Javascript Regex: How to put a function argument inside a regular expression?
How do you use a variable in a regular expression?
Show that $U_n:=\left(1+\dfrac{1}{n}\right)^n$, $n\in\Bbb N$, defines a monotonically increasing sequence.   I must show that $U_{n+1}-U_n\geq0$, i.e. $$\left(1+\dfrac{1}{n+1}\right)^{n+1}-\left(1+\dfrac{1}{n}\right)^n\geq0.$$  I am trying to go ahead of this step. How do I change the icon for a particular file type? I'm trying to change the icon for application/x-hwp files. I've added the icons to the proper places, and checked it with assoGiate (after reading ). It shows that my desired icon is associated with the file type. Nevertheless, Nautilus is still showing the old icon. How can I make Nautilus show the correct icon? Add new alias to Gmail without SMTP (forwarding-only address) Can I buy PSN games and DLC without giving Sony my credit card info? Like the title said, I want to install Celestia. I already downloaded the packages  and then, I tried all the things that I found on some posts (also, they're outdated, cause the last one is for Ubuntu 16.04) but nothing works.  How can I install it on Ubuntu 18.04.1? Old usernames stick to Community Wiki posts On a whim the other day, I changed my meta name from Lord Torgamus to Popular Demand.  I just noticed that the old name has "stuck" to the author tag of ; everywhere else on meta, my new name displays as expected.  Is this a feature?  Is it a bug?  Mostly I'm just curious, as I can't think of a strong reason in favor of keeping this behavior or a strong reason for changing it.  A question somewhat like this has been raised before as , but the previous poster implied that the issue had something to do with migration, which my situation shows is not the case. .cache/upstart/Unity7.log growing to consume the entire free disk space. Python cypto suspected Making dual power supply from single for opamp? For the circuit of opamp 741. we have to supply the dual power for it. How can I make a dual power supply from single. For example, make a (+9V)-GND-(-9V) from single 9V battery ? Getting the class name of an instance? How do I find out a name of class that created an instance of an object in Python if the function I am doing this from is the base class of which the class of the instance has been derived?  Was thinking maybe  might have helped me out here, but it doesn't seem to give me what I want. And short of parsing the __class__ member, I'm not sure how to get at this information. Indefinite article in title of thesis How to customise GNOME default background and lock screen image? I am building a Custom ISO of Ubuntu 18.04 LTS using CUBIC and I'd like to change the default background and lock screen image.  I added the backgrounds in /usr/share/backgrounds, changed the background in /usr/share/gnome-background-properties/ubuntu-wallpapers.xml file, but it does not seems to affect new users (for example the OEM user).  Also, I did not find any way to change the lock screen image. Limit as $x\to 2$ of $\frac{\cos(\frac \pi x)}{x-2} $ Relationship between balloon size and pressure I see numerous websites talking about how a small balloon is at higher pressure than a big balloon. This is a fun counter-intuitive factoid... unless it isn't a fact at all.  Young-Laplace gives  $$T = \Delta p \frac R2 $$  Which means that for a given tension, increasing the radius does decrease the pressure. But why would the tension be constant? A latex balloon is like a 2D spring, right? So the tension in a inflated spherical balloon should be proportional to the surface area, correct?  $$T \propto R^2 $$  But this gives  $$\Delta p \propto R$$  Which means the bigger the balloon, the higher the internal pressure. Which, again, would be the normal intuition - but it would burst the bubble of some simplified explanations. (har har) Chat requirement to post images should be made explicit There is (apparently) a 100 reputation requirement to upload and post images through chat.  There isn't any easily located documentation on this, however. 100 global reputation is listed as the privilege for , while the chat FAQ and help both do not mention any restrictions on uploading images.  As such, could somewhere other than  be used to indicate that there is a reputation requirement in chat for uploading images? "The product key entered does not match any of the Windows image" I have a HP with Windows 7 installed. I want to do a clean installation of Windows 8 from a bootable DVD.   I purchased my Windows 8 32-bit core from the Microsoft store and I received my product key. I then burned the .ISO file to a blank DVD using imgburn. When I restart and change my BIOS to boot from internal CD/DVD and then boot from my internal DVD, I start the installation process.  After I pass the screen where I select the language and location, and click Install it stays there for a minute and then it says:     The product key entered does not match any of the Windows image   I did my research and learned that I need to add a PID.txt file to my source file containing the Windows 8 .ISO but the thing is: I do not know how to add files to the .ISO. The guide I researched is for a bootable USB and I am using a DVD. What is a contrast matrix? What exactly is contrast matrix (a term, pertaining to an analysis with categorical predictors) and how exactly is contrast matrix specified? I.e. what are columns, what are rows, what are the constraints on that matrix and what does number in column j and row i mean? I tried to look into the docs and web but it seems that everyone uses it yet there's no defition anywhere. I could backward-engineer the available pre-defined contrasts, but I think the definition should be available without that.  &gt; contr.treatment(4)   2 3 4 1 0 0 0 2 1 0 0 3 0 1 0 4 0 0 1 &gt; contr.sum(4)   [,1] [,2] [,3] 1    1    0    0 2    0    1    0 3    0    0    1 4   -1   -1   -1 &gt; contr.helmert(4)   [,1] [,2] [,3] 1   -1   -1   -1 2    1   -1   -1 3    0    2   -1 4    0    0    3 &gt; contr.SAS(4)   1 2 3 1 1 0 0 2 0 1 0 3 0 0 1 4 0 0 0 The question is, what elements on a DM screen are essential? I'm new at playing and DMing, altough a lot of experience watching games, just got a group to play with now. Started with the starter set in 5E and the Lost Mine of Phandelver adventure, however I've noticed the game can come to a stop when checking the rules or how to do something, while getting the books and stuff like that. So I thought to make a DM screen with some cheat sheets, of the most usual things new players, and new DM's have doubts on, and how to make the game flow well without long rule-checking breaks. What are the essential things to have on that screen? So far this is what I found  but not sure if it has all I need or so much stuff that'll also make the game stop a lot while cheking it out. When there are several cottages each with several tariffs (depending on the season), should the plural be "cottage tariffs" or "cottages tariffs"?  For context, this is to be a section title on a website renting out the cottages.  An explanation of the grammatical rules would be helpful. Prove if $ p$ is a prime of the form $3n+1$, then $p$ is also of the form $6m+1$ Prove that if $p$ is a prime of the form $3n+1$, $p$ is also of the form $6m+1$.  I guess one could use the division algorithm for this; but, what's the best method? Existence of subgroup of order six in $A_4$ Show that  the  alternating  group  $A_4$  of all even permutations of $S_4$ does not contain a  subgroup of order $6$.   For me am thinking to write all elements of $A_4$ and trying to find every cyclic subgroup generated by each element of $A_4$, then I have to check whether there exist such a subgroup or not! This is a long procedure for me, I ask if there is a short way to do this.