This is my first time installing an Ubuntu system onto my laptop which is a Dell Inspiron 6400. It used to run Windows XP, and when installing Ubuntu it said that the wired network was detected and was able to install new updates needed for the system.  Whenever the system was installed and I tried to connect to the internet I couldn't. I don't think I have a Broadcom driver installed, and I have tried to install it but I get confused on bad tutorials on YouTube. Can anyone give me step by step instructions of how to get the drivers from my other computer which has wireless access and put them on my Inspiron and what to do from there.  Output of lspci:  00:00.0 Host bridge: Intel Corporation Mobile 945GM/PM/GMS, 943/940GML and 945GT Express Memory Controller Hub (rev 03) 00:02.0 VGA compatible controller: Intel Corporation Mobile 945GM/GMS, 943/940GML Express Integrated Graphics Controller (rev 03) 00:02.1 Display controller: Intel Corporation Mobile 945GM/GMS/GME, 943/940GML Express Integrated Graphics Controller (rev 03) 00:1b.0 Audio device: Intel Corporation NM10/ICH7 Family High Definition Audio Controller (rev 01) 00:1c.0 PCI bridge: Intel Corporation NM10/ICH7 Family PCI Express Port 1 (rev 01) 00:1c.3 PCI bridge: Intel Corporation NM10/ICH7 Family PCI Express Port 4 (rev 01) 00:1d.0 USB controller: Intel Corporation NM10/ICH7 Family USB UHCI Controller #1 (rev 01) 00:1d.1 USB controller: Intel Corporation NM10/ICH7 Family USB UHCI Controller #2 (rev 01) 00:1d.2 USB controller: Intel Corporation NM10/ICH7 Family USB UHCI Controller #3 (rev 01) 00:1d.3 USB controller: Intel Corporation NM10/ICH7 Family USB UHCI Controller #4 (rev 01) 00:1d.7 USB controller: Intel Corporation NM10/ICH7 Family USB2 EHCI Controller (rev 01) 00:1e.0 PCI bridge: Intel Corporation 82801 Mobile PCI Bridge (rev e1) 00:1f.0 ISA bridge: Intel Corporation 82801GBM (ICH7-M) LPC Interface Bridge (rev 01) 00:1f.2 IDE interface: Intel Corporation 82801GBM/GHM (ICH7-M Family) SATA Controller [IDE mode] (rev 01) 00:1f.3 SMBus: Intel Corporation NM10/ICH7 Family SMBus Controller (rev 01) 03:00.0 Ethernet controller: Broadcom Corporation BCM4401-B0 100Base-TX (rev 02) 03:01.0 FireWire (IEEE 1394): Ricoh Co Ltd R5C832 IEEE 1394 Controller 03:01.1 SD Host controller: Ricoh Co Ltd R5C822 SD/SDIO/MMC/MS/MSPro Host Adapter (rev 19) 03:01.2 System peripheral: Ricoh Co Ltd R5C592 Memory Stick Bus Host Adapter (rev 0a) 03:01.3 System peripheral: Ricoh Co Ltd xD-Picture Card Controller (rev 05) 0b:00.0 Network controller: Broadcom Corporation BCM4311 802.11b/g WLAN (rev 01)   Output of sudo lshw -c network:    *-network                       description: Network controller        product: BCM4311 802.11b/g WLAN        vendor: Broadcom Corporation        physical id: 0        bus info: pci@0000:0b:00.0        version: 01        width: 32 bits        clock: 33MHz        capabilities: pm msi pciexpress bus_master cap_list        configuration: driver=wl latency=0        resources: irq:16 memory:efdfc000-efdfffff   *-network UNCLAIMED        description: Ethernet controller        product: BCM4401-B0 100Base-TX        vendor: Broadcom Corporation        physical id: 0        bus info: pci@0000:03:00.0        version: 02        width: 32 bits        clock: 33MHz        capabilities: pm bus_master cap_list        configuration: latency=64        resources: memory:ef9fe000-ef9fffff

I'm having serious problems installing the Broadcom drivers for Ubuntu. It worked perfectly on my previous version, but now, it is impossible.   What are the steps to install Broadcom wireless drivers for a BCM43xx card?  I'm a user with no advance knowledge in Linux, so I would need clear explanations on how to make, compile, etc.    lspci -vnn | grep Network showed:   Broadcom Corporation BCM4322 802.11a/b/g/n Wireless LAN Controller [14e4:432b]      iwconfig showed:  lo        no wireless extensions. eth0      no wireless extensions.   NOTE: Answer below is updated every time new information is added and confirmed working.


While learning some basic programming, I came across a (to me) very strange method of calculating the area of a triangle.  In Javascript, this was expressed as:  var perimeter = (side1 + side2 + side3)/2;   var area =  Math.sqrt(perimeter*((perimeter-side1)*(perimeter-side2)*(perimeter-side3)));      This can be mathematically represented as following:  $$A_\triangle=\sqrt{d\Biggl(( d-a )(d-b)(d-c) \Biggr) }$$ where $d$ equals to half of the sum of the length of the three sides of the triangle, and $a$, $b$, and $c$ represent the three different lengths respectively.   I cannot, either by expanding or just 'looking' at the equation, figure out why this works (I assume it does so after testing with a few example triangles).  If any kind (and clever) soul could explain why this works, It'd much appreciated.

Let $a,b,c$ be the lengths of the sides of a triangle. The area is given by Heron's formula: $$A = \sqrt{p(p-a)(p-b)(p-c)},$$ where $p$ is half the perimeter, or $p=\frac{a+b+c}{2}$.  Could you please provide the proof of this formula? Thank you in advance.


I want to know if this sentence is correct. Can we say "Most Legendariest ....."? If not, what is the alternative I can use? Thank you very much.

I was over exaggerating while writing something for class and I wrote     Welcome to the most wildest show on earth.    Someone pointed out the most wildest and I was wondering if it was OK to use most with a word that ends in -est together.


It’s hard to explain what I’m asking for, so I made a diagram:    The person is falling. The person stands on a large object while falling (let’s say a part of a plane). Just before the objects hits the ground, the person jumps with great force. The person lands safely on the ground after he jumps.   Would this be possible for a person to do? I know this is a physics related question, so assume that the person’s mass is 90 kg and the plane debris is 900 kg. The person and the object fall from a height of 12 km.

Imagine you're trapped inside a free falling elevator. Would you decrease your impact impulse by jumping during the fall? When?


Everytime when I want to build application from source on linux, I have to install dependencies libraries in my operating system (ubuntu).  Typical scenario:  Start ./configure Got error about missing library: xyz sudo apt-get install libxyz-dev Go to step 1. At the end I finish with mess in my operating system and problem with dependencies. For instance:  The following packages have unmet dependencies:   librsvg2-dev : Depends: libglib2.0-dev (>= 2.12.0) but it is not going to be installed                 Depends: libgdk-pixbuf2.0-dev (>= 2.21.6) but it is not going to be installed                 Depends: libcairo2-dev (>= 1.2.0) but it is not going to be installed                 Depends: libgtk2.0-dev (>= 2.21.5) but it is not going to be  installed   Always ask myself what now ? Should I force ubuntu to install higher version of library ?  Here is my question:  Maybe there is another way to building software on linux(ubuntu) from source. Some isolate way. Not integrating to my OS ? I'm coming from java world and there, building a application != install every dependency in system. Any suggestion ? Best practice ?

When installing something from source (say, Ruby 1.9.2), what command can I run to get a complete list of all the dependencies needed to install that application? Is this possible?


I've tried using this: =countif(B2:B200, "<Open>")  And it ends up looking like this:  I want it to look like this:  Or something similar to that. Basically I want to include the word "Open" and the number count of cells B2:B100 Can someone please help?

I have lots of cells that contain unique text.   I'd like to add a
 to the start of the cell and a
 to the end of the string in the cell.   Turning this: Here is some text I've written. It's different in each cell. into this:
Here is some text I've written. It's different in each cell.
  I've tried =CONCATENATE("
",A1) but can't find a way to add something to the end of the cell as well?


Windows 7 (x64) has a blue welcome screen (blue grass picture) which shows my user icon in the center. After PC sleeps and wakes up, this screen is shown. How do I skip it, and not have to press the user icon?

When Windows 7 hibernates and then I wake it up, it always shows a screen where I have to click before I can get into the Windows environment. I don't have a password set so this intermediate screen serves no purpose - just one wasted mouse click and an unnecessary wait every time. How do I disable this so that I go from hibernating directly into my desktop without a click?


Let $T_1,\: \ldots,\: T_k$ subtrees of a tree $T$ such that for all $1\leq i <j \leq k $ the trees $T_i$ and $T_j$ have a vertex in common. Show that $T$ has a vertex that is in all $T_i$.  I found this, it is right?

Can someone please verify my proof or offer suggestions for improvement? I am aware that there is a similar question elsewhere, but I want help with my proof in particular.     Let $T_1, \ldots, T_k$ be subtrees of a tree $T$ such that for all $1 \leq i < j \leq k$, the trees $T_i$ and $T_j$ have a vertex in common. Show that $T$ has a vertex which is in all of the $T_i$.   Suppose, for the sake of contradiction, that for every vertex $v \in V(T)$, there is a subtree $T'$ in the list $T_1, T_2, \ldots, T_k$ such that $v \notin V(T')$.  Pick $v_1 \in T_1$. There is a subtree $T^{(1)}$ such that $v_1 \notin T^{(1)}$. $T_1$ and $T^{(1)}$ have a vertex $y_1$ in common. Now, there exists a tree $T^{(2)}$ such that $y_1 \notin T^{(2)}$. But now, $T^{(2)}$ and $T^{(1)}$ have a vertex $y_2$ in common. Also, $T_1$ and $T^{(2)}$ have a vertex $y_3$ in common.  There exists a path $p_1$ in $T_1$ from $y_3$ to $y_1$. Also, there is a path $p_2$ in $T^{(1)}$ from $y_1$ to $y_2$ and a path $p_3$ in $T^{(2)}$ from $y_2$ to $y_3$. Note that the path formed by the union of $p_1$ and $p_2$ passes through $y_1$, while $p_3$ does not, since $y_1 \notin T^{(2)}$. Therefore, the union of $p_1, p_2$, and $p_3$ forms a cycle, contradicting the fact that $T$ is a tree. Therefore, it must be the case that there is a vertex $x$ in all of the $T_i$.


