Consider two moving objects along X-axis direction with different speeds and different initial starting points. Let the initial distance of the objects be d0 and v1 is greater than v2 i.e v1>v2.   Physics says:  x1 = v1 * t + x01 = v1 * t  x2 = v2 * t + x02 = v2 * t + d0  If we put x1 = x2 we obtain :   t = d0 / (v1 - v2)  and O1 because of its greater speed will eventually reach to O2.  But philosophy says something else:  O1 in t1=(something calculable) will reach to O2's current position but in this time interval O2 will move x1=(something calculable) toward.  Again in the new situation O1 in t2=(something calculable) will reach to O2's current position b but in this time interval O2 will be x2=(something calculable) toward.  By repeating this procedure tn and xn approaches to zero but does not become zero, therefore O1 will never reach O2.  How do you explain this?  Thank you so much.

It seems to me, perhaps naïvely, that Aristotle resolved  well, when he said that,      Time is not composed of indivisible nows any more than any other magnitude is composed of indivisibles,    and that Aquinas clarified the matter for the (relatively) modern reader when he wrote      Instants are not parts of time, for time is not made up of instants any more than a magnitude is made of points, as we have already proved. Hence it does not follow that a thing is not in motion in a given time, just because it is not in motion in any instant of that time.     For me, any further attempts at explanation and resolution, such as Russell's, (bar rather tenuous appeals to connections with quantum physics) simply reiterate, and rather labour Aristotle's initial erudite explanation.  What serious arguments exist that counter Aristotle's objection, if any, and why is Aristotle's objection not considered a resolution to this paradox?


Due to large number of reviews waiting do be done - at the time about 46,000 - did you consider - maybe temporary increase daily close votes limit from 40 to higher number ?  I know there is limit daily 50 question that we can vote to close, however review limit could be higher - not every review need to be closed.

Today, the size of the close-votes queue is 55k questions and growing. Is that a problem?   Which action could be taken to clean it up? It seems to be growing faster than Stack Overflow members are capable to handle it.


var URLS = ['https://www.vsss.co.in/Admin/uploads/722661/bb.jpg','https://www.vsss.co.in/Admin/uploads/755153/scs.jpg','https://www.vsss.co.in/Admin/uploads/704543/1606.jpg'] URLS.forEach(function(element){     var image_name = element.replace("https://www.vsss.co.in/Admin/uploads/722661/", "");     console.log(image_name); });       Anyone can please help me How can I get image name and extension of the image from URL. I tried but I statically typed URL when 722661 is dynamically generated serial How can I solve this issue?

I have a url like   I need a javascript function to give me the 'th' value from that.  All my urls have the same format (2 letter filenames, with .html extension).  I want it to be a safe function, so if someone passes in an empty url it doesn't break.  I know how to check for length, but I should be checking for null to right?


I’m looking for a book I remember. A girl her father and brother (?) leave earth on an ark ship headed to another planet. After several years (?) they arrive on the new planet, but it is much harder to survive than anyone thought.  I specifically remember crops not growing the way everyone thought they would and their animals dying. Wheat is crystalline and practically inedible, etc.  There were also some kind of moth people.  The kids end up helping everybody because they are more adventurous than the timid adults and try new foods etc.  They get through the first year and realize they should be recording their history in some way.  They find out the girl had been keeping a diary and begin reading it aloud. The first sentences are the first ones of the book.

I read a story back in the early 90s about a group of colonists who landed on a planet where the wheat (or wheat-like equivalent) is some kind of crystalline plant. The colonists face starvation until one of them figures out how to process the wheat.  I think it was by Asimov but so far I haven't found it by looking for his works.  I also cannot remember if it was a novel or a short story.


I am a part of multiple groups in my corporate Gmail account, and would like to filter out all emails from my Inbox that come to group1@gmail.com so that they are marked as read and archived, except when the message is also addressed to group2@gmail.com, in which case I want to keep it in my Inbox.  To summarize:   If a message is addressed only to group1@gmail.com, filter it out of my inbox If a message is addressed only to group2@gmail.com, keep it in the inbox If a message is addressed to both group1@gmail.com and group2@gmail.com, keep it in the inbox.   I tried a lot of filters but somehow could not get it right. Is there a way to achieve this ?

I receive email to these addresses:   my-team@example.com : This is my team's primary method of communication. I want all of this email to go to my Inbox. other-team@example.com : This belongs to another team at my organization, but I monitor it. I have a filter on this sort of email. It skips the Inbox. I'll usually read it later.   If an email is sent to both my-team@example.com and other-team@example.com, the label for 'other-team' is applied, and the email is removed from my Inbox. But, this email was sent to my-team@example.com, so I would like this email to remain in my Inbox.  How can I tell Gmail to leave any email to my-team@example.com in my Inbox, even the email matches other rules?  Or, to ask the question another way, can I tell Gmail to stop processing filters after it has matched a filter? This is a common practice with Microsoft Outlook.  I tried to create a Filter using a Label named "Inbox", but Gmail says "Sorry, you can't create a label named "inbox" (it's a reserved system label)."


I have a two years multiple C Class visa and i want to take my wife and children for a holiday in UK. I will be bearing all expenses of their travel. What will be procedure to apply for the visa for them, whether my wife will be the primary applicant in this case.

We are sponsoring a family to visit us in UK as friends from Madagascar for two weeks. They have a 6 year old and a 16 month old.   Do the kids need their own visas, and are they the standard visitor visa or a special child visa?   Also, when I try and apply on the website I can only apply for one person so how do I apply for all the individuals in the family?   I have looked on the Immigration website and can't find the answers I need.


Imagine a character has a t shirt. I would like to add my logo (a JPEG file) to stick onto the jersey. What is the best method? I tried UV but it didnt work.

How do I add flat text onto the back of a soccer jersey? The jersey itself isn't flat but I would like the text to take the shape of the back so it looks like a proper jersey like the image attached:


I wish to create space on my computer, deleting XP permanently from my harddrive. I have only 2 partitions! due to the dualboot I installed without knowing exactly what I was getting into!  I cannot unmount it and fear there's no other exit strategy... I'd have to uninstall the whole lot again?

I installed Ubuntu in the dual-boot configuration so that I can still boot up in Windows. But I just want to get Windows off of the machine.  Anyone know how to do this without having to go through another Ubuntu install? Also are all of the Ubuntu updates safe to take? Does Ubuntu have restore points in case something goes haywire from the updates?


I have recently moved my domain to new hosting. Now when I try to access my site (example.com) it is being redirected to http://example.com/cgi-sys/defaultwebpage.cgi  If I use the domain name with a dot at the end, the website loads normally. I do not have any redirection configured, so what might be causing this?

It's often the case that I want to change name servers because my site is messed up.  Well, it takes a very long time for the name server to propagate.  Is there something in DNS, or registrar or anything I can do to speed that up.  Flushing my dns server using  and it rarely works


What is causing this effect? Same thing is happening when I try looptools -> circle.

I've watched several tutorials and very often they applied the location, rotation or scale to the object when they transformed it in Object Mode. They always said it is important, but why?


I want to format a 2TB USB which I plan use for storing media (some of which may go over 10+GB). As I don't plan on using it on any other system aside from Linux-based system I don't really care about compatibility. So, as mentioned in the title, what is the best file system format (NTFS, FAT32, exFAT etc...) I can go for?

I would like my external drives to be readable and writable from Linux, Mac OS X and Windows.   FAT32 works, but the 4 GB file size limit is a showstopper these days. Are there any alternatives?


How to view files, created by Linux and programs in /tmp directory? The file names are hidden, command ls -al /tmp only show the presence of files not their names.  Edit: I find that place in saved session logs:  # ls -al /tmp drwxrwxrwt    2 0        0              40 Jan  1 00:00 . drwxr-xr-x   19 1005     1005          219 Aug  2  2017 .. # grep -r config /tmp # grep -r bin /tmp # umount /mnt # ls -l ---- drwxrwxrwt    2 0        0              40 Jan  1 00:00 tmp ---   Third line show that /tmp directory have 19 files(?), but I don't see it. Or I have missed something?

A question for ls command.  root@cqcloud script]# ls /var/www/html -la  total 36  drwxr-xr-x  9 root root 4096 Aug 31 01:12 . drwxr-xr-x  7 root root 4096 Aug 31 01:10 .. drwxr-xr-x  2 root root 4096 Aug 26 04:07 cmd drwxr-xr-x  5 root root 4096 Jul  3 10:07 cn.fnmili.com drwxr-xr-x  7 root root 4096 Aug 30 11:42 internal drwxr-xr-x  3 root root 4096 Jul 25 02:03 node drwxr-xr-x  4 root root 4096 Jul 11 01:26 sandbox drwxr-xr-x 13 root root 4096 Aug 26 03:45 tpshop drwxr-xr-x  2 root root 4096 Aug 31 01:12 trash  [root@cqcloud script]# ls /var/www/html/cmd -la  total 16  drwxr-xr-x 2 root root 4096 Aug 26 04:07 .  drwxr-xr-x 9 root root 4096 Aug 31 01:12 ..  -rw-r--r-- 1 root root 52 Aug 26 04:07 .htaccess  -rw-r--r-- 1 root root 73 Aug 26 04:02 df.php   You can see that the cmd folder has a link count of 2, but it actually has 4 links, including 2 files, . and .. folder. Can anyone explain why?


...in Ubuntu Gnome 18.04.2  Dolphin doesn't tick all my boxes and I much rather prefer using Nemo.  In the Kubuntu you can set this under default applications, not in the Gnome  DE. How can this be done?

I installed Ubuntu 12.10, then installed Nemo. Now I would like to make Nemo the default file manager.  I've searched the web for a solution but every time I restart my computer Nautilus come back.  Does anyone know an effective solution?


