My solution  I tried to use VirtualBox to simulate , but experienced problems (see below). My solution was to use Hyper-V (as answered in  comment). How to access Hyper-V: Type in the Start Menu search Hyper-V Manager.  My problem  I'm using Windows 8.1 Pro x64 build 9600. My goal is to simulate Windows 10 Technical Preview x64 on VirtualBox. I downloaded VirtualBox 4.3.16 from . This is my system information:  Steps i've tried:   I enabled virtualization:   I executed command in CMD: "C:\Program Files\Oracle\VirtualBox\VBoxManage.exe" modifyvm "Windows 10" --longmode on I enabled Hyper-V feature:  I also tried to use a 32-bit ISO of Windows 10 Technical Preview. If the status of Hyper-V is  or , I get the following error when I start simulating Windows 10 Technical Preview:  However, if I  Hyper-V, I get the following error:  If I hit Continue, the following error comes:    I still cannot use 64-bit operating systems:
My host is x64 bits Windows 8.1.  I downloaded the latest Virtual Box (4.3) and I'm trying to create a VM with a 64 bits Ubuntu OS (ubuntu-12.04.3-desktop-amd64).  When I go to New VM wizard, it doesn't give me option to select "Ubuntu (x64)" as I have seen in other people's screenshots, only just "Ubuntu". As a result, the ISO can't boot. I tried in another PC and Virtual Box gives the x64 variants to most listed OS...  Control Panel shows x64 OS, x64 processor. My host laptop is a Sony Vaio VPCZ22UGX/N, Intel® Core™ i7-2640M processor. CPUz shows Vx-t is available on my processor, of course.  Here is what I tried so far:   I enabled IO APIC as required in the docs. I have virtualization enabled in the BIOS. It works fine in VMware. Check that Hyper-V is not running or even installed on my Windows. Same for VMware. I also tried running the command:  VBoxManage modifyvm [vmname] --longmode on    for that VM, but no change.. I think the issue is really that I can't select x64 variant of the Ubuntu OS for that VM. Other people seem to indicate that's a requirement, but I don't get that option for some reason.  I spent a lot of time and can't find what's wrong... Anyone knows what could be missing here?  Thank you very much!!  Eduardo
A teacher wants to randomly form two teams of 5 students from a group of 5 girls and 5 boys for a sports activity. A teacher wants to randomly form two teams of 5 students from a group   of 5 girls and 5 boys for a sports activity. Two of the girls, Ann and   Alice, are selected as team leaders. Find the probability that one   team has exactly 3 girls.   If i do this way $$\dfrac{{3 \choose 2}{5\choose 2}{1\choose 1}{3\choose 3} \times 2!}{{8 \choose 4}{4 \choose 4}} = \dfrac{6}{7}$$  Which turns out to tally with the answer. But i got one big question, is my way correct. Do i really need to times $2$ here? Please see my link below to my previous question cause the previous question make me doubt if i should times $2$. Reprojected MODIS NDVI has range from -32768 to 32767, expected -1 to 1 Reload the page on hitting back button The disk that contains Ubuntu on my computer is 115GB in size.  When the disk was 114.7GBfull.  I started deleting some files here and there to free up around 5GB.  But I noticed the disk was 114GB filled again. I thought it was some cache or swap thingy so didn't give it much thought and went ahead and freed around 40GBby shifting some media files out of the disk.  I have a notification in an hour or so that the disk is full yet again!! 40GB!!! All gone!  So I debugged the problem down to the /var/log/syslog file which was initially definitely less than 20GB. I know this because /var folder was 17GB before I cleared the memory.  /var/log/syslog file is currently 55.9GB!  Could someone be so gracious to explain this anomaly? Is this a bug? Or am I affected with some malware or virus? Eclipse menus are cut off or don't show I'm using Ubuntu 13.10 (with JDK 1.7.0_45).  I've downloaded and uncompressed Eclipse Kepler for Java EE Developers.  The software menus are messed up. I didn't notice similar problems in other software.  When I click any menu in Eclipse, the drop-down seems to be "cut". Sometimes the drop-down shows, but the options are invisible.  I tried Eclipse Indigo, but the same problem occurs. Can I visit the US for tourism on a previously unused B1/B2 visa? Note: This is NOT a duplicate of  Difference: In both other questions, the posters traveled once to the US for the original purpose for which the B1 visa was obtained. Their question is about visiting again using the same visa. However, I've not traveled to the US yet, and I'm planning my visit. What I want to understand whether I can use this visa for a visit whose purpose is not the same as what was submitted along with the application.  Can I use a B1/B2 visa for tourism that was originally obtained for business purposes BEFORE I actually visit the US even once? I had applied for a business visitor visa for a valid business reason but by the time I got it stamped, my plan changed. So I've not visited the US even once. Can I now use this visa to visit as a tourist without having used that visa for its original intended purpose? PS: I live in India. Practical Uses for the "Curiously Recurring Template Pattern" What are some practical uses for the ""?  