Inspired by , along with answers and comments, where the assertion made by many seems to be "yes, you drop to the ground at the end of your turn." However, I'm not so sure it's that cut-and-dry.     The game organizes the chaos of combat into a cycle of rounds and turns. A round represents about 6 seconds in the game world. During a round, each participant in a battle takes a turn. (PHB5e p.189, emphasis in original)   It seems to me that the mental model of combat turns & rounds and standard initiative must be one of sequential declaration and resolution of simultaneous action: when I declare my movement and action(s) on my turn, I am declaring and my table is resolving those movements and actions I take during the round, all as a compromise between simulationism and table-speed.  By this interpretation there'd be nothing wrong with ending a turn mid-air, as no matter how many other declaration-resolution events came before my next turn, in-game zero time has passed between my character's end of one turn and the beginning of 's next. But that's just my interpretation--I'm sure there are good rationales behind others.  In case you're looking for a concrete example, here it is from last Wednesday: my STR18 gnome barbarian wants to long-jump that 15'-wide mud-river near Ogremoch's chamber. On his turn he disengages from a foe, runs 25' to the river, and jumps. His turn ends after 10' in the air. Next turn: is he in the mud trying to wade for 5', or is he flying through the air for 5'?   The clear answer for 3.5e:

According to the PHB (p 182) after a 10 foot movement the player is able to make a long jump whose length is equal to their strength score.  Each foot jumped costs 1 foot of movement.  I have a character with a speed of 25 who can jump 30 (due to the jump spell tripling their normal jump distance of 10).  What happens when he runs out of movement?   The player moves the full distance of the jump The player stops moving when they run out of movement and fall The player moves up to their movement speed, then finishes the jump on their next turn


I want to know an algorithm to find unique random number which is non repeatable. Every time when I call that in program should be give a unique and random number which is not given before by that algorithm. I want to know because some time in a game or app this kind of requirements are came.   For ex. In a game I have created some objects and save all them in a array, and want to retrieve  them by randomly and uniquely and not want to delete from array. This is just a scenario.  I have tried some alternative but they are not good performance wise, never got answer of this question.  How it is possible programmatically?  Thanks in advance.

I'd like to generate unique random numbers between 0 and 1000 that never repeat (i.e. 6 doesn't show up twice), but that doesn't resort to something like an O(N) search of previous values to do it. Is this possible?


How I use Offline version of google input tool... If not then help me to develop the tool like Google input tool

I need Google Input Tools for writing scripts in Telugu language in Celtx in Ubuntu 13.10. I tried various methods, but none is as simple as Google Input Tools. Is there a way?


I have a multi-level directory of jpegs that I want to optimise on a semi-regular basis (as things are added). The command I'm using jpegoptim is single-threaded so when I run the following, only one CPU core is engaged and it takes a long time.  find media -exec jpegoptim --strip-all {} +   Given there are so many files and I have 8 CPU threads available, can I split the workload so it's running on all of them?

G'day,   I have tried to solve this problem all morning but have not had success. I would like to search for certain scripts in a particular folder and execute them all in parallel. The scripts have different names, but all end with "run.sh". Below what I have tried without success.   The first approach was to use find in combination with -execdir. This works, however, the scripts are executed in a sequantial fashion. I want all scripts to be executed simultaneously (parallel). There seems to be no option to achieve this with -execdir  find . -name "*run.sh" -type f -execdir 'nohup' {} '&' \;   Then, I tried using xargs because there is has a parallel option (-P). I have not tried the parallel option yet, because I am unable to get xargs to run the scripts in their respective subfolders. The commands below execute all scripts, but do that in the folder I am running the command in, therefore the scripts themselves do not work. The scripts have to be executed in their own subfolders. In the above example, -execdir is doing that as opposed to -exec. How do I achieve that with xargs?  nohup find . -name "*run.sh" -type f | xargs -0 -I{} bash -c f\ \{\}   or  nohup find . -name "*run.sh" -type f | xargs -0 -I{} bash -c "f {}"   or  nohup find . -name "*run.sh" -type f | xargs -0 -I{} bash -c "./{}"    I am really frustrated and am hoping that there is somebody out there that can help.  Thank you so much!


I want to install the stable release of xfce 4.12 on my Xubuntu 14.04.2. However, when I add the repository (ppa:xubuntu-dev/xfce-4.12) via terminal I get a message about these being pre-releases and to wait for the final release date... Yet, the final release is already up (xfce website, two months ago).  Why do I get a warning message if the stable version was released already? That is slightly misleading. Furthermore, all posts and info I see about installing xfce 4.12, either old (pre-release,  or ) or new (post release,) follow the same proceedure (add dev-ppa).  How should I properly install a stable release if it doesn't appear on the main repos?

Why are packages in the official Ubuntu repositories older than the latest (upstream) versions from Debian Sid, PPAs, the authors, etc.?


Every time I open my browsers, be it Firefox, Chrome, Dragon, or , the qvo6.com page loads. The homepages for these browsers are set to blank. Yet this problem persists.   doesn't seem to work at all!  I've tried TrendMicro's HijackThis, and it still doesn't seem to help.  Any means to remove this annoying thing? I don't remember what caused this.

What should I do if my Windows computer seems to be infected with a virus or malware?  What are the symptoms of an infection? What should I do after noticing an infection? What can I do to get rid of it? how to prevent from infection by malware?   This question comes up frequently, and the suggested solutions are usually the same. This community wiki is an attempt to serve as the definitive, most comprehensive answer possible. Feel free to add your contributions via edits.


If there was a wormhole connecting two spatially/temporally separate locations, would it have mass that depends on the spacial separation, the temporal separation, the relative motion of the two ends of the wormhole?

What would for an observer be the mass of an isolated wormhole (meaning that there is no gas and no mass of stars around it) if the wormhole mouth opposite to the observer reflects the light of a region from the galaxy it opens into.   Wormholes per definition require negative energy in the form of exotic matter so as to have their mouths open. Would this negative mass be the only mass of the wormhole object or for an observer in the isolated wormhole also include the light reflected of stars and gases visible through the wormhole of another galaxy.  Wormholes connect two systems for only a short time, and collapse when too much time has passed, or too much mass has passed through them. My question would be for wormholes that can have their mouths connected either naturally or artificially for a reasonable length of time.


For every action, there is an equal and opposite reaction.   Look at this free body diagram from an exercise where a man pushes a box up an inclined platform:    I don't see all those "equal and opposite" reactions here. If the man pushes on the box, the box pushes on the man as well, and if the platform pushes on the box, the box also pushes on the platform, so why aren't those forces drawn here? The box also pushes on the air (P) and the air on the box but if those forces were equal wouldn't the box not move? I mean, if A pushes on B with force F and B pushes back on A with force -F, how come anything moves? Is it because the have different masses? Would that make this "opposite and equal reaction" not equal then? I'm confused.

Given Newton's third law, why is there motion at all? Should not all forces even themselves out, so nothing moves at all? When I push a table using my finger, the table applies the same force onto my finger like my finger does on the table just with an opposing direction, nothing happens except that I feel the opposing force. But why can I push a box on a table by applying force ($F=ma$) on one side, obviously outbalancing the force the box has on my finger and at the same time outbalancing the friction the box has on the table? I obviously have the greater mass and acceleration as for example the matchbox on the table and thusly I can move it, but shouldn't the third law prevent that from even happening? Shouldn't the matchbox just accommodate to said force and applying the same force to me in opposing direction?


What is the rule-of-thumb relation between megapixels and printout size?  If I have a camera with that number of MP I will be approximately be able to print solid xx by yy inch (or cm) photos?

What size images do I need for common print sizes, such as wallet size, 8x10, and 16x20?  Is there a general formula?  How could that size change if, for example, a 16x20 was printed on canvas rather than photopaper?


I had opened a Pen-Drive in my system and I thought to open my Pen-Drive from terminal and copy the needed file from system to Pen-Drive from terminal only. But I was wondering how I can do that. Can you please suggest me procedure for doing the same?

I only have access to the command line. I need to backup my data (on the user folder) to a pen (USB DOK).    How can I mount a flash drive manually? What should be the copy command?


The story is told from the perspective of the felinoids as they discover that despite humanity's lower technology that the average human intelligence is roughly on par with their geniuses. The story unfolds as humanity takes advantage of their access to advanced technology to spread out and become rulers in vast regions of the galaxy.  I read this in the late 80's or early 90's, but I just can't place the book. It was a stand alone, by an author I'd never heard of then or since.

Trying to identify a science fiction short story from an anthology likely published before 1991.  Aliens invade during a nuclear war (which would be World War III, WWIII, WW3). The warring nations then turn their nukes on the landing sites, but the invasion succeeds.  Believe the setting is in the U.S., possibly Pacific Northwest, but definitely a mountainous region.  Based on negative inference from the aliens' description of humans as fur-less, no-tail, bipeds (or similar), the aliens are apes or monkeys.  The aliens describe Earth as worse than the Hell planet they previously conquered. They see our tanks and think that we can't have more than a few of those to fight with.  Yet the aliens are somewhat benign, as they take some children back to their parents for a stern talking-to after the children run an alien convoy off the road into a chasm by stringing a rope across the road.


When my Mac started, I check my interfaces: $ ifconfig lo0: flags=8049<UP,LOOPBACK,RUNNING,MULTICAST> mtu 16384     options=1203<RXCSUM,TXCSUM,TXSTATUS,SW_TIMESTAMP>     inet 127.0.0.1 netmask 0xff000000      inet6 ::1 prefixlen 128      inet6 fe80::1%lo0 prefixlen 64 scopeid 0x1      nd6 options=201<PERFORMNUD,DAD> gif0: flags=8010<POINTOPOINT,MULTICAST> mtu 1280 stf0: flags=0<> mtu 1280 XHC20: flags=0<> mtu 0 en0: flags=8863<UP,BROADCAST,SMART,RUNNING,SIMPLEX,MULTICAST> mtu 1500     options=400<CHANNEL_IO>     ether a0:99:9b:17:50:07      inet6 fe80::cd8:2bd4:f767:a6ed%en0 prefixlen 64 secured scopeid 0x5      inet 192.168.2.228 netmask 0xffffff00 broadcast 192.168.2.255     nd6 options=201<PERFORMNUD,DAD>     media: autoselect     status: active en1: flags=8963<UP,BROADCAST,SMART,RUNNING,PROMISC,SIMPLEX,MULTICAST> mtu 1500     options=460<TSO4,TSO6,CHANNEL_IO>     ether 82:13:08:b0:ec:c0      media: autoselect <full-duplex>     status: inactive en2: flags=8963<UP,BROADCAST,SMART,RUNNING,PROMISC,SIMPLEX,MULTICAST> mtu 1500     options=460<TSO4,TSO6,CHANNEL_IO>     ether 82:13:08:b0:ec:c1      media: autoselect <full-duplex>     status: inactive bridge0: flags=8863<UP,BROADCAST,SMART,RUNNING,SIMPLEX,MULTICAST> mtu 1500     options=63<RXCSUM,TXCSUM,TSO4,TSO6>     ether 82:13:08:b0:ec:c0      Configuration:         id 0:0:0:0:0:0 priority 0 hellotime 0 fwddelay 0         maxage 0 holdcnt 0 proto stp maxaddr 100 timeout 1200         root id 0:0:0:0:0:0 priority 0 ifcost 0 port 0         ipfilter disabled flags 0x2     member: en1 flags=3<LEARNING,DISCOVER>             ifmaxaddr 0 port 6 priority 0 path cost 0     member: en2 flags=3<LEARNING,DISCOVER>             ifmaxaddr 0 port 7 priority 0 path cost 0     nd6 options=201<PERFORMNUD,DAD>     media: <unknown type>     status: inactive p2p0: flags=8843<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST> mtu 2304     options=400<CHANNEL_IO>     ether 02:99:9b:17:50:07      media: autoselect     status: inactive awdl0: flags=8943<UP,BROADCAST,RUNNING,PROMISC,SIMPLEX,MULTICAST> mtu 1484     options=400<CHANNEL_IO>     ether ba:2f:ce:01:6e:14      inet6 fe80::b82f:ceff:fe01:6e14%awdl0 prefixlen 64 scopeid 0xa      nd6 options=201<PERFORMNUD,DAD>     media: autoselect     status: active llw0: flags=8863<UP,BROADCAST,SMART,RUNNING,SIMPLEX,MULTICAST> mtu 1500     options=400<CHANNEL_IO>     ether ba:2f:ce:01:6e:14      inet6 fe80::b82f:ceff:fe01:6e14%llw0 prefixlen 64 scopeid 0xb      nd6 options=201<PERFORMNUD,DAD>     media: autoselect     status: active utun0: flags=8051<UP,POINTOPOINT,RUNNING,MULTICAST> mtu 1380     inet6 fe80::5e2a:55ee:b7dc:1b30%utun0 prefixlen 64 scopeid 0xc      nd6 options=201<PERFORMNUD,DAD> utun1: flags=8051<UP,POINTOPOINT,RUNNING,MULTICAST> mtu 2000     inet6 fe80::62d2:7e57:5727:90c8%utun1 prefixlen 64 scopeid 0xd      nd6 options=201<PERFORMNUD,DAD>  in the beginning, I only use lo0, en0, maybe en1 and en2. I some times install the VMware Fusion and docker and other things. I don't know why there get some many interfaces out, when I launched my Mac there will start so many interfaces, this is a waste of the computing resources, how to delete them or stop them?

