Sorry, I put my explanation in comments instead of editing the question. The important point about why it isn't a duplicate is that I have tried the answers to similar questions and they haven't worked. I have put the solutions I have tried in the comments. So my question remains and its why I started originally by saying "Really struggling with the previous answers to these questions."  I have a bootable usb with a fresh download of 18.04.2 on it. I booted to it from an option in Windows 10 to boot from usb. The install seemed to work okay. I chose both LVM and full drive encryption and really wish I hadn't now. The install seemed to work but when I restarted machine after removing usb I get: Failed to open \efi\boot\mmx64.efi - not found Failed to load image \efi\boot\mmx64.efi - not found Failed to start MOKManager - not found. So I have been into BIOS numerous times, switched off secure boot, saved settings. No change. Set a supervisor password and looked for the option to 'select a uefi file as trusted' but no such option. If I could boot from usb again and re-install without the LVM and encryption option I would but it won't boot from usb even though I have put it first in the list. I tried the usb in another machine and it worked just fine. So, I can only get to BIOS screen, not to a terminal or anything else. The BIOS screen doesn't have the 'trusted' option and I feel really stuck. I would reinstall windows to start again but machine came without CDs so can't do that either. There is a lot about this problem, going back a long way, but most of it is not applicable because I cannot boot up at all, from anything. Any and all help much appreciated. Thanks.

I tried to install Ubuntu 18.10 on my XPS 15 9570 earlier. Everything was working fine until I got to the partition selection part of the installation. That's when the installer crashed and I had to shut down my machine. I think it's because I had my SATA configuration set to RAID ON instead of AHCI, which is now fixed.  Now when I try to run the installer from my bootable USB I get the following error  Failed to open \EFI\BOOT\mmx64.efi - Not Found Failed to load image \EFI\BOOT\mmx64.efi: Not Found Failed to start MokManager: Not Fond Something has gone seriously wrong: import_mok_state() failed   Hoping someone might have some idea as to what is going on


I have user registration and user login form on same page and want to customize the field of both the forms?

I previously asked this  about modifying the default user registration form. The default form is largely fine, I just want to add some text and some links above and below the form (i.e. instructional advice etc).  One of the answers to my previous question suggested creating a module with the hook form_alter. I did this, however, it seemed all that achieved was adding adding new text fields to the form. I don't want to add new text fields, just some additional text/html before and after the form.  Is there any way to do this with form_alter, and if so, could you detail the code I'd need to do this (such that is does not add another user visible field)?  If there's another way to modify the page directly (not just the form) could you detail it? Keep in mind I want this to work with all themes, so when I change themes my changes do not disappear (which is why I was hoping to be able to do it in a module).


Suppose sets $A$ and $B$ are not empty and are bounded from above. Prove that $\sup(A) + \sup(B) = \sup(A + B)$ without using $\epsilon$. This is exercise 1.3.6 from Understanding Analysis by Abbot, 2nd edition.  Here is my start:  Let $s = \sup(A)$, $t = \sup(B)$, then for any $a \in A, b \in B$ we have $a \le s$ and $b \le t$ and, consequently, $s + t \ge a + b$.  And here I get stuck:  Let $u$ be an arbitrary upper bound of $A + B \implies a + b \le u$. Show that $t \le {u - a}$.  $b \le {u - a}$ is promising, but I don't see how to proceed rigorously from here on.  EDIT  The other question has answers that prove the same thing (some of them w/out epsilon), but they don't do it the way the book proposes to. I am interested in the book's way as well.

If $A,B$ non empty, upper bounded sets and $A+B=\{a+b\mid a\in A, b\in B\}$, how can I prove that $\sup(A+B)=\sup A+\sup B$?


I'm looking for a straightforward answer that actually works...not a 'duplicate question' flag. None of the other solutions posted in similar threads actually work...they all have dead-end answers and/or links. I've searched for hours and spent many more actually trying the methods I've found and none seem to work.  As for my question; I'm looking to generalize the polygons of a shapefile to reduce their resolution. Topology needs to be maintained for future geometry functions such as difference and union. There doesn't seem to be any way to preserve topology in QGIS...is there any other way? Any suggestions will help (as long as it doesn't involve ArcGIS).  Previous questions which don't have useful answers:   - topology is not considered   - no accepted answer    Also another questions of mine:

I have a polygon Shapefile, which I need to generalize. How can I generalize the poligons and ensure that there are no topological errors like "slivers".   I already tried:   Vector -> Geometry Tools  -> polygones to lines Vector -> Geometry Tools  -> simplfy geometries ... here I can already see on the screen, that I am producing overlaps and gaps nevertheless now I try Vector -> Geometry Tools  -> lines to polgones   and here the program show an error and crashes


I noticed that the about section has a copyright date range from 2014 to 2015. This should probably be extended to the current year. It makes me wonder why that was apparently hard coded instead of automatically updating to the current year. So maybe this isn't really a bug?  App Version: 1.0.95   About Copyright 2014 – 2015, Stack Exchange Inc.

Should be 2016, not 2014-2015.       App Version: 1.0.85   Device Manufacturer: samsung   Device Model: GT-N8000   OS Version: 4.1.2 (N8000XXCMJ2)


First off I am a car guy, if I have a schematic or details I can solder what I need.  I have a client that fitted a digital temperature gauge to his car, he also wants to have the gauge on the instrument cluster to work. Now from experience, I know this can not be done by just splicing wires and I need to make an op-amp buffer from what I have read.  All I need are some examples of what wire goes where to the gauges and power and signal wire from the sensor. Also, what are the part numbers of components needed?  The sensor that is fitted is fairly common and from what I found is it decreases in resistance as the car warms up, unfortunately, there are no numbers on the sensor.  Hope this is enough information thank you.

Is it possible in circuit design to split like say a temperature sensor line reading into 2 wires, and read by 2 different system/circuitry? My motive is to tap the signal line in a safe way without affecting or disrupting the other system functioning.


I am creating a randomly-generated environment for a game I'm developing. I am using OpenGL and coding in Java.  I am trying to randomly place trees in my world (to create a forest), but I don't want the models to overlap (which happens when two trees are placed too close to each other). Here's a picture of what I'm talking about:    I can provide more code if necessary, but here's the essential snippets. I am storing my objects in an ArrayList with List<Entity> entities = new ArrayList<Entity>();. I am then adding to that list using:  Random random = new Random(); for (int i = 0; i < 500; i++) {     entities.add(new Entity(tree, new Vector3f(random.nextFloat() * 800 - 400,      0, random.nextFloat() * -600), 0, random.nextFloat() * 360, 0, 3, 3, 3); }   where each Entity follows the following syntax:  new Entity(modelName, positionVector(x, y, z), rotX, rotY, rotZ, scaleX, scaleY, scaleZ);   rotX is the rotation along the x-axis, and scaleX is the scale in the x-direction, etc.  You can see that I am placing these trees randomly with random.nextFloat() for the x and z positions, and bounding the range so the trees will appear in the desired location. However, I would like to somehow control these positions, so that if it tries to place a tree too close to a previously placed tree, it will recalculate a new random position. I was thinking that each tree Entity could have another field, such as treeTrunkGirth, and if a tree is placed in the distance between another tree's location and it's treeTrunkGirth, then it will recalculate a new position. Is there a way to accomplish this?  I am happy to add more code snippets and details as necessary.

I'm starting a 2D game where I want all the letters A-Z displayed in a random position and, then, the player collects them all in the correct order. I need to randomly instantiate the letters without overlapping. I use C#.


As far as I understand, it is possible for post scored +3 or higher to land in Low Quality queue and be deleted by 6 "No Comment" recommendations.  Besides a , what happens in this case? As far as I understand,   moderators can't find about this since system doesn't raise a flag for their attention authors can't find it out since there's neither , nor  that could be visible in profile, nor is it listed in  in their profile deleted post is added to the list of recently deleted in  page   Is my understanding correct? Is there something worth worrying about in this process?    For the sake of completeness, same seems to be happening to old posts without votes at all, or those having zero reputation "balance" due to up/down votes split. I don't ask about these because I don't even know whether there is a reason to worry about deletion of higher voted posts.

are pretty cool... You get a birds-eye view of activity on the site, a "dashboard" view of what's happening. Some of the individual tools haven't scaled particularly well with Stack Overflow's growth, but the concept behind them is still sound: we trust you to enough to be a bee watcher now.  ...and then there's . What a let-down! Once upon a time, this queue contained spam and offensive flags, which one might reasonably assume were important enough to put in front of the more trusted members of the site. Re-flagging them brought them that much closer to deletion, while editing them offered salvation to some hapless author. Nowadays, it's a bunch of Not an Answer flags and a smattering of assorted cruft. 10K users can't even vote to delete these; only 20K users have that privilege. Re-flagging them does nothing but increase their priority in the moderator flag queue, where they frequently outrank more pressing issues;  has . Also, it's , and the behavior has diverged far enough from that of the moderator flag queue on which it is based that it has become an active hindrance to further development of the tooling there. Worst of all, we have  that's available to anyone with the editing privilege. It even has logic built in to prioritize answers likely to be deleted for users with . It's like we gave you a car for your 10th birthday, and then replaced it with a rusty bicycle when you turned 16. It was a nice idea, but it has outlived its usefulness. Proposed changes The /tools/flagged route goes away. Period. No replacement. The rest of the 10K tools stick around as informational pages. Not an Answer flags go into /review/low-quality, . Then we beef up the Low Quality review process to make better use of more experienced reviewers and solve this whole "declined / helpful / disputed" flag debate once and for all:  Effective # of reviews required == ReviewsRequired + # of applicable flags (where ReviewsRequired is 2 on Stack Overflow, 1 everywhere else). So 1 VLQ or NAA flag means EffectiveReviewsRequired=3. LQ tasks are not dequeued until one of the following conditions is met:  Post is edited from within review. Outcome: flags are marked "helpful" (current behavior). Post accumulates 3 Delete votes (can only happen when post scores <= 0 and reviewers have >= 20K rep). Outcome: post is deleted, flags are marked "helpful". Task accumulates EffectiveReviewsRequired "Looks Good" reviews. Outcome: if the number of (Recommend)Delete reviews is >= the number of Looks Good reviews, mark flags "disputed" and raise DisputedLowQuality mod flag. Otherwise, mark flags "declined". Task accumulates 6* RecommendDelete + Delete reviews. Outcome: mark flags "helpful". If the post scores > 0 then raise DisputedLowQuality mod flag, else just delete post (current behavior).   As under the current system, flags on posts that've already completed one full review cycle without being deleted should skip /review and go directly into the mod queue.  End result  Flags get handled faster, more accurately, and with less wasted effort from 10K reviewers. Moderators are free to focus on situations that can't be handled by the community - the ! Developers are free to make enhancements to the moderator tooling without having to work around 10K user restrictions.  Questions Am I forgetting anything here? I haven't really spent much time in the 10K flag queue since back when it was filled with spam flags and therefore useful - is there a use-case that you depend on that would be lost with its removal? Post 'em below. *: on Stack Overflow, only .


