Plug power adapter into 19V laptop
Can a 20V 4.51A power supply be used with a computer that requires a 19V 3.42A power supply?
Should your PhD students call you by your first name? Making overview with linked detailed maps in QGIS? Do effects with the duration of one minute end at the beginning or the end of your turn? The Rage class feature of the Barbarian allows you to rage for one minute given you either took damage or attacked every round. A round is defined as a 6-second interval. So the rage can last up to 10 rounds. Now my question is, does it end at the end of your 10th round or at the beginning of your 11th round? There are other effects like that, also concentration spells with the duration of 1 or 10 minutes. Sometimes those are activated before combat starts and end during combat. In general: Does an effect/concentration end at the end of your last turn during the timespan or at the beginning of your first turn after the timespan? What is the most "pythonic" way to iterate over a list in chunks? How to clone/copy all file/directory attributes onto different file/directory? I want to copy the attributes (ownership, group, ACL, extended attributes, etc.) of one directory to another but not the directory contents itself.  This does not work:  cp -v --attributes-only A B cp: omitting directory `A'              Note: It does not have to be cp. When will my device get the Android 5.1 update (Lollipop)? Android 5.1 (Lollipop) was officially announced on March 9th, 2015.  You can review the high-level changes at the announcement on the official .  Of course, not all devices will get this update right away and others won't get it at all. Each manufacturer and carrier often choose to add their custom modifications which tend to delay the official release.  When will each device get Android 5.1, either officially or unofficially, if ever?  See also: Coloring a black and white PDF graphic I have a graphic in PDF format (originally converted from an SVG) that is monochromatic (black on white). Is it possible using TikZ or PSTricks but not (Illustrator or Inkscape) to include this image in a different color?  Example:    While it lasts (there seems to be no long term way to host a pdf), you can .  Edit: Simple was perhaps a bit of a misnomer - the pdfs are cropped and monochromatic, but to intricate to redraw on my own. The above example is a character from a font (which I can recolor), but it gives a good example of what shapes I am talking about. Let $R= \mathbb{Q}[x^2 ,x^3 ]$, the set of all polynomials over $\mathbb{Q}$ with no $x$ term. Show that a gcd of $x^5$ and $x^6$ does not exist in $R$.   I am reasoning for the absurd and I am assuming that $gcd (x ^ 5, x ^ 6) = ax ^ 2 + bx ^ 3\in\mathbb{Q}[x^2 ,x^3 ] $, then, for the Bezout identity there exists $p (x) = cx ^ 2 + dx^3$ and  $q(x)= ex ^ 2 + fx ^ 3$ in $\mathbb{Q}[x^2 ,x^3 ]$ such that $x ^ 5p (x) + x ^ 6q (x) = ax ^ 2 + bx ^ 3$, which is absurd since $$9 = deg (x ^ 5p (x) + x ^ 6q (x)) \neq  deg (ax ^ 2 + bx ^ 3) = 3.$$  Is it okay what I did? Thank you very much. How can I prove that $\frac{n^2}{x_1+x_2+\dots+x_n} \le \frac{1}{x_1}+ \frac{1}{x_2} +\dots+ \frac{1}{x_n}$? How can I prove that $\frac{n^2}{x_1+x_2+\dots+x_n} \le \frac{1}{x_1}+ \frac{1}{x_2} +\dots+ \frac{1}{x_n}$?   im trying to use AM-GM  $\sqrt[n]{ \frac{1}{x_1} \frac{1}{x_2} \frac{1}{x_3} ..\frac{1}{x_n}}   \le \sum_{k=1}^n \frac{{\frac{1}{x_1} +\frac{1}{x_2}+ \frac{1}{x_3}+ ..\frac{1}{x_n}}}{n}$  $ln\sqrt[n]{ \frac{1}{x_1} \frac{1}{x_2} \frac{1}{x_3} ..\frac{1}{x_n}} \le ln \frac{1}{n} \sum_{k=1}^n {\frac{1}{x_1} +\frac{1}{x_2}+ \frac{1}{x_3}+ ..\frac{1}{x_n}}$  $ \frac{1}{x_1} \frac{1}{x_2} \frac{1}{x_3} ..\frac{1}{x_n}\le  \sum_{k=1}^n {\frac{1}{x_1} +\frac{1}{x_2}+ \frac{1}{x_3}+ ..