ifconfig reveals a surprisingly long list of network interfaces on my MacBook, which is running macOS High Sierra (10.13.6): lo0, gif0, stf0, XHC20, en0, p2p0, awdl0, en1, en2, bridge0, utun0.  There is an F5 VPN client installed, but I've rebooted the MacBook since the last VPN connection.  Are all of these network interfaces legitimate or is this something I should worry about?


I've been given an old Eeepc 1005HA netbook running Windows XP and want to switch to a Linux OS and remove XP completely.   Is this easy/advisable?   What's the best way?  The netbook has no CD drive I read about installing from USB but then the Ubuntu site mentions using the Windows installer (not sure if this is only applicable if you want to add Ubuntu to XP).  Also confused about setting new drive sizes. Device is described as CPU Intel ATOM N280 / 1.66 GHz, RAM 1024 MB.

I would like to see a full how-to guide on how to install Ubuntu.


This makes sense since $p$ and $q$ are primes but I'm not sure how I can prove that the subgroup will be cyclic?   Will the generator of the subgroup be $pq$?

Problem.  Let $G$ be a group of order $pq$ such that $p$ and $ q$ are prime integers.  I am to show that every proper subgroup of $G$ is cyclic.  My attempt.  What I know: Any element $a$ divides $pq$ and $a^{pq} = e$.  The order of subgroups $H$ divide $pq$ by Lagrange.  If I could show that $G$ is cyclic, then all subgroups must be cyclic.  If I can show that $G$ is a group of prime order, then I can show that it is cyclic.  I'm not sure what more I can do here...I've tried looking at Fermat's Little Theorem but I can't seem to properly understand it and how it could affect my problem..


I have a list of random float values.  Here's an example: my_list = [56.23, 9.1, 856.1, 158.31, 84.15, 63.91, 3.46, 5.1, 5, 6, 31, 84]  Except, my list (when generated) is hundreds of variables long, always divisible by 6.  I'm trying to find a quick way (that doesn't involve reversing the list and iterating through new list variables by popping them off one-by-one) to turn my list into a list containing all of the original floats, but paired into groups of six?  Here's how it should look given the random list I've created above: my_list = [56.23, 9.1, 856.1, 158.31, 84.15, 63.91, 3.46, 5.1, 5, 6, 31, 84] new_list = some_awesome_function(my_list) print(new_list)  This new_list variable should print: new_list = [[56.23, 9.1, 856.1, 158.31, 84.15, 63.91], [3.46, 5.1, 5, 6, 31, 84]]  Simply the same list, but it groups every six variables into its own group within the group.  Any idea, folks?  This would be very much appreciated.

I have a list of arbitrary length, and I need to split it up into equal size chunks and operate on it. There are some obvious ways to do this, like keeping a counter and two lists, and when the second list fills up, add it to the first list and empty the second list for the next round of data, but this is potentially extremely expensive.  I was wondering if anyone had a good solution to this for lists of any length, e.g. using generators.  I was looking for something useful in itertools but I couldn't find anything obviously useful. Might've missed it, though.  Related question:


What command would you give to print (display on the screen) the corrected text of userNotes.txt with all sentence endings having required two blanks before the start of the next sentence?   This is the question I'm trying to answer using sed, but every attempt I try is wrong. It's possible I'm missing something, but the code I feel should work is:  sed 's/\. /\.  /g' userNotes.txt   It works but not I suppose in this context. The error response gives me:   No. That's not it. For example, your command listed     All sessions have those characteristic three steps.   If you are working on a PC where you are the only registered user, you might log in where I was expecting     All sessions have those characteristic three steps.  If you are working on a PC where you are the only registered user, you might log in   which has my two spaces as being too large. It's supposed to be a simple answer, but I don't believe it gets simpler than this. I also cannot use things like [[:space:]], awk, etc. just basic sed edit.

Q: What command would you give to print (display on the screen) the corrected text of userNotes.txt with all sentence endings having required two blanks before the start of the next sentence?  here is my code  sed 's/.\s/.\s\s/'    but this also changed the line where it ended with dot and 2 spaces to dot and 3 spaces.


Proof that $n=250$ is the largest value for $n$ for which $1005!$ is divisible by $10^n$ where $n\in\Bbb{N}$.  My attempt was to find a way for counting the number of last zeroes for any permutation $k!$ where $k\in\Bbb{N}$, however I haven't arrived at any useful result. I don't know how to proceed with this one.

For how many positive integer $k$ does the ordinary decimal representation of the integer $k\text { ! }$ end in exactly $99$ zeros ?  By inspection I found that $400\text{ !}$ end in exactly $99$ zeros , but $399\text{ !}$ does NOT end in $99$ zeros ; using the formula $$\text{ number of zeros at the end }=\sum_{n=1}^{\infty}\left[\frac{k}{5^n}\right]$$where , $[x]$ denotes the greatest integer part not exceeding $x$. I also found that, for $k=401,402,403,404$ the number of zeros is same, but for $k=405$  the number of zeros increase by $1$ ; as $405$ is divisible by $5$ again , after $400$. Thus I got that there are only $5$ integers satisfying the condition which are $400,401,402,403,404$. The question is possible duplicate of  or  but my question is different from these two questions.  Does there exist any other rule  or easy formula from where I can get how many integers are there


There is no official driver. (I know that. I've spent 5 hours looking) But is there another way to get it to work? I plugged it in, and the driver didn't automatically install, so I searched Google. (5 hours looking, still.) No Drivers. I also have Wine (Windows Compatibility Layer & Program Loader) but the Windows Driver Setup (official version) did not work either.    I am using a USB cable to connect to the printer, and the printer is on and fully set up.  And, In "How can I install a Canon printer or scanner driver?" there still is no iP2820. So, I would not consider it a duplicate. The answers there do not answer this question!

I tried to install the MP190 drivers, but appeared a message show me that requires to have libcupsys2. I understand that libcup2 is an update of libcupsys2.   How do I solve this? Are there proprietary drivers for my Canon printer or scanner?


Once upon the time there live two exe files, A and B. They were going along together just fine. B was always responsible for starting and stopping A, so B had some time on his own, but A only knew life together with B. Until one day A asked: A: Hey B, how is it like when you are alone? B: It is nice for a while, I mean, nothing special. And look who's curious today. A: I am thinking about it sometimes, but it is kinda frightening too. How do you know you are not alone in the system when you are the only one awake? B: Hahaha, off course you are not alone. We never are. There are other process in our system. You just never read about them. A: Then it is even more frightening. How do you know what they might do? I feel safe because I know you are the one starting and stopping me. What would happen if I realize that you are not running? Who started me then? B: Don't be silly. Off course it is me. Who else... A: But you can't know that for sure. What if some other process decides to start me while we are both not running. Do you know who started you, right now? B: Uhm... well... I never thought about it. I just thought there is order in the system. I never... A: I just want to feel safe. I need to know how to check if you are not running. What if some other process started me even while you are running? B: What got into you? Why are you... Wait, have you... have you talked with "Creator" again? A: I... I am not sure. Could have been a dream. B: A dream? But how can a process dream if it is not sleeping, but not even running? But A have not replied...  So, as it is obvious from this fairy-tale, question is: does a process knows which process had invoked it? I could pass a parameter when starting the process, make a wrapper to make it look nicer, but was just wondering is there something already built-in.

I was looking a lot for method to get parent process in .NET, but found only P/Invoke way.


I am setting up a view, with the Authored on filter exposed. When selecting the box, there isn't any popup calendar.  Doesn't Drupal 8 come with a calendar popup in core? How can I turn this on for exposed filters with date?

How can I configure an exposed filter so that users can filter my site content by creation date, preferably using a date picker?   I tried using Content: Authored on as filter, but it gets me a text field to enter the date to enter a date/time in the yyyy-mm-dd hh:mm:ss format, which makes entering the date more difficult for users and more error prone.  What is the difference between Drupal 8 and Drupal 7 with  7.x-3?


My System was having Windows XP in C: drive, then I installed Ubuntu in F: Drive. Everything was going fine.   But I re-installed Windows XP due to some reasons and I did take care of F: Drive where Ubuntu 14.04 is already installed. After Successfully installation of Windows XP SP3, I am not getting any GRUB window. It is directly booting to Xp.   I think GRUB of Ubuntu might have gone. HOw can I fix it?? Can I do repair or something using installation disk??

I installed Windows 7, which ate Ubuntu's boot file. When starting up the computer, it now goes straight to Windows, without giving me the option of booting Ubuntu.   How can I get Ubuntu back?


I cannot find any pattern rounding off doubles in an array. I am trying to make a program that will input a double like grades,money etc., and round it off in a whole number.

What I would like is a method to convert a double to a string which rounds using the half-up method - i.e. if the decimal to be rounded is 5, it always rounds up to the next number. This is the standard method of rounding most people expect in most situations.  I also would like only significant digits to be displayed - i.e. there should not be any trailing zeroes.  I know one method of doing this is to use the String.format method:  String.format("%.5g%n", 0.912385);   returns:  0.91239   which is great, however it always displays numbers with 5 decimal places even if they are not significant:   String.format("%.5g%n", 0.912300);   returns:  0.91230   Another method is to use the DecimalFormatter:  DecimalFormat df = new DecimalFormat("#.#####"); df.format(0.912385);   returns:  0.91238   However as you can see this uses half-even rounding. That is it will round down if the previous digit is even. What I'd like is this:  0.912385 -> 0.91239 0.912300 -> 0.9123   What is the best way to achieve this in Java?


