I was looking for a community to ask a question for a website recommendation but can't find one. What is the best or closest community for these questions?
Is there any Stack Exchange site where I can ask others to recommend me good web sites for solving specific problems?  For example I would like to know if there is any URL shortening website that can allow me to define the url.  For example instead of http://bit.ly/1gX2dD0 I would like it to be http://bit.ly/superflow - if "superflow" is not available then I will invent another word.  I can imagine that such services are paid but I don't need the link to last more than one day, and maybe there is such a website.
Is there a good resource or tool to help build a palette/color scheme around colors I select? No matter how nice the composition, flow, and lines of my design are, if I am not copying directly from nature, I have a very difficult time picking a decent color scheme.  It either looks too drab, or too garish.  Is there a good resource that will help me to choose a color scheme that has 2 or 3 colors, and the colors do not clash?  I'm not looking for specific colors or color schemes.  What I need is a resource that will help me choose a color (or colors) that go nicely with, or provide a good accent to, whatever main color I am working with on the design. Import a module from a relative path Number of equivalence classes of matrices under switching rows and columns I have been thinking about this problem:  Suppose we have all $R$ by $C$ matrices, where the values are integers in $[1,n]$. Two matrices are equivalent under interchanging rows and columns. For example,   1 5     0 0       would be equal to itself and to  0 0 1 5   and would be equal to  0 0  5 1   and would be equal to   5 1 0 0   How many unique such matrices are there?  Any ideas how to go about it? Any help much appreciated! Does eating infected flesh have an effect? I don't remember what actually happends when people eat infected flesh. I have in mind :  Gareth and the cannibals eating bitten Bob's leg in . It seems that the cannibals survive for a while after eating Bob's flesh and they seem OK.  The Saviors eating pigs that ate walkers in . We don't know for how long this process has been on, but  has his routine and looks used to doing that. Can we assume that Saviors are eating infected pig flesh for a while now ?  Does it have negative effect in long term ? Help needed in understanding proof: Every odd prime $p$ has exactly $(p-1)/2$ quadratic residues and $(p-1)/2$ quadratic nonresidues. Help needed in understanding proof: Every odd prime $p$ has exactly $(p-1)/2$ quadratic residues and $(p-1)/2$ quadratic nonresidues.   We assume there exist $k$ incongruent quadratic residues and each yield two solutions of the equation $x^2 \equiv a (\mod p)$. Also each of these solutions are incongruent, right ? So we have $2k$ solutions to quadratic congruences.  Then there are $p-1$ squares of the least residues, $1$ through $p-1$. But these need not be incongruent (consider $p = 7$ and $1^2, 6^2$). Then $2k = p-1$, why ?  Could someone explain to me in details what the reasoning is ? Class imbalance strategies When dealing with the class imbalance problem in a binary classifier, there are three ways I know of to address it: over-sampling, under-sampling and using cost-sensitive methods.   Are there any guidelines, rules of thumb or general strategies to choose among these methods? A possible answer would be: over-sample when the positive class has more than 100 instances (I just made it up). OAuth 2.0 access token request failed with error "must use HTTP POST" OAuth 2.0 Auth token request failed with below error   { "error": "invalid_request", "error_description": "must use HTTP POST" }   What does this error mean?  I am using Postman. Have a connected app. I have used Post method, Url has https. Same request works for other Orgs. Did I missed any configuration/Permission check?  https://testOrg.lightning.force.com/services/oauth2/token?grant_type=password&amp;client_id={{CLIENT_ID}}&amp;client_secret={{CLIENT_SECRET}}&amp;username={{USER_ID}}&amp;password={{PASSWORD}} Why do universal constants have the values they do? This is meant to be a generic question of the type that we get repeatedly on this site, in different versions:        Why do universal constants have the values they do? Can we predict their values theoretically? Do they change over time? How would the world be different if a particular constant had a different value? The polymorph spell states, in part:     The target’s game statistics, including mental ability scores, are   replaced by the statistics of the chosen beast. It retains its   alignment and personality.   Does retaining its personality suffice to let it remember who its allies are?  