How can I strip the subdomain and .com/.org etc from a domain in Javascript?
How to get domain name from URL
Finding all differentiable $f(z) = u(x) + iv(y)$ in $\mathbb{C}$ where $u(x),v(y)$ are real valued functions.   I’m not sure what to do. Would $f$ be differentiable simply if and only if both $u$ and $v$ were differentiable?   My thinking is that if the limit $$ \lim_{h \to 0}\frac{f(z+h)-f(z)}{h} $$  exists then it would be equal to  $$ \lim_{h \to 0}\frac{u(x+h)-u(x)}{h} + i\lim_{h \to 0}\frac{v(y+h)-v(y)}{h} $$  and therefore would exist if they existed. But that doesn’t seem quite right.  I also thought about using Cauchy-Riemann equations, but seeing that I’m trying to find ones that are differentiable rather than those that aren’t, I thought they wouldn’t be of much help. The Windows Domain I manage has hundreds of computer names which I don't recognise and I'd like to remove old ones which aren't in use before trying to track down the misnamed ones.  Is there someway to see when the last time a machine logged onto the network? Either via dhcpd or a user login event or something else. Prove convergence of the sequence $(z_1+z_2+\cdots + z_n)/n$ of Cesaro means How to get the current date/time in Java Is there a way I can share the 3.42 GB download of Windows 8.1 from Windows Store? Windows 8.1 is out, and I would like to know if it is possible to share the Windows 8.1 download upgrade between different computers so that I don't have to download it over and over again?  This might be helpful for people who are on a metered connection. Store is downloading 3.42&nbsp;GB of data so it must be stored somewhere. Is there a way I can copy it to my other computers and start the setup so that I don't have to download it over and over again on each computer I own? Create longer arrows Which Ubuntu repositories are totally safe and free from malware? Link button in post editor escapes square brackets in code What is port forwarding and what is it used for? There are a lot of questions on , but there doesn't seem to be one that clearly states what it is and what it's used for. So:   What is port forwarding? What is it used for, and why would I need it? How do you scrape AJAX pages? Please advise how to scrape AJAX pages. If it was possible to dig a hole that went from one side of the Earth to the other... ...And you jumped in.  What would happen when you got to the middle of the Earth? Would you gradually slow down, until you got to the middle and once you were in middle would every direction feel like it was up? Why is the electric field inside a conductor zero in equilibrium? My textbook says the field inside a conductor must be zero in order for the system to be equilibrium and therefore there must be no excess charge inside.  Their proof:  1) Place a gaussian surface inside the conductor. Since the system is at equilibrium, all points on the surface must have an electric field of zero.  2) Therefore the net flux is zero, implying the charge inside is zero.  3) If there is no charge inside, all excess charge must lie on the surface.  My problem:  "Since the system is at equilibrium, all points on the surface must have an electric field of zero."  Why?  Consider an conductor with no excess charge. To simplify things, say the conductor consists of a 100 free electrons and a 100 ions of charge 1$e^+$. The conductor is neutral and at equilibrium.  Now consider the field on one specific electron. There a total of 99 other electrons and 100  ions. So there would be a net field acting on that specific electron. So even though the system is at equilibrium, the net field on the individual particles is non-zero.  So a system can be at equilibrium, even if the net field inside is non-zero. What am I misunderstanding?  Another example: Consider a system consisting of one electron and one proton. If nothing is holding them back they will attract each other until they touch. After they touch, the force acting on them is still non-zero, yet they wouldn't accelerate. What if MSE used a different rep model for privileges? Is there a way to do the following using LINQ?  foreach (var c in collection) {     c.PropertyToSet = value; }   To clarify, I want to iterate through each object in a collection and then update a property on each object.  My use case is I have a bunch of comments on a blog post, and I want to iterate through each comment on a blog post and set the datetime on the blog post to be +10 hours. I could do it in SQL, but I want to keep it in the business layer. Let $E$ be a Banach space, $\mathcal B(E)$ the Banach space of linear bounded operators and $\mathcal I$ the set of all invertible linear bounded operators from $E$ to $E$. We know that $\mathcal I$ is an open set, and if $E$ is finite dimensional then $\mathcal I$ is dense in $\mathcal B(E)$. It's not true that $\mathcal I$ is dense if we can find $T\in\mathcal B(E)$ injective, non surjective with $T(E)$ closed in $E$, since such an operator cannot be approximated in the norm on $\mathcal B(E)$ by elements of $\mathcal I$ (in particular $E$ has to be infinite dimensional).  