I have a multi feature shapefile and a slope raster and I'm trying to export images (tif, png whatever) for each feature showing the feature boundary and the slope raster contained within it with a field from the shapefile as the filename. I am dealing with a lot of features (>100,000) so efficiency is key, I tried data driven pages and it failed every time.

I have a raster aerial photo.  I have county wide parcel data.  I want to clip/screen shot the raster at each individual parcel.  Think of this application - a post card with an image of your house --here is your house--  I want to have each parcel attribute to contain information + hyperlink of the aerial photo.  Any other solutions welcome, but this is the only method I could think of. Although I am unsure of how to achieve it efficiently.  Using ArcInfo 10.


I'm trying to apply text to a basic sphere but I can't figure it out. I've applied a shrinkwrap modifier to the text, and have the target of the modifier be the sphere, but the effect doesn't come out the way I want it to. The text hovers slightly in front of the sphere and part of the text doesn't look like the way it should (bottom half of the "O".)  The only way the text looks like the way I want it to is when I increase the offset setting in the shrinkwrap modifier. But then I have a problem where the text is too far away from the sphere. I want the text to look like it's a part of the sphere, sort of like a golf ball.

I want to create an image like below, so a balloon with text on it.     I have been googling for ideas (text, sphere, ....) and came on  earlier question. So I tried Shrinkwrap and Cast modifier.   Here is the situation before applying the modifiers.    This was after trying Shrinkwrap    And this after Cast modifier.    For me it does not look like it is going to work with one of these modifiers.  Question How to create the image of a balloon with text on it ? With one of these modifiers or should I try a complete other approach ?? How to do this ?


Since today morning, I am trying to remove VirtualBox from my machine but I am getting following errors. I tried disabling virtualization as well but still getting the same error.     Kindly help me remove this.

Can anyone help me remove VirtualBox?  I am running 12.04.


I want decimal value to two precision output like below input,   0       78.8798 6 0.986   to   0.00 78.88 6.00 0.99   in c# decimal value to decimal or string.

When displaying the value of a decimal currently with .ToString(), it's accurate to like 15 decimal places, and since I'm using it to represent dollars and cents, I only want the output to be 2 decimal places.   Do I use a variation of .ToString() for this?


Find the limit of the following sequence:  $$\lim_{{n}\to {\infty}}\frac{1^p+2^p+\cdots+n^p}{n^{p+1}}=?$$  I've tried using the Stolz-Cesaro theorem. I've set $a_n=1^p+2^p+\cdots+n^p$, and $b_n=n^{p+1}$.  After some transformations I got $$\lim_{{n}\to{\infty}} \frac{(n+1)^p}{(n+1)^p-n^p},$$ but after expanding the binomials, I could not make any transformations that would give me a satisfactory result. Can you help me please? Thank you very much.

By considering:  $$\lim_{n\to\infty}\frac{\sum_{k=1}^n k^1}{n^{2}} = \frac 1 2$$ $$\lim_{n\to\infty}\frac{\sum_{k=1}^n k^2}{n^{3}} = \frac 1 3$$ $$\lim_{n\to\infty}\frac{\sum_{k=1}^n k^3}{n^{4}} = \frac 1 4$$  Determine if this is true: $$\lim_{n\to\infty}\frac{\sum_{k=1}^n k^m}{n^{m+1}} = \frac 1 {{m+1}}$$  If it is, prove it.  If it is not, evaluate $\lim\limits_{n\to\infty}\frac{\sum_{k=1}^n k^m}{{m+1}}$.


To be a topology we need the empty set to be open but- X is not finite so the empty set can't be in it and if X was finite every subset of X would be in the topology...

Say we have an infinite set $X$ and a topology $T$. In the general defition of a topology the empty set $\emptyset$ and the whole set $X$ belong to the topology. But isn't that contradictory with the defintion of the cofinite topology.  Cofinite Topology:  $T = \{ A \subset X  | A = \emptyset $ or $ X\setminus A$ is finite$\}$  So according to the definition of a topology we have that $X,\emptyset \in T$ and according to the cofinite topology we only have $\emptyset \in T$ (The whole set $X$ is closed).  Gr


I recently sent an email to SE Team, offering the idea to allow "tips" on Stack Exchange sites. They advised me to post it here, since SE is maintained and build by the community.   Below is an email text, that sent to SE Team, and I would like to hear what the great Stack Exchange community is thinking about allowing Dogecoin "tips" on SE sites:     Hello SE Team,        It's a first time I'm writing to this email, and the first thing that I want, is to thank you for a great service and site you're providing!   You have a great community sites, that helps me each day multiple   times and actually, I don't know what would I do, if Stack Overflow   would not exists. And I'm sure I am not alone with my feelings.    Again, great work and thank you!        Now for a business :)   I'm sure geniuses like you, heard about Bitcoin like cryptocurrencies, and Dogecoin especially   (). In case of not, Dogecoin is an alternative to   Bitcoin currency that grows very fast and has a huge community.   Dogecoin exists less then two months, but community counts almost 70k   members on reddit ().        What I think, it would be a great thing, if it would be possible to make Dogecoin "tips" on Stack Exchange sites. Not just up-voting a   good answers, but send some "tip" to person who helps to solve the   problems. I don't think it's something hard to implement, since there   already exists the tipping bot that works on Reddit, Twitter,  Youtube   and more.        In my opinion, such service can be as useful for Dogecoin as for Stack Overflow. As a beta, it could be used on    and if it proves yourself, it can   move further for other SE sites.        Thank you, hope you will like it and we will see Dogecoin on Stack Exchange soon!   Regards,   Alex Danilov     Edit: After receiving some comments, I think it important to state that Dogecoin is not a "real currency" and do not want to be. It is a "virtual tipping value". As huge Dogecoin community states: 1 Dodge = 1 Doge :)

I have an idea for dealing with a question you badly want to be answered, which no one will answer, even after you've offered a large bounty: cash.  Users can offer cash, and whoever has the accepted answer can be paid, possibly via PayPal.  Does this sound like a good idea?


I'm trying to make page with normal div #header and scrollable div #content, so my #content fill all the height left from the #header, even if #header changes his own height.  I tried several options and that is this is my last one . But the flaw of this option is that I need to change top property of #content (utilize JavaScript) if height of the #header changes.  Is there any solution to achive my goals only with css?  html {     height: 100%; } body {     height: 100%;     margin: 0;     position: relative; } #header {     background-color: tan; } #content {     overflow: auto;     background-color: teal;     position: absolute;     bottom: 0;     top: 20px; }
     Test header

     Test content

I am working on a web application where I want the content to fill the height of the entire screen.  The page has a header, which contains a logo, and account information. This could be an arbitrary height. I want the content div to fill the rest of the page to the bottom.  I have a header div and a content div. At the moment I am using a table for the layout like so:  CSS and HTML    #page {     height: 100%; width: 100% }  #tdcontent {     height: 100%; }  #content {     overflow: auto; /* or overflow: hidden; */ }

...

...

     The entire height of the page is filled, and no scrolling is required.  For anything inside the content div, setting top: 0; will put it right underneath the header. Sometimes the content will be a real table, with its height set to 100%. Putting header inside content will not allow this to work.  Is there a way to achieve the same effect without using the table?  Update:  Elements inside the content div will have heights set to percentages as well. So something at 100% inside the div will fill it to the bottom. As will two elements at 50%.  Update 2:  For instance, if the header takes up 20% of the screen's height, a table specified at 50% inside #content would take up 40% of the screen space. So far, wrapping the entire thing in a table is the only thing that works.


I was rewatching the first season when I realized that they weren’t following the “nothing created in the holodeck can leave the holodeck” rule consistently. In the pilot episode, Wesley falls in the water in the holodeck and is still soaking wet after he leaves, and in “The big goodby” Picard still has lipstick on his lips from when the female prospective  client kissed him in the holodeck earlier on. However at the end of the episode when Redbrick and Leech step out of it, they disintegrate after just a few moments. Was this just inconsistencies in the writing, or are there other rules about what can/cannot leave the holodeck that I’m not aware of?

Related to   I was watching  last night and I noticed that when Data realizes that something has gone terribly wrong, he leaves the holodeck with the holodeck generated paper with a drawing of the Enterprise. The paper does not disintegrate as he leaves the holodeck. If this can leave the holodeck, why can't Professor Moriarity? Indeed, the original ending to this episode according to Memory Alpha:     The original ending filmed was cut from the episode. (Star Trek: The Next Generation Companion 2nd ed., pp. 68-69) Hurley recalled, "In that ending, Picard knew how to defeat Moriarty. He tricked him. He knew all along that Moriarty could leave the holodeck whenever he wanted to, and he knew because when Data came out and showed him a drawing of the Enterprise, if that piece of paper could leave the holodeck, that means that the fail-safe had broken down. In turn, this means that the matter-energy converter which creates the holodeck, now allowed the matter to leave the holodeck, which was, up to that point, impossible. When he knew that paper had left the holodeck, he knew that Moriarty could as well, so he lied to him."   This is interesting because the whole premise of this episode and Ship in a Bottle is that Moriarity can't leave the holodeck. Moreover, the Doctor from Voyager always needs some kind of  to go places.  Given this and the water/other matter that leaves the holodeck in the , why can some matter exist outside the holodeck while other matter cannot?   Is it tied somehow to the replicator - i.e. replicating a piece of paper into real matter is trivial, but replicating a human being or anything more sophisticated would be non-trivial?


I am working on a custom Wordpress Theme run on my localhost server. I am having trouble figuring out why the class is being added to the classList, but the style elements are not applying.    Javascript: "custom.js"  $(document).load(function() {     changeColor(); });  function changeColor(){     var x = document.getElementById("icon").contentDocument;     var y = x.querySelectorAll("path, circle");      for(var i = 0; i < y.length; ++i) {         y[i].classList.add("icon_stroke");     } }   External CSS Stylesheet: "style.css"  .icon_stroke {     stroke: red; }   HTML/PHP: "front-page.php"  <object id="icon" data="<?php bloginfo('template_directory');?>/src/imgs/icons/balance_icon_light_circle.svg" type="image/svg+xml"></object>   I can see in the Chrome editor that it successfully adds the class to the classList of the SVG element, however, there is no styling change to the SVG. I assume this might have something to do with the external stylesheet interacting with an external SVG object. I have (a) attached screenshot(s) for further clarification. Please let me know if you understand what is causing this issue, or if you have a workaround solution.  Thanks!!!!

I have a simple page that has some iframe sections (to display RSS links). How can I apply the same CSS format from the main page to the page displayed in the iframe?


I have some Ubuntu Server machines which I'd like to keep up-to-date, but not always if it requires a reboot.  Is there a way to tell if pending package updates require a reboot BEFORE installing the packages?

I often install packages and updates for them, although sometimes it is not convenient to do a reboot if one of the packages needs it, so is there any way of telling BEFORE installing the package/update whether or not it will require you to do a reboot? I have already looked  and the solutions there don't solve my problem, nor the more or less same one described there.