I've got two Ubuntu boxes running who have both developed the same problem.  They keep throwing up error messages about how I'm out of space.   Error: BrokenCount > 0    Tried to run sudo apt-get -f install:  dpkg: error processing archive /var/cache/apt/archives/linux-image-4.4.0-83-generic_4.4.0-83.106_amd64.deb (--unpack):  cannot copy extracted data for './boot/System.map-4.4.0-83-generic' to '/boot/System.map-4.4.0-83-generic.dpkg-new': failed to write (No space left on device) No apport report written because the error message indicates a disk full error                                                                               dpkg-deb: error: subprocess paste was killed by signal (Broken pipe) Examining /etc/kernel/postrm.d . run-parts: executing /etc/kernel/postrm.d/initramfs-tools 4.4.0-83-generic /boot/vmlinuz-4.4.0-83-generic run-parts: executing /etc/kernel/postrm.d/zz-update-grub 4.4.0-83-generic /boot/vmlinuz-4.4.0-83-generic Preparing to unpack .../linux-image-4.4.0-93-generic_4.4.0-93.116_amd64.deb ... Done. Unpacking linux-image-4.4.0-93-generic (4.4.0-93.116) ... dpkg: error processing archive /var/cache/apt/archives/linux-image-4.4.0-93-generic_4.4.0-93.116_amd64.deb (--unpack):  cannot copy extracted data for './boot/vmlinuz-4.4.0-93-generic' to '/boot/vmlinuz-4.4.0-93-generic.dpkg-new': failed to write (No space left on device) No apport report written because the error message indicates a disk full error                                                                               dpkg-deb: error: subprocess paste was killed by signal (Broken pipe) Examining /etc/kernel/postrm.d . run-parts: executing /etc/kernel/postrm.d/initramfs-tools 4.4.0-93-generic /boot/vmlinuz-4.4.0-93-generic run-parts: executing /etc/kernel/postrm.d/zz-update-grub 4.4.0-93-generic /boot/vmlinuz-4.4.0-93-generic Preparing to unpack .../linux-image-4.4.0-96-generic_4.4.0-96.119_amd64.deb ... Done. Unpacking linux-image-4.4.0-96-generic (4.4.0-96.119) ... dpkg: error processing archive /var/cache/apt/archives/linux-image-4.4.0-96-generic_4.4.0-96.119_amd64.deb (--unpack):  cannot copy extracted data for './boot/System.map-4.4.0-96-generic' to '/boot/System.map-4.4.0-96-generic.dpkg-new': failed to write (No space left on device) No apport report written because MaxReports is reached already                                                               dpkg-deb: error: subprocess paste was killed by signal (Broken pipe) Examining /etc/kernel/postrm.d . run-parts: executing /etc/kernel/postrm.d/initramfs-tools 4.4.0-96-generic /boot/vmlinuz-4.4.0-96-generic run-parts: executing /etc/kernel/postrm.d/zz-update-grub 4.4.0-96-generic /boot/vmlinuz-4.4.0-96-generic Errors were encountered while processing:  /var/cache/apt/archives/linux-image-4.4.0-97-generic_4.4.0-97.120_amd64.deb  /var/cache/apt/archives/linux-image-4.4.0-83-generic_4.4.0-83.106_amd64.deb  /var/cache/apt/archives/linux-image-4.4.0-93-generic_4.4.0-93.116_amd64.deb  /var/cache/apt/archives/linux-image-4.4.0-96-generic_4.4.0-96.119_amd64.deb E: Sub-process /usr/bin/dpkg returned an error code (1)   Deleted a load of files, still wouldn't fix my dependencies.  How'd my pipe break and what should I do to fix this?   df:     Filesystem                  1K-blocks     Used Available Use% Mounted on udev                          3529056        0   3529056   0% /dev tmpfs                          710068    17808    692260   3% /run /dev/mapper/ubuntu--vg-root 953106324 11889680 892778580   2% / tmpfs                         3550320      800   3549520   1% /dev/shm tmpfs                            5120        4      5116   1% /run/lock tmpfs                         3550320        0   3550320   0% /sys/fs/cgroup /dev/sda2                      483946   474540         0 100% /boot /dev/sda1                      523248     3664    519584   1% /boot/efi tmpfs                          710068       84    709984   1% /run/user/1000 /home/frank/.Private        953106324 11889680 892778580   2% /home/frank   Any help would be appreciated, thanks!

My first issue was when I tried to apt-get update or apt-get upgrade. On upgrade I get the following error:  You might want to run 'apt-get -f install' to correct these. The following packages have unmet dependencies: linux-image-server : Depends: linux-image-3.2.0-27-generic but it is not installed E: Unmet dependencies. Try using -f.   I tried running apt-get install -f and this was the output(after saying yes on prompt)  (Reading database ... 186183 files and directories currently installed.) Unpacking linux-image-3.2.0-27-generic (from .../linux-image-3.2.0-27-generic_3.2.0-27.43_amd64.deb) ... Done. dpkg: error processing /var/cache/apt/archives/linux-image-3.2.0-27-generic_3.2.0-27.43_amd64.deb (--unpack):  failed in write on buffer copy for backend dpkg-deb during `./boot/System.map-3.2.0-27-generic': No space left on device  No apport report written because the error message indicates a disk full error                                                                           dpkg-deb:    error: subprocess paste was killed by signal (Broken pipe) Examining /etc/kernel/postrm.d . run-parts: executing /etc/kernel/postrm.d/initramfs-tools 3.2.0-27-generic   /boot/vmlinuz-3.2.0-27-generic run-parts: executing /etc/kernel/postrm.d/zz-update-grub 3.2.0-27-generic /boot/vmlinuz-3.2.0-27-generic Errors were encountered while processing: /var/cache/apt/archives/linux-image-3.2.0-27-generic_3.2.0-27.43_amd64.deb E: Sub-process /usr/bin/dpkg returned an error code (1)   I tried running apt-get autoremove and it gives me the same error as apt-get upgrade.  When I run df, I get this for /boot:  /dev/sda1                    233191     230297         0 100% /boot   So, I read elsewhere that I should try to purge old kernels. I checked for what kernels I had with:  $ dpkg -l linux-image-\* | grep ^ii ii  linux-image-2.6.38-13-server  2.6.38-13.52  Linux kernel image for version 2.6.38 on x86_64 ii  linux-image-3.0.0-13-server   3.0.0-13.22   Linux kernel image for version 3.0.0  on x86_64 ii  linux-image-3.0.0-14-server   3.0.0-14.23   Linux kernel image for version 3.0.0  on x86_64 ii  linux-image-3.0.0-15-server   3.0.0-15.26   Linux kernel image for version 3.0.0  on x86_64 ii  linux-image-3.0.0-16-server   3.0.0-16.29   Linux kernel image for version 3.0.0  on x86_64 ii  linux-image-3.0.0-17-server   3.0.0-17.30   Linux kernel image for version 3.0.0  on x86_64 ii  linux-image-3.2.0-24-generic  3.2.0-24.39   Linux kernel image for version 3.2.0  on 64 bit x86 SMP ii  linux-image-3.2.0-25-generic  3.2.0-25.40   Linux kernel image for version 3.2.0  on 64 bit x86 SMP ii  linux-image-3.2.0-26-generic  3.2.0-26.41   Linux kernel image for version 3.2.0  on 64 bit x86 SMP   When I try to remove the oldest with this:  $ sudo apt-get purge linux-image-2.6.38-13-server Reading package lists... Done Building dependency tree Reading state information... Done You might want to run 'apt-get -f install' to correct these: The following packages have unmet dependencies: linux-image-server : Depends: linux-image-3.2.0-27-generic but it is not going to be     installed E: Unmet dependencies. Try 'apt-get -f install' with no packages (or specify a solution).   How can I free up or extend boot without messing up my installation?


After Hogwarts, Harry and Ginny have children, but from what I remember, it doesn't mention what he does for a living, nor does it mention what Ron and Hermione do.   At one point, I distinctly remember Harry wanting to be an Auror, but what exactly does he do there, and do Hermione and Ron do the same thing?  EDIT: The question was answered, and not a duplicate. The question marked as duplicate asks for Ginny's profession, and is answered by the person with Harry's profession. I mentioned Ron and Hermione and wanted to know the specifics on the main 3's jobs.

After the end of the Second Wizarding War Harry Potter later married Ginny Weasley, and the couple had three children of their own: two sons James Sirius, Albus Severus, and one daughter Lily Luna. What are Harry and Ginny's professions? I heard that Harry became an Auror, but what about Ginny, Ron, and Hermione?


I'm doing a problem on hackerRank and the problem is:  Problem Statement  Here we have to count the number of valleys does XYZ person visits.  A valley is a sequence of consecutive steps below sea level, starting with a step down from sea level and ending with a step up to sea level.  For One step up it U, and one step down it is D. We will be given the number of steps does XYZ person traveled plus the ups and down in the form of string, i.e,   UUDDUDUDDUU   Sample Input  8 UDDDUDUU   Sample Output  1   Explanation  If we represent _ as sea level, a step up as /, and a step down as \, Gary's hike can be drawn as:  _/\      _    \    /     \/\/   He enters and leaves one valley.  The code I wrote doesn't work   static int countingValleys(int n, String s) {         int count = 0;     int level = 0;     String[] arr = s.split("");     for(int i = 0; i<n;i++){         if(arr[i] == "U"){             level++;         } else{             level--;         }             if(level==0 && arr[i]=="U"){             count++;         }     }     return count; }   But another solution I found does, however no matter how I look at it the logic is the same as mine:  static int countingValleys(int n, String s) {     int v = 0;     // # of valleys     int lvl = 0;   // current level     for(char c : s.toCharArray()){         if(c == 'U') ++lvl;         if(c == 'D') --lvl;          // if we just came UP to sea level         if(lvl == 0 && c == 'U')             ++v;     }     return v; }   So what's the difference I'm missing here that causes mine to not work?  Thanks.

I've been using the == operator in my program to compare all my strings so far. However, I ran into a bug, changed one of them into .equals() instead, and it fixed the bug.  Is == bad? When should it and should it not be used? What's the difference?


I understand when we lift an object (a mass), its potential energy increases. Also we know $E=mc^2$, does it mean when we lift an object in the gravitational field (like on earth),  its mass increases?

I was just  that any type of energy contributes to mass of the object. This must indeed include potential energy in gravitational field. But here, things cease to make sense, have a look:   I have object at some distance $r$ from radial source of gravitational field. The potentional energy is calculated like this: $E_p = m*a*r$ where $a$ is gravitational acceleration and $m$ is mass of your object. But that means, that the object is a bit heavier - because of the potentional energy of itself - $m = m_0 + \frac{E_p}{c^2}$ ($m_0$ here is the mass without the potentional energy) That would mean that the gravitational force is a bit stronger at higher distances.   Now, I do understand that the rules of physics are not recursive and the mass and force will be finite. But what is the correct approach to this situation? What is the correct equation for potentional energy?


I had Windows 10 and Ubuntu 16.04 both working with Grub.   After Windows update, I got a screen saying there is no OS installed. I tried Boot-Repair using Boot-Repair-Disk and used recommended repair. Boot-Repair finished and I got a message to restart. After restart, I still get a "No OS" in opening screen.    Any chance I won't have to reinstall OS?  PC is Dell Inspiron 15 3000 series

I was installing ubuntu 12.04 on my system. There were 4 partitions on my system and I selected one of the four partition for the installation and chose the option of resizing the partition. Initially my partition was of size 100+GB and i created another partition out of it of size 15GB (EXT4). Now the moment I changed this partition structure my original partition got lost along with its data and I am left with 50GB partition and 50GB unallocated free space.   Now the data that I have lost is meant a lot to me and I want to recover that data. So is there any way I can recover it? And I haven't checked "format" option while resizing the partition.