I experience several odd errors and glinces after upgrading from ubuntu 18.04 to 20.04. The first thing, I noticed were the funny green pixeled lines on the background wallpaper. They can be overlayed by windows and disappear when switching to a different image but remain on the original image, when switching back. This is also the case for other background images from the standard stock).  Further -- and much more annoying -- is that ubuntu repeatedly crashes at standby/when suspended, e.g. when closing the lid. So, it won't wake up again or rather, it isn't asleep (blinking lights indicate the difference). When booting again, I can choose to start up in recovery mode ... I checked all packages and the file system, updated the boot-loader (2.04-1ubuntu26.6), etc. In some cases, the system won't start up at all. I couldn't find a pattern yet. I found  describing that the screen remains black after waking up, but adding the option GRUB_CMDLINE_LINUX="nouveau.modeset=0" to grub (/etc/default/grub) didn't help. I am out of ideas. Some further info: $ ls -al /var/crash total 8 drwxrwsrwt  2 root whoopsie 4096 Feb  9  2020 . drwxr-xr-x 16 root root     4096 Nov 14 11:04 ..  and $ls -al /usr/share/gnome-shell/extensions total 20 drwxr-xr-x 5 root root 4096 Nov  5 22:00 . drwxr-xr-x 7 root root 4096 Nov  5 22:11 .. drwxr-xr-x 2 root root 4096 Nov  5 22:00 desktop-icons@csoriano drwxr-xr-x 3 root root 4096 Nov  5 21:33 ubuntu-appindicators@ubuntu.com drwxr-xr-x 3 root root 4096 Nov  5 21:34 ubuntu-dock@ubuntu.com  and the system (Asus notebook -- no Nvidia graphics) $ lspci 00:00.0 Host bridge: Intel Corporation Xeon E3-1200 v5/E3-1500 v5/6th Gen Core Processor Host Bridge/DRAM Registers (rev 08) 00:02.0 VGA compatible controller: Intel Corporation Skylake GT2 [HD Graphics 520] (rev 07) 00:04.0 Signal processing controller: Intel Corporation Xeon E3-1200 v5/E3-1500 v5/6th Gen Core Processor Thermal Subsystem (rev 08) 00:14.0 USB controller: Intel Corporation Sunrise Point-LP USB 3.0 xHCI Controller (rev 21) 00:14.2 Signal processing controller: Intel Corporation Sunrise Point-LP Thermal subsystem (rev 21) 00:15.0 Signal processing controller: Intel Corporation Sunrise Point-LP Serial IO I2C Controller #0 (rev 21) 00:15.1 Signal processing controller: Intel Corporation Sunrise Point-LP Serial IO I2C Controller #1 (rev 21) 00:16.0 Communication controller: Intel Corporation Sunrise Point-LP CSME HECI #1 (rev 21) 00:17.0 SATA controller: Intel Corporation Sunrise Point-LP SATA Controller [AHCI mode] (rev 21) 00:1c.0 PCI bridge: Intel Corporation Sunrise Point-LP PCI Express Root Port #1 (rev f1) 00:1c.5 PCI bridge: Intel Corporation Sunrise Point-LP PCI Express Root Port #6 (rev f1) 00:1f.0 ISA bridge: Intel Corporation Sunrise Point-LP LPC Controller (rev 21) 00:1f.2 Memory controller: Intel Corporation Sunrise Point-LP PMC (rev 21) 00:1f.3 Audio device: Intel Corporation Sunrise Point-LP HD Audio (rev 21) 00:1f.4 SMBus: Intel Corporation Sunrise Point-LP SMBus (rev 21) 02:00.0 Network controller: Intel Corporation Wireless 7265 (rev 59)  Since there are usually not two separate root causes, I suspect that both errors are linked. Thx Update I reconfigured my swap partition (see those two very informative posts on a step-by-step-guide  and for encrypted swap ). Nevertheless, I still experience the problem. Further, after crashing at suspend, the system starts-up automatically. However, when choosing "ubuntu" from the recovery booting list, the screen remains black and no startup is visible.

I have recently upgraded Ubuntu 19.10 to latest LTS Ubuntu 20.04. After updating, I get serious artifacts on my screen. Every time I reboot (or log-in), my screen is fuzzy or scrambled (picture attached):     This is temporary. The fuzzy screen goes away when I change the background. But it reappears the moment I reboot or log back in.   I have Intel HD Graphics 520 (Skylake GT2).  The output of lspci -nn |grep -E 'VGA|Display' is:  00:02.0 VGA compatible controller [0300]: Intel Corporation Skylake GT2 [HD Graphics 520] [8086:1916] (rev 07)   Update:   On enabling Wayland in Ubuntu 20.04 and logging in to, these artifacts are however cured.   This is okay for now, but I am not sure about Wayland as I have not yet used it before.   Is there a way to correct the graphic issue with normal Ubuntu startup?


I just started reading Lie Algebras in Particle Physics by Howard Georgi and I'm finding it frustratingly fuzzy. What I mean is that he often makes non-trivial statements without proof, is imprecise with definitions, and so on. However, what other books I can find seem to swing a bit too far the other way, and I simply don't have time for the most comprehensive and rigorous treatments. The ideal book would be somewhere in the middle. It should be a quick read, but prove or sufficiently motivate important statements. And it should cover the essentials needed in introductory theoretical particle physics; i.e. basic representation theory, basic Lie theory, and something about $SU(2)$ and $SU(3)$. Are there any good alternatives?

I am looking for a good source on group theory aimed at physicists. I'd prefer one with a good general introduction to group theory, not just focusing on Lie groups or crystal groups but one that covers "all" the basics, and then, in addition, talks about the specific subjects of group theory relevant to physicists, i.e. also some stuff on representations etc.  Is Wigner's text a good way to start? I guess it's a "classic", but I fear that its notation might be a bit outdated?


I am trying to construct a proof and would like to know if I have started it correctly. The proof is as follows.  "Prove that for every odd integer n, there is a group with exactly n elements of order 2."   Written more compactly I have it as:  "$\forall n \in \mathbb{Z^{+odd}}, \exists$ a group G with exactly n elements of order 2."  To prove this universal statement, I figure I should disprove the negation. Thus I have:  Assume: "$\exists n \in \mathbb{Z^{+odd}} , \nexists$ a group G with exactly n elements of order 2."  I am new to proofs and would like to know if the beginnings of this proof are sound. Thanks in advance.

Prove that for every odd integer n, there is a group with exactly n elements of order 2.  I am new to abstract algebra and proofs in general. Proving existence is difficult for me, but I will show what I have.  $$n = 2k + 1$$ $$k \in \mathbb{Z^+}$$  $$\exists G \supset H = (a_1 , a_2 , ..., a_n, e)$$  $$s.t. |a_1| = |a_2| = ... = |a_n| = 2$$  My instinct is to use Lagrange's Theorem, although I would like to try another method to prove this as we have not gone over cosets in class yet. If someone could just give me a hint of how to start, it would be very beneficial. Thank you.


I need some help in order to understand the type of visa required to travel through Germany airports. My itinerary to india is Boston-Munich-Mumbai and my return flight is Mumbai-Munich-Frankfurt-Boston. I hold indian passport and have US visa in the form of approved I797 but passport is not stamped while going from US to India. The plan is to get passport stamped and take the return flight as mentioned above. While going from US to India, I just have one layover in Munich but while coming back I have two lay overs- one in Munich and other in Frankfurt (both in the same country). Do I need a German visa for my returning flight to US? I am really confused- Do I need a airport transit visa? or Do I need a visitor visa? Basically what type of visa I need to get for my round trip- US to india, and India to US.  The more I read, the more I get confused. I tried calling German embassy in boston and also Lufthansa airline but I don't have any response yet. The whole terminology is confusing to me- Schengen vs transit or if they are same?   Can anyone please provide me the response based on my case and if someone in the same situation or have traveled in the past.

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


When i put the command \pause on my beamer, the subsections are "white completely" (before appearing) while i want that they are "shaded" ! Do you have a solution for that ? Thanks in advance and sorry for my english

I tried all overlay options like hide, uncover, visible but didn't get solution. I don't know how to partially hide the content that will display in next slide. Here is the example what I really want to do. In which the bullet 2 content will display in next slide but partially hide or a shadow in current slide.


One of the ways replacing a string with sed can be done as follows:  sed -i 's/old_str/new_str/' file.txt   However if replace.sh is   sed -i 's/$1/$2/' $3   the command ./replace.sh old_str new_str file.txt doesn't seem to work -- after making replace.sh executable of course. Why is that?    I am aware rpl does exactly the same as I intend to do with replace.sh, but I'd like to understand why is it not working.

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}/'


What makes the journal "prestigious" in the first place? I can't myself find any sensible answer.   One candidate reason is that some journals have better reviewers. But reviewers are usually not paid, so if it were true that the good reviewers flock to these select few journals, they must be doing so because those journals were prestigious or attractive in some sense in the first place, and so we are back at our original question.   Another possible reason is that some journals only publish papers of a high quality. This seems wrong as well. For example, if I decided to create a journal which only published extreme-super-duper-mega-high quality papers, nobody would care about it. Rather it seems to be the other way around: these journals publish the best papers because they are prestigious and therefore receive the attention of the best academics and their best papers. So again, we are back at the original question.   A third reason could be readership, but, again, the readership is a consequence of the prestige the journal already possesses. We still don't know where it came from.

Journals like Nature and Science have impressive impact factors. How and why did these top journals become top journals? Why are they able to sustain their statuses?


In order to clean some string, I have to remove some substring that contains some special UTF-8 characters.  example:   source = "Skoda" to_be_clean = "Škoda Rapid"   I need to replace from to_be_clean the string source by nothing. Obviously, the to_be_clean string contains some special character. Is there a way to do this task simply. Here is how I am doing it today.  output = to_be_clean.replace(source + ' ', '')   I was thinking about a regular expression but I need to list all the possible characters.

I have a Unicode string in Python, and I would like to remove all the accents (diacritics). I found on the web an elegant way to do this (in Java):  convert the Unicode string to its long normalized form (with a separate character for letters and diacritics) remove all the characters whose Unicode type is "diacritic".  Do I need to install a library such as pyICU or is this possible with just the Python standard library?  And what about python 3? Important note: I would like to avoid code with an explicit mapping from accented characters to their non-accented counterpart.


I would like to install Chrome on Ubuntu 14.04 32bit, but it's no longer supported.

I tried to install using following command for 32-bit system.  wget https://dl.google.com/linux/direct/google-chrome-stable_current_i386.deb   But I got an error:  Resolving dl.google.com (dl.google.com)... 216.58.199.174, 2404:6800:4009:807::200e Connecting to dl.google.com (dl.google.com)|216.58.199.174|:443... connected. HTTP request sent, awaiting response... 404 Not Found 2016-06-30 20:05:59 ERROR 404: Not Found.