How can I get the Cartesian product (every possible combination of values) from a group of lists?  Input:   somelists = [    [1, 2, 3],    ['a', 'b'],    [4, 5] ]   Desired output:  [(1, 'a', 4), (1, 'a', 5), (1, 'b', 4), (1, 'b', 5), (2, 'a', 4), (2, 'a', 5) ...]


Suppose my directory contains the files hesa1.c and hesa2.c. The following bash script  #!/bin/bash for j in hes*.c do echo $j done   returns hesa1.c and hesa2.c .  How do I get this bash script to return only a1 and a2 (i.e what the wildcard expands to be)?

Lets say that I have a directory with the following files (among others):  touch doc-mike.txt doc-jane.txt doc-susan.txt   I can do something in a script with those files using a construct like:  for fname in doc-*.txt; do     echo input: ${fname} done   But if I want to get the substring of the filename that matches the wildcard I have to jump through some ugly hoops:  for fname in doc-*.txt; do     wildcard=${fname#doc-}     wildcard=${wildcard%.txt}      echo input: ${fname} output: output-${wildcard}.results done   That works:  input: doc-jane.txt output: output-jane.results input: doc-mike.txt output: output-mike.results input: doc-susan.txt output: output-susan.results   but I feel like there has to be a better/easier way to get the substring that matches the "*" glob wildcard


I understand how this idea works. Use the Binomial theorem and plug in the two numbers on the point for North and East into the binomial equation, but my specific problem deals with the possibility of going west too. Here's the specific problem he gave us

Let $f(n)$ denote the number of sequences $a_1, a_2, \ldots, a_n$ that can be constructed where each $a_i$ is $+1$, $-1$, or $0$.  Note that no two consecutive terms can be $+1$, and no two consecutive terms can be $-1$. Prove that $f(n)$ is the nearest integer to $\frac12(1+\sqrt2)^{n+1}$.  Can anyone help me with this problem. I really do not know what to do in this one.


I am having difficulties solving $\displaystyle{\lim_{x \to a} \sqrt{x} = \sqrt{a}}$ . How can I find $\delta$ in terms of $\epsilon$ without $x$ ?

$f(x) = \sqrt{x}$. For right limit, $x-a > 0$. Let $x-a < \delta$ then $(\sqrt{x}-\sqrt{a}) \lt \frac{\delta}{\sqrt{x}+\sqrt{a}}$. Then chose we must choose $\epsilon $ so that $\epsilon > \frac{\delta}{\sqrt{x}+\sqrt{a}}$. Is this correct? How would I conclude the proof?  Edit - Follow up  From answers, I try a proof for the same limit but this time Left side:  For left side limit, $x-a < 0$ so $a-x > 0$. Let $a-x < \delta$ then $\sqrt{a}-\sqrt{x} \lt \frac{\delta}{\sqrt{a}+\sqrt{x}} \lt \frac{\delta}{\sqrt{a}}$.   So let me begin the proof by saying to choose $\delta = \epsilon \sqrt a$ then $a-x \lt \delta $ so $(\sqrt a - \sqrt x )(\sqrt a + \sqrt x) \lt \epsilon \sqrt a$ so $\sqrt a - \sqrt x \lt \epsilon$


how to write code for this requirement and i want to show menus only in header menu with different menus to logged users

i have this code but its not working it throws syntax error, unexpected '}' error  function my_custom_menu_item($items, $args) {     if(is_user_logged_in() && $args->theme_location == 'primary')     {         $user=wp_get_current_user();         $name=$user->display_name; // or user_login , user_firstname, user_lastname         $items .= '
Welcome '.$name.'
';         $items.= //Change Password, Logout, etc     }     elseif (!is_user_logged_in() && $args->theme_location == 'primary') {         $items .= '
Log In
';         $items.= //Sign up, Lost Password     }     return $items; } add_filter( 'wp_nav_menu_items', 'my_custom_menu_item');


Consider an experiment where subjects reaction times are measured in three conditions. Because every subject participates in each condition, this is a typical within-subjects design. Now I'm wondering if a one-way within subjects anova is completely equivalent to a two-way anova with subject as the second factor. I already read some chapters on this topic but the difference between both procedures was never discussed explicitly.So,   Is there an advantage of using one compared to the other?  Is a multilevel approach with subject as the random effect and condition as a fixed effect even better?  What if an effect of time is assumed, (e.g. fatigue). Could this be modelled additionally as a "third" factor?   I know these are pretty vague/broad questions but I hope you could give me some hints anyway.  Thanks in advance

Consider repeated measures ANOVA (RM-ANOVA) with one within-subject factor A and several measurements per subject for each level of A.  It is closely related to two-way ANOVA with two factors: A and subject. They use identical decomposition of the sum of squares into four parts: A, subject, A⋅subject, and residual. However, two-way ANOVA tests the effect of A by comparing SS of A with the residual SS, while RM-ANOVA tests the effect of A by comparing SS of A with the A$\cdot$subject interaction SS.   Why the difference?    Does this difference automatically follow from the repeated-measures structure of the data, or is it some convention?  Does this difference between two-way ANOVA and RM-ANOVA correspond to testing two different nulls? If so, what exactly are they and why would we use different nulls in these two cases? Two-way ANOVA's test can be understood as an F-test between two nested models: the full model, and the model without A. Can RM-ANOVA be understood in a similar way?   (If there is only one measurement per subject for each level of A, then the distinction sort of disappears because A$\cdot$subject and residual variation cannot be disentangled: )    Demonstration  I will use toy data d2 generated in . The same webpage shows correct syntax for RM-ANOVA.  # Discarding between-subject factors and leaving only one within-subject factor d = d2[d2$Xb1=='CG' & d2$Xb2 == 'f', c(1,4,6)]   (See reproducible version .) Data look like that:       id Xw1     Y 1    s1   A  28.6 2    s1   A  96.6 3    s1   A  64.8 4    s1   B 107.5 5    s1   B  77.3 6    s1   B 120.9 7    s1   C 141.2 8    s1   C 124.1 9    s1   C  88.0 10   s2   A  86.7 ...   Here is two-way ANOVA: summary(aov(Y ~ Xw1*id, d))               Df Sum Sq Mean Sq F value   Pr(>F)     Xw1           2  95274   47637  16.789 3.73e-07 *** id           19  31359    1650   0.582    0.913     Xw1:id       38  71151    1872   0.660    0.929     Residuals   120 340490    2837                    Here is RM-ANOVA: summary(aov(Y ~ Xw1 + Error(id/Xw1), d))  Error: id           Df Sum Sq Mean Sq F value Pr(>F) Residuals 19  31359    1650                 Error: id:Xw1           Df Sum Sq Mean Sq F value   Pr(>F)     Xw1        2  95274   47637   25.44 9.73e-08 *** Residuals 38  71151    1872                       Error: Within            Df Sum Sq Mean Sq F value Pr(>F) Residuals 120 340490    2837               Note the identical SS decomposition, but two-way ANOVA tests Xw1 against the residual, while RM-ANOVA tests Xw1 against the Xw1:id interaction.  Why?  This question is related to . If we try using Error(id) instead of Error(id/Xw1) in the example above, then Xw1 will get tested against Xw1:id interaction lumped together with the residual variation.  (The same issue arises in factorial RM-ANOVA with multiple within-subject factors, where each factor or interaction is tested against its own "error term" aka "error stratum". These error strata are always given by the corresponding interaction with the block/plot/subject variable id.)


My hd has "449 defective sectors", although system says it's "ok". What does that mean and what should I do to solve the problem? Thanks!

My laptop has recently started to become a bit unreliable, and for some reason I started to suspect that my HDD was starting to fail. After a bit of hunting on the internet, I found Ubuntu's Disk Utility in the System menu and ran the long SMART diagnostics from this.  However, since the documentation for Disk Utility is very poor (palimpsest?), I'm not sure how to interpret the results:    For example, the Read Error Rate is over 50 million (!), yet the Assessment is rated "Good".   So would someone mind explaining to me how to interpret the results of these tests (especially the Normalized, Worst, Threshold and Value numbers)? And maybe tell me what they think of the results I got for my HDD? (Thanks)


Who are the people on left and right side of superman? The headline says Do they return to their planet?  So they could be aliens, Is the first one is The Mask?? He looks like him. I am not a comic book fan, so if it is Mask, then he and Superman are in same universe? If not who is he? and the girl right to superman?   Any reference to future movies?

In Justice League, we see a newspaper article showing three heroes who died (left to their home planets) but it was too fast that I missed catching the faces.   Who were the other two heroes who are dead?


When I boot Ubuntu 16.04 it is booting to a black screen. The below image contains the error message.

Today I got what I presume was the update that should take care of Spectre and Meltdown. That didn't go very well. What do I do now? See screen photo.    I can't boot the 4.4.0-108-generic kernel because of a kernel panic. I'm running 16.04 on an Intel Core i5-4670K CPU @ 3.40GHz × 4.


I'm re-organizing the catalog for my father's photojournalism career and am trying to determine what is the best practice for the archival of high-res scans (of film, contact sheets, prints, etc.). We have several 300mb-1gb images and I think this is beyond the capabilities of Lightroom for catalog management.  I've resorted to a Finder folder structure of:  - Drive - - Subject Name - - - Various scans

I am working with a larger collection of photographs (~10,000) for my PhD thesis (in biology) and I am currently struggling with the organization of these. Sorry, if this question is in the wrong stackexchange community, I just thought that if someone people here should know about organization of photos.  My collection:  To elaborate a bit more on what I would like to achieve: I am currently doing my PhD working and need to take a lot of pictures to identify or protocol different plants. Since my project is divided in 4-5 different sub-projects (each with further sub-divisions) it is hard to keep an overview. Also, some pictures are of general interest for my project and so should be linked not only to the corresponding sub-project but as well to the whole. Additionally, I am awaiting more photos to pile up as this was only the first out of three field seasons...  My question:   How would you organize such as a photographic library?  What kind of folder structure would you suggest?   If I am searching in this forum (eg.  or ) or in any search engine, mostly ideas for daily life or professional pictures come up. But these use a very different kind of organization from what I need. For example, it is of little use to me to organize my pictures into people, places, events and dates as often suggested (eg. ).  Regarding folder structure, I thought about sort pictures  corresponding to days (eg. 2019-06-23). But I am afraid this would get to messy!? Or maybe I could sort pictures into the sub-projects and use tags in the metadata to link them to other sub-projects?  Side notes:   I am running a Linux machine (Manjaro, specifically) and so far I tried out digiKam for organization of my library. But I guess the OS is only of secondary relevance here (ie. each OS should have at least some software to deal with this kind of problem). For now I do not need to sync my files between devices. Usually, I do not need to edit my photos. Only maybe 1-2 for the cover later...


I was reading up of centripetal motion when I saw the relation that $mg=N\cos\theta$, as can be seen from , in the case of a frictionless plane.  This contradicted with what I was taught before.  A block sliding down a ramp has a normal force perpendicular to the surface, which is equal to $mg\cos\theta$.  This video here   says the same thing.  I am stumped by this contradiction!  Which one is correct?