My canon 2000d not firing the yn560 iv speed light

I was wondering if someone can help me out in finding which speedlites I can use on a Canon 4000D, as this camera does not have a centre connection on it.


Can you generally substitute dry yeast for fresh yeast and vice-versa? Is there any desirable result that can be accomplished by one, but not the other? Or are they completely equivalent if you just find out the correct conversion ratio?

A "compressed yeast cake" is called for in each of my great-grandmother's bread recipes. Can I use active dry yeast as a substitution for one? If so, how much active dry yeast should I substitute per compressed yeast cake?


How do credit card companies make money from cardholders who do not carry a balance?  It seems credit card companies are eager to offer their services to borrowers even if they have a tendency to pay in full each month. How do banks and credit card companies make money from these individuals who avoid interest charges?

How does a credit card company make any money off of me using their card if there are no fees associated with the card (I don't pay any extra) and I pay off my balance on time every month (so I don't pay any fees ever for this either).  Are they just banking on the fact that many people don't do this and end up owing them money?


I saw this movie when I was about 12 (20 years ago), and it's stuck with me for some reason.  A group of survivors are onboard an escape pod after their space station exploded. Amongst them is a dwarf engineer with a cyber arm and a blind man. The members start dying and it turns out the blind man (who is not really) is the killer, and the original saboteur.  I would guess it can out after Alien, it has a similar aesthetic (although much lower budget). It may have been a straight-to-video release.

I saw this movie years ago and can't quite remember it. All I remember is there was a crew trapped in space and they're trying to survive but someone on the crew is sabotaging them. The drinking water gets poisoned so they have to drink their own urine. There's a man with a leg injury that he can't tell is getting really infected and bad because the saboteur gave him these injections that numb his leg.  That's pretty much all I can remember, so if anyone can help me with the title somehow, that would be amazing. Thanks!


In the Leonard Susskind Lectures on Classical Mechanics on youtube, while he disusses symmetry and its relation to conservation laws, he uses the notation $\delta$ to refer to a certain "small quantity", but then again he uses it in a sense of operator (variation, eg. $\delta S$ is the variation in the action) which is proportional to the quantity $\delta$. Please help in clarifying this, I may have understood something pretty badly.

What is the exact use of the symbols $\partial$, $\delta$ and $\mathrm{d}$ in derivatives in physics? How are they different and when are they used? It would be nice to get that settled once and for all.  $$\frac{\partial y}{\partial x}, \frac{\delta y}{\delta x}, \frac{\mathrm{d} y}{\mathrm{d} x}$$   For what I know, $\mathrm{d}$ is used as a small infinitisemal change (and I guess the straight-up letter $\mathrm{d}$ is usual notation instead of italic $d$, simply to tell the difference from a variable). Of course we also have the big delta $\Delta$ to describe a finite (non-negligible) difference. And I have some vague idea that $\partial$ is used for partial derivatives in case of e.g. three-dimensional variables. Same goes for $\delta$, which I would have sworn was the same as $\partial$ until reading this answer on Math.SE:    Then to make the confusion total I noticed an equation like $\delta Q=\mathrm{d}U+\delta W$ and read in a physics text book that:     The fact that the amount of heat [added between two states] is dependent on the path is indicated by the symbol $\delta$...   So it seems $\delta$ means something more? The text book continues and says that:     a function [like the change in internal energy] is called a state function and its change is indicated by the symbol $\mathrm{d}$...   Here I am unsure of exactly why a $\mathrm d$ refers to a state function.   So to sum it up: down to the bone of it, what is $\delta$, $\partial$ and $\mathrm{d}$ exactly, when we are talking derivatives in physics.  Addition  Especially when reading a mathematical process on a physical equation like this procedure:  $$\delta Q=\mathrm{d}U+p\mathrm{d}V \Rightarrow\\ Q=\Delta U+\int_1^2 p \mathrm{d}V$$  It appears that $\delta$ and $\mathrm{d}$ are the same thing. An integral operation handles it the same way apparently?


Currently, when I need to explain the issues with recommendation questions, I link to . ... except that that's more or less just about shopping recommendations on SU. Now that we've expanded, can we have a canonical, site-agnostic meta post that details why most recommendation (product/book/software/etc) questions are bad, what defines a "good" recommendation question, and outlines a policy on this?

My question was closed for being a "shopping list question", even though it was very much related to the topic of the site. Why?


In Windows 10 there are virtual desktops. Unfortunately, the are by default Desktop 1, Desktop 2, etc. Or as in my screenshot Bureaublad 1, Bureaublad 2. Is there a way to rename them to something more useful?

When adding  on Windows 10 they are just named sequentially: Desktop 1, Desktop 2, ... etc  Is there a way to modify these names to provide something more meaningful? i.e. Home, School, Work, Project?    Note: This has been a  for


Let $G$ be a group and consider the subgroup $H=\{(g,g)\mid g \in G\}$ of $G\times G$. Show that if $H$ is a normal subgroup of $G\times G$, then $G$ is abelian. (Hint: consider $(a,e) \in  G\times G$ and $(h,h) \in H$.)   I'm not sure how to prove this since $(a,e)(h,h)=(h,h)(a,e)$ isn't implied even if its a normal subgroup. Is there another way to attack this with the hint given?

Let $G$ be a group and let $D=\{(g, g):g\in G\}$. If $D$ is a normal subgroup of $G\times G$, prove that $G$ is an abelian group.  My attempt:  $D$ is a normal subgroup of $G\times G$.  $\implies(a, b)D=D(a, b)\ \forall(a, b)\in G\times G$  So for a given $(a, b)\in G$ and $(g, g)\in D$, $\exists(g', g')\in D$ such that  $(a, b)(g, g)=(g', g')(a, b)$  $(ag, bg)=(g'a, g'b)$  $ag=g'a$ and $bg=g'b$  I feel like I've used all of the information given but don't know how to conclude that $G$ is abelian. Any suggestions?


I just posted a question on Stack Overflow dealing with a specific AWS Data Pipeline configuration question. I have a second unrelated AWS Data Pipeline question I also need help with, but when I click the Ask Question button it keeps opening the edit screen for my previous question I posted.  I've tried clicking on the Ask Question button from the home page, but the same thing happens. Can I not ask two questions simultaneously within a certain time period or is this a bug? If needed, .

I've seen lately that new question editing is stored somewhere for later use if we wander off the new question without posting it and then return back to the page. Which is a good functionality addition in it's own right.  What I'd like to also have is the Discard this draft functionality that would clear form data and forget it. Somehow we find an answer in the meantime and the question isn't valid any more.  So having a Discard saved draft or something similar would be a nice contra-functionality to auto-save to remove stored data. The way it's implemented now seems too hidden hidden and unpredictable to users.  Additional edit  When adding hidden auto functionality usually means creating the opposite as well by either giving the possibility to preference of not having automatism at all or giving the possibility to clear what's been auto saved.  Let's see how GMail doesn't work (and I think we all agree that from UX perspective it does the job as expected:   User clicks Compose message User starts writing a new email message User decides to not send the message and checks their inbox User clicks Compose message again A clean form is presented to user (old one being part of drafts)   I'm not suggesting we should have something like Saved drafts but we surely should have the possibility to clear previous question draft.  Since this new functionality was introduced I should point out that I would use the discard functionality more frequently than the saved one. I do welcome saving messages, but discarding of saved drafts is anything but a rare situation one might want to do. It wouldn't be a problem if this was a 1% against 99%. To me it's more like 50/50.  Best possible solution  When providing saved drafts there should (from the UX perspective) be the opposite functionality as well. Namely discarding of it. But first thing we should be asking ourselves is:    do users more frequently need pre-filled saved question draft or do users more frequently need empty form with the possibility to populate it with a saved draft   User testing should provide the usage frequency between the two and the one that's more likely to happen (my guess is that there would be a big difference between the two) should be implemented. So one of these:   Pre-populate question fields with saved draft on question form load, while also providing a button to clear the draft and start writing anew without the need to manually clear all the fields (which would be the optimal solution in case of a single field form) Question form should always load empty while also having a button that would pre-populate it with a saved draft.   I think this would be the best consensus related to saved question drafts and their usage. But as we've seen this issue has been swept under the rug for an indefinite time.


I have the following simple structure (backend is using Python Flask):  <!DOCTYPE html> <head>     <meta charset="UTF-8"> </head> <body>     <script type="module" src="static/js/AClass.js"></script>     <script type="text/javascript">         var logging_url = "http://127.0.0.1:5000";         var a_class = new AClass("some data");         a_class.initialize();     </script> </body> </html>   And in my static/js folder I have the following files:  static/js/AClass.js:  import DataManager from './DataManager.js';  class AClass {      constructor(constructor_param) {         this.datamanager = undefined;     }      initialize() {         console.log("Initializing...");         this.datamanager = new DataManager();     }  }   DataManager.js currently is an empty class in static/js/  When I run this stuff in my browser I the get following error:  Uncaught ReferenceError: AClass is not defined  However, I do not know why?

What is the scope of variables in javascript? Do they have the same scope inside as opposed to outside a function? Or does it even matter? Also, where are the variables stored if they are defined globally?


I wanted a lightweight distro for an older laptop. I wanted to be able to use this laptop for arduino and 3d printing. But not only is the wifi-driver not installed, but networking in general isn't.   $ ifconfig Command 'ifconfig' not found, but can be installed with: sudo ap install net-tools  Is this a joke? Who could possibly think this is a good idea? I don't have ether net at my home. I have wifi. And your distro comes without networking or wifi? I'm stunned.  Guess it's time to try a different distro.

I've just installed Ubuntu 18.04 and selected "minimal install". I then tried to run ifconfig in the terminal and got the following message  -bash: ifconfig: command not found   How come the  is not installed by default any more?


anyone can figure out what's the 2nd icon from the left ?  Thanks

I'm concerned about an app on my child's phone. I saw an app icon in the notification area that looked strange (Andy Android head, slightly tilted as its icon).  How can I find out what app it is from just having seen that icon in the notification bar?


I user the spacebar to move in my document, when i zoom i can use spacebar to move to the infinit but when i unzoom, the document stay at center and i can't go on the left side at infinit.

Lets say I am zoomed in, 500%, and I want to go beyond the edge, right edge, and when I try to drag it using the hand tool it doesn't work and the scrollbar doesn't work.


The older Android versions are called "cupcake" and "eclair". Where does 2.2 get it's name from?

Many people refer to Android versions by "codenames" rather than version numbers (e.g. Android "Gingerbread"). What are the names of the various versions of the Android OS, and how are these names chosen?