Is it in the direction of the velocity ?   If it is, can anybody describe it somehow that matches my physical feeling?   How the shear stress affects another layer of fluid ?   I faced a question today that fluid is moving alongside a horizontal tube and and if we write momentum equilibrium we must omit gravity force because it is not in the direction of the velocity, but what about shear stress ?

One book defines the shear stress $\tau$ of a (Newtonian) fluid as  $$\tau = \eta \frac{\partial v}{\partial r} $$  where $\eta$ is the viscosity. There is not much context, so I've made some guesses. Are my following assumptions correct?   $v$ is the velocity of the flow line, parallel to the wall. $r$ is the distance of the flow line from the wall. the flow must be laminar for the above to hold. (Otherwise, what would $v$ mean?) the "wall" must be a tube for the above to hold. (Otherwise, what would $r$ mean?)


I have the following image...    ...that I'm trying to get a vector outline for in a similar way to the Illustrator Offset command.  I'm looking to have a finished vector look similar to this...    (Note: This is simply a stroke layer style that has been added to the original)  The two outlines must be vector shapes.  Is there anything in PhotoShop that will allow me to do this?

I drew paths thinking i was drawing a shape but later realized it is only a path. Now i could create a temporary shape like a box and paste this in and delete the box path. But just as there is a option to convert path to selection, is there an option to convert the selected path into shape?


I'm from mathematical background, I want to LEARN tensor as well as relativity(mathematical approach), which book is helpful for me?and what do I need to know first to better understand those topics? Your help will be highly appreciable...

I am currently a 3rd year undergraduate electronic engineering student. I have completed a course in dynamics, calculus I, calculus II and calculus III.  I've started self studying tensor calculus, my sources are the video lecture series on the YouTube channel; "MathTheBeautiful" and the freeware textbook/notes; "Introduction to Tensor Calculus" by Kees Dullemond & Kasper Peeters. Other textbooks go much more in depth in advanced math topics. I have been through the first 3 chapters and watched the first 5 videos, but I don't seem to understand the content. I don't know what I should take from these lectures and notes and what part of the work to focus on in order to start practicing as soon as possible.  I want to learn tensor calculus in order to study more advanced mathematics and physics such as; General Relativity, Differential Geometry, Continuum Mechanics etc. I've also seen many other textbooks on continuum mechanics and tensor analysis for mathematicians/physicists. All of these sources seem quite different and seem like I require much more advanced topics in mathematics in order to understand. How should I approach tensor calculus? through a physics or through a mathematics perspective?  From what I've seen, tensor calculus seems very abstract and more towards the proving side of the spectrum (like a pure mathematics subject), it doesn't look "practicable" as appose to other calculus courses where I could go to any chapter in the textbook and find many problems to practice and become familiar with the concept.  Is my current knowledge in calculus and physics + dynamics enough, or do I need to first learn a few more concepts in mathematics in order to begin attacking tensor calculus problems?


I'm trying to do this exercise:     Let $n \in \Bbb{N}$. Let $x_1,x_2,\ldots,x_n$ be positive real numbers   such that $\prod_{i=1}^n x_i = 1$. Prove that $\sum_{i=1}^n x_i \ge n$   Here is my attempt:  Let $S = \{n \in \Bbb{N} | \sum_{i=1}^n x_i < n \}$ and $S \ne \emptyset$.  By the well ordering principle, S has a least element.  If $ n = 1$, we have:  $\prod_{i=1}^2 x_i = 1 \implies x_2 = \frac{1}{x_1} \implies \sum_{i=1}^2 x_i  = \frac{x_1^2+1}{x_1}$  and $\frac{x_1^2+1}{x_1} \ge 2 \iff x_1^2+1 \ge 2x_1 \iff x_1^2 -2x_1 +1 \ge 0 \iff (x_1 - 1)^2 \ge 0$  Therefore 1 is not the least element of S.  Let k be the least element of S. We can conclude the following:     $k \ne 1  \implies k \ge 2 \implies (k-1) \in \Bbb{N} $ (1)      $\sum_{i=1}^k x_i < k \implies  \sum_{i=1}^{k-1} x_i < k - x_k$ (2)   If $\prod_{i=1}^k x_i = 1$ there are 3 cases:  (i). $\prod_{i=1}^{k-1} x_i = 1$ and $x_k = 1$  (ii). $\prod_{i=1}^{k-1} x_i < 1$ and $x_k > 1$  (iii). $\prod_{i=1}^{k-1} x_i > 1$ and $x_k < 1$  Assuming cases (i) or (ii) would imply a contradiction with out assumption that k is the least element because we would have:  $\sum_{i=1}^k x_i < k \implies  \sum_{i=1}^{k-1} x_i < k - x_k \le k-1$  So $(k-1) \in S$ and $S = \emptyset$  In case (iii) I'm stuck. Can we derive a contradiction assuming that $\prod_{i=1}^{k-1} x_i > 1$ and $x_k < 1$ ??? Or is there another approach to this problem? Any help will be appreciated.

Please give me the proof for the following: Let $a_1,\,a_2,\,\dots\,a_n$ be $n$ positive real numbers whose product is equal to $1$. Prove that $$a_1+\cdots+a_n \geq n$$ and that the equality sign holds only if every $a_k$ is  equal to $1$.


$$\nabla\cdot(\mathbf{u}\times\mathbf{v}) = (\nabla\times\mathbf{u})\cdot\mathbf{v} - (\nabla\times\mathbf{v})\cdot\mathbf{u}$$   Hi, the above is a vector equation, where u and v are vectors. I am trying to prove this identity using index notation. I am able to get the first term of the right-hand side, but I don't see where the second term with the minus in front comes from. Any help? Thanks!  EDIT: I don't think this is a duplicate of that thread since the question in that thread has a scalar f and a vector v, whereas my problem has two vectors u and v, and no scalars.

Verify the vector identity:  $\nabla \cdot (a  \times b) = b \cdot \nabla \times a - a \cdot \nabla \times b $  Given that:  $a = (R_a, S_a, T_a)$, $b = (R_b, S_b, T_b)$ and $\nabla = (\frac{\partial} {\partial x},\frac{\partial} {\partial y},\frac{\partial} {\partial z} )$.  Where $R_i, S_i, T_i$ have continuous partial derivatives.   I attempted it on paper but cannot get it to work. Can anyone show me how this is done?  My working:  LHS:  $\nabla \cdot (a  \times b) = \frac{\partial}{\partial x}(S_a T_b - S_b T_a) + \frac{\partial}{\partial y}(T_a R_b - R_a T_b) + \frac{\partial}{\partial z}(R_a S_b - R_b S_a)  $  RHS:  $\nabla \times a = (\frac{\partial}{\partial y} T_a - \frac{\partial}{\partial z} S_a)\hat i - (\frac{\partial}{\partial x} T_a - \frac{\partial}{\partial z} R_a)\hat j + (\frac{\partial}{\partial x} S_a - \frac{\partial}{\partial y} R_a)\hat k$  $b \cdot (\nabla \times a) = R_b(\frac{\partial}{\partial y} T_a - \frac{\partial}{\partial z} S_a) - S_b(\frac{\partial}{\partial x} T_a - \frac{\partial}{\partial z} R_a) + T_b(\frac{\partial}{\partial x} S_a - \frac{\partial}{\partial y} R_a)$  Now I computed the other part of the RHS as well however I can't see how I would be able to maninipulate it into the LHS.  Anyone have any idea?


My desktop PC keeps waking up every time I put it to sleep. I put it to sleep, it wakes up. I put it to sleep again, it wakes up. I put it to sleep once more, it wakes up! It only stays asleep for about half a minute and then just wakes up again. Why is it doing that? I mean I know that Microsoft was trying to be smart with Windows 8 (on so many levels!) and they have put in place some wake timers so that the PC may wake up in order to install updates or perform some "maintenance" tasks. But I have already been over those settings. They are disabled, and there are no pending maintenance tasks.  Have a look:  Microsoft Windows [Version 6.3.9600] (c) 2013 Microsoft Corporation. All rights reserved.  C:\Windows\system32>powercfg /lastwake Wake History Count - 1 Wake History [0]   Wake Source Count - 0  C:\Windows\system32>   This output is unintelligible! Not human! If a specific service or process has waken the PC, this command should point it out. But nope, it just says 0. Thanks Microsoft! That says a lot!  These are my currently set wake timers:  Microsoft Windows [Version 6.3.9600] (c) 2013 Microsoft Corporation. All rights reserved.  C:\Windows\system32>powercfg /waketimers There are no active wake timers in the system.  C:\Windows\system32>   That's right, none!  These devices are armed to wake the PC:  C:\Windows\system32>powercfg /devicequery wake_armed HID-compliant mouse (002) Realtek PCIe GBE Family Controller Realtek PCIe GBE Family Controller #2 HID Keyboard Device (001) Logitech Optical Gaming Mouse G400s (001)  C:\Windows\system32>   Here is my power configuration setting:    Here is my Action Center setting:   As can be seen, all the relevant settings have been set to disabled. So what's the problem then? How do I stop this?  Update:  It appears now that this has nothing to do with network devices waking my computer, WOL (wake on lan). I have ensured that all my NICs have WOL enabled only for magic packet. If there was any wakes caused by WOL, there should be no wakes caused by WOL wakes anymore. Instead, this appears to be a Windows maintenance issue. I will post my findings at the linked duplicate question page.

When I put my computer into sleep mode, it will wake up while I'm away from it. There's nothing near the computer that could move the mouse or accidentally press a button and I have no idea what might be causing it.  I tried checking what woke it, apparently LASTWAKE only tells me that it has been in sleep mode, not what woke it up.    I also couldn't find anything in my Power Options regarding Sleep that seems off. Poking around in the Event Viewer I notice the following:   The Power-Troubleshooter event at the top notes the following:     The system has returned from a low power state.      Sleep Time: 2012-10-27T11:31:53.408927000Z    Wake Time: 2012-10-27T12:25:51.887029300Z      Wake Source: Unknown   So does anyone have an idea to find out what might be causing it and how I can prevent my computer from randomly waking up?


I am creating a wordpress site (Arabic). It shows arabic text  in home page. but when I include footer page the Arabic text in footer shows ?????. Arabic  text is displaying properly in my home page. Problem occurs on included page.I have included  <META HTTP-EQUIV="Content-Type"  CONTENT="text/html; CHARSET=iso-8859-6">   in my inluded footer page. But no luck.Can somebody please help me?

I'm setting up a new server and want to support UTF-8 fully in my web application. I have tried this in the past on existing servers and always seem to end up having to fall back to ISO-8859-1.  Where exactly do I need to set the encoding/charsets? I'm aware that I need to configure Apache, MySQL, and PHP to do this — is there some standard checklist I can follow, or perhaps troubleshoot where the mismatches occur?  This is for a new Linux server, running MySQL 5, PHP, 5 and Apache 2.