Even if transformed into something stupid like a T-rex?  What does it even mean for a beast with Int 2 to have someone's "personality"? In how many different ways can you split $10$ people into two groups of $5$ people? A familiar limit, but in general form . At  there is this "only in ubuntu" that says "Built in virus protection":  What is the Ubuntu built it protection? What is the program in charge of this and how does it work? Why don't files from Xbox 360 show up when USB drive is plugged into computer? I'm using a Lexar JumpDrive S73 32GB USB flash drive. I've configured it on my Xbox 360 and got a message saying it's compatible and meets the standards, but when I plug in it in my computer no files show up, even in Horizon.   After the driver was installed, both the USB mass storage and Lexar JumpDrive USB device were ready to use (installed properly), but it said no driver found for Xbox 360.    I tried looking for some sort of driver (which sounds silly) but I couldn't find anything.  I'm attempting to mod Minecraft on my Xbox and I don't want to buy another USB. Solve $x\equiv 1\pmod2$, $x\equiv 2\pmod3$, $x\equiv 3\pmod4$, $x\equiv 4\pmod5$, $x\equiv 5\pmod6$ and $x\equiv 0\pmod7$ $$\begin{align*} x&amp;\equiv 1\pmod2\\ x&amp;\equiv 2\pmod3\\ x&amp;\equiv 3\pmod4\\ x&amp; \equiv 4\pmod5\\ x&amp;\equiv 5\pmod6\\ x&amp;\equiv 0\pmod7\\ \end{align*}$$  So the solution says we can eliminate $x\equiv 5(\bmod6)$ because the first two cases cover it, but I don't really know how it does. How do we solve it in cases like this where the moduli are not mutually relatively prime. First order differential equations with 2 varriables Does anybody know how to solve the following differntial equation?  $$w^2\cdot r+\frac{dw}{dt}\cdot r+\frac{dr}{dt}\cdot w=3g$$  where w and r are a function of time so $w(t)$ and $r(t)$. $g$ is a constant  EDIT: This equation came from a thought problem of mine which I will now explain since I still do not know how to approach the problem.  Basically I want to design a spiral track in which a vehicle will accelerate. However the total acceleration needs to be constant.   The vehicle will have 2 acceleration components, a radial component ($a_r$) and a change in speed component ($a_s$). Since we want constant acceleration: $a_r + a_s = constant$  From circular motion we know that $a_r = \omega ^2 r$ where $r$ is the radius, and $\omega$    Further we know that $v=\omega*r$, therefore: $a_s=\frac{d}{dt}(\omega r)$  For constant acceleration $a_{total} = a_r + a_s = \omega ^2 r + \frac{d}{dt}(\omega r) =constant$  Further usefull information: Length of the track covered at a certain time $l=v*t=\omega r t$  With all this the radius will be a function of time, $r(t)$ and the angular velocity will be a function of time, $\omega (t)$  Boundary conditions: $r(0)  = 0$ $\omega (0) = 0$  Now I would like to find a possible set of solutions to create a track by implementing end boundary conditions that i choose e.g. $v(t_{end})=100 [m/s]$ and $l(t_{end})=5000 [m]$  Here is a diagram for clarity: Why can't I mine diamond, gold ore, or redstone ore? Normal blocks I can mine fine, but when it comes to diamond and gold ores, the block just gets "destroyed" (as in you can't pick it up). I'm playing on multiplayer with no spawning monsters. Write this equation I want to write this equation in this way down but I have been unsuccessful. How can I improve this codes in order to get the equation below?  \[ DeltaC{t} = \left\{ \begin{array}{ll}  -1.40- 0.588w_{t-1} - 0.5351\DeltaC_{t-1}+ 0.169\DeltaBC_{t-1} &amp; \mbox{ if $w_{t-1}&lt;- 0.62$} \\ -1.40 - 0.588w_{t-1} - 0.5351\DeltaC_{t-1} + 0.169\DeltaBC_{t-1} &amp; \mbox{$w_{t-1}&gt;0.62$} \end{array} \right. \] Radius of convergence of a sum of power series I have  two series  $\displaystyle\sum_{n=1}^{\infty} a_n x^{n}$   $\displaystyle\sum_{n=1}^{\infty} b_n x^{n}$  with radius of convergence $2$ and $3$ respectively.  How can I find the radius of convergence for the following?     $\displaystyle\sum_{n=1}^{\infty} (a_n +b_n)x^{n}$   Can anyone help me? Hubble's law says that the universe is expanding. How come the Milky Way and the Andromeda galaxies are on a collision course? How will they end up colliding with each other? Compiz Problems (Plugin Missing, Performance Issues, Development) I've recently set up the compiz cube again, and I was very happy to find that that flickering window glitch is gone! However, the cube reflection and deformation plugins are also gone.  I am running a fresh 12.10 install, and I have every compiz plugin package installed (including compiz-plugins-extra, which supposedly contains everything that compiz-fusion-plugins-extra package used to have), but those two plugins are still missing. I haven't been able to find anyone with the same problem.   Any ideas? (thanks!)