\frac{1}{x_n}}$  im not sure is this right or not, however i dont know how to include the $n^2$ in the nominator? is there also alternative proof using jensen inequality? Why Java needs Serializable interface? We work heavily with serialization and having to specify Serializable tag on every object we use is kind of a burden. Especially when it's a 3rd-party class that we can't really change.  The question is: since Serializable is an empty interface and Java provides robust serialization once you add  implements Serializable - why didn't they make everything serializable and that's it?    What am I missing? Resistor in series needed with LED string? Can someone explain how combinatorial proofs work?  I've included an example questions that's been giving me a hard time.  Any insight on the topic would be great.  $$\sum_{k=1}^{n}k{n \choose k} = n2^{n-1}$$  Another one:  $${2n \choose 2} = 2{n \choose 2} + n^2$$  The solution says:  LHS: Pick two people from a pool of n men and n women. RHS: Pick two women, pick two men, and pick one of each.  But I don't see how this applies.  How does $n^2$ show that we're picking "one of each?"  Thanks for the help :) I have 4 servers with Debian Wheezy OS. I have Apticron installed that informs me about updates. Debian updates are realized so often that when I finish to update the last of 4 servers I get new email about new updates on the first server. I try to update all servers when I get a notification but I never know if there is a need to reboot the servers. I have read that if the directory "/var/run" contains file "reboot-required" I have to reboot the server. But I never have seen this file in "/var/run". How can I know when reboot is required? I don't want reboot my servers every time when I install new updates if it's not needed.  I understand that if I update PHP or MySQL, etc I don't need to reboot the server but updates usually contain many "lib...".  Below are 9 updates (I have received this week).  krb5-locales 1.10.1+dfsg-5+deb7u3 libdbus-1-3 1.6.8-1+deb7u6 libgssapi-krb5-2 1.10.1+dfsg-5+deb7u3 libk5crypto3 1.10.1+dfsg-5+deb7u3 libkrb5-3 1.10.1+dfsg-5+deb7u3 libkrb5support0 1.10.1+dfsg-5+deb7u3 libruby1.8 1.8.7.358-7.1+deb7u2 libxml2 2.8.0+dfsg1-7+wheezy3 ruby1.8 1.8.7.358-7.1+deb7u2   I have no idea what is "libkrb,libgssapi", etc. How can I detect if reboot is needed? Please do not suggest to install UnattendedUpgrades to let the servers update automatically because this can cause websites going offline if something updates not correct. Convert char to int in C# Proof verification: Set of partial limits of a sequence is closed highest power of prime $p$ dividing $\binom{m+n}{n}$ Give each site a parallel site for polling, recommendations and subjective-ish stuff How deterministic is floating point inaccuracy? I love admin-ajax.php. But I hate having to localize in order to point frontend scripts to it, and I wish there was an equivalent, easy-to-find file for themes. (It also just bothers me to see frontend requests go through "/wp-admin/". No practical reason, just looks ugly IMO.)  So I've simply copied admin-ajax.php to the root dir at "/ajax.php", adjusted the include paths and removed the WP_ADMIN constant definition. Seems to work like gangbusters (I can now just direct all my frontend AJAX requests to /ajax.php! And I can still use the normal wp_ajax hooks in my plugins!).  But is this safe? What might go wrong? Since this isn't built into core, I assume there's a good reason as to why not. But looking through the code, I can't see any immediate problems.   You're smart--tell me if this approach is crazy. Or if there's a simpler method that I'm overlooking. I am teaching how to convert from one base to another base, however, I can't find a way to do something like this:    I know little about Tikz, the only thing I have been able to produce is a simple square with a couple of lines over it, so I don't even know where to start. Any suggestions? I don't mind typing all the numbers, what I want to do is to automatize the process of creating the lines.