From SEO perspective: Are there any reasons NOT to switch to HTTPS-only for a homepage?
New Google SEO benefit with SSL - with only a few sections in SSL, or always on?
What is the difference between Interest Rate and APY on savings accounts, CDs, etc?  Is there a simple formula to convert the two? Intuitive proof of $\sum_{k=1}^{n} \binom{n}{k} k^{k-1} (n-k)^{n-k} = n^n$ Is there an intuitive way, though I am not sure how to find a conceptual proof either, to establish the following identity: $$\sum_{k=1}^{n} \binom{n}{k} k^{k-1} (n-k)^{n-k} = n^n$$ for all natural numbers.  I am thinking about binomial formula $$\sum_{k=0}^n\binom nk x^{n-k}y^k=(x+y)^n$$ but I'm not sure how to use it.  I find this problem tantalizing because it looks as if there should be some sort of intuitive way so that is why I share it here. I am looking for an answer like  if possible. Can you find one? I am using texlive 2013, and just ran the following command to update the packages.  sudo ./tlmgr update  -all   After it finished, I tried to compile tex documents that uses tikz package as the following MWE shows:   \documentclass{article}  \usepackage{tikz}  \begin{document}       aaaa  \end{document}   Then pdflatex complains; it said:   (/usr/local/texlive/2013/texmf-dist/tex/latex/pgf/utilities/pgfrcs.sty  (/usr/local/texlive/2013/texmf-dist/tex/generic/pgf/utilities/pgfutil-common.tex  ! I can't find file `pgfutil-common-lists.tex'.  l.556 \input pgfutil-common-lists.tex   The problem is that, pgfutil-common-lists.tex is indeed in the directory:   /usr/local/texlive/2013/texmf-dist/tex/generic/pgf/utilities/   Why is that? pdflatex should be able to find it, right? I even download the  again, and replace the pgf directory in   /usr/local/texlive/2013/texmf-dist/tex/generic/   Nothing changed at all........... Any idea? Thank you for your critics.  %=====================================================================  Then followed the comments, I type the following command in the terminal:    sudo mktexlsr gives me command not found;  mktexlsr gives me:  mktexlsr: /usr/local/texlive/2013/../texmf-local: directory not writable.     Skipping...  mktexlsr: /usr/local/texlive/2013/texmf-config: directory not writable. Skipping...  mktexlsr: /usr/local/texlive/2013/texmf-dist: directory not writable. Skipping...  mktexlsr: /usr/local/texlive/2013/texmf-var: directory not writable. Skipping... mktexlsr: Done; Forkpsewhich pgfutil-common-lists.tex, nothing pops up. There's a spaceship, nearing the end of its journey. Everybody on board is in cryosleep. For some reason the wake-up system malfunctions, and the ship will fly on indefinitely. The people at the space port realise this, and try to wake someone up. Their last resort is finding someone on board who is telepathic, and wake this person up. They find one, but it turns out to be an unborn baby. I have connected speakers to the back panel of my computer at work and I would like to have them always enabled (I can switch them off on the speaker casing). However when I connect headphones on the front panel system automatically says that the rear output is unplugged.  I found a solution to disable auto detection with Alsamixer and it works almost ok except the fact that after system restart I need to reconfigure the settings again... How can I set this once and forget about it? I'm writing a script and I would like to pass the results from bc into a variable. I've declared 2 variables (var1 and var2) and have given them values.  In my script I want to pass the results from bc into another variable say var3 so that I can work with var3 for other calculations.  So far I have been able write the result to a file which is not what I'm looking for and also I've been able to echo the result in the terminal but I just want to pass the result to a variable at moment so that I can work with that variable.  echo "scale=2;$var1/var2" | bc How do you make a deep copy of an object? Viewed, deleted comments staying in inbox Lets start with a life-like scenario.  User A receives an offensive comment in his inbox from the OP of a question. A then clicks on the notification in order to flag the offending comment. A mod sees the flag and deletes the comment. Shortly after, the question is also deleted. Because A clicked on the notification in the inbox, that notification is still in A's inbox, with the offensive part of the comment still visible. Edit: The flag was marked helpful because the post was deleted, not because the comment was deleted by a mod.  Please note that although the behaviour of the notifications is as it is supposed to be, this does not fix the possible problem of such notifications &quot;hanging around&quot;. User A can't get rid of that comment in any way, and it may be a long time before it is flushed out by new messages. This issue is mentioned in  but it is supposed to be that comments on a post that you own can hang around, not on someone else's post.  is speaking about comments which have not been read and this . To me this seem like an important issue. To have to see an offensive message every time you open your inbox is not a good thing. I can think of two ways in which this problem can be avoided:  Make sure notifications for deleted comments don't hang around (this I'm sure is the easier option) Allow users to delete unwanted notifications (this could be useful, as this would also allow users to remove notifications that they are not interested in, or even just to keep their inbox uncluttered. It would most likely be hard to implement, though.)  