Nine hours ago I got the  ("Shared a link to a question that was visited by 25 unique IP addresses...") for following question: .  But   this question is not mine there is and was no link in the question there is no comment (with question from me) I haven't edited the question   (Also see .)  Can somebody explain me why I got the badge or is there currently a bug with this badge?
I understand that the Announcer badge can be earned if the question is visited 25 times.  But is this only when I share a link to this question in one of my answers, or can I also share the link (with my user id somewhere to count the accesses) somewhere else, maybe Facebook?
How do I run executable scripts in Nautilus? What is the plural of "cottage tariff"? Application of Complex Numbers I was just wondering how complex numbers can be applied in electrical engineering and why we use complex numbers over regular, real numbers for this application (e.g what capabilities does the complex number have that real numbers do not in electrical engineering)?  I have done some research concerning impedances and understand how they are written in complex form, however I am still confused why complex numbers are necessary in this field over regular numbers. Are the limits $\lim\limits_{n\to \infty }\left|\frac{a_{n+1}}{a_n}\right|\,$ and $\lim\limits_{n\to \infty }\sqrt[n]{|a_n|}\,$ equal? Let consider the power series $$ \sum_{k=1}^\infty a_kx^k. $$ We know that it converges when  $$\lim_{n\to \infty }\sqrt[n]{|a_n|}|x|&lt; 1\quad\text{or}\quad |x|&lt; \frac{1}{\lim_{n\to \infty }\sqrt[n]{|a_n|}}$$  But D'Alembert test tells us that it converges if $$|x|&lt; \frac{1}{\lim_{n\to \infty }\left|\frac{a_{n+1}}{a_n}\right|},$$ so since the radius of convergence is unique, we should have that $$\lim_{n\to \infty }\sqrt[n]{|a_n|}=\lim_{n\to \infty }\left|\frac{a_{n+1}}{a_n}\right|.$$  I tried to prove it, but this result looks strange to me. So if it doesn't work always, how can we have those to limit as radius of convergence? I guess the equality of those two limit should be true most of the time.  So under what conditions is it true? I want to install the latest Firefox on my Ubuntu (64bit) box.  What is the best way to do this? Is there a specific update site or should I download the binaries manually? If doing manually, in which directory should I put the files? In my home directory, or is there a better place? Last month, I was travelling on a backpacking trip across Russia and the Baltic states (Schengen zone). I'm an Indian by nationality. So I had to get the respective single entry visa for Russia and Schengen Europe.  At the border crossing into Estonia by road (at Ivangorod-Narva), I exited the Russian border with an exit stamp (so now I can't go back to Russia since I had a single entry visa). When I was at the immigration checkpoint of Estonia, I was heavily questioned on the intent of my travel to Europe while entering Estonia by road.   Though I finally got into Europe, It got me wondering - what happens if a foreign national is denied entry into a country not at the airport but by land between 2 countries he cannot go into ?  Generally, if you are denied entry at the airport the airline has the obligation to fly you back to your country. But what happens when you are stuck between two countries and you cant get into either ? What happens to you then ? Alternating sum of squares of binomial coefficients Can't kill a sleeping process How to change charset of my website to utf8? How is Faulhaber's formula derived? What is the function __construct used for? I have been noticing __construct a lot with classes. I did a little reading and surfing the web, but I couldn't find an explanation I could understand. I am just beginning with OOP.  I was wondering if someone could give me a general idea of what it is, and then a simple example of how it is used with PHP? Blender 2.8 - Transparent background Mechanics around a rail tank wagon What will happen with Blender 2.8 game engine? Blender has just purged the entire game engine from 2.8. There is no "Game Engine" mode anymore and there isn't even a logic editor. I tried installing a GitHub Blender release with the game engine mode working but it failed to install because all the game code was gutted. Does this mean that Blender 2.8 is going to lose the game engine, or is the game engine just being redone for better compatibility and whatnot? How do I turn off some formats in GeoServer's WMS? Should Emergency Funds be Used for Infrequent, but Likely, Expenses? Say we break down non-monthly costs into the following three categories.   High level of predictability: This would include oil changes that may be needed every 2 to 4 months depending on usage, car insurance (if paid every 6 month), car registration, etc. Medium level of predictability: There are some expense which one can reasonable assume will occur on an infrequent basis.  For example, car repairs, house repairs, or even doctor visits during flu season. Low level of predictability: For example, losing a job, significant medical expense, etc.   Which of these categories are emergency funds meant to cover?  I think it is pretty clear that a high level of predictability costs should not use emergency funds while a low level of predictability should.  But medium level of predictability costs seem different, and it left me wondering what is generally defined as an "emergency".  While you do not know when these costs will occur or how much they will be, you could devise some pretty good rules of thumb on frequency and cost. Say you know your 2007 Volvo should have a repair cost averaging out to $100 per month.  Conceptually you could save $100 each month and when your car breaks, not have to spend any emergency funds on the repair.  Is doing this "double-saving" and not suggested if you already have the 6 month emergency fund saved up?  Note: this is a question on how to save money for expenses.  It is not a question about if you should spend emergency fund money to fix a car when you have no other money set aside. I have seen some examples about using "in" with time expressions. They give some examples as shown below:     I will leave for vacation in a month. (Exactly one month from now I   will go on vacation.)      We’ll be there in an hour.  (Exactly one hour will go by and then we   will arrive.)   But these comments confused me. Then I looked the usage of "in" up in a dictionary and it says about usage of "in" with time expressions :"before or at the end of a particular period". I think the comments and the definition in the dictionary contradict each other?    I have examples of mine:     1- Dinner will be ready in ten minutes. (Maybe dinner will be   ready at the 5th minute? or 8th. Does it strictly mean dinner will be   ready at the end of the ten minutes?)      2- My letter arrived in two days. ( Does that mean it took   exactly two days to arrive? or Could it be just one day because he/she   doesnt remember the exact time?)      3- Imagine you are on the first day of a month and your friend says:   I will be going outside the country in this month. 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