Parenthesis after UIViewController
What does the text inside parentheses in @interface and @implementation directives mean?
How do I iterate over the properties of an anonymous object in C#? Let $x_1,x_2,\ldots,x_n$ be the roots for $1+x+x^2+\ldots+x^n=0$. Find the value of   $$P(1)=\frac{1}{x_1-1}+\frac{1}{x_2-1}+\ldots+\frac{1}{x_n-1}$$   Source: IME entrance exam (Military Institute of Engineering, Brazil), date not provided (possibly from the 1950s)  My attempt: Developing expression $P(1)$, replacing the 1 by $x$, follows $$P(x)=\frac{(x_2-x)\cdots (x_n-x)+\ldots+(x_1-x)\cdots (x_{n-1}-x)}{(x_1-x)(x_2-x)\cdots (x_n-x)}$$    As $x_1,x_2,\ldots,x_n$ are the roots, it must be true that   $$Q(x)=(x-x_1)\cdots(x-x_n)=1+x+x^2+\ldots+x^n$$ and  $$Q(1)=(1-x_1)\cdots(1-x_n)=n+1$$ Therefore the denominator of $P(1)$ is  $$(-1)^{n} (n+1).$$ But I could not find a way to simplify the numerator.  Another fact that is probably useful is that  $$1+x^{n+1}=(1-x)(x^n+x^{n-1}+\ldots+x+1)$$ with roots that are 1 in addition of the given roots $x_1,x_2,\ldots,x_n$ for the original equation, that is  $$x_k=\text{cis}(\frac{2k\pi}{n+1}),\ \ k=1,\ldots,n.$$  This is as far as I could go...    Hints and full answers are welcomed. OrderBy and OrderByDescending are stable? The server version of Ubuntu does not have the  command. How can I add a  (PPA) to the server without this command? What is this story about 20 y.o. inexperienced "kids" fighting against a stronger foe in space? Correct usage of will and would Consider the following sentence     It will/would rain tomorrow.   I understand "would" usually means something that is really improbable.  So "it would happen" means it might happen but it is very unlikely; while "it will happen" means it is going to happen  But what if I want to say      It will not happen?   Because the meaning of "it will not happen" represents something that is unlikely or, worse still, not going to happen, shouldn't it be more accurate to say "it would not happen"?  However, to contravene the aforesaid suggestion - if I am confident that the thing is not going to happen, should I use "will" to indicate the definite nature of my statement?  To further complicate the issue, what if I want to say     I think you will not be able to do it.    or      I think you would not be able to do it.    Which one is more accurate/correct,  given that "I think" already conveys a sense of "less than definite" and "will/would not be able to" conveys the same sense as "unlikely"? Does Calculate Value (Model Only Tool) work correctly in tools run in Batch? Am I correct that if my model has a model-only tool (Calculate Value), and then I run the model as a batched process, it will not run the Calculate Value expression?   I wrote a model to upload, define, project (and clip) XY data from excel files. I had thought to use iterate tables, but it wasn't working. (I assume due to having to choose which worksheet within xlxs). So I thought to do a batch, but this seems to leave that annoying $ that arc appends to table names (and is an invalid character in most tools...)  My guess is that the Calculate value that removes my $ is not being run in the batch. Ideas? Confirmations? Lightning:input type="date": how to change the date fomat - Summer'18 I'm granted a one-entry Schengen visa and now I can't go. Will having an unused visa in my travel passport have any consequences like future visas refusal? Do I need to do anything special? Rounding Percentages Today my lecturer put up on the board that:  If $\lim\limits_{n\to\infty}\frac{a_{n+1}}{a_n}$ exists and $a_n&gt;0$ then   $\displaystyle \limsup\limits_{n\to\infty}\left(a_n^{\frac{1}{n}}\right)=\lim_{n\to\infty}\frac{a_{n+1}}{a_n}$  however I am not sure why this is true, can somebody give me a hint or something as to how to go about proving this.  thanks for any help Make Excel open some hyperlinks with non-default browser A bunch of our network/server/storage hardware uses web interfaces for their administrative portals. I'm currently using an Excel 2010 worksheet to keep track of each device. I have one column set aside to list the URL for each web interface. This makes it easy to simply click the URL to open each administrative portal.  My default browser is Firefox. However, some of the administrative portals don't play well with Firefox and require the use of IE. Until now, when I want to open a hyperlink in IE, I have to manually open IE, copy the URL from the Excel worksheet, and paste it into the IE address bar (otherwise it will open in Firefox if I simply click it). It's just an annoying extra couple of steps.  So without changing Firefox as my default browser, is there a simple way in Excel 2010 to tell it which hyperlinks to open in IE when they are clicked? I want to choose specifically which links open in which browser  (For reference I'm using Windows 7 Enterprise 64-bit) "Activity" tab for the Community user's network profile sometimes leads to a server error Show that if $u$ is harmonic in $\mathbb R^n$ and $u=o(|x|)$, then $u$ is a constant.(Hint: use the solid version of the mean value property $u(x)=\frac{1}{\omega R^n} \int _{B_{R(x)}} u(y)dy$, and estimate $|u(x)-u(x')|$.)  Can anyone tell me how to use this hint? Write space with TCPDF into a PDF file Implicit newline at the end of each paragraph? Did all Headmasters get a portrait in Hogwarts? Throughout the Harry Potter series, we see that deceased Headmasters of the school get a semi-sentient portrait of themselves in the Headmaster's Office, at the service of the current Headmaster. Do all Headmasters get a portrait? What are the conditions of getting one? For instance, there are a couple of times when Dumbledore is temporarily deposed as Headmaster: Dolores Umbridge takes over the job in Order of the Phoenix, and Minerva McGonagall takes the job in Chamber of Secrets and Half Blood Prince. Will Umbridge and McGonagall have portraits in the Headmaster's Office when they expire? Mixing plural and singular list items with a single verb A friend wants to write,   There is no hardware to purchase, no additional software to install and no key fobs to worry about.   This is awkward because the verb "is" doesn't match up with the third item, which is plural and demands "There are" as the subject. However,    There is no hardware to purchase, no additional software to install and there are no key fobs to worry about.   sounds awkward as well.  Is there a good workaround for this problem where some list items are singular and some are plural, so they don't share a common verb? Recently, the titles to some questions have been displaying as "undefined":    "undefined" is replaced with the question's true title upon refreshing the page. Is this a bug? Setup restarts the laptop and then restarts the installation all over and over again?