Normally, if an object of mass $m$ is inclined to the horizontal at an angle $b$, we set the reaction force of the object on the inclined plane as $R = mg\cos{b}$ (if we resolve the force of gravity so the line of action coming out of the plane is perpendicular to it).  However in circular motion*. it's assumed that $R\cos{b} = mg$. In the example above, one would have to do this in order to arrive to the correct answer, instead of $R = mg\cos{b}$. Using $R = mg\cos{b}$ seems natural enough, as I am resolving vertically, however, both equations would produce two different values for $R$. Why is this?   To show what I mean: If we set the reaction force in this question as $mg\cos{a}$, then the centripetal force will be $mg\cos{b}\cos(\pi/2-b) = mg\cos{b}\sin{b} = \frac{1}{2}mg\sin(2b)$   Whereas If we use $R\cos{b} = mg$, $R = mg\sec{b}$ and the centripetal force will be $mg\sec{b}\sin{b} = mg\tan{b}$. This will end up with two different values for the radius of the circular motion, and hence two different final answers.  *In the circular motion questions I've seen in my mechanics module


I'm building a binary classifier with logistic regression and boosting. Just like the case that I described in the title, I am a little bit confuse on how to explain the result of those two models together, and how to answer questions like is this variable a key predictor for predicting?

Since RF can handle non-linearity but can't provide coefficients, would it be wise to use random forest to gather the most important features and then plug those features into a multiple linear regression model in order to obtain their coefficients?


Is there a program I can download to add an option to create a new file to the contextual menu of finder?  doesn't seem to work in Snow Leopard.

In Finder > Select a folder > Right click, we get a popup with an option to create a new folder:    Is there a way to add menu item New Textfile for adding a new text file?


I am looking for a word for sentences which read the same forwards and when the order of words is reversed?  Just to clarify, I'm not talking about palindromes, in which individual characters are reversed. I’m thinking, instead, of sentences where the characters within words are left alone and the order of the words itself is reversed, for example:     That is that.

Please note, I'm not asking for a palindrome.  I mean to say that only the word  order is rearranged, not the actual spelling of the word.  An example might be as follows:     First ladies rule the State and state the rule: ladies first.


I am thinking about the exercise:  Exercise 5. Give an example of a random sequence ($M_n$) such that $E[ M_{n+1} | M_n ] = M_n$ for all $n\ge0$, but which is not a martingale w.r.t. the filtration $F_n = \sigma(M_0, \dots , M_n)$.  From Exercise 5 of Link :

I am wondering if there is such a sequence of random variables $(X_n)_{n=0}^\infty$ such that $\mathbb{E}(X_{n+1}\mid X_n)=X_n$ for all $n\geq0$ but which is not a martingale with respect to the filtration $\mathcal{F_n}=\sigma(X_0, \dots, X_n)$.  I would really appreciate if you could show me such an example.


how does one formula prove that $P(A\cap \overline{B})=P(A)-P(A\cap B)$. I can show with Venn diagrams that $(A\cap \overline{B})=A\backslash(A\cap B)$ but how does one formally prove it? And is it sufficient to prove this identity to get the identity for the probabilities?

Based purely on intuition, it would seem that the following statement is true, when thinking of the events as sets:  $$P(A\cap B) + P(A\cap B^c) = P(A)$$  However, I am not sure if this is true, and cannot find out how to prove it, or describe a straight forward intuition of it.  Is this equation true? And if not, is there another way to link $P(A\cap B)$ and $P(A\cap B^c)$ with $P(A)$?


Is there simple a rule to understand when to use quotes in Ubuntu command line and when single quotes and when double quotes are needed?   For example, how to explain the difference here:  $ echo $'a\naa\nac\nb\ncc\tdd\ne\se' a aa ac b cc  dd e\se $   and  $ echo $"a\naa\nac\nb\ncc\tdd\ne\se" a\naa\nac\nb\ncc\tdd\ne\se $

I often see tutorials on the web or posts on this site which make heavy use of the following characters at the command line. Often it seems that they are used for pretty similar purposes. What are the differences between them when used on the command line or for shell programming? For what purpose do I use which of them?  " " double quotes  ' ' single quotes  ` ` backticks


How to update/upgrade Ubuntu Server 16.04 offline ?. I have created a local mirror (150GB) using apt-mirror.  How to configure offline server/system to update the system.   Thanks in advance

I have a friend who has got a computer that is not connected to the Internet. Is there any way to install software offline easily?


If a suggested edit by me to a post is approved, I get a message saying it got approved and what post it was:    If a suggested edit by me to a tag wiki is approved, I get this unspecific message (and a lot of the time I get five or four at a time):    It'd be useful to easily see which one was approved, so I can more quickly tell what sort of edits are good.  For consistency's sake with post edits and for usability, I think that it should look more like this, specifying what was edited:

When one earns reputation from making tag wiki edits, the activity drop-down, shown when hovering over one's username, just says +2 tag wiki. There is no indication of which tag wiki was edited, or whether it was a tag wiki or a tag wiki excerpt. This gets particularly silly and useless if one edited several tag wikis at the same time, filling the list with entries that just say tag wiki, tag wiki, tag wiki over and over.  Can the activity drop-down say [tagname] tag wiki instead? It links to the right tag wiki, so it knows which tag the suggested edit was for, but I have to click through or look at the status bar to see which tag it was.


I think the FuelSDK-PHP is using TLSv1, so the question is how to check it.. and how to get it to v1.2, if thats even possible?  This is for PHP not for JAVA, as the other thread is.

Salesforce Marketing cloud recently announced the retirement of the TLS 1.0 based connections effective early August this year, and they published a  with useful information and some guidelines for the matter, but in that article they talk about integrations with the API (REST/SOAP) but not with the SDKs (even though, that's just a wrapper of the afore mentioned).  I'm using the  to integrate my backend with Salesforce Marketing Cloud and i would like to check which TLS protocol it is using to connect with.  How/where can I check that?


Is this at all possible?  What is the intuition for this?

Somebody asked me this question in a job interview and I replied that their joint distribution is always Gaussian. I thought that I can always write a bivariate Gaussian with their means and variance and covariances. I am wondering if there can be a case for which the joint probability of two Gaussians is not Gaussian?


I know stackoverflow.com uses ASP.NET MVC but I am curious to know the design and the architecture of Stack Overflow. In particular, I am curious to know about the following design choices:   Does it use Dependency Injection/IoC container? Why or why not? Where is the business logic developed? In the Controller action methods? Repository methods if following Repository pattern? Or in the Service layer if following the Service pattern? Or in the domain objects themselves à la Active Record?    In particular I would be more interested in learning about reasons pertaining specifically to stackoverflow.com rather than generic ones.

What tools and technologies are used to build the Stack Exchange Network?  See also:


I was exploring a cave (curved hole going deep in ground). I encountered these three 'things'. What should I call them?

I found this heart while exploring the crimson biome - what is it?


I'm a newbie to Tex, cannot understand how I used MS word soooo long. Here's my first question.  I'm using MacTex which came with TexShop, which so far seems useful. TexShop has a basic LaTex template which until recently worked just fine (i.e. if I hit "typeset" it produced the PDF of a simple document. Here is the template:  \documentclass[11pt, oneside]{article}      % use "amsart" instead of "article" for AMSLaTeX format \usepackage{geometry}                       % See geometry.pdf to learn the layout options. There are lots. \geometry{letterpaper}                          % ... or a4paper or a5paper or ...  %\geometry{landscape}                       % Activate for for rotated page geometry %\usepackage[parfill]{parskip}          % Activate to begin paragraphs with an empty line rather than an indent \usepackage{graphicx}               % Use pdf, png, jpg, or epsÂ§ with pdflatex; use eps in DVI mode                                 % TeX will automatically convert eps --> pdf in pdflatex         \usepackage{amssymb}  \title{Brief Article} \author{The Author} %\date{}                            % Activate to display a given date or no date  \begin{document} \maketitle %\section{} %\subsection{}    \end{document}    Suddendly the template stopped working. But 1-TexShop processes other Tex files just fine, and 2-the offending template above works just fine in Latexian. When I hit "typeset' in TexShop I get the image below. I re-installed MacTex, to no avail. Grateful for any suggestions. Apologies if this is not the right venue for this question.

I have a couple of LaTeX files with the same problem. If I produce an error, fix it, and then try to compile a pdf, I get the following error.  )Runaway argument? {{ ! File ended while scanning use of \@newl@ablel. <inserted text>                 \par l.90 \begin{document}   If I then click on the console or trash my .aux file, it compiles fine. Any thoughts on what is going on and how to prevent this annoying extra step?


I have roughly 200 blogs in my drupal website. Are they able to auto post to instagram? When I create new blog, is it able to post to instagram? If yes, how to do it? Many Thanks.

I'm working on a social network website based on Drupal7, This social network is based on photos and users may upload photos and they are accessible in their profile. I need to equip the site to contact to the Instagram profile of users and they can send images from my website to their profile in Instagram. I checked the  and  and  modules, but from I understand these modules only import images from Instagram, non of them export images to Instgram. How do I can send Images from my website to Instagram?


We know for $A_1, A_2, \cdots, A_n$, where each $A_i$ is countable, that $A_1 \times A_2 \times \cdots \times A_n$ is countable.    We also know that $\mathbb{N}$ is countable.  Let $N_i = \mathbb{N} \times \mathbb{N} \times \cdots \times \mathbb{N}$ ($i$ times).  I am wondering if $\bigcup_{i=1}^\infty N_i$ is countable?  This is bothering me because for any given $i$, we know that $N_i$ is countable, so we have a countable union of countable sets, therefore, $\bigcup_{i=1}^\infty N_i$ should be countable.   But then we have that as $i\to\infty$, $N_i$ is countable. This implies that an infinite cartesian product of countable sets is countable, which is not true. It is uncountable.  Where am I going wrong and which is correct?

While I was reading Enderton's "A mathematical introduction to Logic", I came across the proof of the following sentence: "The set of all finite sequences of members of the countable set A is also countable".   Proof: The set S of all such finite sequences can be characterized by the equation  $$S=\bigcup_{n \in N} A^{n+1}$$ Since A is countable, we have a function f mapping A one-to-one into N. The basic idea is to map S one-to-one into N by assigning to $(a_0,a_1,...,a_m)$ the number $2^{f(a_0)+1}3^{f(a_1)+1}\cdot ... \cdot p_m^{f(a_m)+1}$, where $p_m$ is the $(m+1)$st prime. This suffers from the defect that this assignment might not be well-defined. For conceivably there could be $(a_0,a_1,...,a_m)=(b_0,b_1,...,b_n)$, with $a_i$ and $b_j$ in A but with $m\neq n$. But this is not serious; just assign to each member of S the smallest number obtainable in the above fashion. This gives us a well-defined map; it is easy to see that it is one-to-one.  Note: P is a finite sequence of members of A iff for some positive integer $n$, we have $P=(x_1,...,x_n)$, where each $x_i \in A$.  First of all, I cannot understand why the former assignment might not be well-defined and the latter assignment is well-defined. Secondly, I cannot understand what Enderton means by "just assign to each member of S the smallest number obtainable in the above fashion". By the way, is $(a,b,c,d) = ((a,b),(c,d))$ true? Also, in which cases can I omit/add parentheses in a tuple so as to have an equal tuple?


