \pmod{100}$  I don't know how to go on as $11^{40}$ is bigger than $11^{10}$ What is the difference between a tatkal and premium tatkal ticket in Indian Railways? "Items collection must be empty before using ItemsSource." I'm trying to get images to display in a WPF ListView styled like a WrapPanel as described in this old ATC Avalon Team article: .    When I try to populate the ListView with a LINQ-to-Entities queried collection of ADO.NET Entity Framework objects I get the following exception:  Exception     Items collection must be empty before   using ItemsSource.   My code&hellip;  Visual Basic  Private Sub Window1_Loaded(...) Handles MyBase.Loaded     ListViewImages.ItemsSource = From g In db.Graphic _                                  Order By g.DateAdded Ascending _                                  Select g End Sub   XAML  &lt;ListView Name="ListViewImages"           SelectionMode="Single"           ItemsSource="{Binding}"&gt;     &lt;local:ImageView /&gt; &lt;/ListView&gt;   I put a breakpoint on that line.  ListViewImages.ItemsSource is Nothing just before the LINQ assignment. I have a simple shutdown script which i want to run as root  shutdown -h +30; echo "succesfull";   I have followed these answer, to make my script root.  first I run this command  sudo chown root.root $HOME/test/test.sh sudo chmod 4755 $HOME/test/test.sh   and then made changes in sudoers  sudo visudo   added this command after this line %sudo   ALL=(ALL:ALL) ALL  eka ALL=(ALL) NOPASSWD: $HOME/test/test.sh   But when i executed my script its showing this error  shutdown: Need to be root succesfull Is it possible to have an object ignore a certain light source but still be affected by others? I want to create an effect on a character where their skin and clothing are effected by two different light sources. The clothing should only reflect a bright bounce light, but have the skin should not be affected by this light source.    In the example image I have two objects a cube, a sphere and three emission  lights . I want the two white lights to hit both objects, and I need the purple light to hit and reflect off of the sphere, but ignore the cube entirely (no reflections).  Someone suggested to composite the layers together, it works... but this is very impractical and cumbersome because it forces the background to be transparent and it will be a pain to try and layer together a more complex scene, especially if its animated which is what I want this effect for.  I know you can have objects ignore shadows and all kinds of other things so im hoping someone knows how to get an object to ignore light with a few settings.