Trim a string to get only domain name in PHP
Parsing domain from a URL
How does a capacitor function in a 120V AC motor circuit? I don't understand the direction of current flow when a capacitor is wired in series with the start windings in, say, a fridge or other AC motor  running at/under 120V AC. Wiring diagrams seem to suggest that voltage energizes the hot leg of the circuit and current flows through the run windings and then returns via the neutral leg. Without a capacitor, the same thing would happen to the start windings. Problem there I guess is that both windings would be in phase and thus no spin created for the rotor. So, a capacitor is wired in series with the start windings which I kind of understand. But I don't know how the voltage and current behave. Does voltage energize the hot leg, flow through the start windings and then charge the capacitor? When voltage on the hot leg oscillates down to zero, does the capacitor discharge back toward the starter windings, or does current flow through the capacitor to the neutral leg? Basically I don't understand where the capacitor's charge goes when the hot leg is hot and when it is not. Lastly, is the capacitor placed between (downstream from) the start windings and neutral, or could it be wired between incoming voltage and the windings? Which groups have precisely two automorphisms Which groups $G$ have precisely two automorphisms, i.e., precisely one non-trivial automorphism?  Examples: $G= C_3, \mathbf{Z},\ldots$.  I think $G$ has to be abelian. In fact, we have $ \vert G\vert \geq 3$. Therefore, if $G$ is not abelian, we have at least two non-trivial inner automorphisms.  If we can show that $G$ is cyclic the above examples are all of them. What do the E and R prefixes stand for in the names of Intel 32-bit and 64-bit registers? Problem 20-9 in Lee's Introduction to Smooth Manifolds (2nd Ed.) asks to prove that for a Lie group $G$, and for $X, Y\in \text{Lie}(G)=\mathfrak g$, there is $\epsilon&gt;0$ and a smooth map $Z:(-\epsilon, \epsilon)\to \mathfrak g$ such that   $$(\exp tX)(\exp tY) = \exp\left(t(X+Y) + \frac{1}{2}t^2[X, Y] + t^3 Z(t)\right)$$   What we want to show is that the first and second term in the Taylor expansion of $\exp^{-1}\left((\exp tX)(\exp tY)\right)$ are $t(X+Y)$ and $\frac{1}{2}t^2[X, Y]$ respectively.  Calculating the first term is easy since we just need to differentiate $\exp^{-1}((\exp tX)(\exp tY))$ with respect to $t$ at $t=0$ once, and this gives the desired result.  But for the second term we need to take the second derivative at which I am stuck. How does Ascending work? The next upgrade I am likely to get is "ASCENSION" for Amenhotep.  The mouseover text on the ability says it restarts the game and gives a single hero soul.  Does anything else cross over (heroes, gold, achievements, etc.)?  When would be the best time to Ascend?  Should I wait until I unlock all the heroes or buy all their abilities?  I'm on level 85 now (not yet beat the boss), should I wait until a specific level? Young Adult Fantasy about children living with an elderly woman and learning magic related to their skills What early-2000s show about dimension hopping has a character who can swap limbs? An earlier question asked about a show that made me think of another one I can't remember.  It was a live action show about exploring different dimensions, and I think the main character was searching for his dad.  I remember seeing it in the US, but I don't know if it was limited to that.  I'm a little fuzzy on the details, but I think the main character could swap his limbs or something like that. How to call the method correctly in Preference.OnPreferenceChangeListener() Continuous weighted random distribution, biased toward one end I am currently contributing to a particle system for our game and developing some emitter shapes.  My uniform random distribution along a line or along a rectangular area works fine - no problem.  But now I would like to have something like a 1 dimensional gradient in this distribution. This would mean for example lower values are more common than higher values.  I don't know what would be appropriate mathematical terms for this problem, so my search skills are rather useless with this one. I need something that is computationally simple, as the particle system needs to be efficient. On the websites, whenever the OP comments on an answer, or on his question, his name is highlighted. This is a handy feature because you can easily tell whether the comment is from the OP or not.   But on the Android mobile app (don't know about iOS),  this feature is not there. Can we have it please!? bash: syntax error near unexpected token `}' 'Possible duplicate' comment not appearing for questions with deleted comments containing the link I posted a comment to a duplicate question on . But I decided to delete it. Afterwards I voted as duplicate and thought a comment would be generated like     possible duplicate of ...   