A friend of mine applied for UK Visa and it was refused. On examining the reasons for refusal it is clear that the Visa Officer has made mistakes. For instance, at one Paragraph the visa officer admits that the monthly salary is Rs 80,000.00, and on the next paragraph he says the expected expenditure for the travel Rs 300,000.00 is 3 times of the applicant's annual salary! Isnt my friend entitled to a re consideration of the decision as this is a glaring mistake?

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?


Say that I have a collection of points, as shown below with the circle, and I have a plane that I want to merge them onto. The points and plane are perfectly parallel, and the end goal is that the plane I'm merging onto doesn't move. Is there a way to do this? I think it could be done in a roundabout way with a boolean modifier, but there must be a better way.

Coming from SketchUp one of the tools I miss most is the circle draw tool which lets you draw a circle on any face and then you could extrude it in/out. The only tool that I know of that comes close to this is the knife tool but this would be very impractical to cut out with the knife  Example:    Is there any tool in blender that can match this function? also how could you do this with squares?


SharePoint modern look is good but seems to have less options for customization.  What should be done to add custom js and css files to the site? Is there a way we could add a section to masterpage , like we could in classic look?  Could anyone share their experience of branding the modern site?  I would like to know how to add styles to Master Page not Site Page.  Thank you.

So I have created a Site Page that has the "New Experience" look and I would like to change its style a little. Nothing major, just the height, width, color, etc. However, I can not seem to figure it out.   For example, I tried to change the height of the .pageHeader to a smaller value.   .pageHeader{ height: 150px !important } //for example of CSS in file   Here is a reference image of the page i'm trying to change    I tried adding   <link href="../SiteAssets/file.css" rel="stylesheet" type="text/css">   to the .aspx page using SharePoint Designer and it didn't work.    I also tried adding   <SharePoint:CssRegistration ID="CssRegistration" Name="SiteAssets/file.css" runat="server" />   to the .aspx page and it didn't work    I tried to use the "Embed" feature to add the CSS; however, it complains and says,     This embed code doesn't seem to work. We only support iframe based embeds.   Question:   How can I add custom CSS to this type page?  I can't seem to figure it out and I'm not sure exactly why the page will not load the file.  Is this even possible?


I have some Java code running on server in infinite loop. Currently I am using "kill -9 process_id" to stop process. But kill command forcefully stop Java process without cleaning resource.   I want to implement signal handler in Java just like C++ so that I can clean all resource and gracefully stop Java process.   Can anyone please suggest me the right way to do this?

How do I stop a Java process gracefully in Linux and Windows?  When does Runtime.getRuntime().addShutdownHook get called, and when does it not?  What about finalizers, do they help here?  Can I send some sort of signal to a Java process from a shell?  I am looking for preferably portable solutions.


I want to ask a question in Stack Exchange with a data file. I'm new to Stack Exchange & I don't how to post my excel data file here.  I'd be grateful if anyone can tell me how to do it.

I want to attach a code file to my question, but I am not able to find a link to do it. Is attaching files possible at all?


I don't understand why we use this formula:    Instead of this formula:    I mean, why we ignore $\omega\cdot t$ part.

I've read that plane wave equations can be represented in various forms, like sine or cosine curves, etc. What is the part of the imaginary unit $i$ when plane waves are represented in the form $$f(x) = Ae^{i (kx - \omega t)},$$ using complex exponentials?


I have to prepare a document with the following criteria - 1.5 spacing, text in Times New Roman, Size 12 (with footnotes throughout in Calibri, Size 10). Since I'm using luaLaTeX to get the fonts I'm not sure if the  answers apply. In my MWE I am able to get the times font and have the 1.5 line spacing but how can I set the footnote font to size 10 and Calibri?  \documentclass[12pt,a4paper,onecolumn]{article} \usepackage[margin=1.5in,footskip=0.25in]{geometry} \usepackage{fontspec} \usepackage{microtype} \setmainfont{times} %\setmainfont{Calibri} \usepackage{titling} \setlength{\droptitle}{-2cm} \usepackage [autostyle=once,english=british]{csquotes} \usepackage [UKenglish,american,british]{babel} \usepackage[notes, backend=biber, includeall=false,]{biblatex-chicago}  \usepackage{setspace} %\doublespacing \onehalfspacing  \begin{document}  This is test.\footnote{Test footnote.}  \end{document}

How can I change font family (and size) for footnotes? Would be great to see a small example.


I'm using sed to modify a file. In simple terms, my modifier looks as so   sed -e '11s/$/ $LinuxUsername/'   This is suppose to add in their linux username at the end of line 11, however, it is instead posting the actual variable name "$LinuxUsername" at the end of line 11. How can i make it post the actual value of the variable?  I've tried using quotes and double quotes in different parts of the expression, but still failed to get it to work properly.  Currently, line 11 is looking like the following...    john.doe william.mcmillion jonny.doeboy $LinuxUsername $LinuxUsername   Edit  The following is correct. Error was found further upstream.  sed -e "11s/$/ $LinuxUsername/"

I want to do:  cat update_via_sed.sh | sed 's/old_name/new_name/' > new_update_via_sed.sh   in my program.  But I want to use variables, e.g.  old_run='old_name_952' new_run='old_name_953'   I have tried using them but the substitution doesn't happen (no error). I have tried:  cat update_via_sed.sh | sed 's/old_run/new_run/' cat update_via_sed.sh | sed 's/$old_run/$new_run/' cat update_via_sed.sh | sed 's/${old_run}/${new_run}/'


When I first installed Ubuntu I dual booted with awful disgusting windows and just decided this week to go pure Ubuntu. I love it however now I have a large formatted volume 500 gigs (where windows was, I formatted it in Linux) but my OS is only 20 gigs. I want to triple or quadruple my os partition and not lose any of my files.  Is there a way I can take space from the 500 gig partition and add it to my 20 gig os partition?

Previously, I have installed Windows 7 on my 320 GB laptop with three partitions 173, 84 and 63 GB each. The 63 GB partition was where the Windows was installed. The rest were for file containers.  Now I changed my OS to Ubuntu 12.04 LTS. I installed Ubuntu by replacing the entire Windows 7 on the 63 GB partition. The rest of the partitions remain as an NTFS Windows partition and I can still access them both (the 173 and 84 GB partitions).  Now I want to change the two partitions of Windows into an Ubuntu format partitions plus most importantly, I want to extend the 63 GB partition to more than a 100 GB because at the moment I am running out of disk space. Whenever I try to install any application, especially using wine, it always complains for a shortage of disk space.  How do I do the extending activity before I entirely format my laptop again and lose all the important files on my partitions?


I don't actually own an Apple device, I'm just curious if what I just read is true: Allegedly all iPhones have a function that locks them after 10 wrong passcodes were entered. There is a delay after each attempt, but over an hour or two anyone can enter 10 wrong passcodes. This function can not be turned off. After the phone is locked, the only course of action that remains is to connect the phone to a computer and erase all data that was stored on the phone. Is this actually true?

A relative managed to change her password, yet can not input the correct password.  She does not want to reset the phone to avoid loss of data (pictures, contacts, messages, etc.).  Will the phone eventually stop accepting logon attempts?


In the realm of kinetic theory of gases, the internal energy of gas is solely due to the sum of kinetic energies of all particles, since kinetic energy is frame dependent I was thinking whether a container having gas will heat up if I put it in a moving train, which is accelerating?

In (non-relativistic) classical physics, if the temperature of an object is proportional to the average kinetic energy ${1 \over 2} m\overline {v^{2}}$of its particles (or molecules), then shouldn't that temperature depend on the frame of reference - since $\overline {v^{2}}$ will be different in different frames?  (I.e. In the lab frame  $K_l = {1 \over 2} m\overline {v^{2}} $, but in a frame moving with velocity $u$ relative to the lab frame, $K_u =  {1 \over 2} m \overline {(v+u)^{2}}$).


I have a website where I use PHP in server side and mysql as database. I use the following script to retrieve data from database. Could anybody let me know whether this code is vulnerable to injection attack? If so could you please give a solution?  <?php // PHP script   $usrname=$_POST['usrname']; $_SESSION['usremail']=$usrname; $usrpassword=$_POST['passwd'];  $db=mysql_select_db('mydb',$connection); $result=mysql_query("select usrfname,usrlname from userinformation where usremail='$usrname' and usrpassword='$usrpassword'") or die('failed to login');   Any help is greatly appreciated.  Thanks

If user input is inserted without modification into an SQL query, then the application becomes vulnerable to , like in the following example:  $unsafe_variable = $_POST['user_input'];   mysql_query("INSERT INTO `table` (`column`) VALUES ('$unsafe_variable')");   That's because the user can input something like value'); DROP TABLE table;--, and the query becomes:  INSERT INTO `table` (`column`) VALUES('value'); DROP TABLE table;--')   What can be done to prevent this from happening?


I want it to have color. Like a diamond here. I really don't know what to do. Like do I use tellraw like "color":"red" or what? Do I use &a stuff? I haven't ever used a command with a name/lore.  I am trying to make deathrun but one thing is the reward I need which is the Diamond with name that they can change into items like shopkeepers plugin, yes it's mine, but right now I am just using command blocks and I have this 4 second before re-fill issue and deathrun  is quite hard to make. I just need how to get color into that name all I need.  NOTE: Its a Minehut server, there are certain plugins I can have and not have.

I came across a map and when I was playing I found some coloured and bolded item names. I thought it isn't possible as at most you can only use the custom name tag to rename things! Is there a way to colour and bold item names in vanilla Minecraft? External programs are OK. Oh, and the wiki page of formatting codes doesn't really do much.


How to compute this limit: $\lim_\limits{n\to\infty} \sum_\limits{k=1}^n\frac{1}{1+3^k}$ or written as:  $\lim\limits_{n\to\infty}(\frac{1}{1+3^1}+\frac{1}{1+3^2}+\frac{1}{1+3^3}+...+\frac{1}{1+3^n})$  this limit includes computing a summation of series: $\sum_\limits{k=1}^n\frac{1}{1+3^k}$ so that also arouses a more general question: how to compute a summation like $\sum_\limits{k=1}^n\frac{1}{1+a^k}$, where $a=2,3,...,$?

Is there a method for evaluating infinite series of the form:  $\displaystyle\sum_{k=1}^{\infty}\frac{1}{a^{k}+1}, \;\ a\in \mathbb{N}$?.  For instance, say $a=2$ and we have  $\displaystyle\sum_{k=1}^{\infty}\frac{1}{2^{k}+1}$.  I know this converges to $\approx .7645$, but is it possible to find its sum using some clever method?.  It would seem the Psi function is involved. I used the sum on Wolfram and it gave me  $$-1+\frac{{\psi}_{1/2}^{(0)}\left(1-\frac{\pi\cdot i}{\ln(2)}\right)}{\ln(2)}$$  I am familiar with the Psi function, but I am unfamiliar with that notation for Psi. What does the 1/2 subscript represent?