The "" example commonly shown just isn't a convincing example to me. Fetch the row which has the Max value for a column ANOVA assumption normality/normal distribution of residuals Downgrade Windows 7 Ultimate to Home Premium without a clean install Currently I've got an installation of Windows 7 Ultimate x64. I would like to downgrade to Windows 7 Home Premium x64 without a clean install. I've got a (legal) retail disc and tried the following tricks:        Still the Windows setup keeps telling me I can't upgrade because I've got a higher version installed (Ultimate). The trick seems dead. Does anyone know a way to change from Ultimate to Home Premium without the hassle of a clean install? Convert Shapefiles to GeoJSON? I'm trying to convert Shapefiles from the  website into a GeoJSON file for use with Google Maps API. I'm using QGIS to facilitate but I can't get the projection/coordinates right. So far I've tried Google Mercator (EPSG:900913) and WGS 84 (EPSG:4326) with no luck. I'm using the OpenLayers to verify results and it keeps placing Texas near the  Gulf of Guinea (0 lat, 0 lng). Why do people risk death by joining Starfleet if not for money or preservation of their homes? Watching Star Trek made me think of a few "deeper" questions about Starfleet, which are all related to the Star Trek TV series.  So, let's take for example the Dominion War: people are dying every second, ships get destroyed and cadets are still joining although they know they are probably going to die unless they are with Picard or Sisko.  As I read and got to understand, money has no value anymore, latinum is the general trading currency in the universe. But people on Earth don't trade and don't earn their paychecks. Earth is a much better place than today and yet young boys and girls from every culture/civilization are joining Starfleet as they are willingly signing their death note.  Why are they joining, what motivates them? They might know that they're probably going to die.  They don’t earn paychecks. They could be doing any other job, yet they choose this. And what's more interesting how many died on battlefields must be lined up in front of StarFleet every day?  What do they receive after service? Why are they doing it other than preserving their homes? Multiple Author and email with location? I am trying to add multiple Author with their email and location but not working.  I am trying to get something like this     first_person^1 , second person^2, third_person^3            {1^mail, 2^mail, 3^mail}@gmail.com                   institution name                      location Where can you ask about Career Advice? The  specifically says not to ask  for career advice but people do it anyway.  Should I consider the Help Center outdated or only loosely enforced?    And what about a career advice site on the network?  There are 70+ sites, and most of them are for relatively narrow interests (which is not a criticism, I enjoy looking through the many sections).  A career section seems like it would be very popular.  Also, a careers section would help keep career questions off the other sites. What identifies an action-reaction pair of forces? This is a question on a worksheet that I'm giving to a student:  A man of weight $W$ steps into the lift. The lift then moves downwards with a constant speed. If $R$ represents the force acting on the man by the lift floor, which of the following statements is/are correct? (3) $R$ and $W$ are an action-reaction pair according to Newton's third law  Why isn't this statement (3) correct? Differences between /bin, /sbin, /usr/bin, /usr/sbin, /usr/local/bin, /usr/local/sbin I have six directories with command files. These are /bin, /sbin, /usr/bin, /usr/sbin, /usr/local/bin and /usr/local/sbin.  What are the differences between these? If I'm writing my own scripts, where should I add them?    Related: What cross-platform command-line tool allows me to get my external IP address? How do I get my external IP address  from the Windows and Linux command line? On Windows, ipconfig shows an internal network IP address, but it does not show the external one. How is prototyping done in a professional EE environment? Do you do your prototypes on breadboards, on copper clad boards, Manhattan style, or do you just draw schematics, order PCBs made and assembled and work with them, hacking here and there if necessary? Differential equation: autonomous system This isn't homework. I have no idea what theorems I should be looking at to solve this. Guidance, partial and total solutions are all welcomed.     Let $f$ be a locally lipschitz function in an open set $G\subseteq \Bbb R^n$. Consider the autonomous system $y'=f(y)$.      Let $y(x,\xi)$ be the value at point $x$ of the maximal solution that satisfies the initial condition $y(0)=\xi$.         Prove that the domain of $y(\cdot, y(s, \xi))$ is $I-s$, where $I$ is the domain of $y(\cdot ,\xi)$.   Prove that for all $s, t$ such that $y(s, \xi)$ and $y(t+s, \xi)$ exist, then $y(t,y(s,\xi))$ also exists and $y(t,y(s,\xi))=y(t+s, \xi)$.   If $y$ is a maximal solution and there exists $T&gt;0$ such that $y(0)=y(T)$ and $f(y(0))\neq 0$, then $y$ is a periodic solution and not constant.   If $y$ is a solution whose domain is $(a,+\infty)$, if $\eta:=\lim _{x\to +\infty}y(x)$ and $\eta \in G$, then $f(\eta)=0$.      EDIT  I found an alternative solution for 3. Please check my proof and give feedback in comments:  let $u$ be the restriction of $y$ to $[0,T]$, now let $\overline u$ be the periodic extension of $u$ to $\mathbb R$. It is easy to see that $\overline u$ is a solution to the given differential equation. But since $f$ is locally lipschitz, $\overline u$ must coincide with $y$ wherever they are both defined. Since $y$ is a maximal solution, it must be $\overline u$, so $y$ is defined on $\mathbb R$. Cascading Drop down in SharePoint Online