I have a CloudPage that is populating a Journey when people sign up to simply send them an email. The problem is that when they fillout the form since they are not a member of our All Subscribers list they are being errored out with this message.  Failed - Email.JourneyBuilder.Activities.EmailActivity.EmailAddress: Error binging data bound member  I tried re configuring the data extension to make sure the field type was set to email, as well as having the data extension the CloudPage drops into set as sendable. I've also made sure I was sending into a publication list as apposed to All Subscribers, but I am still running into these errors. I have other Journeys running that can execute email sends but this is the only CloudPage Journey we have running.  Any help would be greatly appreciated!

In my journey, entrants get admitted into it, but emails arent been sent. When I check the history, they have the following status:     Failed: Email.JourneyBuilder.Activities.EmailAddress: Error binding   data bound member   What does this mean and how do I resolve it?


I replaced my 250Gb HDD with a 500Gb SSD. The problem is that after installing my new SSD and copying all my stuff onto it, my SSD reports it has a single partition of 250Gb and free space of 250Gb instead of a single 500Gb partition.  This has more than likely come about because I cloned my SSD from my old HDD (it seemed like a good idea at the time!).  If I open Disk Utility, select my SSD and click the Partition button it shows the free space and the SSD with a resize control on the border between the two. The resize control won't let me drag it to the left (clockwise into the free space) no matter how much I try. It also won't let me create a new partition in the free space.  My OS is High Sierra and the format is APFS.  I've had a look at some third party tools but haven't found any that work with APFS.  All the googling I've done on this subject suggests that Disk Utility doesn't work with all the features of APFS.  It seems it's possible to increase the size of a partition from the command line in Terminal but I can't find any instructions that deal specifically with my scenario. Here's the output from the diskutil list command:    ...and the output from sudo gpt -r show /dev/disk1:    I've tried to resize the container using:  diskutil apfs resizeContainer disk0s2 500g   but this command throws an error:     The size (500g) must not be greater than the partition map allocatable size   Can anyone help? Ideally I'd like to have a single 500Gb partition.

Hi I am having issues trying to resize my Mac OS partition, I previously had a very large recovery partition almost 100gb as a result of removing my linux installation, I since resized this to 650mb. The problem is I am unsure on how to increase the size of my main Mac OS partition as I have no experience with this new container disk stuff.   Here is what diskutil list shows:  /dev/disk0 (internal, physical):    #:                       TYPE NAME                    SIZE       IDENTIFIER    0:      GUID_partition_scheme                        *251.0 GB   disk0    1:                        EFI EFI                     209.7 MB   disk0s1    2:                 Apple_APFS Container disk1         150.4 GB   disk0s2    3:                  Apple_HFS Recovery HD             650.0 MB   disk0s3  /dev/disk1 (synthesized):    #:                       TYPE NAME                    SIZE       IDENTIFIER    0:      APFS Container Scheme -                      +150.4 GB   disk1                                  Physical Store disk0s2    1:                APFS Volume Mac OS                  122.1 GB   disk1s1    2:                APFS Volume Preboot                 20.3 MB    disk1s2    3:                APFS Volume Recovery                506.6 MB   disk1s3    4:                APFS Volume VM                      1.1 GB     disk1s4   As you can see I resized the Recovery HD partition but the container is still 150gb.  I also tried the following command to try reduce the container size:  sudo diskutil apfs resizeContainer disk0s2 1g jhfs+ Media 0b   But I get the following error:  Error: -69605: There is not enough free space in the APFS Container for this operation   Additionaly within Disk Utility app if I view the partitions, it shows I have 99.6 GB of "Free space" but I am unable to resize the Mac OS partition as previously mentioned.  Any help would be greatly appreciated, Thank you


If G contains a normal subgroup $N \cong \mathbb{Z}_2$ and $G/N \cong \mathbb{Z}$, then $G\cong \mathbb{Z}\times \mathbb{Z_2}$.  I'm trying to create an isomorphism $\phi : G \rightarrow \mathbb{Z}\times\mathbb{Z_2}$ as $g \mapsto (gN, ??)$. What can I use for my second coordinate?

Let $G$ be a group containing a normal subgroup $H \cong \mathbb{Z_2}$ such that $G/H$ is infinite cyclic. Then $G \cong \mathbb{Z} \times \mathbb{Z_2}$.  Since $G/H$ is infinite cyclic it's isomorphic to $\mathbb{Z}$. And since $H \cong \mathbb{Z_2}$, we have $G/H \times H \cong \mathbb{Z} \times \mathbb{Z_2}$. So the question now is can we make $G/H \times H \cong G$ (without any recourse to the Isomorphism theorems please)?  Any hints appreciated.


I'm teaching myself C# and I am up to studying the try, catch and finally. The book I'm using is discussing how the finally block runs regardless of whether or not the try block is successful. But, wouldn't code that is written outside of the catch block be run anyway even if it wasn't in finally? If so, what's the point of finally? This is the example program the book is providing:  class myAppClass {     public static void Main()     {         int[] myArray = new int[5];          try         {             for (int ctr = 0; ctr <10; ctr++)             {                 myArray[ctr] = ctr;             }         }         catch         {             Console.WriteLine("Exception caught");         }         finally         {             Console.WriteLine("Done with exception handling");         }         Console.WriteLine("End of Program");         Console.ReadLine();                 } }

Whatever is inside finally blocks is executed (almost) always, so what's the difference between enclosing code into it or leaving it unclosed?


Find the general solution $(x, y)$ ∈ $\mathbb Z × \mathbb Z$ for the system of equations $355x − 113y = 1$ ... eq$1$ $355x + 113y = 1$ ... eq$2$ You need one parameter $t ∈ \mathbb Z$ to describe the general solution.  My attempt: Euclid's Algorithm: gcd($355,113$) $= 1$ $1 = 355(-7)+113(22)$ So for eq$2$ $(x,y)=(-7,22)$ And for eq$1$ $(x,y)= (-7,-22)$ So general solution is $(-7,22t)$, where $t$={$-1,1$} Is my answer correct? If not, please how do we solve this?

Find the general solution $(x, y)$ ∈ $\mathbb Z × \mathbb Z$ for the system of equations $$355x − 113y = 1 \tag 1$$ $$355x + 113y = 1 \tag 2$$ You need one parameter $t ∈ \mathbb Z$ to describe the general solution.   My attempt: By Euclid's Algorithm: $\operatorname{gcd}(355,113)=1$ $1 = 355(-7)+113(22)$ So for equation $2, (x,y)=(-7,22)$. And for equation $1, (x,y)= (-7,-22)$. So the general solution is $(-7,22t)$, where $t=\{-1,1\}.$ Is my attempt correct? If not, please can you show me how do we solve this?


private PreconfigGroupOpenLPolicyRulesService openlApi;  @Override public Object[] getPackageEligibility(IRulesRuntimeContext context, Dimension dimension) {     return openlApi.PackageEligibility(context, dimension); }   I am new to jUnits. Can anyone help me to write test case for method getPackageEligibility. Which are all i need to do @Mock.  i tried  PreconfigGroupOpenLComponentService preconfigGroupOpenLComponentService = new PreconfigGroupOpenLComponentService();  @Mock PreconfigGroupOpenLPolicyRulesService openlApi; @Mock IRulesRuntimeContext context; @Mock Dimension dimension;    @Test public void testGetPackageEligibility() {      Object[] arg = preconfigGroupOpenLComponentService.getPackageEligibility(context, dimension);     assertNotNull(arg);  }   But getting  java.lang.NullPointerException     at com.exigen.eis.preconfig.policy.group.services.impl.PreconfigGroupOpenLComponentService.getPackageEligibility(PreconfigGroupOpenLComponentService.java:32)     at com.exigen.eis.preconfig.policy.group.services.impl.PreconfigGroupOpenLComponentServiceTest.testGetPackageEligibility(PreconfigGroupOpenLComponentServiceTest.java:28)

How do I unit test (using xUnit) a class that has internal private methods, fields or nested classes? Or a function that is made private by having  (static in C/C++) or is in a private () namespace?  It seems bad to change the access modifier for a method or function just to be able to run a test.


I am using shp2pgsql in a bash script to import shapefiles into postgres. I can successfully do this for shapefiles with hundreds of records however shapefiles with tens of thousands of records (in this case ~40,000) hangs so I have to use the postGIS shapefile importer in pgAdmin (which works ~30-45 seconds to complete).   I realize it's a substantial jump in magnitude regarding the number of records. Is it possible if I wait long enough it will succeed?  what are the runtime/data limits for shp2pgsql?

I have to import large Shapefiles (> 1 million records) into PostGIS, and I have been wondering about the best way to do it.    In my question I used the word "hack", instead of tool, on purpose because I think this is not so much a matter of which tool, but which set of steps, or configuration settings to use. So far, I have tried the  plugin (QGIS), the  Postgis tool and the GDAL  tool. You can view my full review on  post. So far, I find all of them really unresponsive, when dealing with a large dataset. I was wondering if someone experienced a similar issue, and if you could share something about the approach.


I have a situation with two structures that are combined as members of a larger structure. The first one is 44 bytes, and the second one is 1047. The second structure ends with a char. Excerpt:  typedef struct {     ... (total of 44 bytes, all members naturally aligned) } StructA;  typedef struct {     ...lots of stuff totaling 1046 bytes     char flag; } StructB;  typedef struct {     StructA a;     StructB b; } StructC;   Printing sizeof of StructA and StructB produces the expected sizes of 44 and 1047 respectively. Printing sizeof StructC produces 1092, which is 44 + 1047 + 1. It seems pretty clear to me that the compiler is padding the overall structure because of the single byte at the end of StructB. But it's at the end...there are no following members that require alignment. So why is it padding StructC? And why does it not pad StructB the same way?  This is built with Microsoft Visual Studio 2013; we're also cross-platform, but I don't yet know if GNU compiler on Linux treats this the same or not. If it doesn't, that will also be a concern.  Thank you, Doug  Follow up:  My question was marked as a duplicate but the referral doesn't answer the specific issue I'm trying to address, which is specifically why padding was added at the end of the structure in one circumstance, but not in the other.

Why does the sizeof operator return a size larger for a structure than the total sizes of the structure's members?


I ran mkfs.vfat /dev/sdb (whole device, not just one partition) on my backup drive, ironic, right. Is there any way to recover my files.

When I was installing Mint Debian edition unlike the classic edition, the installation automatically formated my home partition when I did not specify to format.  So the formatting previously was ext4 as is now. I believe the data is still there as it was a quick format.   I have now booted the computer up on a live USB to prevent writing on it.  Ran testDisk. Is there anyway to recover to a previous superblock so i can recover my data?


