Big-O calculation using math method def fib(N):     if N &lt;= 1:         return N     return fib(N-1)+fib(N-2)   I cannot calculate the Big-O for this function, anyone can help me using math method. Thanks！
Computational complexity of Fibonacci Sequence I understand Big-O notation, but I don't know how to calculate it for many functions. In particular, I've been trying to figure out the computational complexity of the naive version of the Fibonacci sequence:  int Fibonacci(int n) {     if (n &lt;= 1)         return n;     else         return Fibonacci(n - 1) + Fibonacci(n - 2); }   What is the computational complexity of the Fibonacci sequence and how is it calculated?
Can a Raspberry Pi run Ubuntu? I was thinking about buying a , and running Ubuntu on it. I have looked around the web, and a lot of stuff says that it's difficult for it to work on ARM processors. Has anyone figured out how to get a Raspberry pi to run Ubuntu? How to prove reflexivity, symmetry and transitivity for the following relation? In the Avengers movie, was Thor going to kill Captain America during his woods battle with Iron Man? I often see tutorials on the web or posts on this site which make heavy use of the following characters at the command line. Often it seems that they are used for pretty similar purposes. What are the differences between them when used on the command line or for shell programming? For what purpose do I use which of them?  " " double quotes  ' ' single quotes  ` ` backticks Showing that ${\rm E}[X]=\sum_{k=0}^\infty P(X>k)$ for a discrete random variable Let $X$ be a discrete random variable whose range is $0,1,2,3,\ldots$. Prove that $$ {\rm E}[X]=\sum_{k=0}^\infty P(X&gt;k). $$  How to prove this? I tried a bit but unable to post due to formatting issue. Can anyone help? Is setting a higher nice level for a process an effective way to reduce its impact on system load/CPU time? I have an rsync cron job which is pushing the server load and triggering monitor alerts.  If I set the job to be run with a high nice level, would that effectively reduce the impact it has on system load values? What are valid values for "data defined" labeling settings? I'm using QGIS 1.8. I'd like to customize label features on an existing shapefile using the new label engine and it's "data defined settings" option. I'd like to know what the attribute table field types should be for each of the settings: All 7 font options, all 2 buffer options, and all 6 position options. Should they all be numeric fields, or some text, or both? I want to create these fields in the attribute table correctly so that I can map them to the label field settings. I can't find information on the proper field types anywhere. Thanks for your thoughts. How to run untrusted Ruby code inside a safe sandbox? How to get rid of blank pages in PDF exported from SSRS I have a two-page SSRS report. When I exported it to PDF it was taking 4 pages due to its width, where the 2nd and 4th pages were displaying one of my fields from the table. I tried to set the layout size in report properties as width=18in and height =8.5in.  It gave me the whole table in a single page of PDF, but I am still getting the 2nd and 4th pages blank.   Is the way I am doing it incorrect?  How else can I get rid of those blank pages? I am new to this and not sure what to make of all the options available. I am interested in putting a machine-learning-related preprint, which will potentially be submitted to places like NIPS/ICLR/ICML in the future.   arXiv.org perpetual, non-exclusive license to distribute this article (Minimal rights required by arXiv.org)  Creative Commons Attribution license (CC BY 4.0)  Creative Commons Attribution-ShareAlike license (CC BY-SA 4.0)  Creative Commons Attribution-Noncommercial-ShareAlike license (CC BY-NC-SA 4.0)  Creative Commons Public Domain Declaration (CC0 1.0) Proving that $\lim\limits_{x \to 0}\frac{e^x-1}{x} = 1$ I was messing around with the definition of the derivative, trying to work out the formulas for the common functions using limits. I hit a roadblock, however, while trying to find the derivative of $e^x$. The process went something like this:  $$\begin{align} (e^x)' &amp;= \lim_{h \to 0} \frac{e^{x+h}-e^x}{h} \\ &amp;= \lim_{h \to 0} \frac{e^xe^h-e^x}{h} \\ &amp;= \lim_{h \to 0} e^x\frac{e^{h}-1}{h} \\ &amp;= e^x \lim_{h \to 0}\frac{e^h-1}{h} \end{align} $$  I can show that $\lim_{h\to 0} \frac{e^h-1}{h} = 1$ using L'Hôpital's, but it kind of defeats the purpose of working out the derivative, so I want to prove it in some other way. I've been trying, but I can't work anything out. Could someone give a hint? How to change 'et al' to italic font in citation call-outs, with 'agsm' bibliography style When is the vector space of continuous functions on a compact Hausdorff space finite dimensional? I know that the vector space of all real valued continuous functions on a compact Hausdorff space can be infinite dimensional.  When will it be finite dimensional?  And how will I identify that vector space with $\mathbb{R}^n$ for some $n$? What are "Community Wiki" posts? Some questions and answers are marked Community Wiki and are owned by a community wiki user:  (In fact, this very question is one of them)  Why have Community Wiki posts? How do Community Wiki posts work? How does a post become a Community Wiki post? How can the Community Wiki status be removed from a post? How can I find Community Wiki posts? How do you associate the .exe file extension with a program in Windows? When I double-click to select text in GNOME Terminal, the selection stops at spaces but continues over hyphens:      Some of my filenames contain uncommon characters such as the  and are not selectable by double-clicking:    Is there a way to make double-click selection continue over these characters as well? How does ssh run a command? I'm using Bash on both client and server. When running a command over SSH:   ssh &lt;host&gt; 'declare' gives a list of shell variables. ssh &lt;host&gt; 'mount' gives a list of mountpoints.   However, declare is a Bash builtin, while mount is an external command. How does SSH know which to run if there is a shell builtin and an external command with the same name on the server? How does the tmp folder work? It stores lots of junk files and takes space My tmp folder is set to /sites/default/files/tmp/ and I checked what's inside and for example there is folder inside called /update-cache-b2903cc4/ it keeps all modules in .zip that I installed via 'Install from a URL'. So why are those modules .zip files are kept there in tmp folder, isn't it a waste of storage? I don't really like it when the site is full of unnecessary files.  Am I supposed to delete these by myself all the time? Variation of the metric with respect to the metric For a variation of the metric $g^{\mu\nu}$ with respect to $g^{\alpha\beta}$ you might expect the result (at least I did):  \begin{equation} \frac{\delta g^{\mu\nu}}{\delta g^{\alpha\beta}}= \delta^\mu_\alpha\delta^\nu_\beta. \end{equation}  but then to preserve the fact that $g^{\mu\nu}$ is symmetric under interchange of $\mu$ and $\nu$ we should probably symmetrise the right hand side like this:  \begin{equation}\frac{\delta g^{\mu\nu}}{\delta g^{\alpha\beta}}= \delta^\mu_\alpha\delta^\nu_\beta + \delta^\mu_\beta\delta^\nu_\alpha.\end{equation}  Is this reasonable/correct? If not, why not?  It seems that I can derive some weird results if this is right (or maybe I'm just making other mistakes). Which profile details does an account merge preserve? When one has to merge two accounts, they're prompted by something like this with input fields for each account link:     Account 1:  Account 1 link.       Account 2:  Account 2 link.    When the merge completes, which account details are preserved, like the display name, or the profile description? Account 1, or account 2?