Let $\alpha = \frac{1+\sqrt{5}}{2} \hskip 20pt \beta = \frac{1-\sqrt{5}}{2}$  be the two real roots of the quadratic equation $x^2 - x - 1 = 0.$ Prove that $f_n = \frac{\alpha^n - \beta^n}{\alpha - \beta}$ for all $n \in \mathbb Z^+$.  I'm confused as to how this could be simplified after doing the induction step where you add 1 to all of the "n's" making it, $f_n = \frac{\alpha^{n+1} - \beta^{n+1}}{\alpha - \beta}$
This formula provides the $n$th term in the Fibonacci Sequence, and is defined using the recurrence formula: $u_n = u_{n − 1} + u_{n − 2}$, for $n &gt; 1$,  where $u_0 = 0$ and $u_1 = 1$.   Show that     $$u_n = \frac{(1 + \sqrt{5})^n - (1 - \sqrt{5})^n}{2^n \sqrt{5}}.$$    Please help me with its proof. Thank you.
Microscopic interpretation of pressure in liquids When should N-Gons be used, and when shouldn't they? Support for N-Gons (polygons consisting of more than 4 vertices) has been in Blender for a while now, but many of us still may not know when to use them, and how to do so effectively.  In what situations do N-Gons really come in handy? When should they be just plain left out? Do they have any place in finished models? I'm working on moving my current server setup to newer hardware, and migrating from ubuntu karmic koala to lucid lynx. Currently i'm using gw6c (compiled from the gogo6 website, as opposed to the version from the repositories) to get ipv6 access for my systems. On the karmic koala system, i used simple init.d script to get the ipv6 client started   #! /bin/sh /usr/local/gw6c/bin/gw6c -f /usr/local/gw6c/bin/gw6c.conf   I figured since this runs at any runlevel, it should translate to  respawn console none  start on startup  stop on shutdown  script exec /usr/local/gw6c/bin/gw6c -f /usr/local/gw6c/bin/gw6c.conf emit free6_ipv6_started end script   this works fine started from initctrl, but it apparently fails to start when it boots. - its status being stop/waiting. It works fine (and respawns) when started otherwise.Any ideas on where i'm going wrong, and what would be the appropriate 'start on' arguement?  EDIT: the exact error is 'init: gw6c main process (xxx) ended with status 8' followed by the process respawning , with xxx being a PID i suspect. I'm also half suspecting this is cause gw6c starts before networking does, and i need my eth0 up before gw6c is Choosing GeoCoding service? I'm looking for a web service providing a full address based on coordinates (and reverse).  I'm ready to pay for that service.  I don't want to use Google's API. A file manager with free icon placing option Can one TeX file output to multiple PDF files? I'd like to be able to create a TeX file that will output multiple PDF files with one compilation.  I'm not even sure if this is possible.  Here is the setup:  I am writing dozens of cover letters for job applications, and wish for them to all look "personalized".  So I defined a function which calls multiple variables, such as the address, name of the institution, open position, etc., and outputs a "personalized" cover letter for each function call.  The problem is that compilation of the TeX file outputs just one file.  Since I will be submitting all of these files online eventually, I would like each letter to be in its own file.  Is there a way to do this at the TeX level? What is the relationship between redshift and conformal time ?   For example in a paper i found:   taking $z_e = 3234 $ at the time of radiaton-matter equality yields the conformal time $\frac{\eta_e}{\eta_0} = 0.007$ and taking $z_E=0.39$ at matter-$\Lambda$ equality yields $\frac{\eta_E}{\eta_0}=0.894$ and setting redshift at decoupling $z_d=1089$ yields $\frac{\eta_d}{\eta_0} = 0.0195$  where $\eta_0$ is the present decoupling time.  Further some cosmological parameters are given as :  $\Omega_r = 8.36 \times 10^{-5}, \Omega_m = \Omega_b + \Omega_{dm} = 0.044 +0.226, \Omega_\Lambda = 0.73,  H_0=0.72$  Now how can i calculate all those $\eta_e, \eta_E, \eta_d, \eta_0$ from given redshift values and/or above parameters ? I searched whole of my text books trying to find an explicit relation for conformal time $\eta$ but all i got was $ \mathrm{d}t=a(t)\mathrm{d}\eta$. Any help would be very helpful. Cannot remove JDK – /usr/sbin/alternatives: No such file or directory When I try to remove Java with sudo apt-get remove jdk1.8.0-40 I get this:    Reading package lists... Done Building dependency tree        Reading state information... Done The following packages will be REMOVED:   jdk1.8.0-40 0 upgraded, 0 newly installed, 1 to remove and 0 not upgraded. 