I'm having some trouble using ID3D11DeviceContext::Map() correctly. Here's the whole function so far:  Color Graphics::GetPixel(int x, int y) const {     //Temp frame buffer descriptor;     CD3D11_TEXTURE2D_DESC pFrameDesc;     pFrameDesc.Width = WindowWidth;     pFrameDesc.Height = WindowHeight;     pFrameDesc.CPUAccessFlags = D3D11_CPU_ACCESS_READ;     pFrameDesc.Format = DXGI_FORMAT_B8G8R8A8_UNORM;     pFrameDesc.MipLevels = 1u;     pFrameDesc.ArraySize = 1u;     pFrameDesc.SampleDesc.Count = 1u;     pFrameDesc.SampleDesc.Quality = 0u;     pFrameDesc.Usage = D3D11_USAGE_DEFAULT;     pFrameDesc.BindFlags = D3D11_BIND_UNORDERED_ACCESS;     pFrameDesc.MiscFlags = 0u;      // Create temp frame buffer(2d texture)     wrl::ComPtr<ID3D11Texture2D>pFrame = nullptr;     HRESULT hr = pDevice->CreateTexture2D(&pFrameDesc, nullptr, &pFrame);     GFX_THROW_INFO(hr);      hr = pSwapChain->GetBuffer(0, __uuidof(pFrame), &pFrame);     GFX_THROW_INFO(hr);               D3D11_MAPPED_SUBRESOURCE map;     map.RowPitch = WindowWidth * 4;     map.DepthPitch = WindowHeight * 4;          //Throwing here, CPU access flags problem.      hr = pContext->Map(pFrame.Get(), 0u, D3D11_MAP_READ, 0u, &map);     GFX_THROW_INFO(hr);      pContext->Unmap(pFrame.Get(), 0u);            return { 0.0f, 0.4f, 0.0f, 0.0f }; }  I'm getting an exception thrown at pContext->Map() "Map cannot be called with MAP_READ access, because the Resource was not created with the D3D11_CPU_ACCESS_READ flag. " Which is confusing as the newly created resource has the D3D11_CPU_ACCESS_READ flag enabled. This is also true If I try MAP_WRITE and change the access flags to match. I've also tried ORing the flags together with no luck. The ultimate use of this function is to be able to create a CPU side array of Color objects (Colors are currently a struct of four floats) Which I can then send onto the NewTek NDI sdk. But I feel it would also be useful for saving screen shots, creating colour pickers etc. Any ideas welcome!

I want to get access to a texture's pixel color data on the CPU. When trying to map the texture, I get E_INVALIDARG in return from ID3D11DeviceContext::Map.  ID3D11ShaderResourceView* resourceView; //represents my texture, already loaded up //...  //Getting the resources of the texture view... ID3D11Resource* res = nullptr; ID3D11Texture2D* tex = nullptr; resourceView->GetResource(&res); res->QueryInterface(&tex); D3D11_TEXTURE2D_DESC desc; tex->GetDesc(&desc); //Correct data gets filled out D3D11_RESOURCE_DIMENSION dim; res->GetType(&dim); //value gets set as Texture2D which it should  D3D11_MAPPED_SUBRESOURCE mappedResource; HRESULT h; h = context->Map(tex,0,D3D11_MAP_READ,0,&mappedResource); //This always fails h = context->Map(res,0,D3D11_MAP_READ,0,&mappedResource); //This also fails   The idea is that I keep only shaderResourceViews for my textures, because that is all I needed until now, and get the relevant resources here.  I tried mapping as WRITE_DISCARD also, but to no success. I am really confused, because I never had any problem with mapping constant buffers and vertex buffers. I seem to be certainly missing something? By the way, I am using Wic Texture loader and DDS Texture loader for the DirectXTex toolkit, and tried this code for png, dds textures, with and without mip-maps.


I'm referring to the  section in our editing help.  It includes this helpful line:     You can use either , like lang-cpp or lang-sql, or you can specify a tag, and the syntax highlighting language associated with this tag will be used:   However, the link takes us to an answer on , which contains no list of prettify language codes. That answer in turn links to the FAQ question , which does contain the list, and which the previous question is closed as a duplicate of.  There's no value now in linking to that intermediate page, so could the help article be updated to  directly link the FAQ question?

Reading the help center article on syntax highlighting, one of the paragraphs within it reads:     You can use either , like lang-cpp or lang-sql, or you can specify a tag, and the syntax highlighting language associated with this tag will be used:   Note the link in there, which goes to .  Problem is, a long time ago we removed the list of options from several questions/answers across meta Stack Exchange because it was a pain trying to keep all of them updated. It makes a lot more sense to just have one list that we keep updated, and the most logical place for that list was in the , which is where it now resides.  Can the link in the help center be updated to point directly to the list, rather than to a post that explains that the list has been moved?


I have copied the div element to the alert box. Now when I pressed ok button is it possible the text is copied to the user's clipboard.  Here is the code for reference:  $(document).ready(function(){     $("#bn").click(function(event){         $(alert($('#demo').text())     }); });

What is the best way to copy text to the clipboard (multi-browser)? I have tried: function copyToClipboard(text) {     if (window.clipboardData) { // Internet Explorer         window.clipboardData.setData("Text", text);     } else {         unsafeWindow.netscape.security.PrivilegeManager.enablePrivilege("UniversalXPConnect");         const clipboardHelper = Components.classes["@mozilla.org/widget/clipboardhelper;1"].getService(Components.interfaces.nsIClipboardHelper);         clipboardHelper.copyString(text);     } }  But in Internet Explorer it gives a syntax error. In Firefox, it says unsafeWindow is not defined. A nice trick without using :


I played on the xbox 360 edition of skyrim with the dawnguard and dragonborn DLC. I deleted my progress last summer by accident that was on my flash drive while clearing space. I haven't been playing since that. I got a hard drive so I can store that data again. I want to play it again but I don't want to start over because I had the best stuff and I invested a lot of time in it. If there is a way to retrieve that progress in any sort of way that doesn't cost money please tell me. I wouldn't prefer to use money but if it is the only than I'll have to resort to that.

I have got really far in my second profile in Skyrim, level 41. It took a long time to get back to that level, because I had got a game-breaking bug on my last profile and I erased it by accident as well as my other messed up profile.  Is there anyway to get my saved data back on the Xbox 360? If there isn't, I will not play Skyrim again for a very long time and I have no other option. Please help.


I understood that size of host id in the class c network is 8 bits(1 Octet)    After started exploring about private networks, in the below link    The host id size of the IP address range belongs to the class C network is mentioned in as 16 byte   192.168.0.0 - 192.168.255.255 (16-bit block private address)   My Assumption:   Class full network is applied for both private and public IP addresses. That is ifthe IP starts with 192.168.x.x is class c network and the size of the host id in the class full network is always 8(1 octet).   Is my assumption is wrong or any theory behind it?

This is a  about IPv4 Subnets.      Related:               How does Subnetting Work, and How do you do it by hand or in your head?  Can someone explain both conceptually and with several examples? Server Fault gets lots of subnetting homework questions, so we could use an answer to point them to on Server Fault itself.   If I have a network, how do I figure out how to split it up? If I am given a netmask, how do I know what the network Range is for it? Sometimes there is a slash followed by a number, what is that number? Sometimes there is a subnet mask, but also a wildcard mask, they seem like the same thing but they are different? Someone mentioned something about knowing binary for this?


After re-watching the Tony vs Thanos scene again, a thought came to mind and made me wonder. At no point did Doctor Strange ever pause time and simply deal with Thanos and proceed further. This would have obviously been the easy way out. Or at least whilst paused, he could have used the sling ring to cut Thanos' head off. I do note about the many different outcomes that he saw, but I still see this as a possibility.

Why didn't Doctor Strange wind back the clock way before Thanos got any of the Infinity Stones?


On Ubuntu, when running sudo apt update; sudo apt upgrade, why sometimes it asks me to restart my OS and sometimes not?   What do the packages that have that restart requirement have in common? Is it not possible to update such a package without restart OS requirement?   If I am correct, sudo apt update; sudo apt upgrade can also update/upgrade kernel. Does kernel update/upgrade also require OS restart?  Thanks.  I often keep my Ubuntu up indefinitely long, because I am always running some programs and I don't want to interrupt them.

I experience that my Ubuntu Linux requires a restart every now and then and also that it needs restart more often than in the old days (maybe it's because it updates more).   I understand that updating the kernel forces a reboot but is that a convenience and technically feasible to update without rebooting and only complicated?  Is it something that is technically impossible to update while the system is running?  "The system will go down for maintenance now...."  I understand that a BIOS update forces a reboot but I don't understand why it is absolutely necessary or if that is for convenience and making it much easier to update.   Reading a , there were not convincing answers.   I believe that it is running binaries that should be replaced.


Let $K$ be a compact set and consider $\mathbb{R}^n\setminus K$. It is easy to show that, if $n\geq 2$, the set $\mathbb{R}^n\setminus K$ contains one (and only one) unbounded connected component. Could someone can help m to show that the remaining connected components of $\mathbb{R}^n\setminus K$ are in finite number? Alternatively, also some references will be well accepted.

Let $X$ be a connected, locally compact space and let $K$ be a compact subset of $X$. Is the number of connected components of the complement $X\setminus K$ finite? If it is not, are there some hypotheses over $X$ for finiteness of connected components?


If I put the cylinder on the bottom i replace F2 with normal force N. But it will be at most equal to F1 plus the cylinder weigh N=F1+$\rho$gV.  So how can it get a bigger boost from the bottom to be able to float?

Let's say a 10N cube (in air, on Earth) rests flat on a scale at the bottom of a tank of water, and the scale reads 8N, so there is 2N of buoyant force on the cube.  How does the buoyant force manifest itself on the cube?  I assume the force is normal to the surface of the scale, but if there isn't any water under the cube, how does the water push up on the cube?


While I can easily set up a style template for lists to have the "keep with next" paragraph option, it is usually convenient to have the very last item of a list not having this option such that a page break between the list and the following text is actually permitted. But is there any way to have this automatically applied instead of having to manually change the last item's pagination option?

I'm writing specifications using Word documents with a general style like this:  # Heading 1 intro paragraph * bullet1 * bullet2 * bullet3  # Heading 2 intro paragraph * bullet1 * bullet2  # Heading 3 intro paragraph * bullet1 * bullet2 * bullet3 * bullet4 * bullet5   I want each heading, intro paragraph, and associated bullets to stay together whenever possible. As such, I have styles for each with the Paragraph option "Keep with Next" checked. However, this results in everything sticking together too tightly.  To fix it I currently go to the last bullet in each list and change its style to one that does not have "Keep with Next" checked. For example, the bullets have a style "ReqBullet" and I create another style "LastReqBullet" that inherits from "ReqBullet", but which has "Keep with Next" turned off.  (I could alternatively override the setting on each bullet, but doing it via a style makes it easier to apply, and also easier to see where it is set.)  Using manual style application is slightly cumbersome, and error-prone. If I add a new item to the end, I have to swap styles. Often I will forget to apply the style until I realize that the formatting is wonky.  The question  Is there a way hidden in the bowels of the Style settings to say either:   Keep this paragraph with the next but only if it's the same style, or I don't care what the previous paragraph told you, do NOT keep me with it (which I could apply to  the headings)


I want to copy large amount of big files from folder A to folder B.  I have 2 option in Python.    import shutil shutil.copy(src, dst)    with subprocess  import subprocess command = "ROBOCOPY {} {} /MOVE /E".format(src, dst) subprocess.Popen(command, shell=True)   When I used above methods my Python IDE do copy operation blindly.  Is there some way I can show the file copy progress.