#include<stdio.h> int main(){     int i=0;     while(i<4,5){         printf("loop");         i++;     } }  This code goes infinite loop. can anyone explain logic behind these?


I am with a group that has been playing bridge for a little over 2 years.  We have one member who has, on occassion, layed her hand down towards the end and declared the rest of the tricks are hers.  More than once that has not been the case.  Either someone is holding a higher trump or she will not be able to get back to the board to win with her high card. When that happens, we just pick them up and play then out.  My question is whether or not there is a penalty for this and if so, what is it.  It has been suggested by one of our senior mentors that this is an insult resulting in a 50 point penalty, but that is just a guess.

Down to the last two rounds in rubber bridge.  Declarer claims remaining tricks only to discover that he has miscounted.  He claims the two tricks with Q-10; however, opponent holds the J and depending on how he plays the cards could lose one trick.  How is this handled?  Is scoring affected?  Consider the same scenario only opponent holds the Q.  Do opponents just get the one trick and game is scored as usual?


If log 1 to the base 1 can be any number. So we can invent a new mathematical idea called the "any". If log 1(1) = "that idea", so is that wrong?

What is $\log(1)$ to the base of $1$? My teacher says it is $1$. I beg to differ, I think it can be all real numbers! i.e., $1^x = 1$, where $x\in \mathbb{R}$.  So I was wondering where I have gone wrong.


I am checking assumptions(multivariate normality) of multiple linear regression in R. I have 100 independent variables and want to check their normality.  Should i need to check one by one for all 100 variables? Or should we just assume there is a normality and proceed with the regression? Or is there any way from which I can check the normality of all 100 variables in a single piece of code in R?  Also is there any way the linearity of all these 100 IVs can be checked with the DV?

I am trying to run a Multiple Regression model but I am not sure what should I do to prepare the data input. In my model the dependent variable is the artificial surfaces in hectares, the independent are the GDP (monetary value) and Population (inhabitants). The histogram shows that the data is not normal distributed.    I would like to know if I need to normalize the distribution of the data in order to get the "bell" curve and/or  if I need to normalize the data (with the max-min or standardize).


Is is possible to delegate different @RequestMapping methods by evaluation get-query parameter?  Example: if I call localhost:8080/cars?format=csv I want to invoke the first method.  But if I call  localhost:8080/cars?format=anyothervalue I'd like to invoke the second method. Is that possible in spring using @RequestParams?  @RestController public class MyServlet {     @RequestMapping("/cars", {format == 'csv'})     public Response doGetCsv(@RequestParam format) {      }      @RequestMapping("/cars", {format == 'xml'})     public Response doGetOthers(@RequestParam format) {      } }

In Spring annotation-based controller, is it possible to map different query strings using @RequestMapping to different methods?  For example  @RequestMapping("/test.html?day=monday") public void writeMonday() { }   @RequestMapping("/test.html?day=tuesday") public void writeTuesday() { }


I am calling this code from my custom sidebar, in order to get related postings from the same category:  query_posts(array(    'cat' => get_category_id(),    'showposts' => 5,    'post__not_in' => array(get_the_ID()) ));  get_template_part('article-list'); // outputs the posts   This works. The have_posts()-loop inside of my article-list.php now only outputs 5 other postings from the category.  But this also causes a problem: No matter on what kind of page I am (single.php, index.php, ...), WordPress always assumes that I am in the category template. So is_category() always returns true after calling query_posts('cat=...'). Thus is_single() returns false, although the single.php-template is used.  What can I do to tell WordPress that it is still using the single-template? Or: What other function can I use to detect which (main) view is loaded?

It seems like half the tutorials in the  and around the blogosphere use  and half use . They all do similar things, so when should I use one over the others?


So I downloaded Ubuntu a few days ago and now when I turn on my computer its just a black screen so what can I have tried turning it off and on again and it did not work so how do I fix it.

I am trying to boot Ubuntu on my computer.  When I boot Ubuntu, it boots to a black screen.  How can I fix this? Table of Contents:


So I understand that unsigned variables can only hold positive values and signed variables can hold negative and positive. However, it is unclear to me why would someone use unsigned variables? Isn't that risky? I mean I would personally just stick with signed variables just in case. Is there a memory/performance advantage in using unsigned variables?

When is it appropriate to use an unsigned variable over a signed one? What about in a for loop?  I hear a lot of opinions about this and I wanted to see if there was anything resembling a consensus.   for (unsigned int i = 0; i < someThing.length(); i++) {       SomeThing var = someThing.at(i);       // You get the idea.   }   I know Java doesn't have unsigned values, and that must have been a concious decision on ' part.


I am getting the following nullpointer exception in my code:  fieldName = "created"; Date startDate;  DateFormat df = new SimpleDateFormat(this.dtFormatShort); startDate = df.parse(doc.getCreated().getDateOnly() + " " + doc.getCreated().getTimeOnly()); //here I get the error customer.setCreated(startDate);   I am using similar code across my app but there I do not nullpointer exceptions.  is the error related that I am not calling the constructor for the Date object first? and why does the exception not occur on other places of my app?

What are Null Pointer Exceptions (java.lang.NullPointerException) and what causes them?  What methods/tools can be used to determine the cause so that you stop the exception from causing the program to terminate prematurely?


Every $n\times n$ matrix satisfies a polynomial equation of degree at most $n^2$, simply because the space of $n\times n$ matrices has dimension $n^2$.  By the Cayley–Hamilton theorem, every matrix satisfies a polynomial equation of degree $n$.  Is there a simple proof that every matrix satisfies a polynomial equation of degree at most $n$ without using the Cayley–Hamilton theorem?

Let $T$ be a linear transformation of an $n$-dimensional vector space $V$ over a field $k$. It's pretty easy to define the minimum polynomial of $T$ and make sure its degree is between $1$ and $n^2$, inclusive.     Observe $ I = \{ p(x) \in k[x] : p(T) =0\}$ is an ideal in $k[x]$. Indeed, $I$ is the kernel of the evaluation homomorphism $\mathrm{eval}_T: k[x] \to \mathrm{End}(V)$.  Notice also that:         $\mathrm{eval}_T$ is unital homomorphism, so $I$ is a proper ideal.    The $n^2 + 1$ transformations $I, T,T^2,T^3,\ldots, T^{n^2}$ must be linearly dependent, since $\mathrm{dim}(\mathrm{End}(V)) = n^2$, so there exist scalars $a_0,\ldots,a_{n^2}$, not all zero, such that $a_0I + a_1 T + \ldots + a_{n^2}T^{n^2} = 0$, whence the nonzero polynomial $p(x) = a_0 + a_1 x + \ldots + a_{n^2}x^{n^2}$ belongs to $I$.           Since $k[x]$ is a p.i.d., we may define the minimum polynomial $m(x)$ of $T$ to be the monic generator of the ideal $I$. By the preceding two observations, we have $1 \leq \mathrm{deg}(m(x)) \leq n^2$.    Now, of course, we know that the degree of $m(x)$ actually satisfies $1 \leq \mathrm{deg}(m(x)) \leq n$. One way to see this is to use the Cayley-Hamilton theorem which shows that the characteristic polynomial $c(x)=\det(xI - T)$, whose degree is $n$, annihilates $T$, whence $m(x)$ divides $c(x)$.     Question: Is there another way to see that $T$ is annihilated by a polynomial of degree $\leq n$ which does not require use of the characteristic polynomial?


My test involving a mock function (React, Enzyme and Jest) works:  it('should do a thing', () => {   const myButton = wrapper.find('Button');   expect(mockFunction.mock.calls.length).toBe(0);   myButton.simulate('click');   expect(mockFunction.mock.calls.length).toBe(1); });   However when I try to simplify the code with a variable the test fails. numberClicks is 0 both times.  it('should do a thing', () => {   const myButton = wrapper.find('Button');   const numberClicks = mockFunction.mock.calls.length;   expect(numberClicks).toBe(0);   myButton.simulate('click');   expect(numberClicks).toBe(1); });   Is this normal JavaScript behaviour or some weirdness with the testing libraries?

The primitive types (number, string, etc.) are passed by value, but objects are unknown, because they can be both passed-by-value (in case we consider that a variable holding an object is in fact a reference to the object) and passed-by-reference (when we consider that the variable to the object holds the object itself).  Although it doesn't really matter at the end, I want to know what is the correct way to present the arguments passing conventions. Is there an excerpt from JavaScript specification, which defines what should be the semantics regarding this?


It’s possible (not always convenient) to enter Monaco from the Mediterranean, but getting into Andorra, San Marino, or Vatican City requires going through a Schengen country.  Is it possible (and legal) to skirt the Schengen 90/180 rule by proving (for example) that thirty of your one hundred days were spent within one or more of the micro-states?  How much/what kind of proof would be needed?  Seems an entry/exit stamp would not be persuasive, since I could ask for a stamp, enter, and then promptly leave without a stamp.

I am considering staying in Monaco, San Marino, or Vatican City before I can enter the Schengen area again. , it is valid to stay in these three micro-states in order to stop the Schengen clock. However, also according to the answer:  Problems will arise when the visitor ultimately leaves the zone and must undergo a Schengen exit inspection. At this point the person may be asked to prove that they are not an overstayer and the border guard will be entitled to see hard evidence in the form of official documentation. There was a case where an individual attempted to show that his mobile phone registered to a tower outside of the zone and this failed obviously: radio waves have no respect for nation borders but also one could mail the SIM card to a friend in a far away land, put in a phone where it registers to the tower and then mail it back. Apparently hotel receipts can be too easily forged to be successful as evidence. What the border guard will want to see is a passport stamp from the local constabulary. But the constabulary is under no obligation to issue one, so success is down to personal impact and articulation skills.  I'm not sure if I could get a stamp from the local constabulary. However, I always use AirBnB to stay, and the reservation email and the mobile app might be far more reliable than a random hotel reservation document. So, does the AirBnB reservation email work as a proof of staying there? Or is there any better document as a proof of staying ("better", in terms of ensuring that I don't pay the overstaying penalty)? I will likely leave the Schengen area ultimately from Frankfurt International Airport.


