How to solve the following integral by method of residue?
Evaluating $\int_{-\infty}^{\infty}\frac{1}{(x^2+b^2)^2}dx$
External Styles in JasperReports I'm working on a system that includes a large number of reports, generated using . One of the newer features is that you can define styles for reports.  From the available docs I believe there is some way to have an external file defining styles to use, and you can reference that in your jasper reports. This allows a single style to be used by multiple reports.  I can't find any concrete information on whether this is an actual feature, and if it is, how to use it. Does anyone know if it is possible to have external styles for jasper reports, and if so, how to do it? What is a Pythonic way to pad a numeric string with zeroes to the left, i.e. so the numeric string has a specific length? How to generate PDF/A and PDF/X? I have heard about PDF  PDF/A (for archival) and PDF/X (for printing). How to generate LaTeX documents like that?  I'm also interested in answers with plain TeX and ConTeXt, and hopefully with both pdfTeX and XeTeX engines. How to revert to factory settings? Python List vs. Array - when to use? If you are creating a 1d array, you can implement it as a List, or else use the 'array' module in the standard library.  I have always used Lists for 1d arrays.  What is the reason or circumstance where I would want to use the array module instead?  Is it for performance and memory optimization, or am I missing something obvious? Cancelling upvote on comment? As mentioned on :     For something that can be done so   easily by accident, there should be   the ability to undo mistakes.   I know that I have clicked several times on a comment up-vote without actually wanting to.  I would suggest being able to cancel the up-vote (maybe only for a couple of minutes or even less than a minute, no problem, as long as I can undo a miss-click). How to visualize a value resulted from math node,or just to know it. I tried the way of scaling this value to the scene size and then pick the color and get the value but I want more effective way to do this. Construction of "it's too hard a task" MacBook Pro (15-inch, 2016) with 2 USB-C to HDMI adapters. The setup works great if I start up in that configuration.   If I connect the adapters while the machine is running or simply sleeping, one of the monitors will never get a signal and stay in low power mode. The OS sees the monitor, it shows in the display arrangement settings and I can move the mouse into it, but until I restart, I can't see anything on it.  Once I have restarted I can let the machine sleep or whatever, and the display still works unless I disconnect the adapter. As soon as I do that a restart is required to use it again.   Using MacOS Sierra (10.12.4)  Using this adapter: How do I install gfortran? I am trying to install gfortran in my computer with Ubuntu 12.04 by using these commands,  sudo -i apt-get update apt-get install gfortran   but I found the program saying "unable to locate package gfortran". Then on a Ubuntu page I found some question regarding the same problem and I went through the solution from them but again I couldn't install the gfortran package.  Can anybody tell me how to install it? I haven't found a similar question on here, though I suspect the question may be rather well-covered.   I want to find a conformal map from the vertical strip $\{z:-1&lt;Re(z)&lt;1\}$ onto the unit disc.  Under the exponential map the region is taken to the annulus with radii $e$ and $e^{-1}$, but I'm not sure how useful this will be.  Can anyone advise on what the conformal map may be?  Thanks. What does NOEXEC flag mean when mounting directories on RHEL? I am trying to understand the NOEXEC flag when mounting.  I am having an execution issue within the /tmp directory on someone elses machine that I cannot access atm where the /tmp directory is mounted onto a different drive than '/' and NOEXEC is present.  I wanted to try and recreate this scenario on my machine, but I do not have a second hard drive.  I tried doing the following command:  mount --bind /test1 /test2   I then removed the bind flag and added NOEXEC in /etc/fstab.  Then, I created a file in /test2 called test.sh where it just echos 'hello world'.  I try and run it and it said 'permission denied'.  I then ran chmod 777 test.sh and was able to execute the file just fine.  I thought that the NOEXEC flag should not allow me to execute anything?  Is mount --bind /test1 /test2 not the same as mounting from a completely different physical drive? As in /test1 and /test2 are on different drives? Calculate difference between two dates (number of days)? Problems with \pgfplotstableread and relative paths How do you make a deep copy of an object? Import Large Excel File How unique is the php session id? I got the impression from various things that I've read that I should not rely on two users never getting the same sessionid. Isn't it a GUID? My book (Concepts of Physics by H.C. Verma) writes:  It has been reported () that the force between two masses may be better represented by $$F = \frac{G_{\infty} m_{1} m_{2}}{r^2} \left[1 + \left(1 + \frac{r}{\lambda} \right) \alpha e^{-\frac{r}{\lambda}}\right]$$ where $\alpha \approx - 0.007$ and $\lambda \approx 200~\mathrm{m}$.  What is this? Such a horrendous formula! So, what about Newton's? And what's the difference between $G$ &amp; $G_{\infty}$? Proving square root of a square is the same as absolute value Lets say I have a function defined as $f(x) = \sqrt {x^2}$. Common knowledge of square roots tells you to simplify to $f(x) = x$ (we'll call that $g(x)$) which may be the same problem, but it isn't the same equation. For example, say I put $-1$ into them:  $\begin{align} f(x) &amp;= \sqrt {x^2} \\ f(-1) &amp;= \sqrt {(-1)^2} \\ f(-1) &amp;= \sqrt {1} \\ f(-1) &amp;= 1 \end{align}$  $\begin{align} g(x) &amp;= x \\ g(-1) &amp;= -1 \end{align}$  thereby, we conclude that $f(x)$ and $g(x)$ do not produce the same results even though they are mathematically the same. This is also shown when we try to graph the functions:  :    :    :    From this, we can see that given $f(x) = \sqrt {x^2}$, when simplified is not the same as $f(x) = x$. So, is there any way to prove that $y = \sqrt {x^2}$ is not the same as $y = x$ for negative values, but is infact the same as $y = \mid x \mid$? Can anonymous class implement interface? Is it possible to have an anonymous type implement an interface?  I've got a piece of code that I would like to work, but don't know how to do this.  I've had a couple of answers that either say no, or create a class that implements the interface construct new instances of that. This isn't really ideal, but I'm wondering if there is a mechanism to create a thin dynamic class on top of an interface which would make this simple.  public interface DummyInterface {     string A { get; }     string B { get; } }  public class DummySource {     public string A { get; set; }     public string C { get; set; }     public string D { get; set; } }  public class Test {     public void WillThisWork()     {         var source = new DummySource[0];         var values = from value in source                      select new                      {                          A = value.A,                          B = value.C + "_" + value.D                      };          DoSomethingWithDummyInterface(values);      }      public void DoSomethingWithDummyInterface(IEnumerable&lt;DummyInterface&gt; values)     {         foreach (var value in values)         {             Console.WriteLine("A = '{0}', B = '{1}'", value.A, value.B);         }     } }   I've found an article  that describes one approach. Is this the best way of doing this?