Textbox value using threading ?Cross-thread operation not valid
How do I update the GUI from another thread?
Prove that $(a + b + c)^{13}$ is divisible by $abc$ if $b|a^3$, $c|b^3$ and $a|c^3$. ID for Contact portion of Person Account Is it possible to get the ID of a Contact which is part of a Person Account?  I have a custom object which has a custom field referencing the Person Account, though it seems to be referencing the Contact directly. I have created a button which I am using to pass the ID into a Visualforce Page.  With the Insert Field drop-down on the create/edit button page I can put in {!Account.Id} or {!Contact.Id} but neither of these work. The Account ID is placed in the URL but is not the correct ID and the Contact ID is blank, which I assume is because the button is on a Person Account page and not a Contact Page. Divergence of $\vec{F} = \frac{\hat{\mathrm{r}}}{r^{2}}$ Consider the vector field $$\vec{\mathrm{F}} = \frac{\hat{\mathrm{r}}}{r^{2}},$$ then the divergence of this field is: $$\vec{\nabla}\cdot\left(\frac{\hat{\mathrm{r}}}{r^{2}}\right) = 4\pi\delta^{3}(\mathrm{\vec{r}})$$  What is the proof of this relation? On my Windows machine, my main hard drive has the letter C: and the name "Local disk".   To list the drive letters in Java on Windows, the File object has the static listRoots() method. But I can't find a way to acquire the drive names (as opposed to the drive letters) on Windows.  Has anyone tried this before? I read recently that if you hold a bullet in one hand and a pistol in the other, both hands at the same height, and subsequently fired the pistol at the same time as dropping the bullet, both bullets would hit the ground at the same time (assuming the fired bullet encounters no obstacles).  Is this true, and if so can you explain the reasoning behind it with as few equations as possible? I assume it is essentially that gravity is unaffected by momentum, but it just sounds counter-intuitive. How to set scale across all blender objects and keyframes? I can understand this requirement for the old PPC RISC systems and even for x86-64, but for the old tried-and-true x86? In this case, the stack needs to be aligned on 4 byte boundaries only. Yes, some of the MMX/SSE instructions require 16byte alignments, but if that is a requirement of the callee, then it should ensure the alignments are correct. Why burden every caller with this extra requirement? This can actually cause some drops in performance because every call-site must manage this requirement. Am I missing something? Update: After some more investigation into this and some consultation with some internal colleagues, I have some theories about this:  Consistency between the PPC, x86, and x64 version of the OS It seems that the GCC codegen now consistently does a sub esp,xxx and then &quot;mov&quot;s the data onto the stack rather than simply doing a &quot;push&quot; instruction. This could actually be faster on some hardware. While this does complicate the call sites a little, there is very little extra overhead when using the default &quot;cdecl&quot; convention where the caller cleans up the stack.  The issue I have with the last item, is that for calling conventions that rely on the callee cleaning the stack, the above requirements really &quot;uglifies&quot; the codegen. For instance, what some compiler decided to implement a faster register-based calling style for its own internal use (ie any code that isn't intended to be called from other languages or sources)? This stack-alignment thing could negate some of the performance gains achieved by passing some parameters in registers. Update: So far the only real answers have been consistency, but to me that's a bit too easy of an answer. I have well over 20 years experience with the x86 architecture and if consistency, not performance, or something else concrete, is really the reason then I respectfully suggest that is a bit naive for the developers to require it. They're ignoring nearly three decades of tools and support. Especially if they're expecting tools vendors to quickly and easily adapt their tools for their platform (maybe not... it is Apple...) without having to jump through several seemingly unnecessary hoops. I'll give this topic another day or so then close it... Related Reduction Integration of $I_n=\int{\frac{x^n}{\sqrt{x^2+a^2}} dx}$ How do I derive this using reduction formula?  $$I_n=\int{\frac{x^n}{\sqrt{x^2+a^2}} dx}$$  I got $\sqrt{x^2+a^2}(x^n) - \frac{1}{n-1}(x^{n-1})\sqrt{x^2+a^2} + \frac{1}{n-1}(I_n) $ . I'm not too sure if this is correct. I would appreciate any form of help or correction to my answer. Thank you. Desktop link to Eclipse I was tring to install eclipse on ubuntu. What I did: I unzipped the tar archive of eclipse. I tried to start eclipse from the command line - like this - ./eclipse. It works. But then I tried to create a desktop icon with: gnome-desktop-item-edit ~/Desktop --create-new. In a new icon I showed the path to the eclipse executable which I could launch from the command line. But then eclipse does not start stating:  A Java Runtime Environment (JRE) or Java Development Kit (JDK) must be available in order to run Eclipse. No Java virtual machine was found after searching the following locations: /home/artem/eclipse/jre/bin/java java in your current PATH   The same message appears if I try to launch eclipse by double-clicking its original launcher. So it starts from the terminal but not from the desktop (it does not start when double-clicked) And also I get a message in the terminal (at some stage it appeared):  (gnome-desktop-item-edit:8998): Gtk-WARNING **: Attempting to store changes into `/root/.local/share/recently-used.xbel', but failed: Failed to create file '/root/.local/share/recently-used.xbel.DSV8LW': No such file or directory   I am using Ubuntu 12.04 x32 and eclipse Juno.  PS. PATH variable points at jdk/bin and JAVA_HOME - to the jdk folder PSS. I actually set the environment variables through .bashrc file(JAVA_HOME and PATH) Getting Windows 7 admin account password? Show current ping to website on Taksbar I'm looking for a way to monitor my current internet connection quality by showing the ping-response to a website like google in the taskbar on the right side. I'm using Windows 8.1. Kind of like , but for the ping. Any suggestions?  I want to stop using the command line to ping Google. If you draw two cards, what is the probability that the second card is a queen? hide proof environment for restructuring Opacity problem over white object in Illustrator I have a problem. I'm working with an object at 50% opacity. When it's over the artboard itself the color looks great, but when I put a white object behind it I get this weird color that doesn't look accurate.  This happens with every object and only in CMYK. I'm pretty sure this never happened to me before so maybe I changed something in the settings or I don't know.  Does anyone have any idea? Here comes Bob.  Bob is coming here.  Would anyone please explain what is  the difference between these? Can you terminate more than one common on the furnace C terminal? Virtualbox not seeing any usb devices in the usb filters settings I was following this question but found a problem.   I used guvcview to test the camera, it works. I installed the 12.04 virtualbox release from their website and installed the extension pack. But when I click the usb with the green plus sign it says no devices available. Notifications in browser tab A very nice feature for Stack Overflow (and other Stack Exchange sites) would be to indicate the number of notifications (if any) in the browser tab like seen on Facebook:    Of course that would require automatic update if content has changed. Some kind of 'push-notification' which would be a nice feature as well. Understanding central limit theorem What is wrong with the following sentence:      The Central Limit Theorem  implies that, as the sample size grows, the error distribution approaches normality.   Am I correct by saying that it should in stead state the MEAN of the sample error approaches zero as sample size grows? I would like to take a picture of a street during the day to depict how much traffic and cars there are on the street.  Is there anyway to do this with a long exposure photograph?  I have a Nikon D90 and I set the f stop down to 1/16 (the lowest of my lens) and set the time to 2 seconds. Doing this, the exposure is almost saturated when taken around 5pm with the sun setting behind a tree. Doing this, the cars passing by were very hard to make out against the stationary background, being visible as a blur in the color of the car.  Perhaps this is not possible and I should just do this at night where the cars lights are much brighter than the background.  Please suggest how else I might depict the traffic in a photograph?  Are daytime long exposure photographs even possible?