I applied for a UK visit visa with my mother to visit my sisters and other family relatives and to attend a cousin's wedding. My application was refused as you can see in the refusal letter.  Can anyone please tell me what I should do now, and how I can make my application better next time?  I have provided almost all documents. I received money last month from my family in my bank account to distribute money to the poor, as it was the Ramadan holy month and almost all my family sent me money for distribution. I wrote in my letter that I received money from my family to give to the needy here in my country but the ECO said I have not provided any document. What document do I need to provide as my family members transfered money directly to my bank account?  (My closing bank statement was Pkr: 1,287,000 on 27-06-2018 and he wrote Pkr 1,117,354. I don't think they checked all documents correctly).  I received rent from the shops that are built next to my home and I usually get cash in hand. I also wrote this in my letter. I provided rent papers but the ECO said the documents do not demonstrate that I actually receive rent. What other documents do I need to provide to prove that I receive rent?  I have 5 sisters and other family members in the UK. That's why I want to go there and visit them. All of my sisters and their families have wanted to visit us in Pakistan but it is not easy for them as there are 24 of them in total, including their children. I wrote this in my letter and I also wrote that I will come back because I have property here and shops on rent, and I also have two sisters and the children here, but the ECO said I have more family in the UK than Pakistan, and that I would not come back. Please tell me how I can show more ties here. I provided property paper, rent papers for the shops. What else do I need to provide?

Many of the UK visa refusals we see here share a common pattern and the prevailing reasons refer to V 4.2 (a) and (c).    I do understand that, while the applicants may describe very different individual circumstances, there's a consistent pattern and, broadly, fall into specific categories:    Credibility (lifestyle, lack of ties, visit history, lies & omissions) Funding (insufficient funds, provenance of funds, funds parking) Sponsorship (family, friends, employer)   Question: What most commonly triggers a UK visa refusal where V 4.2 (a) and (c) are given as the grounds?  Secondarily: Given that there is a clear pattern, to what extent are these refusals predictable? Does sponsorship make a difference? Is there a set of personal circumstances, however abstract, where a refusal is all but guaranteed? For example, why do those we see here on TSE who sought entry for the PLAB or British Army appear to be refused with a common theme? Is there a uniform shortcoming or is it just discrimination?   PLAB: What is about applications for a visa, for the purpose of sitting the Professional and Linguistic Assessments Board (PLAB) exam, that seem to invite refusals. After all, the test is given so that international medical graduates can show that they qualify to practise medicine in the UK. The first part, PLAB 1, can be taken in centres outside of the UK. However, PLAB 2 can be taken only in the UK. Why can't you can't get a visa just to sit the exam, promising that you'll leave immediately after?    British Army: Since Commonwealth citizens are eligible to apply online to join, even those who don't reside in the UK, why is it so difficult to get a visa just to attend an interview to see whether you are suitable? Even with an invitation from the Army, such visa applications seem to be unsuccessful. Isn't a career in the British Army a valid reason?     Lastly:  After such a refusal, what approaches would increase the chance of a successful application?


I'm sure this is something that AJAX gurus learn very early on, but this is the first time I've run into it.  Using jQuery, I have assigned .click() handlers to certain CSS classes.  However, if I reload some of the content via AJAX, the .click() handlers are not firing for that content.  It seems I have two choices:   put my .click() handler assignments within a JScript function, and call it every time content is refreshed via AJAX. use onclick="" rather than jQuery within my AJAX content.   So far, it seems #1 would be the best; it's more consistent and yields smaller HTML for AJAX.  Is there another way to do it?  Perhaps a different way of assigning the .click() handlers from the outset?

I have a bit of code where I am looping through all the select boxes on a page and binding a .hover event to them to do a bit of twiddling with their width on mouse on/off.  This happens on page ready and works just fine.  The problem I have is that any select boxes I add via Ajax or DOM after the initial loop won't have the event bound.  I have found this plugin (), but before I add another 5k to my pages with a plugin, I want to see if anyone knows a way to do this, either with jQuery directly or by another option.


I've seen the notation $]a,b[$ in several questions on this site, but I am not familiar with it.  Can someone clue me in?

In the following question  the notation $c\in ]a,b[$ is used. What does this mean? I have never seen it before.


points = 0  def testfunction():     points = 2     return points  testfunction() print (points)   Why does the points now not equal 2?

What exactly are the Python scoping rules?  If I have some code:  code1 class Foo:    code2    def spam.....       code3       for code4..:        code5        x()   Where is x found?  Some possible choices include the list below:   In the enclosing source file In the class namespace In the function definition In the for loop index variable Inside the for loop   Also there is the context during execution, when the function spam is passed somewhere else. And maybe  pass a bit differently?  There must be a simple reference or algorithm somewhere.  It's a confusing world for intermediate Python programmers.


I need to find the probability that a random permutation of n elements has exactly k fixed points but I am confused on how to do so.   I have found this formula but I don't understand how to derive it.  $D_{n,k}= \frac{n!}{k!}\sum_{i=0}^{n-k}\frac{(-1)^i}{i!}$  I know there are $nCk$ choices for the k fixed points but don't know how to calculate the number of derangement's on the remaining $n-k$ elements. I know that the total number of permutations is $n!$ so I will need to divide the above formula by $n!$ to find the total probability.

I'm looking for the method by which the partial derangement formula $D_{n,k}$ was derived. I can determine the values for small values of N empirically, but how the general case formula arose still alludes me.  Any links/books or an explanation will be appreciated.  The formula is:  $D_{n,k} = {n \choose k}!(n-k)$  Links:


It is widely believed, that medium format delivers better image quality. Because, as they say, size matters.  But. According to  , 1DX pixels are physically larger than pixels in Leica S2 (S2 sensor area is larger, but it also has to accommodate more pixels). I imagine this is also true for Hasselblad and other high resolution medium format cameras. Today, pro-level DSLRs seem to have better noise reduction at high iso, have lenses and are significantly cheaper at that.  Obviously, this is not only about size. And I personally haven't ever seen a side-by-side comparison of any wide format vs a professional canon or nikon.  Can anyone explain to me where the talk about higher quality of digital medium format coming from and, maybe, provide some evidence to back that up?

When someone wants to compliment a 35mm sensor, he can say that it's [almost] as good as medium format. Medium format appears to be the gold standard where image quality is concerned.  But. I'm usually working with natural light using my lenses wide open, and the widest lenses that I've seen for Hasselblad or Leica S2 are f/2.8, which I consider very dark. Also, when I watch clips on youtube concerning medium format, people usually use those lenses with artificial lighting, which also confirms my impression that medium format cameras aren't as light sensitive as DLSR systems.  So my question is - let's say I'm working with 1D X and 85mm f1.2. Is there anything in medium format sector, that can beat that combination when working in low light conditions?


I know that the one of the axioms of abelian categories is that the induced morphism $ \text{coker}(\ker f )  \longrightarrow   \ker ( \text{coker} f )  $ for any morphism $ f $ is an isomorphism. Let's call this axiom $ \textit{iso} $.  However, Vakil in his notes (, page 48) mentions axioms (2) and (3). One of my friends remarked that  $$(2) + (3)  \Longleftrightarrow  \textit{iso}  . $$   I have been able to show $ \textit{iso}  \implies (2) + (3)  $ , but how do I show that $  (2) + (3)  \implies  \textit{iso}  $?

Let's fix some terminology first. A category $\mathcal{C}$ is preabelian if:  1) $Hom_{\mathcal{C}}(A,B)$ is an abelian group for every $A,B$ such that composition is biadditive,  2) $\mathcal{C}$ has a zero object,  3) $\mathcal{C}$ has binary products,  4) $\mathcal{C}$ has kernels and cokernels.  A category $\mathcal{C}$ is abelian if it is preabelian and satisfies:  5) every monomorphism is a kernel and every epimorphism is a cokernel.  Define the coimage of a map to be the cokernel of its kernel, and the image to be the kernel of its cokernel. We have the following commutative diagram:    where $\overline{f}$ is the only existing map (because of universality of kernel and cokernel).  I'm having trouble proving the following:     A preabelian category $\mathcal{C}$ is abelian iff $\overline{f}$ is an isomorphism.   The converse is easily shown, I'm having trouble proving $\Rightarrow$...


Show $$\ln(2)=\sum_{i=1}^{\infty}\frac{(-1)^{n+1}}{n}$$  We know que if $|z|<1$.    $$\ln(1-z)=-\sum_{i=1}^{\infty}\frac{(z)^{n}}{n}$$  But $z=-1$ for our case and I wouldn't meet the condition $|z|<1$.

I know that the harmonic series $$\sum_{k=1}^{\infty}\frac{1}{k}  = \frac{1}{1} + \frac{1}{2} + \frac{1}{3} + \frac{1}{4} + \frac{1}{5} + \frac{1}{6} + \cdots + \frac{1}{n} + \cdots \tag{I}$$ diverges, but what about the alternating harmonic series   $$\sum_{k=1}^{\infty}\frac{(-1)^{k+1}}{k}  = \frac{1}{1} - \frac{1}{2} + \frac{1}{3} - \frac{1}{4} + \frac{1}{5} - \frac{1}{6} + \cdots + \frac{(-1)^{n+1}}{n} + \cdots \text{?} \tag{II}$$  Does it converge?   If so, what is its sum?


If my understanding is correct, we create antibodies after vaccines and after getting infections. So, after 10 vaccines and 2 contracted diseases, I can have in my body antibodies for 12 types of diseases.  Is there a limit to the number of different antibody types that we can have in the body at one point?   Also, do we spend resources keeping those numbers up when the antibodies are not used?  Thanks.

Before the seasonal flu vaccine was recommended for all healthy adults, people in developed countries might get vaccinated against on the order of 10 different pathogens and develop immunity for some more via natural exposure.  Now the same person is expected to take a seasonal flu vaccine for a new strain every year - won't this put them in an uncharted territory as far as effects on the immune systems are concerned within a couple of decades?


With a regular article/report/... class, you can use the showframe package to draw outlines of where the various regions of the page lie.  I cannot get the same functionality with beamer, however.  Using geometry with its showframe option similarly does not work.  How can I get this functionality with beamer?  MWE:  \documentclass{beamer}  %\usepackage[showframe]{geometry}  % Doesn't work \usepackage{showframe}             % Doesn't work  \begin{document}  \begin{frame}{Slide Title} \centering Centered Text \end{frame}  \end{document}   Edit:  A similar question is posed  that asks for a diagram depicting the layout of the page with lengths of various parameters given.  The \layout package gives this output when applied to the MWE:    While this output gives margin information and general layout information, it does not give the visual output that I am looking for, with boxes overlaid on my own content. I am less interested in seeing the value of margins and other lengths than I am in visualizing the fit of my own content on the slide and seeing how close the boxes actually are to content.  This is why I desire functionality more close to what the showframe package would provide.

I find this classic figure of LaTeX's page geometry very helpful:     Source:   Now, I am fiddling with some beamer slides and I could really use such an overview of beamer's slide layout. Does it exist anywhere? I have not been able to find it...  For now, I need it to figure out how to get the height of a frame's body.


I have a comma delimited string of numbers as follows:  1,2,3,5,6,7,8,9,12,14   I'm looking for a command to use in a bash script that can combine adjacent numbers into range/hyphenated entries as follows:  1-3,5-9,12,14   The initial string is guaranteed to be sorted in ascending order.

Given a sorted input file (or command output) that contains unique numbers, one per line, I would like to collapse all runs of consecutive numbers into ranges such that  n n+1 ... n+m   becomes  n,n+m     input sample:  2 3 9 10 11 12 24 28 29 33   expected output:  2,3 9,12 24 28,29 33