But it didn't. My guess is that the duplicate-comment won't be generated if a comment exists with that link, even if deleted. Problem from iOS 10.1.1 to 10.2.1.  I have no photos at all on my iPhone yet in settings it says my photo library is taking up ~200MB of space. The number of space being taken up keeps changing constantly(in the settings app on my phone). In iTunes, the storage bar at the bottom does(when in the sync menu) not show photos.           What is taking up this storage, and how can I reduce it?  Troubleshooting:   I disabled iCloud photo library and iCloud photo stream, still showing the same thing. Tried doing what @User9125 said, didn't work. I had set the date all the way back when I first got my phone, nothing showed up. Rebooting I had hundreds of photos in Whatsapp, I deleted them but I didn't get the storage back. It didn't even make a dent in the amount of storage being used by Photos so I don't think a third-party app could be taking up this storage. I don't think a system app is taking this space either, because I cleared the pictures in mail and messages. I tried using (through sideloading) in Secure Mode and Fast Mode, but it did not clear up the photos. When reading lens reviews on the Internet, I often find subjective statements about the image quality that a lens produces, such as "good contrast" or "sharp". The problem is that I don't think I am capable to actually see these qualities on an image. I don't even think I could tell the difference between a cheap kit lens and a top lens, if not by "this just looks better".  So my question is: without looking at sharpness tests and MTF curves, how do you learn to judge the quality of a lens based only on sample images? What are the characteristics you look for and what constitutes good or bad in each of them? How to set up RAID 1? How do I create a script file for terminal commands? In Windows I can write a file containing commands for cmd (usually .cmd or .bat files).  When I click on those files it will open cmd.exe and run them commands the file contains.  How would I do this in Ubuntu?         I'm sure this is a duplicate, but I can't find my answer. Its similar to these questions, but they don't answer the question: I have recently started using blender and one of the models I'm working on has dark shadows along edges. I started this model from scratch. I can't remember them being there when I first started the model, but I had trouble joining areas together and think I've pressed something I shouldn't have. However, there are so many options I'm not sure what I did.  Here is an image of what I mean   The one on the left has the shadow. As a test I started a new model, which is on the right in the image, and as you can see it doesn't have any shadows.  Also, occluded vertices partially show through the model. Occlusion doesn't work properly.   In orthogonal view small darkened triangles appear along the the edges.    I don't really want to start the model again from scratch so any ideas on how to remove this shadow would be great. Thanks. Permalink rewrite with custom post type and custom taxonomy I think thats a quick one:  I've got:   Custom post type: Food  Custom taxonomy (Registered to Food): Fruits Terms in Fruits: Apple, Orange, Cherry   If I type in example.com/food?fruits=Apple,Cherry, I get all posts in Fruits with the terms Apple and Cherry, thats great!  But I would like to type in example.com/food/fruits/Apple,Cherry or example.com/food/Apple,Cherry to get the same result.  I´ve tried different permalink and rewrite plugins related to custom posts but nothing helped.  Thank you,  David Why does $PSL(2,\mathbb C)\cong PGL(2,\mathbb C)$ but $PSL(2,\mathbb R) \not\cong PGL(2,\mathbb R)$? Why does $PSL(2,\mathbb C)\cong PGL(2,\mathbb C)$ but $PSL(2,\mathbb R) \not\cong PGL(2,\mathbb R)$? What are the increased possibilities (if any) of being able to crack a private key given the following:   The associated bitcoin (ECDSA Secp256k1-based) public key is known. The private key has been used to generate a public key from a different ECDSA curve and that public key is also known. It is known that the two public keys are derived from the same private key. It is known which ECDSA curves were used to generate the public keys. It is known which ECDSA curve was used to generate which public key.   Does it make any more difference if there is data that is known to have been signed by the private key and the signature(s) are known and the raw data is known?  EDIT: I should have pointed out that the conditions are ANDed, I.e. All conditions are known. Sorry, I should have been clearer the first time.