When copying large files using shutil.copy(), you get no indication of how the operation is progressing..  I have put together something that works - it uses a simple ProgressBar class (which simple returns a simple ASCII progress bar, as a string), and a loop of open().read() and .write() to do the actual copying. It displays the progress bar using sys.stdout.write("\r%s\r" % (the_progress_bar)) which is a little hackish, but it works.  You can see the code (in context)   Is there any built-in module that will do this better? Is there any improvements that can be made to this code?


I've had this problem for at least several months.  I noticed a lot of threads without a happy ending:         And I did try all the suggestions made in these threads including:   Updating the windows to the latest version Troubleshoot network, update, etc killing all other software, changing MSISUPPORTED of my SSD disk in regedit etc.   One thing I noticed is that the problem disappears in safemode.

Since installing the Windows 10 Fall Creators Update, I have a svchost.exe process that is constantly using about 14 % of CPU time:    This svchost.exe instance is responsible for hosting three services:    The CPU time is consumed by a thread inside that process that  cannot attribute to any of these three services:    Given that these three services are considered critical system services, it's hard to do anything about them. These services cannot be stopped or disabled by services.msc, and terminating the process triggers a bugcheck (CRITICAL_PROCESS_DIED). Disabling the Windows Defender Firewall through the settings UI does not reduce CPU usage.  I'm out of ideas. What could be causing this? How can I debug this further? Is there a workaround to stop these services?    Update: After some debugging with , we've isolated this to the Windows Defender Firewall service. Process Monitor shows that it's constantly accessing the registry:    A CSV export of a Process Monitor capture, filtered to that process, is available .  I’m still looking for a way to stop that behavior.    Update 2: Analysis with the Windows Performance Analyzer shows that most CPU time is consumed by code from rpcrt4.dll:


I have Ubuntu 14.04 and I need the latest version of Java JRE to run certain games but I have the old version and I do not know how I can update it. I tried downloading it from  but I couldn't rub the downloaded file, Also tried looking at other people's questions but I couldn't really understand them.The error I get is "the application requires a Java runtime environment 1.6.0" Here's a screen shot of the error:

I want to install Oracle's JRE and to update to the latest version with the Software Updater when they released. Is there a Ubuntu package that is provided by Canonical or Oracle?  Before release Java 7, I followed  to install Java 6.  But it doesn't work for Java 7. There is no package sun-java7-xxx. How can you install Java 7?


I am attempting to see whether a file exists within a  directory then if it doesn't exist, create it. I'm using Anaconda and Python version 3.7.4. However when I run the code I recieve the error NameError: name 'found' is not defined. I'm using Visual Studio Code and am quite new to programming! import fnmatch  import os  print() for file in os.listdir('/home/user/CI6724_J0874321_John/'):     if fnmatch.fnmatch(file, 'CI5232_Logs.txt'):         found = True  if found:     print('File exists') else:     open('/home/user/CI6724_J0874321_John/', 'w')

How do I check whether a file exists or not, without using the  statement?


I am facing an issue and am sure there must be very simple solution for this.Can anyone help me ?  I have bamboo server running which picks up stash rep where I have committed my code from Eclipse Force.com IDE. When I run the bamboo plan , it kind of deploys everything (all files from src) when I have committed only one component (say VF page). I modified mt package.xml to include only that VF page and nothing else. But still deployment runs across all 13k components.   I know I can remove all those components from my src folder and keep only VF page. SO that it deploys only that component. But is there any way , so that it picks up only the commit and not entire src folder ?  Any pointers helps greatly appreciated.

I am setting up a continuous integration for a team development process using GitHub and Ant (and eventually Jenkins) and have a problem with deploying to dev sandboxes to keep them in sync with Production:  How do you programmatically customize the Package.xml and the src/ folders to only include the metadata files that have changed in Production?  Our Production environment has over 5000 files so if I retrieve the entire metadata set from Production to the master branch, rebase the dev sandbox branch and attempt to deploy that to its dev sandbox, I hit the API limit for deploying metadata via the API. The metadata in Production changes both from packages deployed from sandboxes as well as from changes made directly in Production by Admins, so I cannot rely on combining all pushed metadata files and package.xml files.


I'm watching Suits TV Series, and there was something that caught my attention. 2 guys meet, have a drink, chat, and then one guy says:     I mean it's time I told you. I made a deal with Darby to take over the   firm from Jessica.   Why is "told you" in paste tense? What exactly does it mean? He is saying that news right now. If I were to say that, I would say "it's time to tell you" or "it's time I'm gonna tell you".  Thanks!

Why do we use the simple past but not the present or future in the following expressions:  Don't you think it's time we went a little further Don't you think it's time we ate Don't you think it's time we went home


I have a data set with the amount of bicycle accidents and the year in which the bicycle accident occurred. I would like to see if there is a significant increase in the amount of bicycle accident per years and by which amount.  I am doubting between Pearson's correlation and Spearman's Correlation. (Or should I use a linear regression analysis?)

I have a nominal variable (different topics of conversation, coded as topic0=0 etc) and a number of scale variables (DV) such as the length of a conversation.   How can I derive correlations between the nominal and scale variables?


I've made a huge mistake by running rm -r /* on my ubuntu 16.04. But i managed to cancelled the on going command quickly using ctrl-c. Now all my bash is not working. For example if i type 'ls' in my directory, it will show 'command not found'. it seems that all command is affected and i just can use cd command.   what i found out is that my files at /var/www/html is still intact and not deleted and my web application is still running with minor issues.  I have done the change PATH fix but i found out that my /bin is deleted and my home directory is deleted.  Question 1 : is there any way i can repair my ubuntu 16.04 without losing my files at /var/www/html?  Question 2 : is there any way i can salvage my files at /var/www/html?

Please note: The answers and comments to this  question contains content from another, similar question that has received a lot of attention from outside media but turned out to be hoax question in some kind of viral marketing scheme. As we don't allow ServerFault to be abused in such a way, the original question has been deleted and the answers merged with this question.      Here's a an entertaining tragedy. This morning I was doing a bit of maintenance on my production server, when I mistakenly executed the following command:  sudo rm -rf --no-preserve-root /mnt/hetznerbackup /  I didn't spot the last space before / and a few seconds later, when warnings was flooding my command line, I realised that I had just hit the self-destruct button. Here's a bit of what burned into my eyes:  rm: cannot remove `/mnt/hetznerbackup': Is a directory rm: cannot remove `/sys/fs/ecryptfs/version': Operation not permitted rm: cannot remove `/sys/fs/ext4/md2/inode_readahead_blks': Operation not permitted rm: cannot remove `/sys/fs/ext4/md2/mb_max_to_scan': Operation not permitted rm: cannot remove `/sys/fs/ext4/md2/delayed_allocation_blocks': Operation not permitted rm: cannot remove `/sys/fs/ext4/md2/max_writeback_mb_bump': Operation not permitted rm: cannot remove `/sys/fs/ext4/md2/mb_stream_req': Operation not permitted rm: cannot remove `/sys/fs/ext4/md2/mb_min_to_scan': Operation not permitted rm: cannot remove `/sys/fs/ext4/md2/mb_stats': Operation not permitted rm: cannot remove `/sys/fs/ext4/md2/trigger_fs_error': Operation not permitted rm: cannot remove `/sys/fs/ext4/md2/session_write_kbytes': Operation not permitted rm: cannot remove `/sys/fs/ext4/md2/lifetime_write_kbytes': Operation not permitted # and so on..   I stopped the task and was relieved when I discovered that the production service was still running. Sadly, the server no longer accept my public key or password for any user via SSH.  How would you move forward from here? I'll swim an ocean of barbed wire to get that SSH-access back.  The server is running Ubuntu-12.04 and hosted at Hetzner.


I have a jsonline file like below:  {"id":0,"country":"fr"} {"id":1,"country":"en"} {"id":2,"country":"fr"} {"id":3,"country":"fr"}   I have a list of codes, i want to attribute a code to each user, by updating the file lines.   The result should be the following:  {"id":0,"country":"fr", code:1} {"id":1,"country":"en", code:2} {"id":2,"country":"fr", code:3} {"id":3,"country":"fr", code:4}   This is how i do it now:  import ujson fh, abs_path = mkstemp()  with open(fh, 'w') as tmp_file:     with open(shooting.segment_filename) as segment_filename:         for line in segment_filename:             enriched_line = ujson.loads(line)             code = compute_code()                 if code:                     enriched_line["code"] = code             tmp_file.write(ujson.dumps(enriched_line) + '\n')   My question is, is there a faster way to do this ? May be via a linux command launched via sarge for example ? or any pythonic way without having to read the read / write / replace the original file ?   Thank you !

I want to loop over the contents of a text file and do a search and replace on some lines and write the result back to the file. I could first load the whole file in memory and then write it back, but that probably is not the best way to do it.  What is the best way to do this, within the following code?  f = open(file) for line in f:     if line.contains('foo'):         newline = line.replace('foo', 'bar')         # how to write this newline back to the file


My wife has multiple lenses from her old Canon Ae1 film camera with a doubler, I would like to upgrade her to a Canon rebel T5. Is there an adapter available to make use of her old lenses ? If so , where would I purchase one ?

I have a Canon AE-1 (film) and I bought a digital slr camera Canon EOS 60D. I have lenses from the AE-1 camera, but I don't know if there are some adaptors to use so they fit in the 60D camera... any ideas?


While I really like low temperature cooked dishes, I ask myself whether all microorganisms are killed with these methods. I'm worried that not all parasites and bacteria are killed at 60-70°C.  Is there a table with meat cooking temperatures and the corresponding surviving species that might remain in the products?

What general rules do I need to follow to keep my food safe? How do I know what temperature to cook something to, or whether my food is safe at room temperature?


Is it acceleration or speed that leads to time dilation or both?   For example, when a spaceship accelerated to (almost) the speed of light, then reversed course to come back towards earth, does this affect time dilation in the same way as if the the spaceship landed on a planet with very high gravity for a while?  I notice that in many videos they say that speed is the relevant factor that makes time slow down. But speed is relative, isn’t it? Both would travel with almost the speed of lost.   Is it therefore only the the acceleration that matters?