1 not fully installed or removed. After this operation, 245 MB disk space will be freed. Do you want to continue? [Y/n] y (Reading database ... 231488 files and directories currently installed.) Removing jdk1.8.0-40 (1.8.040-1) ... find: `/usr/java/*': No such file or directory /var/lib/dpkg/info/jdk1.8.0-40.postrm: line 586: /usr/sbin/alternatives: No such file or directory /var/lib/dpkg/info/jdk1.8.0-40.postrm: line 598: /usr/sbin/alternatives: No such file or directory dpkg: error processing package jdk1.8.0-40 (--remove):  subprocess installed post-removal script returned error exit status 127 Errors were encountered while processing:  jdk1.8.0-40 E: Sub-process /usr/bin/dpkg returned an error code (1)   Output of  ls -1 /var/cache/apt/archives/*jdk*:  openjdk-7-jre_7u75-2.5.4-1~trusty1_amd64.deb openjdk-7-jre-headless_7u75-2.5.4-1~trusty1_amd64.deb   Output of sudo dpkg --purge --force-all jdk1.8.0-40:  (Reading database ... 231488 files and directories currently installed.) removing jdk1.8.0-40 (1.8.040-1) ... /var/lib/dpkg/info/jdk1.8.0-40.postrm: line 586: /usr/sbin/alternatives: No such file or directory /var/lib/dpkg/info/jdk1.8.0-40.postrm: line 598: /usr/sbin/alternatives: No such file or directory dpkg: error processing package jdk1.8.0-40 (--purge): subprocess installed post-removal script returned error exit status 127 Errors were encountered while processing:  jdk1.8.0-40   When trying the edit I get this:  (Reading database ... 231488 files and directories currently installed.) Removing jdk1.8.0-40 (1.8.040-1) ... /var/lib/dpkg/info/jdk1.8.0-40.postrm: line 586: /usr/sbin/alternatives: Permission denied /var/lib/dpkg/info/jdk1.8.0-40.postrm: line 598: /usr/sbin/alternatives: Permission denied dpkg: error processing package jdk1.8.0-40 (--remove):  subprocess installed post-removal script returned error exit status 126 Errors were encountered while processing:  jdk1.8.0-40 E: Sub-process /usr/bin/dpkg returned an error code (1) How can I generate a sin wave with power law noise? Table of Contents for set of PDF files How to make Table of Contents for a set of PDF files?  Here's my code!  \documentclass{book} \usepackage{pdfpages} \usepackage[pdfauthor={&lt;somename&gt;},pdftitle={&lt;sometitle&gt;},pdftex]{hyperref} \usepackage{fancyhdr} \usepackage{tocloft} \usepackage[margin=0.5in,bottom=0.75in,top=0.75in]{geometry}   \pagestyle{fancy} \renewcommand{\headrulewidth}{0.4pt} \fancyhead[L]{X Y Z} \fancyhead[R]{} \begin{document}  \tableofcontents \newpage  \clearpage \phantomsection \includepdfset{pages=-,pagecommand=\thispagestyle{fancy}} \addcontentsline{toc}{chapter}{SAMPLE PDF 1\\ \textit{description}} \includepdf[pages=-]{template1.pdf}  \clearpage \phantomsection \addcontentsline{toc}{chapter}{SAMPLE PDF 2\\ \textit{description}} \includepdf[pages=-]{template2.pdf}  \clearpage \phantomsection \addcontentsline{toc}{chapter}{SAMPLE PDF 3\\ \textit{description}} \includepdf[pages=-]{template3.pdf}  \clearpage \phantomsection \addcontentsline{toc}{chapter}{SAMPLE PDF 4\\ \textit{description}} \includepdf[pages=-]{template4.pdf}  \clearpage \phantomsection \addcontentsline{toc}{chapter}{SAMPLE PDF 5\\ \textit{description}} \includepdf[pages=-]{template5.pdf}  \end{document}   Here's the output.    My problem is that the page number is not aligned with the title, it is aligned with the description. Also I'd like to put dots.   My desired output looks like this: Why is logistic regression a linear classifier? Since we are using the logistic function to transform a linear combination of the input into a non-linear output, how can logistic regression be considered a linear classifier?  Linear regression is just like a neural network without the hidden layer, so why are neural networks considered non-linear classifiers and logistic regression is linear? I'm about to start exploring the world of long exposure shots, using my Canon EOS M. The camera has a standard max exposure time of 30 seconds, but in bulb mode I can keep the shutter open indefinitely (using a wireless remote to control the shutter.)  