Changing entries in attribute table from text to rational number
Convert String to Integer in QGIS tables
i know that|$S_n$|=$n!$ and |$A_n$|= $\frac{n!}{2}$ but i'm not sure where to go from there. Thanks. Why using IN(...) when selecting on indexed fields, will kill the performance of SELECT query? Of Half-elven and mortal life When half-elvens choose mortal life, how would their bodies behave?  Half-elven are always elves by nature. Ever since they're born, their physical body and behaviour would be elvish - they have keen senses, they don't get physically weary, no illness, and so on.  Half-elvens are then offered a choice - Immortal elvish lives or mortal fate of men. When they choose the latter, like Elros and Arwen did, what would happen to their elvish nature? Would they lose it? I don't think they would lose their pointy ears, but what about the other elvish features that I mentioned before?  Are there any canonical references? Is for open connected $U$ the set $U_\varepsilon$ for small $\varepsilon$ connected? Let for an open connected subset $U\subset \mathbb R^n$ and a number $\varepsilon &gt;0$: $$ U_\varepsilon=\{x\in U: dist (x, \partial U)&gt; \varepsilon \}. $$ Then  $U_\varepsilon$ is open but in general not connected.  But I suppose that for sufficiently small $\varepsilon &gt;0$ also  $U_\varepsilon$ is connected. How to prove its?  Edit. Let's assume that additionally $U$ is bounded. Is then $U_\varepsilon$ connected? I am lost in normalizing, could anyone guide me please.  I have a minimum and maximum values, say -23.89 and 7.54990767, respectively.  If I get a value of 5.6878 how can I scale this value on a scale of 0 to 1. Why are so many different types of objects white, yet appear gray when they are wet? There are many things with different textures that appear white – salt, beer foam, paper, shaving cream, snow, talcum powder, white paint, etc. The most common answer is all of the frequencies must be reflected in order for us to perceive white, which I already know. There must be more underlining details why such a huge variety of things are white. Furthermore, if you wet paper, snow or talcum powder, they appear off-white or gray. Why is this? Reasons not to use a 741 op-amp? How to switch render source (VSE or Camera)? If you create a scene for the Video Sequence Editor and start working on a project Blender will render the output from the VSE. But if you want to later switch it to render your 3D scene again (the camera output) where is the setting to select the source?  Usually I keep a separate .blend for VSE edits so I don't need to switch, but I feel like I ought to learn how to do this as it's pretty basic. I would expect to find this in the Render context but I see no place to specify the source.  Thanks. Word for lights on police cars, etc How to solve the diffencial equation for power series $(1+x²)y'' - 6xy=0$ in $x_{0}=0$ I have tried for the power series but when suppose the solution is $y(x)=\sum _{n=0}^\infty a_nx^n$ appeared sums dependents of $a_n$,  $a_{n+2}$ and $a_{n-1}$ and this is not possible. Do professors care about their rating on websites such as RateMyProfessor or Koofers? I am wondering if a professor is already an Associate Professor, do they still care about their reputation in the eyes of the department considering tenureship is already granted? How to know the motherboard BIOS version using the command line How can get the BIOS version of my motherboard?  The command dmidecode gives you some information about the BIOS, but I can't find what I need...    I tried dmidecode command before asking and I didn't find what I needed - I want only the BIOS version and nothing else in the output. What is the precise definition of a rigid shape? How will a particle with energy less than $V_{\rm min}$ behave? My brother owns Skyrim on steam. We use Steam Family Share, but we were wondering how both of us could play it at the same time? It is my understanding that metals are a crystal lattice of ions, held together by delocalized electrons, which move freely through the lattice (and conduct electricity, heat, etc.).   If two pieces of the same metal are touched together, why don't they bond?   It seems to me the delocalized electrons would move from one metal to the other, and extend the bond, holding the two pieces together. If the electrons don't move freely from one piece to the other, why would this not happen when a current is applied (through the two pieces)? Let $\alpha,\beta,\gamma$ be the roots of $x^3-3x^2+1 = 0$. Prove that $$\alpha^n+\beta^n+\gamma^n \equiv 4^n+5^n+(-6)^n \pmod{17}$$ where $n$ is an integer.   It sort of makes sense why they are congruent since we can say $x^3-3x^2+1 \equiv (x-4)(x-5)(x+6) \pmod{17}$, but since $\alpha,\beta,\gamma$ aren't integers, how do we prove this? How can I block all traffic *except* Tor? How to use only part of screen, as if the monitor was a smaller one? Water was sprayed on my 19" monitor and damaged some parts of it. I need a solution that will let me specify the screen area to be used by Windows, as if it was a smaller monitor. Its default menu doesn't have this option. Studying for CISSP these choices seemed limited:     What is the advantage of digital signatures over message authentication codes?         Digital Signature provides integrity verification while message authentication code does not   Digital Signature provides confidentiality while message authentication code does not   Digital Signatures provide authenticity while message authentication code does not   Digital Signatures works faster than message authentication codes      Using the following chart as a reference, I'm leaning towards #2, but none of the choices really fit properly…  Cryptographic primitive | Hash |    MAC    | Digital Security Goal           |      |           | signature ------------------------+------+-----------+------------- Integrity               |  Yes |    Yes    |   Yes Authentication          |  No  |    Yes    |   Yes Non-repudiation         |  No  |    No     |   Yes ------------------------+------+-----------+------------- Kind of keys            | none | symmetric | asymmetric                         |      |    keys   |    keys   Hopefully an expert here can clarify.