What causes time dilation?  Acceleration or velocity?  I've seen multiple comments on this forum that assert velocity is the cause, but that doesn't seem right to me.  You can't have velocity without acceleration.  It's the inertial force with acceleration that breaks the symmetry.  My understanding is that the asymmetry is where the inertial frame changes.  Measuring time between two objects with different inertial frames is where you have time dilation.  When the acceleration ends, the object is effectively at rest in a new inertial frame and has velocity relative to another object in the original inertial frame.  In other words, acceleration (changing reference frames) is the cause...velocity and time dilation is the effect.  Am I right about this?  If there are flaws in my logic I'd like to find and correct them.


i have download one source code (glibc，linuxthreads） form GNU site .and install it in /usr/local.  I want to compiler glibc and change some code ，but i don't know where can download the source code. question:   is other program  need？  how can i install it？

I am assuming that all application installed through apt-get are open source; but for those that are available in that manner, where can I get the source code for these applications as well as update them?   I have a couple applications I use regularly that aren't being actively developed any longer and I would like to add features. Where would I go to get the rights to update these applications?  In this case specifically, I am referring to the hellanzb package


In Infinity War Cull Obsidian loses his arm when a worm hole closes up,                                So could Thanos have lost his arm like this too WHEN he had all the stones on the Gauntlet?

Doctor Strange seemingly has the ability to open portals wherever he wants. We see at the beginning of Infinity War what happens when he closes a portal and someone isn't fully through it.  Is there any reason why he can't open a portal around the left-elbow of Thanos, and then close it?  I realize that Thanos probably wouldn't allow this to happen normally,      but when he is mostly asleep, and Tony and Spider-Man are pulling on the gauntlet, Doctor Strange has ample opportunity, and plenty of space to just sever Thanos' arm.   Why doesn't he?


I like some of the changes in the new stackoverflow/stackexchange site but I miss the section with the top questions (when you clicked on the stackexchange name) - it was like my morning newspaper! Can I find the top questions somewhere else?

Since the new top bar has been rolled out - a number of different people, established and new users alike, have asked questions on where a specific link has disappeared to with the new top bar design. Where has the link to <X> gone?


Looking for a 1960s book about people who think they are exploring a planet until they find they are on a huge space 'ark' going somewhere that has been travelling for generations.

The story starts with a tribesman going on a exploratory voyage around the land, meeting other progressively more and more distant tribes, learning about the world. Gradually he or she discovers that the "world" is actually a giant spaceship flying through space.  The story climaxes by the hero ascending to the commanding deck and learning who actually pilots the ship and to what purpose.


I'm trying to make these corners sharper after SubSurf.      The solution that comes to my mind is adding edge loops to limit its space, but when I try to add edge loops they also affect the intake shape in front of the object in the same loop, deforming it in the way I don't want (I want sharper edges, but not round as I've done)    Any ideas besides boolean?

I tried to apply a Subdivision Surface on a part of my object. I can't keep the angles sharp, they all turn into rounded angles.  The angle before applying the Subdivision surface...   ...And after


I'm trying to have an boost::container::vector containing instances of a few class that all inherit from the same superclass, and then have some functions only apply to the instances of a specific class, but I can't seem to get it to work.  This is the first time I try this, so maybe I just made a rookie mistake, can one of you tell me where I went wrong, and why ?  Here's an example code :  using boost::container::vector;  class card{ public:     card(int aa,int bb):a(aa),b(bb){}     virtual ~card(){}     int a,b; }; bool operator==(card l, card r){ return l.a==r.a; } bool operator<(card l, card r){     if(l.a<r.a){ return true;}     else{ return l.b<r.b; } } std::ostream& operator<<(std::ostream& os, card c){     os << c.a << ":" << c.b;     return os; }  class subcard:public card{ public:     subcard(int a, int b):card(a,b){}     virtual ~subcard(){}     int c=0; };    int main() {     cout << "Hello, World!" << endl;     vector<card> v1;     v1.push_back(card(2,2));     v1.push_back(subcard(1,1));     for (int i = 0; i < v1.size(); ++i) {         cout<<v1[i]<<endl;     }     for (int i = 0; i < v1.size(); ++i) {         if(subcard* sc = dynamic_cast<subcard*>(&(v1[i]))){             cout<< "found : " << sc <<endl;         }     }     return 0; }   Thank you very much :)

Someone mentioned it in the IRC as the slicing problem.


I want to store symbols like █ ▄ in my mysql db and show them with php. I tried to use ord and chr but it shows this symbol after: â  How can I do that?  Kind regards, Damon

I'm setting up a new server and want to support UTF-8 fully in my web application. I have tried this in the past on existing servers and always seem to end up having to fall back to ISO-8859-1.  Where exactly do I need to set the encoding/charsets? I'm aware that I need to configure Apache, MySQL, and PHP to do this — is there some standard checklist I can follow, or perhaps troubleshoot where the mismatches occur?  This is for a new Linux server, running MySQL 5, PHP, 5 and Apache 2.


I have asked similar question before also but want to try again -   I followed everything from this project but still, the magnet is not levitating -   The best I can do is to make the magnet jump up and down fast but it never levitates. Have tried changing PID setting from the project as aggressive and mild but still didn't achieve the final result.  I need advice from an expert to tell me what I am doing wrong here. All components are in good condition and 5v electromagnet is strong enough.   So what am I missing here?

I am following a hackster project on magnetic levitation here -   However, I have followed everything but still, it's not working.   Here are changes to the circuit I made:   The electromagnet which I am using is that of 5V instead of 12V The transducer which I am using is ss8050 instead of TIP120 Hall sensor is tapped just at the bottom of the electromagnet   Electromagnet link -   Update:-  The best I can do is to make the magnet jump up and down fast but it never levitates. Have tried changing PID setting from the project as aggressive and mild but still didn't achieve the final result.  I need advice from an expert to tell me what I am doing wrong here. All components are in good condition and 5v electromagnet is strong enough.  So what am I missing here?


$x_1, x_2, x_3,.\cdots ,x_n$ and $y_1, y_2, y_3,\ldots,y_m$ are two series of positive integers, such that $m\not=n$.     Given that  $1<x_1< x_2<x_3<\cdots<x_n<y_1< y_2< y_3<\cdots<y_m$ and  $x_1+ x_2+ x_3+\cdots+x_n > y_1+ y_2+ y_3+\cdots+y_m$, prove that  $x_1x_2x_3\cdots x_n>y_1y_2y_3\cdots y_m$.  I have tried to prove it for conservatives. I have no idea how to deal with this type of inequality properly.

For two positive integer  sequences $x_1,x_2,\ldots,x_n$ and $y_1,y_2,\ldots,y_m$  satisfying  $x_i\neq x_j\quad  \text{and}\quad  y_i\neq y_j\quad \forall i,j, i \ne j$  $1<x_1<x_2<\cdots<x_n<y_1<\cdots<y_m.$  $x_1+x_2+\cdots+x_n>y_1+\cdots+y_m.$   Prove that: $x_1\cdot x_2\cdots x_n>y_1\cdot y_2\cdots y_m$.  (from internet) I don't have an idea for this problem. Thanks for your help.


I have this counter which I have defined using \newcounter{myCounter}.  Printing the value of myCounter can be easily done via \arabic{myCounter}. How can I print the value of (myCounter - 2)?

I have defined a new counter that keeps increasing each time I call the macro that's using it. How can I print the counter value minus one? Something like \value{\theCounter-1} but formatted for text?  MWE  \documentclass{article} \usepackage{parskip} \newcounter{myCount} \setcounter{myCount}{1} \newcommand\newSec[1]{\par\underline{\textsc{newSec}~\themyCount}\hspace{0.5em}{\footnotesize(#1~number)}\stepcounter{myCount}\par}  \begin{document}     \newSec{2}     Some text      \newSec{5}     Here I refer to the counter used before it was incremented: \themyCount. Should print 2.  \end{document}


Can someone explain the answer to this question:  'Imagine there are a 100 people in line to board a plane that seats 100. The first person in line realizes he lost his boarding pass so when he boards he decides to take a random seat instead. Every person that boards the plane after him will either take their "proper" seat, or if that seat is taken, a random seat instead.  Question: What is the probability that the last person that boards will end up in his/her proper seat.'  If instead of only the first person having lost their ticket the first two people have lost their tickets and take random seats?

I recently came across a quite interesting problem:  "One hundred passengers are lined up to board a full flight. The first passenger lost his boarding pass and decides to choose a seat randomly. Each subsequent passenger (responsible enough to not lose their boarding pass) will sit in his or her assigned seat if it is free and, otherwise, randomly choose a seat from those remaining. What is the probability that the last passenger will get to sit in his assigned seat?"  I figured out that the probability would be 0.5. If you would like to know why I would link you to another topic on this site where this problem was discussed.    However, I kept thinking about what the probability would be if there were multiple people who lost their boarding pass. So for example, the first 5 people out of the 100 passengers lost their boarding pass so they take a random seat. Every person that boards the plane after him will either take their "proper" seat, or if that seat is taken, a random seat instead. Then what is the probability that the last passenger will get to sit in his assigned seat? I have trouble figuring it out and I hope that some of you could help me.  Thanks in advance!


Is there a way, I can use of strlen() to find the length of the arrays, instead of specifying in the loop. First Code: Working With x < 4 Which is the size of the array of temps[4].  #include <stdio.h> #include <string.h>  int main(){     float temps[4] = {72.5, 73.4, 74.7, 75.2};     int x;     printf("Local Temperatures\n");     for(x = 1; x < 4; x++){         printf("Station %d: %.1f\n",x,temps[x]);     } }   My Second Code, Not Working, But Looking At What, I Am Trying To achieve with strlen() to find the size of the array.:  #include <stdio.h> #include <string.h>  int main(){     float temps[4] = {72.5, 73.4, 74.7, 75.2};     int x;     float size;     size = temps;     printf("Local Temperatures\n");     for(x = 1; x < strlen(size); x++){         printf("Station %d: %.1f\n",x,size[x]);     } }

How do I determine the size of my array in C?   That is, the number of elements the array can hold?