So I already know I can stable 3 horses and ride one, but I’m just curious how many horses can I actually have? I find myself wanting to tame more horses and I don’t want to lose any of them.

Can you have more than 3 horses stabled, or is that all the horses we get? Or can we have 3 stabled and 1 to ride?   I would like to have all the superior horses if possible, but if not I'm going to have to pick my favorite 3 and go with those.


I try to import on my sheets a table o this url  I use this sintaxis: =IMPORTHTML("http://travian.kirilloid.ru/build.php#b=18&mb=1&s=1.45";"table";1)  What is the error?

Google Sheets has several import functions   IMPORTDATA IMPORTFEED IMPORTHTML IMPORTXML   Sometimes the above functions returns errors like #N/A Imported content is empty and would like to be sure that there isn't a problem with the resource content to be imported.  How do I know if these functions are able to get the content that I looking to import?  I know that there also exist IMPORTRANGE but that function only is able to import content from Google Sheets spreadsheets


I often come across posts containing really irritating typos, but the post is otherwise OK.  This has been asked before in different forms (e.g., ), but previous requests have included things like a tick-box for minor edits that would automatically fill out the comment box with 'minor edit/typo'.  I would like to suggest a modification of the existing edit function so that edits below a certain threshold (say 5 characters?) are automatically applied without   prompting for a comment requiring approval bumping the question putting the 'last edited by' box on the post contributing to the number of edits made by a user gaining reputation   I know some people will think this doesn't matter and isn't worth the effort to implement, but typos/grammatical errors can throw off a fluent reader of a language quite badly. This would also allow for fixing tiny but vitally important errors in code.  Perhaps there could also be an acknowledge button 'are you sure there is nothing else to fix?' to avoid people submitting a tiny edit accidentally.  Edit: I do not believe this to be an exact duplicate, though if others disagree on the utility of the suggestion that is fine. But to make it clear, I suggest this to be a modification of the existing edit function, available to users with sufficient rep to do normal edits, which would cut out some of the effects of editing for very minor edits only to avoid spamming the board or getting 'too minor; reject' reviews.

Related, but subtly different, proposals (they were created before the edit for the masses changes):       StackOverflow guidelines encourage users to correct typos, and I often do. However a new feature has now sprang up, which allow users who do not have sufficient reputation to edit on their own to propose an edit and have it reviewed. In order not to be spammy (I guess) there is also a restriction: they must at least edit 6 characters in the post.  This, however, prevent the correction of simple typography/spelling errors by those same low-reputation users (which I am on other stack exchange sites)... and the simple way to get around this is to pad the questions with whitespaces.  Now, this work-around is fair and all... but really unsatisfying: if the goal of the 6 characters limit is to prevent minor editions, then it fails utterly because of this "whitespace" bug.  My proposal is therefore:  Creating a new threshold for minor-edits of posts  The current edit treshold is at 2000 points; minor edits (those under that 6 characters count) could be allowed from as low as 500 points.   This would reduce the "noise" in the edits to approve. This would remove this annoying "warning" for users who only wish to improve things   Of course the user whose post has been edited should be notified as for a "regular" edit (unless it's community wiki ?)  I have no strong opinion as to bumping those minorly edited posts.


On my PC & Laptop I have a dual boot between Windows 10 & Ubuntu. Whenever I go into Ubuntu and then reset into Windows 10, Windows time jumps a few hours forward. Is there any fix for this?

Dual boot system Windows XP Pro and Ubuntu 12.04.  I have the bios set for the correct time and Ubuntu set for US Eastern time.  Ubuntu will boot up and the time will be off by -4 hours.  If I correct the time in Ubuntu then when I boot up in Windows XP the time will be off by + 4 hours.  This is a fresh install of 12.04. I did not have this problem before reinstalling Ubuntu.


I am reading Mathematical Statistics with Applications by Wackerly et al. (7th edition). In Chapter 11, the book discusses linear models and least squares, specifically $Y = \beta_0+\beta_1x+\epsilon$ where $E(\epsilon)=0$ and $Var(\epsilon)=\sigma^2$, with $E(Y)=\beta_0+\beta_1x$ being deterministic.   The book derives $\hat\beta_0=\bar Y - \hat\beta_1\bar x$ and $\hat\beta_1=\frac{\sum(x_i-\bar x)(Y_i-\bar Y)}{\sum(x_i - \bar x)^2}$ as estimators of $\beta_0$ and $\beta_1$ respectively from minimizing the SSE. The book states if $\epsilon$ is normally distributed, then each $Y_i$ from an independent sample is normally distributed and  $\hat\beta_0$ and $\hat\beta_1$ are also normally distributed since they are linear combinations of $Y_i$. I am assuming this is true based on ?   However, the book later goes further to state that $\hat\beta_0$ and $\hat\beta_1$ being normal implies that a linear combination $\hat\theta = a_0\hat\beta_0 + a_1\hat\beta_1$ is also normal. This confuses me since $Cov(\hat\beta_0 ,\hat\beta_1)=\frac{-\bar x\sigma^2}{\sum(x_i-\bar x)^2}$ may not be zero, which means for $\hat\theta$ to be normal, the joint distribution of $\hat\beta_0$ and $\hat\beta_1$ must be normal (per ) but the book makes no reference to the joint distribution. Is it always true that $\hat\theta$ is normally distributed? If so, how is it shown?

I have a simple linear OLS regression $Y_i = \alpha+ \beta_1 X_{1i} + \beta_2 X_{2i} + e_i$ where $e_i \sim N(0,\sigma)$. I have estimated the regression from the data and obtained estimates for my coefficients as well as the corresponding covariance matrix. Assume my dataset is large (>500)  Now I would like to construct the 95% confidence interval for $Z = a_1 \beta_1 + a_2 \beta_2$. My first thought was that I could assume that Z follows a normal distribution because my regression coefficients are approximately normal and a linear combination of normal variables is also a normal variable. I do find some sources where they treat $Z$ as a normal random variable.  But now I am in doubt because I found that a linear combination of normal random variables is only normal if they are independent. So is it still save to assume $Z$ is random?


I am looking for professional help to verify some results I am working on and maintaining in a write-up. However, I can't get anyone for free since I was forced to leave my old university, Case Western Reserve, (due to disagreements) and I don't know if I can find an online program that assists undergraduates in their research (I should have graduated my senior year with a bachelor's degree but am technically a freshman. I have studied rigorously up to differential equations; It's complicated). Moreover, professors are busy and would most likely ignore my requests no matter how much money I offer. Therefore, is there a way to pay for professional research help? How can I receive feedback on what I am working on? Details: My field is mathematics. I think the work may be complicated enough that graduate students won't be able to rigorously answer everything. I need someone with a Ph.D. on the level of professors. (Technically, I am working on developing a finitely additive measure and sum that takes the average of functions defined on countably additive measure zero sets. I am looking to verify if my measure and average on a function gives in fact what I am looking for. For reference, the link to my pdf is ).

In short, How does one go about hiring a professor or someone really well established in their field for a private tutoring session?  I tried looking online but can’t find much, mainly websites for tutors that are practitioners or “experts” as in with with n years of experience at best. This doesn’t cut it at my level as I am a researcher with a PhD and already have published papers on my topic.   However, I am very passionate about my subject and always looking to grow. So I do have questions, very technical (in my case computer science) and would happily pay a fee for consulting with a professor in the field.  Any advice?


I have a two columns document. And I to force a figure into a full paper width.  I tried this:  \begin{center}    \makebox[\textwidth]{\includegraphics[width=\paperwidth]{figures/reviewprocessmodel}}  \end{center}   But the figure overlaps with the text. any ideas!

I have a series of images that I'm displaying using a table environment. However, pdflatex places my table over the references portion of my paper.     I've tried [htb!] options for the table, and it doesn't seem to make much of a difference. I've also tried to use:  \usepackage{float} \restylefloat{table}   with the [H] option, but that hasn't worked either.   Any ideas on how to prevent this from happening?


This was an exam question. I know that my answer is wrong, but I believe myself to be on the right track. Can someone help me finish my construction? Here is the question.  Find a set $E$ with the property that for any open interval $(a,b)$, $m(E \cap(a,b))= \frac {b-a}{2}$ or prove such a set cannot exist.  Here's what I figure so far:  1) Obviously $E$ itself is not an interval. If it was, $m(E \cap E)=m(E)/2,$ which is only true if $m(E)=0,$ so $E$ is not an interval.  2) Furthermore, $E$ does not contain any intervals. If it did, then choose $E' \subset E,$ where $E'$ is an interval. Then $m(E' \cap E)=m(E')=m(E')/2$ as before. So $E'$ is not an interval and therefore $E$ contains no intervals.  Now, during the exam, my brain jumped to a Cantor set, so I attempted to build a Fat Cantor Set based on removing $2^{k-1}$ pieces of length $\frac {1}{2^{2k}}$ from the middle of each unit interval in $\Bbb R$. I know that this set has measure $1/2$, but if $(a,b)$ is one of the intervals deleted in the construction of the cantor set, the measure of the intersection is not half the measure of the interval. There are also infinitely many unit intervals in  $\Bbb R,$ so in order to have disjointness, I'd have to be tiling $\Bbb R$ with these sets, but then clearly taking any set not centered appropriately doesn't meet the hypothesis either. So this set doesn't work as I thought it did.  In hindsight, I'm skeptical as to whether such a set actually exists. But how to prove it?  Edit: A particularly nice solution would be one that gets me from $E$ has no intervals to $E$ does not exist.

Possible Duplicate:          Is there a measurable set $E \subset [0,1]$ such that for any $0 < a < b<1$, the Lebesgue measure $$m(E \cap [a,b])= \frac{b-a}{2}?$$  I am stumped and have no idea.


/*Graph.h*/ template<typename Tv, typename Te> class Graph { public:     virtual ~Graph() = 0;      /*顶点操作*/     ...      /*边操作*/     ...  protected:     int n;  //顶点数     int e;  //边数 };  #pragma once #include "Graph.h" #include <vector> #include <iostream>  template<typename Tv> struct Vertex {     ... };  template<typename Te> struct Edge {     ... };   template<typename Tv, typename Te> class GraphMatrix : public Graph<Tv, Te> { public: ...     ~GraphMatrix() {         for (int i = 0; i != n; ++i)         {             for (int j = 0; j != n; ++j)             {                 delete E[i][j];             }         }     } ... };  when i Comment out virtual ~Graph() = 0; in Graph.h, I can run the program again. The complier said 错误  LNK2019 无法解析的外部符号 "public: virtual __thiscall Graph<char,int>::~Graph<char,int>(void)" (??1?$Graph@DH@@UAE@XZ)，该符号在函数 "public: virtual __thiscall

Is it wrong to write:  class A { public:     virtual ~A() = 0; };   for an abstract base class?  At least that compiles in MSVC... Will it crash at run time?


