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How can I fix a 404 Error when using a PPA or updating my package lists?
Has the Magical Community breached the Final Frontier? (aka Wizards in Space?) Have they? Given that Muggles put the first man in space in 1961, even by 1991 a lot of Muggleborns perfectly aware of the space-travel would have passed through Hogwarts and into the Ministry, even the Department of Mysteries (which seems to be a bit like their research division/Area 51 combo) And even leaving Muggle technology (which Wizards don't care for or about) aside, Humans have wondered about air travel to &quot;other worlds&quot; and meeting aliens from the time of the Ancient Greeks, surely some Witch or Wizard somewhere might have wondered if it really was possible to fly to the moon? So, is there any canon (aka Books + Pottermore + Rowling interviews) evidence of the Wizarding community having ever travelled or trying to travel to space / other planets or satellites? ETA: Note, I am also totally okay (and in fact would be eager for) historical &quot;Famous Wizard&quot; card-like tidbits from canon-sources.  AWESOME example (that I'm frankly not expecting): When the Muggles managed to land on the Moon, the Department of Mysteries had to scramble to hide the Silver-backed Moon Dragon conservatory they had been maintaining near the landing site. ALSO AWESOME example (that I am hoping for): Warlock Flibberti and Witch Tigget misused this earth-based spell and amusingly found themselves on the moon with their pet monkey instead! I am trying to create a beamer animation using tikz, but I can't even get basic rotating of a tikz image working as desired.  I have a rectangle specified by  \draw[rounded corners,dotted] (-3.5,0) rectangle (-0.5,2);   I would like to rotate this rectangle about the point (-1,.5) (which is near the bottom right corner of the rectangle).  I've tried:  {\rotatebox[origin=c,x=-1,y=.5]{130}{             \draw[rounded corners,dotted] (-3.5,0) rectangle (-0.5,2);}}   But this produces an error.  If I just use the origin=c option, it compiles, but it rotates the rectangle about the point (0,0).  I've also tried it with just the x=-1,y=.5 (without the origin option), and it fails to compile.  I have searched the documentation, which is where I learned about the options x=xdim and y=ydim.  However, I can't find a single example demonstrating how these options should be used.  Any suggestions would be greatly appreciated.    Also, if there is a better command for rotating things that will be more suitable for use in a beamer animation, please let me know.  Thanks! OBB vs OBB Collision Detection Say you have two Bounding Box Objects each of them storing the current vertices of the box in a vector with all the vertices of the object rotated and translated relative to a common axis.  Here is an image to illustrate my problem:   How can I work out if the two OBB's are overlapping any links to help explain the solution to the problem would be welcome. Nothing too convoluted please... 1.7.4 Problem with mobs spawning I have just updated to Minecraft 1.7.4 and now all of a sudden there are barely any mobs spawning.  I checked to make sure that I was in normal difficult and I saw 1 creeper but that is all.  Also I tried different difficulties. Another thing - mobs seem to to spawn normally in the nether and all other mobs except aggressive mobs spawn like they should.  Please if you know how to fix this, please help! addtocontents not working with certain other packages This is a follow up question on   How do I change the toc dept mid document while using packages (in this case only mathtools).  An example:  \documentclass[a4paper,10pt,oneside]{book}  \usepackage{mathtools}  \begin{document}   \frontmatter             \chapter{hello}  \section{hello}  \subsection{hello}  \subsubsection{hello}   \setcounter{tocdepth}{3}  \tableofcontents   \mainmatter   \chapter{hello}  \section{hello}  \subsection{hello}  \subsubsection{hello}   \chapter{hello}  \section{hello}  \subsection{hello}  \subsubsection{hello}   \appendix   \addtocontents{toc}{\setcounter{tocdepth}{0}}   \chapter{hello}  \section{hello}  \subsection{hello}  \subsubsection{hello}   \chapter{hello}  \section{hello}  \subsection{hello}  \subsubsection{hello}  \end{document}   This example generates an error and very strangely puts an exclamation mark in the ToC as you can see here   however when I comment out the \usepackage{mathtools} it suddenly works again or replacing it with a different package such as \usepackage[T1]{fontenc} also generates no errors.  But this is not limited to just this specific package, certain other packages also introduce the same behavior (I just took this package to keep the example small). how to add object to a keyframe range? lets assume we have an iron man pointing his hand to a target and shooting few frames later as shown in the picture below:    frame 0 to 10 he will point frame 11 to 15 he will shoot, which is just a long cube with one larger face to give idea or a laser projectile   how can I add the projectile cube only on frame 11? I don't what it to exist before that  thanks While trying some problems along with my friends we had difficulty in this question.   True or False: The value of the infinite product $$\prod\limits_{n=2}^{\infty} \biggl(1-\frac{1}{n^{2}}\biggr)$$ is $1$.   I couldn't do it and my friend justified it by saying that since the terms in the product have values less than $1$, so the value of the product can never be $1$. I don't know whether this justification is correct or not. But i referred to Tom Apostol's Mathematical Analysis book and found a theorem which states, that    The infinite product $\prod(1-a_{n})$ converges if the series $\sum a_{n}$ converges.   