What are your thoughts on this? Save an entire webpage, with all images and css, into just one folder and one file, with wget? How do I get whole and fractional parts from double in JSP/Java? How do I get whole and fractional parts from double in JSP/Java ? If the value is 3.25 then I want to get fractional =.25, whole = 3  How can we do this in Java? Catching poisoned arrows When catching an arrow tipped with poison (like the ones used by yuan-ti) with an ability like the one the monk has or the one given by arrow catching gloves: does the ability reduce the poison damage? If so, is the total damage or the piercing one caused by the arrow only the damage that must be downed to 0 to catch the missile? Enumerated list with square brackets I want to make an enumerated list in the following format:  [1] foo foo [2] foo foo ...    How I can do that using enumerated lists? I have tried the following:  \begin{enumerate}[\left[ 1 \right]]   but it does not work. Roll back from OS X Mavericks ( or any newer OS) to Mountain Lion I installed the developer preview of OS X Mavericks, &amp; too many things broke. I can't stay on it &amp; need to roll back to Mountain Lion. Any ways of doing that? Please help!  I originally installed Mountain Lion &amp; Mavericks through the Mac App Store. Subtracting even and odd binomial coefficients? What governor limits impact Apex Describe methods? Are there any governor limits, or considerations that I should be aware of when using Apex Describe methods?  So for example, the author of this blog post uses the structure below to get the record type instead of doing a soql query.     //Generate a map of tokens for the sObjects in your organization Map gd = Schema.getGlobalDescribe();  //Retrieve the describe result for the desired object DescribeSObjectResult result = gd.get('Account').getDescribe();  //Generate a map of tokens for all the Record Types for the desired object Map recordTypeInfo = result.getRecordTypeInfosByName(); system.debug('RECORD TYPES:' + recordTypeInfo);  //Retrieve the record type id by name String recordTypeId = recordTypeInfo.get('RECORDTYPE_NAME').getRecordTypeId(); I used the inbuilt dataset stackloss here. I used following R code for creating the multiple regression model.  &gt; head(stackloss)   Air.Flow Water.Temp Acid.Conc. stack.loss   1        80         27         89         42   2        80         27         88         37   3        75         25         90         37   4        62         24         87         28   5        62         22         87         18   6        62         23         87         18  &gt; fit &lt;- lm(stack.loss ~ .,data=stackloss) &gt; plot(fit)   And when I plot the model, the four following graphs are displayed.      How to interpret these graphs? What are the significance of these graphs? How to use these graphs? Find the limit of $\lim\limits_{(x,y)\to (0,0)} \frac{x^2y^2}{x^2y^2+(x-y)^2}$ $X$ is Hausdorff if and only if the diagonal of $X\times X$ is closed Prove that the power set of an $n$-element set contains $2^n$ elements Theorem. Let $X$ denote an arbitrary set such that $|X|=n$. Then $|\mathcal P(X)|=2^n$.      Proof. The proof is by induction on the numbers of elements of $X$.      For the base case, suppose $|X|=0$. Clearly, $X=\emptyset$. But the empty set is the only subset of itself, so $|\mathcal P(X)|=1=2^0$.      Now the induction step. Suppose $|X|=n$; by the induction hypotesis, we know that $|\mathcal P(X)|=2^n$. Let $Y$ be a set with $n+1$ elements, namely $Y=X\cup\{a\}$. There are two kinds of subsets of $Y$: those that include $a$ and those that don't. The first are exactly the subsets of $X$, and there are $2^n$ of them. The latter are sets of the form $Z\cup\{a\}$, where $Z\in\mathcal P(X)$; since there are $2^n$ possible choices for $Z$, there must be exactly $2^n$ subsets of $Y$ of which $a$ is an element. Therefore $|\mathcal P(Y)|=2^n+2^n=2^{n+1}$. $\square$      From the above explanation, I don't understand why the set that contains $\{a\}$ will contain $2^{|n|}$ elements when it should clearly be $2^{|1|}$.  The construction of a new set $S$ is the union of the old set with cardinality $n$ and an new element $\{a\}$, therefore the set that do not contain $\{a\}$ still has cardinality $n$ and the set that contains $\{a\}$ is just $\{a\}$, one element...  Can someone please elucidate? VMware won't work after Ubuntu Upgrade I upgraded to Ubuntu 15.10 and now if I want to open VMware Player it doesn't do anything. I also uninstalled and installed it again, still nothing.  What can I do?