I want to install Ubuntu on a computer but it currently is not able to access the internet because it operateed with Windows XP. Can I save the download to a flashdrive and download it to the computer like that?

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


I did that but I get:   $ sudo echo '"Samsung SSD 860 EVO M.2" 190 C "Samsung SSD 860 EVO M.2"' >> /etc/hddtemp.db bash: /etc/hddtemp.db: Permission denied   any suggestions?  Did all from:

When using sudo to allow edits to files, I regularly get 'permission denied'.  For example, my mouse is jittery and sluggish, so I want to disable polling:  sudo echo "options drm_kms_helper poll=N">/etc/modprobe.d/local.conf   I'm prompted for a password, and then get:  bash: /etc/modprobe.d/local.conf: Permission denied   So I tried to do a temporary change to disable polling by using:  sudo echo N> /sys/module/drm_kms_helper/parameters/poll   Yet again the system responded with:  bash: /sys/module/drm_kms_helper/parameters/poll: Permission denied   Any ideas?


This has been asked multiple times, but none of the answers have worked for me.  I have just installed an SSL certificate and need to force https connections for all visitors.  This site has a lot of incoming links, so all existing http links should properly redirect to https.  There should be no www.  There is also a rule that removes .html from files for "friendly" URLs, so that has to continue to work.  This is the old htaccess:  RewriteEngine on RewriteCond %{HTTP_HOST} ^www.example.com [NC] RewriteRule ^(.*)$ http://example.com/$1 [L,R=301]  RewriteCond %{REQUEST_FILENAME} !-f RewriteCond %{REQUEST_FILENAME} !-d RewriteRule ^([^\.]+)$ $1.html [NC,L]   What is the new set of rules I need to use?

This question is here so we can offer users who are looking for information on how to make one or more common or basic redirects in Apache using the htaccess file. All future questions pertaining to finding information that is that is covered by the question should be closed as a duplication of this question. .  Whats the point in this question? The idea while not perfect is catch the most commonly asked questions regarding redirects using the  htaccess on the Apache platform either on  some type of lamp or a live server. The type of answers should be generally those that you could imagine are used by 100,000’s of sites world-wide and are constantly asked here at Pro Webmasters repeatedly over and over in various forms.  A few examples of the type of answers we are looking for:   How can I redirect non-www to www? How can I redirect a sub domain to the main domain? How can I redirect a sub folder from domain to a root or a subdomain?  How can I redirect an old URL to a new URL?   A few examples of the types of answers that we are not looking for:   Answers that do not involve a redirect. Any answers relating to NGinx, IIS or any other non-Apache platform. Answers that involve custom and complex string or query removals.   Resources for Advanced to Complex Mod_Rewrite Rules:      Please note: that this question is still in construction and may need some refining either by myself or a real moderator of Pro Webmasters, if you have any concerns or questions .


When a comment by you, the logged-in user, fits on one line (the signature too) and has a nonzero score, the score indicator is slightly misaligned.              Own single-line comment. Misaligned.   Other single-line comment (forced to two lines due to (invisible) vote and flag buttons). Correctly aligned.   Other single-line comment (not forced to two lines because I upvoted it). Correctly aligned.   Own multi-line comment. Correctly aligned.   (Not circled; just below 2.) Other multi-line comment. Correctly aligned.

I never thought I would be OCD about pixels but whenever I am involved in a Meta post with a lot of comments, I see this, and today I decided to draw some horizontal lines to prove I am not imagining it:    The one that has the votes too far down is my own. (It's on  if you would like to try to repro, but I have seen this on every question where I've had an upvoted comment, I just never took a screenshot before.) I am guessing I can't upvote it or something and this makes the spacing different. Is it like that for everyone? Is it fixable?


I have this concern about my KUL-MNL-KUL ticket. Can I only use my MNL-KUL ticket? Since I will be coming from Manila on the that time. Do they honor my ticket even I didn't show up on my KUL-MNL?

I was browsing flight price at Singapore Airlines website, and a one-way flight from SIN to SFO cost this much:    That's quite expensive. I tried browsing around and found that a return flight from SFO to SIN and back to SFO cost much cheaper:    It's really weird because the second ticket includes the exact same flight that cost 1900+, but it's almost half the price. The reason for this counter-intuitive situation is explained in the answers this question   If I am located in Singapore and my intention is to fly one-way to SFO, is it safe to book the flight in the second picture and only board SFO-SIN leg? Will they deny me because I miss the SIN-SFO flight?


Let $T: \mathbb C^n \rightarrow \mathbb C^n$ be linear. Let $\beta$ and $\gamma$ be any two ordered bases. Prove that the eigenvalues of $[T]_\beta$ and $[T]_\gamma$ are the same.   Can anyone provide tips/hints in the right direction? I'm struggling as I try to understand this intuitively....thank you

Suppose $A$ and $B$ are similar matrices. Show that $A$ and $B$ have the same eigenvalues with the same geometric multiplicities.      Similar matrices: Suppose $A$ and $B$ are $n\times n$ matrices over $\mathbb R$ or $\mathbb C$. We say $A$ and $B$ are similar, or that $A$ is similar to $B$, if there exists a matrix $P$ such that $B = P^{-1}AP$.


public int retrieveID()     {         int lastEntry = 0;         try         {             queryString = "Select ID  from Database";             myComm = new OleDbCommand(queryString, myConn);          }         catch (Exception ex)         {             MessageBox.Show(ex.Message);         }         return lastEntry;     }   I want to retrieve the last primary key used in access database, whereas i set my primary key as autonumber.  elaborating more..  I am working on a database application and want to utilize the primary key, eg if the last entry in the database was 10, i want to retrieve 10, i tried simple query but that didnot work.

What is the best way to get IDENTITY of inserted row?  I know about @@IDENTITY and IDENT_CURRENT and SCOPE_IDENTITY but don't understand the pros and cons attached to each.  Can someone please explain the differences and when I should be using each?


I hold an Indian passport and I'm studying for a Master's in Biology in Israel (to be completed in March 2018). I plan to visit Greece and Turkey on my way from Israel to India after completion of the degree. Since I do not have any offer from any Indian universities as of now, I will have no occupation at the time of travel and I will be seen as a potential immigrant to Greece. Therefore, I need to demonstrate strong ties to home country for which I plan to submit the following:   My ownership of land in India. Mutual fund investment. My bank account statements in Israel and India (Just to demonstrate sound financial conditions that implies I do not need to seek a job/employment immediately).   Is there anything else I can use to show such ties? I can produce a letter from my Israeli university certifying my student status at the time of visa application but that will not be valid at the time of travel.  Also, do you think having used visas from USA (J1- visa), Switzerland (National Visa), Israel and Schengen visas from Spain, Italy and Austria will give me any slight advantage? I have always departed those countries well before the visa expired and hope they will pay attention to such information.   Also, I intend to travel within Turkey after my Greece itinerary by obtaining a Turkish e-visa using the Schengen visa (if approved) as a supporting document. Should I also present the Turkey itinerary to the Greek embassy just to convince them a little more about my intention to depart Greece on time?  Any response will be highly appreciated in this matter.

How can I prove the immigrant officers that I have significant ties in my home country?  Are there any documents that I need?


So this question was asked in an online quiz. The definiteness of the quadratic form   Q(x) = 8$x_1^2$ + 7$x_2^2$ + 3$x_3^2$ - 12$x_1x_2$ - 8$x_2x_3$ + 4$x_3x_2$  I made the following matrix: \begin{bmatrix}8&-6&0\\-6&7&-4\\0&-4&3\end{bmatrix} Any help would be appreciated.  P.S.: I don't need the explanation on how to solve these type of questions, that is already in my notes. Just the solution please.

Is $$ 2x_1^2 + 5x_2^2 + 5x_3^2 + 4x_1x_2 - 4x_1x_3 - 8x_2x_3 $$   positively (semi)definite, negatively (semi)definite or indefinite?   My attempt:  $$2x_1^2 + 5x_2^2 + 5x_3^2 + 4x_1x_2 - 4x_1x_3 - 8x_2x_3,$$ is equal to $$(x_1 + 2x_2)^2 + (x_1 - 2x_3)^2 + (x_2 - 4x_3)^2 - 15x_3^2.$$ I've got three positive squares and a negative one, so the expression could be both negative and positive so I would answer indefinite. However, the answer is supposed to be positively definite. Why?


I am trying (with no luck so far) to calculate the variance of future value of a portfolio. $E= \frac{(1+r)[(1+r)^{t}-1]}{r}$, $r$ is normally distributed random variable.  How to calculate $\text{Var}(E)$?

I want to compute the variance of $FV =A\sum_{k=1}^n(1+r)^k=:g(r)$, assuming interest rate $r\sim\mathrm{N}(\mu,\sigma^2)$ and constant equal payments $A$. As discussed in the comments, the Delta Method gives an approximation $\mathrm{Var}[FV]≈\sigma^2\times(g′(\mu))^2$. Is there a way to get an exact answer?


I know that the sudo password is my account password. Buy when I type it that error messafe comes "Could not get lock.....". What to do?

I get this error when trying to use apt-get:  E: Could not get lock /var/lib/dpkg/lock - open (11 Resource temporarily unavailable) E: Unable to lock the administration directory (/var/lib/dpkg/) is another process using it?     How can I fix this?


I can not log in to my Minecraft account. I have had the account for a few years now and have never had this problem. The unfortunate part is that I have never been able to log in the website, because I am asked security questions that I never had to set. However, now I am unable to even log into my account to play the game. I know that I am using the correct username and password. I put in the email used as opposed to my username, the same way that I have logged in since I got the account, I can log into my younger brothers account without a problem. I was just wondering if anyone else had the same problem I am having, and if anyone knew how to fix it.

We just got a new laptop (ASUS) though we did have a mac.  We are trying to log onto Mojang to download Minecraft and it keeps saying, "The username and password are not recognized."   We have done all the usual procedures; we have reset the password, we are using the email, not the username to sign in, and it looks like the minecraft login servers are working etc. etc.  We quit Minecraft on the old computer and shut off that computer thinking that was the issue.   Still, we can't get onto Mojang.  We are accessing mincraft through firefox and trying to download it to the new computer but we can't get into the account to do that!  What in the world could be the issue?


How could I test whether some label is on the current page, or on the previous or next one. Typically I would like to build a macro \onthispage{label}{text1}{text2} which would print text1 if the page and the text are on the same page and text2 otherwise. This could be useful when one wants to insert something like this into the TeX source:     see the figure \ref{figure}\onthispage{figure}{above}{page \pageref{figure}}.   An extension would be to have this kind of command to compare the current page to \pageref{label} and print this page, previous page,  next page or page \pageref{label} accordingly.   I've tried a dirty trick with a definition of a extra label inside the command \onthispage but this fails. Any ideas ?