This assures that the above product converges. Could anyone help me in finding out where it converges to? And,   Does there exist a function $f$ in $\mathbb{N}$ ( like $n^{2}$, $n^{3}$) such that $\displaystyle \prod\limits_{n=1}^{\infty} \Bigl(1-\frac{1}{f(n)}\Bigr)$ has the value $1$? Why could the pictures and paintings in Hogwarts talk and the photos of Harry's parents couldn't? How to achieve a super leavened cake as the Pierre Herme ones? I made several cakes in my life. I know the difference between different leavening agents. I know that low temperature tends to make flatter cakes, but I never could get this kind of shape. If I use a super hot oven I burn the surface and I don't get this shape, there must be something else. Does anyone have experience doing this? Does anyone have a recipe from any modern pastry chef showing this kind of cake? Maybe gluten content in the flour could help?  Thank you Can I travel domestically within the United States with my USA expired passport? I need to fly domestically within the United States. The only ID I have is an expired USA passport.  Can I use that to pass T.S.A.?  Can I use it as ID? Why do the directories /home, /usr, /var, etc. all have the same inode number (2)? Career Change in to Testing I've around 10+ years of experience in Banking operations including  reconciliations, sales, customer services, asset management, and financial transaction QA.  Coming to academics I've done my PG in commerce (costing, auditing, banking, and statistics) also a diploma in project management, ISTQB foundation, Prince 2 foundation and ITIL foundation.    Can any one advise me if the testing role is ideal for me and how to start with it. Help ID this plant, quite possibly a weed I found this plant near my South Indian home in , India. Most probably it could be some sort of weed. Anyhoo, is this plant of any medical or commercial value? Is it a remedy for something?   It has a white tap root with little veins off the main root It has a really small yellow flower It's leaves are similar to that of a clover, except for that it has three to five leaves        Merci d'avance!  (P.S. Forgive me if this is some very common plant that I should know about, I'm in 7th grade.) Determine whether $(x_n)$ converges if $x_1= a , x_{n+1} = x_n+\frac{1}{x_n}$ for $n \in \mathbb{N}$ I would that the images would appeared for each overlay. Eg, in overlay 1 I have img1.pdf, in overlay 2 I have img2.pdf, and in overlay 3 I have img3.pdf. How I do this?  \begin{center}   \begin{tikzpicture}     \node (img1) {\includegraphics[width=.5\linewidth]{img1.pdf}};     \pause     \node (img2) {\includegraphics[width=.5\linewidth]{img2.pdf}};     \pause     \node (img3) {\includegraphics[width=.5\linewidth]{img3.pdf}};   \end{tikzpicture} \end{center} Why is variance squared? Reference for general-topology I'm automating a web application (the Mantis bug tracker) and I'm getting an interesting response header from it, called Refresh:  HTTP/1.x 200 OK ... Refresh: 0;url=my_view_page.php   It seems to be acting the same way that  does, and the meta refresh technique implies that it is an equivalent of a header in HTTP.  Problem is, I can't find any mention of the Refresh header in the  or any other definitive documentation on how it should be parsed and what the browser should do when it encounters it.  What's going on here? $_POST empty on utf-8 characters I need to knock out a quick animation in C#/Windows Forms for a Halloween display.  Just some 2D shapes moving about on a solid background.  Since this is just a quick one-off project I really don't want to install and learn an entire new set of tools for this.  (DirectX dev kits, Silverlight, Flash, etc..)  I also have to install this on multiple computers so anything beyond the basic .Net framework (2.0) would be a pain in the arse.  For tools I've got VS2k8, 25 years of development experience, a wheelbarrow, holocaust cloak, and about 2 days to knock this out.  I haven't done animation since using assembler on my Atari 130XE (hooray for page flipping and player/missile graphics!)  Advice?  Here's some of the things I'd like to know:   I can draw on any empty widget (like a panel) by fiddling with it's OnPaint handler, right?  That's how I'd draw a custom widget.  Is there a better technique than this? Is there a page-flipping technique for this kind of thing in Windows Forms?  I'm not looking for a high frame rate, just as little flicker/drawing as necessary.   Thanks.  Post Mortem Edit ... "a couple of coding days later"  Well, the project is done.  The links below came in handy although a couple of them were 404.  (I wish SO would allow more than one reply to be marked "correct").  The biggest problem I had to overcome was flickering, and a persistent bug when I tried to draw on the form directly.   Using the OnPaint event for the Form: bad idea.  I never got that to work; lots of mysterious errors (stack overflows, or ArgumentNullExceptions).  I wound up using a panel sized to fill the form and that worked fine. Using the OnPaint method is slow anyway.  Somewhere online I read that building the PaintEventArgs was slow, and they weren't kidding.  Lots of flickering went away when I abandoned this.  Skip the OnPaint/Invalidate() and just paint it yourself.  Setting all of the "double buffering" options on the form still left some flicker that had to be fixed.  (And I found conflicting docs that said "set them on the control" and "set them on the form".  Well controls don't have a .SetStyle() method.)  I haven't tested without them, so they might be doing something (this is the form):      this.SetStyle(ControlStyles.UserPaint, true);     this.SetStyle(ControlStyles.OptimizedDoubleBuffer, true);     this.SetStyle(ControlStyles.AllPaintingInWmPaint, true);    So the workhorse of the code wound up looking like (pf is the panel control):      void PaintPlayField()     {         Bitmap bufl = new Bitmap(pf.Width, pf.Height);         using (Graphics g = Graphics.FromImage(bufl))         {             g.FillRectangle(Brushes.Black, new Rectangle(0, 0, pf.Width, pf.Height));             DrawItems(g);             DrawMoreItems(g);             pf.CreateGraphics().DrawImageUnscaled(bufl, 0, 0);         }     }   And I just called PaintPlayField from the inside of my Timer loop.  No flicker at all.