This is my flow chart. I need this picture to draw in Tikz
I feel intimidated in learning TikZ. I was wondering if there are some nice materials (or just your replies) at different level:   for providing big picture, which is important to beginners to not lose direction during learning. for comprehensive reference.   Examples are important, but only examples are not always clear for understanding the big picture and organization.
I am under DDoS. What can I do? I'm a first time Linux user. My laptop wasn't connecting to the wifi so I followed the instructions from .  On typing sudo apt-get update after that, I got this error:  E: Type 'sudo' is not known on line 2 in source list /etc/apt/sources.list E: The list of sources could not be read.   What can I do? I'm reading .     The graph of $f: A \rightarrow B$ is the subset of $A × B$ consisting   of all ordered pairs $(a, b)$ with $f (a) = b$. If $A$ happens to be   $B^n$ for some $n ∈ N$, then we say that $f$ is a function on $B$ and   $n$ is the arity of $f$.   I don't understand the notation for the exponent of a set, I'm aware of what  is, it's the number of arguments or operands the function takes. I'm just not so sure if I can assume that a set with an exponent such as in $B^n$ means that a function has two operands.  I know the question may be too naive and perhapes the answer is the one I suggested and it's right in front of my face, I'm just searching for a confirmation or the negation of it. Thanks. Fantasy book where a young prince becomes a mage When I was younger (11-12 years old, so the early 2000s) I once read a story where a young boy, who may have been either a young prince or a squire of some sort, is recruited by a wizard and taken to a city to train as a mage.  I seem to remember him living in dorms with the other children at this school, until he gets into difficulty with another of the boys in the dorm. He is kicked out of the dorms and ends up living above a blacksmith shop (I think).  I remember it being the first book in a series of books of which there were about 3 out at the time. I think one of the stories was about the boy going to a tower to do something or other.  Does anyone have any idea what this book series is? I haven't been able to find it for years now but it was a story I really loved. What's a quick way of copying the path to the directory that's currently open in Finder?   Copying that path is very easy in Linux and Windows file managers - you just need to copy it from the address bar. I don't see a corresponding option in Finder. I would like to open all chapters of my PDF ebooks in the same window but neither evince nor okular seems to be capable of doing that (at least not out-of-the-box).  Is there a way to work this out? Difference between processing.runalg() and general.runalg() In the discussion from a question I asked several days ago (), someone suggested that I use general.runalg() instead of processing.runalg() for running QGIS algorithms.    I've now used both, and haven't noticed a difference in either performance or syntax between them.  I'm just wondering what sort of differences there are between these two methods, and which one I should be using. Show that $\lim\limits_{a \to 0^+} \int^1_0 ax^{a−1}f(x)dx=f(0)$. Suppose $f$ is Riemann integrable on $[0,1]$ and continuous at 0. Show that $$\lim\limits_{a \to 0^+} \int^1_0 ax^{a−1}f(x)dx=f(0).$$   Can anyone share some insight on this one? I have no idea where to begin. Maybe a substitution? Is it "legal" to CREATE and DROP #SomeTable more than once? Calculating $\lim_{n\to\infty}\sqrt[n]{2^n-n^2}$ VLC Media Player Green Line I am using Ubuntu 14.10 64bit and the latest version of VLC media player, when I play a video (MP4, MKV AVI etc... it doesn't matter) at the bottom of the screen there is a green line It isn't an issue with my OS, YouTube, and the default media player work fine. Has anyone else had this issue? and if so is there a fix or is it just a software bug? My new laptop came preinstalled with Windows 8. Naively, as I am, I just formatted the harddrive and installed fine old Ubuntu. Now I want to install Windows 8 for dual boot again, but I have no DVD and to download the ISO one needs a product key. That key is not on the back of the laptop anymore but somewhere on the mainboard.  Is there any way to recover the product key from the mainboard using Ubuntu? I have detached a process from my terminal, like this:  $ process &amp;   That terminal is now long closed, but process is still running, and I want to send some commands to that process's stdin. Is that possible? every planar graph can be expressed as a union of five edge-disjoint forests How can I prove that every planar graph can be expressed as a union of (maximum) five edge-disjoint forests?  Only thing I can think about is going somehow like the $5$ color theorem but I get stuck in the middle. Or with induction, but still something doesn't fit. Can you help? At the end of The Return of the King, Frodo, Bilbo, Gandalf, Elrond, and Galadriel left Middle-earth on a ship, along with other elves. I named those five because they were all ringbearers and it seems to be a common trait. Frodo and Bilbo bore the One Ring and the three others bore the three elven Rings.  Why did they have to do that? Why didn't they stay and have a peaceful life now that the Dark Lord was gone? Etymology for “Mc‑” and “O’‑” prefix in surnames There is clearly a prefix in names like McDonald, McChrystal, O’Brian, O’Neal.  What does this Mc- and O- prefix signify? It looks like Donald, Chrystal, Brian, Neal are perfectly fine names on their own, so why is there a prefix before it? List all commands that a shell knows What can I type at my shell (which happens to be bash) that will list all the commands that are recognized?  Also, does this differ by shell? Or do all shells just have a "directory" of commands they recognize?  Secondly, different question, but how can I override any of those? In other words how can I write my own view command to replace the one existing on my Ubuntu system, which appears to just load vim. series of young adult science fiction books from early 1980s about last of a race of martial experts that sees the destruction of his home planet I remember that the main character is trying to find the group that destroyed his home planet while he was on a mission. His planet was very difficult to live on and the people became expert in martial arts and were the best soldiers in the galaxy. They were mercenaries and often helped against tyrants. There was a very memorable section in at least one book about an initiation task that the main character had to do in that he had to survive in their wilderness for days. He was at some point surrounded in a old building by thousands of poisonous worm/snake creatures that he managed to survive until rescued by the leaders. How do I insert a tie (~, non-breaking space, tilde) under expl3 syntax? The covid19 death data for US shows strong periodic trends. It does not make sense to me that people die periodically.   What could be the reason to having such data? I thought it might be the reporting artifacts, for example, people always update data at Monday, but the period seems to be 3-4 days.