Is it possible to make a reference to the page where a figure is rendered?  I would like to write something like   see figure~\ref{figure-xyz} on page NN   where NN will automatically be maintained by LaTeX. The figure that prompted my question is almost a page so it may be floated further in the doc.   I suppose it's possible, after all the figure-to-page mapping is generated by \listoffigures.


I've been working on an Excel macro to calculate performance metrics, based on data obtained from TFS integration. I've come to a point where I'm trying to count ocurrences of some events. Based on my parameters, sometimes it's as easy as count when some specific text is found, but sometimes I'd have to count when the cells contains some text string.  So far, I know I could use the COUNTIFS formula by building it on code and then assign this to any cell. I'm getting error when, while building the formula string, I try to get the string that contains the text. I have a condition to assign this value, as follows:  If rowNumber = x Then     myString = "Found text" ElseIf rowNumber = y Then     myString = "*contained*" End If  formula = "=SUM(COUNTIFS(Range1, Condition1, Range2, " & myString If moreParameters Then     formula = formula & ",Range3, Condition3))" Else     formula = formula & "))" End If  Cells(i,j).Select ActiveCell.FormulaR1C1 = formula   So, when the specific text is found (case rowNumber = x), it works fine, but when I try to use the wildcard, it doesn't understand the quotes as part of the string. I tried with double quotes:  ElseIf rowNumber = y Then     myString = ""*contained*"" End If   But then it throws compile error (Expected: end of statement), and with CHR(34) as well, without success. How come I could include the expression to use the wildcards in the formula string to use later?

How can I construct the following string in an Excel formula:     Maurice "The Rocket" Richard   If I'm using single quotes, it's trivial = "Maurice 'The Rocket' Richard" but what about double quotes?


I understand a photon with a smaller wavelength is more energetic so for a given intensity, less photons are incident on the electrons and so less photo electrons reach the detector per second. However, isnt current the rate of change of charge? If we have more energetic photons, the photoelectrons have larger KE's. They should be arriving more frequently at the detector. Does this not increase the current?  Why does the current necessarily decrease if the wavelength of incident light is decreased, with the sources intensity fixed. Does the decrease in photoelectrons produced win over the increased rate of arrival? Is there any mathematical model for this?

We all know that the amount of current flowing b/w the plates is independent of the frequency. If I were to ask why doesn't it depend then you'd probably say that it depends on the number of electrons rather than the frequency or you might show me a current vs frequency graph.  But here is my theoretical argument. Electric current is defined as the amount of charge flowing through a point/space/wire per unit time. Let I be current due to photo electrons ejected by photons of some frequency. Now if I would increase the frequency, the kinetic energy of the ejected electron would increases, therefore it will move faster and therefore contribute more current (charge will through the same point many times per unit time) . Thereby, giving a net current greater than I.  What is wrong with my argument?  After thinking a lot, I came up with a possible reason. However fast the electrons may move, but when they hit the metal plate, they would lose their velocity and start moving in drift velocity. Now there is a problem with this argument. If this were to be true then I should expect to see a big chunk of extra electrons getting stuck at the anode.  If my reasoning was correct, then why can't I see a big charge buildup at the anode.


I've been noticing the cpu usage go up, back down for a couple minutes, and then go up again, and vice-versa...  Not constant but it happened several times. (almost always up to 23% cpu constant when it happens)  This happened just now only with firefox interaction, got skype and LoLClient running too..  Looking at it in Process Explorer, i see two files taking approximately 10% each:  ntoskrnl.exe dxgmms1.sys  The problem is after looking up that dxmgmms1.sys i found that it stands for "Microsoft DirectX Graphics MMS system driver file." and i can't remember updating it at all. The other one i believe it's what's enabling or something since it's kinda part of the Windows kernel?  I've done sfc couple months ago when i first noticed this, runned malware scans, windows always up-to-date and everything.  How can i fix this?  Edit: It happened again, i done a xperf scan as suggested:     xperf -on latency -stackwalk profile -buffersize 1024 -MaxFile 512   -FileMode Circular && timeout -1 && xperf -d highCPUUsage.etl   I uploaded the file to my dropbox, can someone tell analyze it or something? Or should i post on the msdn forums?    Thanks to whoever helps, hope i recorded it correctly, it displayed  when i started the trace.

I have noticed that from some time my system is freezing and its probably caused by the high CPU usage which is caused by the system process.  All applications I'm running is the Skype, TeamSpeak and Chrome so it definitely shouldnt eat that amount of CPU.  You can see the problem itself and running processes in the screenshot below:    Sometimes CPU usage is reaching 90%, but the average usage is like 40-65%.  My PC parameters:   Windows 8 (customer preview) Intel Core i3 - 2350M 8 GB RAM   I'd appreciate any help attempt! Regards.  --UPDATE--  As the user below posted a great answer, I have noticed that the process that is eating the most CPU in the system is called Arthurx.sys, simple google tells that it's a TPLink driver (an wifi adapter, I have bought like 2 weeks ago!) drivers has been installed from the Windows MSDN, but also tried to install the drivers from the attached CD, but it doesn't help. From the system start, it is using like 5% of the CPU only, but after 2-4 hours of working it is growing up and reaching 40-60% of the CPU usage.  Device name: TPLink WN722N


I'm using the Ubuntu bash on Windows 10(v1804) and am experiencing a problem with the chown command. I'm trying to change the ownership of a file I created on my desktop with the following path:  mnt/c/users/XY/Desktop/filecat.txt   Using sudo -i I switch to the root user and navigate to the mentioned path and run  chown -v user1 filecat.txt   after which I get this message confirming the ownership change:  changed ownership of 'filecat.txt' from amar to user1   However, when I run ls -l filecat.txt it does not show any change in user. It's still the same user which created the file.  Anyone have any idea what might be the problem? I've been searching online but finding nothing similar so here I am asking the question myself.  EDIT:  This is the full output of the command line mentioned in the comments.  $ ls -l filecat.txt; chown user1 filecat.txt; ls -l filecat.txt -rwxrwxrwx 1 amar amar 2054 Jul  8 20:44 filecat.txt -rwxrwxrwx 1 amar amar 2054 Jul  8 20:44 filecat.txt   The file system I'm using is NTFS on both of my partitions.  Using lsblk results in the following output  lsblk: failed to access sysfs directory: /sys/dev/block: No such file or directory   The answer provided in the  suggested editing a certain line in the etc/fstab file. My etc/fstab file contains only the following  line   LABEL=cloudimg-rootfs   /        ext4   defaults        0 0

so I installed this Windows 10 feature since I miss the terminal/bash available on OS X.  One quirk I noticed is that all the files in my data drive (separate HDD from my OS drive) are owned by root. I tried changing ownership to my user (via chown -R my-user-here:root /mnt/d/my-stuff/*) but nothing happens.  I ran   ls -la   and the ownership hasn't changed.  Any way of fixing this?  Thanks


I have the 1.3 update and it's 2019 but it still doesn't work.i have defeated the golem about 20 times now and the lunatic cultist didn't spawn. Please help!

I was searching for more answers on the internet. I kept searching, and I found one thing that help me a little. I went back to Terraria and tried it out, but the Lunatic Cultist didn’t spawn.  Does the Lunatic Cultist spawn on an iPad?


I have mathematical backgroud but I am new to Statistics. So, could you please advice any books on Statistics and/or Biostatistics for beginners?

To give you some background, I have a grasp on the basics of statistics and probability theory and even remember touching Bayes theorem at the university data mining course. But being a few years away from the university made my math got extremely rusty (so much for last-minute pre-exam cramming). While I remember various random basic concepts, there are a lot of gaps in my understanding of them.  What would be a good material (a book, a site, or otherwise equally accessible medium) to revise the fundamentals and go beyond basics? I'd like a book that can be actually read as a book (most statistics books are really dry and are close to being reference material, rather than a book).


I have an issue when I try to pass some ArrayList from an activity to a fragment and I can't find errors; I have found out many answers but can't find anything that works. Here's my code, I'm doing this onResponse from a connection request to a php, it works fine and it puts the correct values in my arraylists:  for (int i = 0; i < res.length(); i++) {                 try {                     String data = res.getString(i);                     String[] items = data.split(";");                     types.add(items[0]);                     distances.add(items[1]);                     startDates.add(items[2]);                     elapsedTimes.add(items[3]);                     ratings.add(items[4]);                  } catch (JSONException e) {                     e.printStackTrace();                 }             }                      bundle.putStringArrayList("types",types);             bundle.putStringArrayList("distances",distances);             bundle.putStringArrayList("startDates",startDates);             bundle.putStringArrayList("elapsedTimes",startDates);             bundle.putStringArrayList("ratings",ratings);         }   Then, in my main activity, I have this to pass the arrays to my fragment:  @Override     public Fragment getItem(int position) {         switch (position){             /*other cases*/             case 1:                 MyFragment f = new MyFragment();                 f.setArguments(bundle);                 return f;         }     }   Finally, in my fragment, to take bundle I do:  @Override public void onActivityCreated(@Nullable Bundle savedInstanceState) {     super.onActivityCreated(savedInstanceState);     Bundle params = this.getArguments();     if(params!=null) {         ratings = getArguments().getStringArrayList("ratings");         distances = params.getStringArrayList("distances");         elapsedTimes = params.getStringArrayList("elapsedTimes");         types = params.getStringArrayList("types");         startDates = params.getStringArrayList("startDates");     } }   But, if I try to print any values in the fragment of the arrays, it's trown the NullPointerException

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?


I have prepared a graph in pdf format by using graph_tool, which is:    I have imported the figure as pdf into tex file. It looks properly on latex preview. However, if I take a pdf output of the tex file, then the lines disappears.    I am working on Overleaf site. They use Tex Live 2016. The tex file is as follows:  \documentclass{article} \usepackage[utf8]{inputenc} \usepackage{graphicx}  \begin{document} \begin{figure} \includegraphics[width=0.45\linewidth]{synthetic_out}\label{sfig:synth_out} \caption{Capt} \end{figure} \end{document}   How can I achieve to see lines on pdf output, too ? Thanks.  EDIT: I have made the lines thicker. But it didn't help too. You can achieve the pdf file via .

I use PCTEX 5.1. When I print from a DVI window my embedded graphics line plots are too thin and almost fade out. When I export the document to a PDF and print it the graphics line weights are much better; however, the PDF driver actually makes every second page, text and graphics, is a little lighter. The dvi driver doesn't do that. So first, can I get the dvi driver to increase the graphics line weights, and second is there a patch for the PCTEX PDF driver problem.