So the question is (maybe a little vague): is there a nice characterization of $\overline{\mathcal I}^{\mathcal B(E)}$ when $E$ is infinite dimensional? Is the case of Hilbert space simpler? I'm having problems with a WFS GetFeature request. I'm using OpenLayers with an OSM map as base layers which use the Google projection. Overlaying the layer with WMS works perfect. When I do a request to return all features within the bounds of a polygon, no features are found.  My layer uses EPSG:28992. the base layer uses: EPSG:900913  My layer configuration in GeoServer:    When I set the declared SRS to EPSG:900913 and set "SRS handling" to "Reproject native to declared" it works fine, but I need OpenLayers to reproject it, not GeoServer.  Below is an example request I would do. I think the problem is that GeoServer does not convert the spatial filter to the native SRS.  http://mydomain.com/wfs?request=GetFeature&amp;version=1.1.0&amp; srsName=epsg:28992&amp; typeName=Namespace:Layer1&amp; propertyName=(*)&amp; CQL_FILTER=year = 2011 and INTERSECTS(geometry,POLYGON((565585.61613069 6816272.786200799,565585.61613069 6817032.3791692,564362.62367835 6817032.3791692,564362.62367835 6816272.786200799,565585.61613069 6816272.786200799)))&amp; outputFormat=GMl2&amp;   Update  I just tried re-projecting some points from OpenLayers (EPSG:900913) via proj4js to EPSG:28992 (PostgreSQL and GeoServer). I took 3 points and  compared them. They all showed an offset.   Converted: POINT(233492,24349424947 582191,0681508556)  In Database: POINT(233530,852147064 582315,680920578)  Difference x: 38,60865281453 Difference y: 124,6127697224 Converted: POINT(133459,1980658749 455770,7481867363)  In Database: POINT(133486,356985081 455879,67223342)  Difference x: 27,1589192061 Difference y: 108,9240466837 Converted: POINT(176920,43262818802 317930,36182729155)  In Database: POINT(176954,154083767 318023,515324756)  Difference x: 33,72145557898 Difference y: 93,15349746445   If the offset was constant I could correct it. Now I'm not sure if the offset is caused by GeSserver or by proj4js. I'm guessing proj4js since the WMS layer does not show any offset. What is the physical significance of dot & cross product of vectors? Why is division not defined for vectors? I get the physical significance of vector addition &amp; subtraction. But I don't understand what do dot &amp; cross products mean?   More specifically,    Why is it that dot product of vectors $\vec{A}$ and $\vec{B}$ is defined as $AB\cos\theta$? Why is it that cross product of vectors $\vec{A}$ and $\vec{B}$ is defined as $AB\sin\theta$, times a unit vector determined from the right-hand rule?   To me, both these formulae seem to be arbitrarily defined (although, I know that it definitely wouldn't be the case).   If the cross product could be defined arbitrarily, why can't we define division of vectors? What's wrong with that? Why can't vectors be divided? Is there an equivalent of 'which' on the Windows command line? As I sometimes have path problems, where one of my own cmd scripts is hidden (shadowed) by another program (earlier on the path), I would like to be able to find the full path to a program on the Windows command line, given just its name.  Is there an equivalent to the UNIX command 'which'?  On UNIX, which command prints the full path of the given command to easily find and repair these shadowing problems. Changing pemalink structure to /%post_id%/%postname%/ I'm currently using permalink structure: /%year%/%monthnum%/%day%/%postname%/  I want to change that to: /%post_id%/%postname%/  I expect it to be:   faster (database is sorted by post_id?) shorter URLs (and clearly visible short verstions, just leaving the %postname%/ out) more SEO friendly - since my content is "evergreen" so publishing date is irrelevant (and written at each post, along with last update date) - so this would give shorter URLs, with no downsides compared to using year/month/day structure.   THE QUESTION: Does WordPress handle all the 301 redirects automatically? I can fix internal links to the new structure (though I'd expect that to be automatic as well), but worry about outsite links, pointing to my posts/articles.  If not, what's the best way to implement this change? Any links or full answers here are welcome.  I have about 120+ posts already, will this change affect the speed since it's not been done from the start? If 20 independent Bernoulli trials are carried out each with a different probability of success and therefore failure. What is the probability that exactly n of the 20 trials was successful?  Is there a better way of calculating these probabilities rather than simply summing together the combinations of success and failure probabilities?