I'm going crazy with this error:  Bad math environment delimiter. \end{equation} You can't use `\eqno' in restricted horizontal mode. \end{equation}   of the following MWE:  \documentclass[border=1 pt]{standalone} \usepackage{amsmath} \usepackage{mathrsfs} \usepackage{tikz-cd}  \begin{document}     \begin{tikzcd}[row sep=huge, column sep=huge]         \textbf{B} \arrow[r,"M"] & \text{Y}\\         \textbf{X} \arrow[r,swap,"M"] \arrow[u,"project"] & \text{A} \arrow[u,"project", swap]     \end{tikzcd} \begin{equation}     project \circ M = M \circ project \end{equation} \end{document}

I was surprised to find that standalone package can not compile a document with an equation:  \documentclass{standalone} \begin{document} \begin{equation} % not working! F(V, T) = E(V) + D(T) \end{equation} \end{document}   Is there an option or some workaround that allows this? The current error is something like:   ! Missing $ inserted.   in line 4. (The idea of course is that the including (main) document can just \input the standalone without knowing if is going to be an equation or something else)


I am trying to parse a file for an instance of a word in Java.  The word is input from a JTextField.  Depending on which selection is made in a JComboBox the filepath may change.  The Text file contains names and their popularity.  The desired output is how that name ranked for the year that is selected.  I'm struggling with setting up an appropriate search.  I have been able to get the file to open and output some of the contents of the file to the Java Console, but the file contains 1000 lines and I notice that the output in the console only begins with entry number 950 or so.    Here is what I have so far:   public void actionPerformed(ActionEvent e)     {         //Parse Input Fields         String name = inputArea.getText();         String genderSelected = genderList.getSelectedItem().toString();         String yearSelected = yearList.getSelectedItem().toString();          String yearFile = "Babynamesranking"+yearSelected+".txt";           try         {             File inputFile = new File(yearFile);             BufferedReader in = new BufferedReader(new FileReader(inputFile));  /**This is where I draw a blank and need help*/              in.close();         }         catch (IOException exception)         {             JOptionPane.showMessageDialog(null, "Error Reading File");         }   I have more work to do after I get this part working to display the results in the GUI and such, but that is easy and I can do that.  Just struggling with how to get this part to work.    Example of text file we are parsing:  1   Jacob   22,507  Emma    18,765 2   Michael 20,524  Isabella    18,564 3   Ethan   20,174  Emily   17,397 4   Joshua  19,133  Olivia  17,030 5   Daniel  18,935  Ava     17,007 6   Alexander   18,639  Madison     16,985 7   Anthony 18,347  Sophia  16,042 8   William 18,337  Abigail     15,045 9   Christopher 17,876  Elizabeth   11,956 10  Matthew 17,526  Chloe   11,802 11  Jayden  17,088  Samantha    11,157 12  Andrew  16,711  Addison     10,742 13  Joseph  16,483  Natalie     10,179 14  David   16,246  Mia     10,156 15  Noah    15,748  Alexis  9,685

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 have a definition that claims that two sets are equal A = B, if and only if:  $\forall x ( x \in A \leftrightarrow x \in B)$  An empty set contains no elements. If I define the sets:  A = $\emptyset$  B = $\emptyset$  then can I conclude that A $\neq$ B? Since they contain no elements? Or would I have to show that an elements exists in one but not the other? To me it seems that these are not equal, but I'm struggling to wrap my head around this.  Thanks, Paul

I Have a question. Given only the definition of equality of two sets, how can we prove that there is one and only one empty set. I mean by equality of two sets the following: $$A=B \iff  \forall x (x \in A \iff x \in B)$$


The question "" was closed for being a duplicate.    The linked question "" was also closed as a duplicate question.    Following this link leads us to the actual question we're looking for, "".    How should these scenarios be handled? Is there a way to suggest updates to the referenced duplicate question?    Edit: This question is different from . I am asking what I should do as a user when duplicates of duplicates are found, while the linked question asks whether duplicate links should be remapped automatically.

On found exact duplicates, should these be voted to close directly against a preferred, or ultimate, canonical question?   Or is a chain of possible duplicates (where one question is closed as duplicate of another, which itself is a duplicate of another, and so on and so on) allowable or OK?  One example of this situation can be found .


As a matter of style, could these pass muster to you in terms of conciseness and punctuation - yes or no? I think they are clear and uncluttered.   5-10 year olds  5-10 year old prodigies  10-15 year mortgage  1-2 inch laceration  $2-3 million a year contract  $5-10,000 per year savings

Without recasting and in lieu of unsightly suspensive hyphenation, could these work? The en dash (which means "to") is used between the figures, and the hyphens are used in the compound modifier. To me, the examples below are concise and clear.  Do you agree that the examples below are 100% punctuated correctly--yes or no?  45–50-year-old men  10–20-mile radius  $45–$55-million-per-year industry  $100,000–$150,000-a-year savings  10–15-degree temperature difference  $2–$5-per-day service fees  45–75-cent-a-week raises  55–65-mph speed zone  15–20-ounce steaks  20%–40%-a-year tax increases


I'm a Linux Mint user, and I use Ask Ubuntu a lot. However, some questions about the Mint GUI don't fit there. Should we start a Mint site?

I have an idea or subject that should have a Q&A, and want to propose a new site. How can I do this?  Related:


I have a 600D and a 7D and I use the kit lens  " EF-S "18-55mm  and the 55-250 mm , and I am thinking of buying a 24-105mm f4 IS USM L... so does the EF-S suffer from the same 1.6x crop factor as the EF? For example, the 24-105 IS USM L on an APS-C sensor is like 33mm to 168mm, and the 18-55mm has is equivalent to 28.8-88mm?

I have a Canon 7D, which has a crop factor of 1.6x.  When using a Canon EF-S lens I get the focal length stated on the lens, when using a Canon EF lens I get the focal length times 1.6 when used on the APS-C body. At least that's what I thought.  I just compared two lenses:   Canon EF-S 15-85mm f3.5-5.6 Canon EF 70-200mm f4   .  The top photo is shot with the 15-85, the bottom photo with the 70-200 - both lenses are set to 70mm. Now why do they look the same?  I thought I would get 112-320mm (70mm*1.6 crop factor). What did I misunderstand about the crop factor calculation? Lightroom also displays the photos as having "70mm" and not 112mm.


I am new to Stack Exchange.  Math and physics newsletters get to my inbox every Thursday, and every Thursday there are 5-day-old answers to questions as I read them for the first time.  Too often a question of interest  has already been closed because of the low quality of recent answers and comments.  I have no reputation, and to do almost anything requires more reputation than I have.  Nothing I have found in Help helps (however I noted one user submitted an "answer" because he said he did not have the reputation to comment.  I have started wondering if Joseph Heller is looking over my shoulder.  Any help, please?  Thank you to those who made useful suggestions.  The question, "How does a new user begin using Stack Overflow/Stack Exchange?," clearly expressed my difficulties.  I would close the question if I knew how.  Good night.

I have been reading Stack Exchange for years - mostly not logged in, and have never posted (this is my first). I'm simply not very talkative, and very good at googling.  Recently a few occasions have come up when I've wanted to comment on a question.  I wanted either to ask for, or provide, clarification which did not warrant a new answer.  How do I gain enough reputation to comment without:   asking questions which have already been answered or that I can figure out on my own, or posting my comment like as an answer (i.e. being  rude)?


I want to prove the following so I decide to rewrite the RHS  $$A \setminus (B\setminus C) = (A\setminus B)\cap (A \cup C)$$ $$ A\setminus(B\setminus C) = A\setminus (B \cap C^c) = A\cap (B\cap C^c)^c = A\cap(B^c\cup C) = (A\cap B^c)\cup(A\cap C) $$ there is way that $(A\cap B^c)\cup(A\cap C)\rightarrow (A\setminus B)\cup(A\cap C) = (A\setminus B)\cap (A \cup C)$?  thanks. EDIT  LHS: $$x\in A \vee x\in A\cap C \rightarrow x\in A \wedge x\in C$$ RHS: $$x\in A \wedge x\in A\cup C \rightarrow x\in A \vee x\in C$$  how it can help me?

Show that  $A \setminus ( B \setminus C ) \equiv ( A \setminus B) \cup ( A \cap C )$  This is an exercise I was trying to do ( not homework ) and I got stuck as follows:  Working from $A \setminus ( B \setminus C )$:  $x \in A \wedge x \notin ( B \setminus C )$ $x \in A \wedge ((x \in B \wedge x \in C) \vee (x \notin B \wedge x \in C) \vee (x \notin B \wedge x \notin C) )$  At this point I'm not sure how to proceed.  Working from the other side $ ( A \setminus B) \cup ( A \cap C ) $:  $ x \in ( A \setminus B) \cup ( A \cap C ) $  $ x \in ( A \setminus B) \vee x \in ( A \cap C ) $  $ ( x \in A \wedge x \notin B ) \vee ( x \in A \wedge x \notin C ) $  $ x \in A \wedge (x \notin B \vee x \notin C ) $  $ x \in A \wedge x \notin ( B \cap C ) $  $ A \setminus ( B \cap C ) $  I could also use some formating tips like how display logical not and how to get the lines to display properly without blank lines inbetween. :-)


Do images in deleted answers stick around forever?  I think I already know the answer and I think this is a dumb and/or obvious question but I just want to make sure.  I have an answer with SE-uploaded imgur images in it. I intend to delete the answer but link to one of the images in a comment elsewhere. I was just going to use the generated link from the answer, and want to make sure it'll stick around as long as the comment does.

What happens to the images from deleted questions and/or answers?  Will they be kept or they will be deleted with the answer?  What happens with the images, that are edited out from the post? The links are still there in revision history, but what with the image under that link?


I have setup a Central Management Server and registered all of my SQL servers (prods and devs). I want to save the results of sp_BlitzFirst from running it against all of my servers to a centralized database 'DBAtools' on my test box for later analysis. What is the most efficient method for achieving this task?  Thank you so much in advance.

I am using , and want to use it to execute the checks on all of my SQL Servers and have it write the results to a single table.   Do I need to create linked servers on the central instance to connect to the other instances, or is there some other way to input the server names into the sp_Blitz stored procedure?


At the end of this month I have a flight from St. Lucia to New York and then New York to Phoenix where I live. There is a 24 hour layover in New York so I figured I would stay an extra day.  In order to change my flight and cancel the existing reservation to change it was about $500. I could book with a separate airline and it will cost a fourth of that. My question is:  If I miss my flight from New York to Phoenix and take a flight with a different airline, will I be OK?

Say I want to book a flight from Fort Lauderdale to Chicago.  Say the airline also flies to St. Louis from Fort Launderdale but has a connecting flight through Chicago.  If I book that flights from FLL->ORD->STL and just get off in Chicago, what possible problems can I run into, assuming I didn't check any bags and only have carry on?  This scenario exist for Southwest, but I wanted this be more of a general question that would apply to all airlines.


I have to process multiple files that I dont have the entire name for.  I am running an if statement using a wildcard. for example...  if [ "ESGSN_*.SMS.EDR" ]; then     echo "There are files to process in this run"     for F in ESGSN_*.SMS.EDR; do         gzip < "$F" > "$F.gz"     done fi   If there are multiple files or a single file this will work and zip them.  But if there are no files it will still run the zip rather than just end.  I was wondering if there is any way to get it to complete and move on.    I have tried using the operators "-f" and "-a" within the brackets just before the filename, but those will error out with:  "binary operator expected"  for some reason the asterisk in the filename is not showing down below in the message.  So the file name is  "ESGSN_"*".SMS.EDR" where the double quotes is the asterisk.

Is there a good clean conventional way to do this?  For example, if there are any ".gz" files in a certain directory, I want to unzip them.  But if there aren't, I don't want to see any error.  If I use gzip -d /mydir/*.gz, I get the error:  gzip: /mydir/*.gz: No such file or directory   If I first shopt -s nullglob and then gzip -d /mydir/*.gz, I get the following:  gzip: compressed data not read from a terminal. Use -f to force decompression. For help, type: gzip -h   I have one method I know will work, which I'm posting as an answer.  I'm wondering if there's a better/cleaner way.  POSIX compatibility is a bonus, but not required.