MySQL Query is throwing error 'mysql_num_rows() expects parameter 1 to be resource, boolean given'
mysql_fetch_array()/mysql_fetch_assoc()/mysql_fetch_row()/mysql_num_rows etc... expects parameter 1 to be resource
Proving $\sum_{k=1}^n{k^2}=\frac{n(n+1)(2n+1)}{6}$ without induction I was looking at: $$\sum_{k=1}^n{k^2}=\frac{n(n+1)(2n+1)}{6}$$  It's pretty easy proving the above using induction, but I was wondering what is the actual way of getting this equation? Repeating “will” for two verbs with “and” There is an "Informed" badge for reading the meta about page but it was awarded zero times and to make sure I tried reading the about page but did not receive it. If the badge is to be awarded here, then this should be 'fixed'. If not, it should be removed from the list of badges. What are the alternatives to the FHS? I'm a long time Linux user for over 15 years but one thing I hate with a passion is the mandated directory structure. I don't like that /usr/bin is the dumping ground for binaries or libs in /usr/lib, /usr/lib32, /usr/libx32, /lib, /lib32 etc... Random stuff in /usr/share etc. It's dumb and confusing. But some like it and tastes differ.  I want a directory structure where each package is isolated. Imagine instead if the media player dragon had it's own structure:  /software/dragon /software/dragon/bin/x86/dragon /software/dragon/doc/README /software/dragon/doc/copyright /software/dragon/lib/x86/libdragon.so   Or:  /software/zlib/include/zlib.h /software/zlib/lib/1.2.8/x86/libz.so /software/zlib/lib/1.2.8/x64/libz.so /software/zlib/doc/examples/... /software/zlib/man/...   You get the point. What are my options? Is there any Linux distro that uses something like my scheme? Can some distro be modified to work like I want it (Gentoo??) or do I need LFS? Is there any prior art in this area? Like publications on if the scheme is feasible or unfeasible?  Not looking for OS X. :) But OS X-inspired is totally ok.  Edit: I have no idea how PATH, LD_LIBRARY_PATH and other environment variables that depend on a small set of paths should work out. I'm thinking that if I have the KDE editor  installed in /software/kate/bin/x86/bin/kate then I'm ok with having to type the full path to the binary to start it. How it should work for dynamic libraries and dlopen calls, I don't know but it can't be an unsolvable engineering problem. How to install Estru3D - Structural Analysis Software? I had problems installing Estru3D. It requires Gambas3 to be installed as a prerequisite. But it doesn't work with the newest Gambas3 installed in Ubuntu 16.04. Without using any non-standard (Windows included) utilities, is it possible to download using the Windows command line?  The preferred version is Windows XP, but it's also interesting to know for newer versions.  To further clarify my question:   It has to be using HTTP The file needs to be saved Standard clean Windows install, no extra tools   So basically, since everybody is screaming , I want simple Wget functionality, without using Wget. I've recently flagged the following , which I got in the flag queue.   The answer does not seem to attempt to address the question at all. It looks like a comment on one of the other answers (probably Luca's).  It got rejected with the following reason:  declined - flags should not be used to indicate technical inaccuracies,            or an altogether wrong answer   I did not flag this because I thought it was wrong, I flagged it because I didn't think it was an attempt to answer the question. For what it's worth, I don't get what the guy who provided that answer even tried to say.  Was I wrong to flag it? If so why? Mac turns off randomly and has lines on screen Remotely uninstall apps? I have tried through the Google Play store and it does not seem possible from there, but does anyone know if it is possible to remove an application remotely?   In other words, if I do not have direct access to my phone, can I make use of some website, app or service to uninstall an app without being able to interact with the phone directly. What's the proof that the Euler totient function is multiplicative? That is,     why is $\varphi(AB)=\varphi(A)\varphi(B)$, if $A$ and $B$ are two coprime positive integers?   It's not just a technical trouble—I can't see why this should be, intuitively: I bellyfeel that its multiplicativity should be an approximation at most. And why the minimum value for $\varphi (n)$ should be $ \frac{4n}{15} $ completely passes me by. This has always been a big want for me. I love using multi-monitor setups but only want a single laptop. Does the 2011 MBP Thunderbolt support chaining multiple monitors together? I know that you can add a monitor and say, a few hard drives, but can you connect it to 2 27" monitors and your flat screen TV (for example)? Thanks! I am trying to solve the following question which is Ex3 from Arthur Engel, Problem Solving strategies. Here is the question: $\sum_{k=1}^n k^3 {n \choose k}$ and asks to find the sum. I am sincerely having a hard time trying to figure out how to solve it and get $n^2 (n+3)(2)^{n-3}$. I would really appreciate if someone could show the step-by-step process. Thank you! How to print original variable's name in Python after it was returned from a function? I have enum and use the variables like myEnum.SomeNameA, myEnum.SomeNameB, etc.  When I return one of these variables from a function, can I print their names (such as myEnum.SomeNameA) instead of the value they returned? Overview of basic facts about Cauchy functional equation The  asks about functions $f \colon \mathbb R \to \mathbb R$ such that $$f(x+y)=f(x)+f(y).$$ It is a very well-known functional equation, which appears in various areas of mathematics ranging from exercises in freshman classes to constructing useful counterexamples for some advanced questions. Solutions of this equation are often called . Also a few other equations related to this equation are often studied. (Equations which can be easily transformed to Cauchy functional equation or can be solved by using similar methods.) Is there some overview of basic facts about Cauchy equation and related functional equations - preferably available online? According to general relativity, inertial mass and gravitational mass are the same, and all accelerated reference frames (such as a uniformly rotating reference frame with its proper time dilation) are physically equivalent to a gravitational field of the same strength.  Refer: Einstein's thought experiment of a Physicist in an Accelerated Box.  I find that the 'How' part of this question is somewhat easy to understand Mathematically but hard to visualize physically and on the 'Why' part I am totally blank. The differences between TeX engines I am confused about what TeX and its offspring (LaTeX, pdfTeX/pdfLaTeX, e-TeX, ConTeXt, LuaTeX, etc.) are.  Some, like LaTeX, seem like add ons to TeX (maybe a change to the eyes and mouth, but not stomach). Others, like pdfTeX, seem like changes to the underlying system (i.e., a change to the stomach).  Is there a good reference that explains the differences and the evolution? Erlang server, Java client - TCP messages get split? What is the difference between DX format and FX format lenses, and which to choose for what purpose?  What are the pros and cons of both? Google Search Console domain property not in the list of properties I can add to Google Analytics The Time That 2 Masses Will Collide Due To Newtonian Gravity