How long can I leave the shutter open without running the risk of prolonged exposure to light damaging my sensor?  For the purposes of this question assume I'm shooting in summer daylight, so that we can go by the worst case. Calculating grid convergence (True North to Grid North) I would like to know how to calculate the grid convergence angle between True North and Grid North for UTM maps. I am using ArcGIS 10.0 (ArcView licence). and have used the  tool from the Cartography toolbox. However, I would like to know how to calculate this angle myself (using Excel) to compare against the ArcGIS result? Have there been any recent attempts to falsify the  hypothesis alternative to the Doppler shift explanation for the red shift, or is it simply ignored like the pilot wave quantum mechanical hypothesis alternative to the Copenhagen hypothesis of quantum mechanics has been? What new evidence would it take to get the tired light hypothesis for the red shift reexamined as the recent fluid dynamics oil drop experiments have done for the pilot wave hypothesis of quantum mechanics? How to properly handle collision in a component-based game? Trying to wrap my head around the ways to properly handle collision in a game designed around components.  I see many examples have some sort of PhysicsComponent that gets added to the entity's list of components but the actual implementation is confusing me.  For this to work, the PhysicsComponent would need access to the world around it. This doesn't make intuitive sense to me. Shouldn't a component be unaware of not only its container (the entity), but its container's container (the world)?  To me, it sounds like the level or scene should maintain a list of these entities and every game update, loop through the entities to determine which collide.  My question is firstly, whether or not this is good design, and secondly, how to determine which entities can collide. I suppose solid entities could implement an empty IRigidBody interface so the level could determine which entities in the list support collision. But is this breaking the component design?  Instead, should they contain an empty RigidBody component? This may actually be better because it may not always be empty and this approach is more future-proof. The only problem with this is the complexity. The scene would have to loop through not only every entity, but also every entity's components to determine if it had this RigidBody component.  Thirdly, when they do collide both entities should be informed somehow and I am unsure on how to accomplish this either.  Let's say that both entities contained a HealthComponent and when they collided both their healths would be decreased by some arbitrary value, 5. I suppose it would be the scene's responsibility to handle this when it detects a collision between two entities?  But then is the scene responsible for too much? I could see this possibly getting out of hand and becoming unwieldy when the scene is responsible for many things entities should not (?) have access to.  Edit: Question updated with more details. Low output volume Too much sugar in soup -- how to make it less cloying? I was making this recipe: , which was from the old Lincoln Del, one of my mom's favourite places. I mistakenly doubled the sugar, putting in 1/2 a cup instead of a 1/4 of a cup. Given the 2/3 of a cup ketchup, which was Heinz, the soup turned out way, way too sweet.   Is there any way I can rescue this? Prove $5\mid2^{4n}-1$ by induction ORA-00979 not a group by expression Prove that a set of connectives is inadequate It is relatively easy to prove that a given set of connectives is adequate. It suffices to show that the standard connectives can be built from the given set. It is proven that the set $\{\lor, \land, \neg\}$ is adequate, and from that set it can be inferred (applying De Morgan laws and such) that $\{\lor, \neg\}$, $\{\land, \neg\}$ and $\{\to, \neg\}$ are also adequate.  Nevertheless, I'm stuck trying to understand how to prove that a given set of connectives is inadequate. I know I have to prove that a standard connective can't be build using only the connectives of the given set, but I can't figure out how to do it.  FYI, I'm trying to prove that $\{\lor, \land\}$ and $\{\leftrightarrow, \neg\}$ are inadequate sets of connectives.  Thanks in advance.