I recently found this insect  near our veranda wall. What insect is this ? Is it poisonous?    As you can see, it has multiple legs fine as hair, but it is not like a common millipede or centipede. I searched for this insect by reverse Google image search without result.  Location: Kolkata, India  Nature: fast-moving, aggressive.  Unlike earthworms, this insect loves basking in sunlight.

I found the insect nside house near Shirdi, Maharashtra. I have captured the image


This is a canonical question that will hopefully encompass all of the questions we get asking us to determine what year a bicycle was manufactured (how old is my bike, how old is my frame, etc.). Each "answer" should address a different way to determine the manufacturing year of a bicycle. To some extent, these will also help you narrow down the model as well as it will tell you what distinguishing features to look at.  The span of answers would include things such as:      Skiptooth cranks Cartridge bottom brackets (BB30/90 etc) Elliptical chainring Quick releases versus contemporary through-axles How the steerer attaches to the fork (quill vs. threadless)  Braking system (especially with mountain bikes: v-brake, direct pull, etc.)   Shifting ramps and pins on cassettes/sprockets and chainrings (versus flat sprockets) Frame material (e.g., shift from tubular steel to use of CF and hydroformed aluminium)  Frame tubing type (e.g. Reynolds 531 tubing introduced around 1934, still used today; Reynolds 501 tubing introduced around 1983). So a frame with an original 501 decal can't be from the 70', 531 decal doesn't help as much because of the range of years produced. Also, see Decals.   *Decals: style/design, amount, placement, color, etc. can help not only determine models, but also year of manufacture. Many changed decal design for the same model bike often yearly, with special/limited editions even more specific. This applies only if decals are original or have been replaced with the identical design. Tubing decals (Reynolds, Columbus, etc.) also changed designs for same tubing made in different years, although the changes aren't made as often, and manufacturers didn't always put tubing Brand decals on every model. Earlier bikes tended to have less fancy, less colorful, less quantity of decals.   Headbadges: most early bikes had actual "badges", often quite detailed and fancy, made of metal, then plastic, and finally just using decals on the headtube. Most bikes lost their metal badges in the 60's and early 70's, although some brands still have actual badges to this day, but in general a real badge indicates an earlier model bike. Dropout style (including the later inclusion of lawyers lips) Presence or absence of CPSC reflectors (USA only) Manufacturing method (shift from lugs to TIG welding, for example)  Number of gears (shift from 2x5 ten-speed to 3x8, 2x9, 1x11, etc.)  Inspection of lug design: pantographs, cut-out, stampings, custom brazing/filing, chrome, fork crow n sweep, etc. Frame/Fork Braze-ons. Race bikes tended have less braze-ons the earlier the year of manufacture. Most 60's racers and earlier had few or none with cable guides/stops, shifters, bidons, etc. being clamp-on. By the 80's if it was clamp-on, it was a sign of very cheap models and most frames had braze-ons for all cables, with multiple bottle and accessory bosses depending on style and use.   and so forth. Please edit this question if you have an answer that isn't in the index above.   A couple of caveats:   A previous owner could have replaced or upgraded components on a bicycle, so this guide only applies to original equipment There is a delay between the introduction of a technology (such as indexed shifting) and when manufacturers start selling products that use it. Low-end manufacturers may continue using technology that is severely outdated (such as one-piece cranks, freewheels, or quill stems) because it is cheaper to do so. A number of bikes are built in a Retro style, but with modern components.  Dutch bikes, trendy coffee cruisers, and beach cruisers may be modern but appear to be 1950s styling.  These tend to have modern rims and brakes as a giveaway.     Note that bicycles.stackexchange does not do valuations of bicycles. How much your bicycle is worth depends on the location of the buyer and seller, how much the buyer wants the bike, etc. etc. etc.


I refinished my kitchen cabinets. I got some water based wood stain on my kitchen wall. I tried to remove it with soap and water on a sponge. It did not work. How can I move it? My kitchen wall is painted with water based satin finished paint.

How do I remove the water based wood stain from my kitchen wall. I got some on my kitchen wall while I was staining my kitchen cabinets?  I tried to remove my using soap and water on a sponge. It did not work. My kitchen wall is painted with water based satin finished paint.


I want to travel from Kenya to Amsterdam and to Athens. Does that need a transit or any other kind of visa? I'm a permanent resident of Greece and I travel with my Kenyan passport.

I found many related questions on this site but I am still not sure about the rules. How can I decide if I need a visa to transit? Schengen members as of May 2021 are as follows:  Austria Belgium Czech Republic Denmark (excluding Greenland and the Faroe Islands - but an open border with the Schengen Area is maintained) Estonia Finland France (excluding overseas departments and collectivities) Germany Greece Hungary Iceland Italy Latvia Liechtenstein Lithuania Luxembourg Malta Netherlands (excluding Aruba, Curaçao, Sint Maarten and the Caribbean Netherlands) Norway (excluding Svalbard) Poland Portugal Slovakia Slovenia Spain (except Ceuta and Melilla) Sweden Switzerland


My supplier sent  my raw material 250 kg short of the full amount .   Is use of '' short '' correct in this sentence ? Can I use this in this way? What I want to say is that My order which was raw material was sent by my supplier. But it was 250 kg less than total amount.

In another  regarding a difference between short on and short of, the  says the following:     ... But this is not always the case. A person can be short on/of money,   but lacking a specific amount, someone can only be €10 short or short   €10. This construction never uses a preposition.   but is that really true? I can see sentences like "I am short of 10 dollars" quite often.


If a rocket is traveling away from earth, why does time pass slower for the rocket if from the rocket's perspective, earth is going away from it?

I read a lot about the classical twin paradox recently. What confuses me is that some authors claim that it can be resolved within , others say that you need . Now, what is true (and why)?


It appears I have missed the  for the quest and nothing I do will trigger it.  's door requires a key and talking to the guards and people do nothing.  Talking to  about buying the house only makes him say that there's a mess.  creating new question as    are similar, but don't share my exact symptoms. Also, it looks like some of them have started them and broken them ()

I've finished the Stormcloak storyline, and now cannot become a Thane of Windhelm without buying Hjerim. The Steward keeps saying something has happened and he can't sell it right now.  What the heck am I missing? I've been doing every random little quest from people in town I can find, hoping to unlock the house. I'm well over the 5/5 requirement of helping people.  Any ideas?


I would like to divide an ellipse into $N$ parts such that these $N$ parts have the same arc length.  So given let's say $a$ and $b$ the semi-axis of an ellipse centered on $(0,0)$ and a positive integer $N$ , the solution should give $N$ angles $A_1 .. A_N$, with let's say $A_0=0$ such that the lines passing by $(0,0)$ and with these slopes will cut the ellipse, "revealing" arcs of the ellipse with equal length. So that the sum of these length obviously equals the perimeter of the ellipse.  In other words I have a pie in shape of ellipse, cut in $N$ slices, such that each "side" of these slices are equals and I need the "angle" of the slices.  I hope that my description is clear enough and that it has a possible simple solution too !  Thanks by advances you mathematicians ! (A programmer)  ps : approximations are most welcome

As an extension to  on equiangular fisheye distortion, how can I calculate equidistant points around an ellipse (or 1/4 segment of) given it's aspect ratio? When it's circular, I can use a simple angle increment around the central point, but as the aspect ratio gets smaller, the length of the arc gets shorter and the angles are no longer equidistant.


How can I give  myself an item with a custom name, and how can I search for a player holding an item with a certain name.  This is what I tried:  /give @p minecraft:acacia_button{display:{Name:"ieat",Lore:[ieat]}} 1   It only gave me a regular acacia button.

In 1.12, the command:  clear @p paper 0 1 {display:{Name:"[Winning Ticket] Musical Minecarts",Lore:[" Take this ticket to the reward "," collections at the entrance of the ", " Games area to claim your prize! "]}}   would remove a piece of paper with that specific name and lore from the player's inventory. I assumed the 1.13 conversion would be:   execute at @p as @p run clear @s paper{display:{Name:"[Winning Ticket] Musical Minecarts",Lore:[" Take this ticket to the reward "," collections at the entrance of the ", " Games area to claim your prize! "]}} 1   but this doesn't work. As well as this, the command:  give @p minecraft:paper{display:{Name:"[Winning Ticket] Musical Minecarts",Lore:[" Take this ticket to the reward "," collections at the entrance of the ", " Games area to claim your prize! "]}} 1   only gives the item, without the custom display name, despite the lore being correct. What is the correct syntax for these two commands?


My book says that you form the character equation as  $\begin{vmatrix} \lambda I - A \end{vmatrix}$. However I see occasionally on stack exchange and other resources that define the character equation as $\begin{vmatrix}A - \lambda I\end{vmatrix}$. Why does this appear to be such a trivial matter? Here are some examples below where I have found the latter being used.        (under "Eigenvalues and the characteristic polynomial"

I understand that both can be used to find eigenvalues and eigenvectors as  $Ax=\lambda x\iff Ax-\lambda x=0 \iff x(A-\lambda I)=0\iff  |A-\lambda I|=0$ And in the same way $Ax=\lambda x\iff 0=\lambda x-AX \iff x(\lambda I-Ax)=0\iff  |\lambda I-A|=0$  So the different between the two will be by plus/minus sign in the characteristic polynomial?  for example $A=\begin{pmatrix}  2 & 0 &1 \\ 0 & 3 &0\\ 1 &0 &2 \end{pmatrix}$ will be $f_A(\lambda)=(\lambda-3)^{2}(\lambda-1)$ for $|\lambda I-A|$ and $f_A(\lambda)=-(\lambda-3)^{2}(\lambda-1)$ for  $|A-\lambda I|$


Intro: I'm not a GD, but bear with me.  I've been doing digital illustrations for a while and never had an issue with posting them anywhere, until this year. I keep getting all my illustrations sort of blurred/pixelated every time I upload them to most social medias. I use Illustrator CC. Most of the time I create my work on a CMYK file (just in case if I ever want it to print it), 300 ppi, align to pixel grid and then export it on RGB. Mostly on square format (20x20cms, I changed it to 1200px x 1200px as someone suggested those measurments me for fb) This is driving me nuts. Believe me I've tried everything (save for web, save for microsoft office, jpg, png, different sizes and resolutions according to fb, tw, pinterest...) The only place they look great are tumblr or behance, since they don't compress anything, so far. I'm ready to try everything one more time, for the sake of my images looking sharp.     Here's an example of what I'm suffering. Left one is the fb uploaded version. Right one the original, how it should look.  Help a girl out! Thanks  Cecily

After uploading an image, Facebook converts it to a new image.  Their conversion process introduces artifacts and mottling to the magenta-ish parts of the image.  Original image:   Facebook's conversion:   Are there ways to preserve the original quality of this image and have the image appearance on Facebook reflect more of the original quality?