Can my Russian girlfriend leave the country if she owes the bank money?
A Russian girl is asking for 500 euros to get a passport in Russia. Is this a realistic amount of money for a passport fee?
Can Ruby import a .NET dll? I am interested in using/learning RoR in a project where I have to use a .NET dll. Is Ruby capable of importing a .NET dll? How to customize Latexian to use other TeX engines or biber? The Mac editor Latexian has built in methods for compiling using latex+dvips, pdflatex and xelatex.  Furthermore, it assumes bibtex and makeindex to deal with bibliographies and indexes, respectively.  How do I customize Latexian to use, e.g. LuaTeX for compiling or Biber for bibliographies? I guess it is too difficult a question to ask about the cardinality of $S_{\mathbb{N}}$ so I would like to ask whether it is countable or not.  I tried to prove it is uncountable somewhat mimicking the Cantor's diagonal argument but failed. Open program/windows on specific monitor Is there a way to tell Windows on which monitor it should open a windows  independently of where it was closed? Etiquette on sending a thank you e-mail to respondents who gave me helpful information Collapsible fieldsets error for previous dates How can I evaluate a C# expression dynamically? I would like to do the equivalent of:  object result = Eval("1 + 3"); string now    = Eval("System.DateTime.Now().ToString()") as string   Following Biri s , I got this snippet (modified to remove obsolete method ICodeCompiler.CreateCompiler():  private object Eval(string sExpression) {     CSharpCodeProvider c = new CSharpCodeProvider();     CompilerParameters cp = new CompilerParameters();      cp.ReferencedAssemblies.Add("system.dll");      cp.CompilerOptions = "/t:library";     cp.GenerateInMemory = true;      StringBuilder sb = new StringBuilder("");     sb.Append("using System;\n");      sb.Append("namespace CSCodeEvaler{ \n");     sb.Append("public class CSCodeEvaler{ \n");     sb.Append("public object EvalCode(){\n");     sb.Append("return " + sExpression + "; \n");     sb.Append("} \n");     sb.Append("} \n");     sb.Append("}\n");      CompilerResults cr = c.CompileAssemblyFromSource(cp, sb.ToString());     if (cr.Errors.Count &gt; 0)     {         throw new InvalidExpressionException(             string.Format("Error ({0}) evaluating: {1}",              cr.Errors[0].ErrorText, sExpression));     }      System.Reflection.Assembly a = cr.CompiledAssembly;     object o = a.CreateInstance("CSCodeEvaler.CSCodeEvaler");      Type t = o.GetType();     MethodInfo mi = t.GetMethod("EvalCode");      object s = mi.Invoke(o, null);     return s;  } Is there any freely available pointcloud data?   I'm especially interested in dense clouds of small areas(5m to 100m radius) but anything else would be fine too.   I've found that these pages have very nice and easy to access point cloud data. I have a website that sells music artists posters. Each artists has a page containing a small bio, and a list of posters we are selling representing the artist.  Currently our HTML looks like that  &lt;h1&gt;{Artist name}&lt;/h1&gt; bio &lt;h2&gt;Posters&lt;/h2&gt; &lt;ul&gt;   &lt;li class="poster"&gt;...&lt;/li&gt;   ... &lt;/ul&gt;   We are redesigning this page, and we have a new template that we really like. Problem is that in this new version the &lt;h2&gt;Posters&lt;/h2&gt; does not appear anywhere on the page.  As you might expect, a significant part of our traffic comes from people typing something like : "{Artist name} poster" on Google.  I fear that, by removing the word "poster" from the page, we will reduce our chances of getting these people to come to the site, since Google might down rank us.  I see several options here :   Give Google a slightly altered page that contains the H2 tags. But I think this falls into the "Black Hat SEO" category. And I don't want that. Put the heading. Hide it with CSS. Everyone wins, including accessibility tools which can determine the structure of the page using the "invisible" heading. But I do not know if this is considered a good practice. Forget about the heading, and find other ways to tell Google that we really are about posters. (via keywords, but do they really have the same "weight" as an H2?) Adapt the design to our SEO need, and find a way to put that heading nicely.   Are there webmasters out there that have been facing the same issue, how did you resolve it? $f(f(x)f(y))+f(x+y)=f(xy)$ Find all functions $f\colon \mathbb R\rightarrow \mathbb R$ such that for all reals $x$ and $y$:   $$f(f(x)f(y))+f(x+y)=f(xy).$$   It was six hours ago in IMO 2017 (problem 2).  I tried  the standard way: $x=0$, $x=y$, $x=1$,etc. but without any success.   Let $f(0)=a$. Hence, for all $x\in\mathbb R$ we have $f(a(f(x))+f(x)=a$. What is the rest?   Also we have $(x-1)(y-1)-1+x+y-1=xy-1$ and  $1-(1-x)(1-y)+1-x-y=1-xy$. I am looking to sell and buy a house. But with the current market being as crazy as it is (houses are selling fast for sometimes 150,000 over asking), I'm afraid if we sell first, we could be stuck without a new house. Or stuck settling on or over-paying for something and wishing we never sold at all. I'm wondering if it's possible to buy first. What is the best way to secure my next house before selling my current house without getting locked into a B-lender mortgage or risking too much?  I know there would be some risk putting an offer on a new house without knowing how much the current house will sell for, or the risk we don't sell the current house before the new house closes. I'm also afraid conditional offers will not be considered. Are there any other options?  (We do have a mortgage on the current house, but because the market has gone up so much there is also a good chunk of equity.) I have an array of Foo objects. How do I remove the second element of the array?  I need something similar to RemoveAt() but for a regular array. What's a recommended alternative to Quickbooks pro? I've just installed Ubuntu to replace Windows. I can't seem to find a good alternative to  to run on Ubuntu. Any help would be appreciated. Bank Deposit Scam I was on Instagram and saw someone's post about making extra cash.  I inboxed her for details and she said her manager will deposit funds into my account, then I would send them $2000 to split between the both of them.  She stated that I would need to overnight my bankcard to her so her manager can process the deposit.  She didn't ask for anything (neither SSN nor routing or account number) but the bank card only.  I assume that it is a scam.  Can anyone elaborate on this type of scam?  She claim it's not a scam. How do people at Hogwarts usually tell the time? Classes and lessons at Hogwarts are presumably scheduled at fixed times of day. The first class might start, for example at nine in the morning.  To be on time for one's lessons, it is therefore crucial to know the current time but we know that electric watches of course do not work at Hogwarts because of all the magical interference. Are there magic watches? Is there maybe a spell to tell the time?  How do people at Hogwarts usually tell the time? Why is the spoken German in many US films and TV shows so inaccurate? Is there a reason why in so many English-language movies and TV series, whenever someone is speaking "German", they (actors, writers etc.) just don't care about if what they say is right or wrong? This can range from:    just minor grammatical errors e.g. "Schieß dem Fenster" in "Die Hard":                                rambling some made-up words and claiming them to be German e.g. "Lebenslangeschicksalssatz" in "How I met your mother"                                wrong German paired with a bad accent e.g. in "Scrubs"                                up to native German speakers talking complete nonsense e.g. Heidi Klum in HIMYM                                  I don't know if this is the same with other languages (for example there is a scene in Scrubs where the cast speaks Spanish, but there might be similar mistakes:                                 Do the creators and actors just not want to speak correct German and at least use correct German words, or is there simply no money in a $100,000,000 movie production to ask a native speaker to look over your script and maybe correct some of the lines? Show that $PF.PG=b^2$ in a hyperbola If the normal at P to the hyperbola $\frac {x^2}{a^2}-\frac {y^2}{b^2}=1$ meets the transverse axis in G and the conjugate axis in G' and CF be the perpendicular to the normal from the center C then show that $$PF.PG=b^2\space and \space PF.PG'=a^2.$$ We know that the equation of the normal at parametric point $P\equiv(a\sec\theta,b\tan\theta)$ is given by  $$a\,x\cos\theta+b\,y\cot\theta=a^2+b^2$$   Equation of the transverse axis is $y=0$ and that of the conjugate axis is $x=0$.   Hence   $$G\equiv(\frac {a^2+b^2}{a}\sec\theta,0), \, G'\equiv(0,\frac {a^2+b^2}{b}\tan\theta)$$  C is the origin and CF is perpendicular to the normal. Hence   $$ CF\equiv b\,x\sec\theta-a\,y\tan\theta=0\implies y=\frac {b\,x\sec\theta}{a \tan\theta}$$   Substituting this in the equation of the normal we get   $$a\,x\cos\theta+b \,\cot\theta\,\frac {b\,x\sec\theta}{a\,\tan\theta}=a^2+b^2\ $$   implies  $$ (a^2 \cos\theta \sin^2\theta+ b^2\cos\theta)x=(a^2+b^2)\sin^2\theta$$  After finding the coordinates of F, the calculation becomes very complicated. So is there an easier way to approach the problem? I would love to see a pure geometric solution to this problem. I am not mathematician by any means so this question might be rather stupid. I came across this Wikipedia article on  and found this bewildering formula,   $$1 + 2 + 3 + \dots  = - \frac1{12}$$  The article also says that "Ramanujan summation of a divergent series is not a sum in the traditional sense". I am wondering then what this summation actually implies?  Is there any interpretation of this confounding result in the physical world that someone not so math-savvy can understand? Is there no electric field inside a conductor? I came across this statement while studying electric currents and I am confused:  "There is no electric field inside a conductor. Hence no current can flow through it".  Is there a fallacy in this statement?  Any help would be appreciated.  The conductor being discussed is ideal. What is the driving force for the current in this case? Where are the Stack Exchange data dumps?