Can't purge old kernels (dependency problems), but /boot is out of space

I'm running Ubuntu 14.04.4 LTS, and I'm trying to install a new package using apt-get. Unfortunately, whenever I try I get messages like:  The following packages have unmet dependencies:  linux-image-extra-3.16.0-70-generic : Depends: linux-image-3.16.0-70-generic but it is not going to be installed  linux-image-generic-lts-utopic : Depends: linux-image-3.16.0-70-generic but it is not going to be installed  linux-signed-image-3.16.0-70-generic : Depends: linux-image-3.16.0-70-generic (= 3.16.0-70.90~14.04.1) but it is not going to be installed   Doing some googling, I found that  (and sure enough, df shows /boot at 100%). However, any time I try running the apt-get commands in the accepted answer there, I get the same errors as above.  Looking for another solution that didn't use apt-get, I came across , which recommends using things like sudo dpkg --purge linux-image-4.2.0-15-generic on old, unused kernels.  dpkg -l | tail -n +6 | grep -E 'linux-image-[0-9]+' | grep -Fv $(uname -r) (from the afore-mentioned post) shows that I have several old kernels in the pi state (desired purged, state is installed according to )  uname -r tells me the kernel I'm running is 3.16.0-62-generic, so I thought I should be safe to remove these old kernels. However, trying to do so with things like sudo dpkg --purge linux-image-3.16.0-49-generic results in:  dpkg: error processing package linux-image-3.16.0-49-generic (--purge):  dependency problems - not removing Errors were encountered while processing:  linux-image-3.16.0-49-generic   Garrg! I'm at my wit's end, and out of my depth (don't really know much about dpkg or apt-get), so I need some help.   Questions:    Why can't I uninstall the old kernels with dpkg? If that question can't be directly solved, I guess ultimately I want to know: What do I need to do to get into a state where I can install new packages again?     Other things I have tried:   sudo apt-get autoremove : results in the original error about unmet dependencies sudo apt-get -f autoremove : results in:    Unpacking linux-image-3.16.0-70-generic (3.16.0-70.90~14.04.1) ... dpkg: error processing archive /var/cache/apt/archives/linux-image-3.16.0-70-generic_3.16.0-70.90~14.04.1_amd64.deb (--unpack):  cannot copy extracted data for './boot/vmlinuz-3.16.0-70-generic' to '/boot/vmlinuz-3.16.0-70-generic.dpkg-new': failed to write (No space left on device) No apport report written because the error message indicates a disk full error                                                                               dpkg-deb: error: subprocess paste was killed by signal (Broken pipe) Examining /etc/kernel/postrm.d . run-parts: executing /etc/kernel/postrm.d/initramfs-tools 3.16.0-70-generic /boot/vmlinuz-3.16.0-70-generic run-parts: executing /etc/kernel/postrm.d/zz-update-grub 3.16.0-70-generic /boot/vmlinuz-3.16.0-70-generic Errors were encountered while processing:  /var/cache/apt/archives/linux-image-3.16.0-70-generic_3.16.0-70.90~14.04.1_amd64.deb E: Sub-process /usr/bin/dpkg returned an error code (1)     Note: I've migrated this question from


Is “need” different from “do need” in this sentence?     However, you do need to create an action and associate it with the   button, so that your app knows what to do when the button is pushed!


Pan frying store baught chicken breast with added glaze/broth solution

When buying store bought chicken such as the one shown in the link below, a lot of times it comes with rib meat and glaze/solution to 'add flavor' etc. When defrosting the chicken breast and beginning to pan fry it with oil, the desired result is to get a golden brown / crispy chicken in the end.   Although the outcome always seem to be far from it with store bought varieties, as during the frying process, the juice/solutions comes out of the chicken breast to the point where the chicken breast which was suppose to be frying is now sitting in a puddle of a broth like solution.   As a result, I find myself spilling out the juices repeatedly throughout frying it, which is a huge turn off and a lot of times, it ends up being chewy as opposed to getting that pan fried effect.   I was just wondering if this is common for others cooking chicken breast as well and if there is any way to prepare store bought chicken breast, to prevent this from happening.   The chicken breast is something like this:


Are there cases known of Big Sur bricking 15" inch MBP 2013 models?

My parents have a 15" Late 2013 MacBook Pro. They would like to upgrade to Big Sur, which is still compatible with that Mac. On the internet, I've read several stories about 2013 MBP's that were unusable after updating. Some articles only named the 13 inch version, others talk about the 2013 MBP in general. I can imagine that this has (almost) only happened to 13 inch versions, because they generally come with less power than the 15 inch version. We'll of course backup it, but we want to prevent everything that brings along extra work. Are there any cases of 15 inch MBP 2013 being bricked after updating to Big Sur, or has that only happened to 13 inch versions? Many thanks in advance!


I wonder if it is possible to say "musical school" instead of "music school" (with the same meaning 'a school of music'). Recently I have come across several sentences like that:  *The obvious genius of the child had been noticed by the family, and his mother took him to a musical school.   In general, I am a classical  Muscovite, who went to musical school in my childhood,  therefore I dream of buying a piano...*  Thanks.


How to boot Chromebook from SD card without entering developer mode?

I have a question. Is it at all possible to install Ubuntu or Chrubuntu onto a SD Card and then boot a chromebook from said SD card? I know this is easily possible, but the chromebook in question belongs to my school, so I cannot enter developer mode, because that would void the license agreement. I don't really care how technical or how many steps this will take, as long as it can be possible. Thanks in advance.


Why does the basic intuition fail here? What is the reason behind it?

We know that $$\int f(ax + b)\,\mathrm dx = \frac1aF(ax + b) + C$$  so while solving $$\int x^2\,\mathrm dx = \frac13x^3 + C$$  also, $$\int (x + 3)^4\,\mathrm dx = \frac15(x + 3)^5 + C$$  but for trig functions like,  $$\int \sin^2x\,\mathrm dx \neq \frac13\sin^3x + C$$  Instead, we have to simplify it first algebraically. So why does the intuition fail here?  Update: I seem to be confused with f. Till now $$\int \sin^2(1*x+0)\,\mathrm dx  \ $$, I have assumed f = (sin(x))^2 with a=1 and b=0. There seems something wrong with my understanding.


I have an  of the Windows 7 installation DVD, but I can't burn it to CD or DVD. I have an empty flash drive with plenty of space. Is there any way I can put the ISO image on it and install from it as if it were a CD?


Reverse DNS - how to correctly configure for SMTP delivery

I started a new service and we need to send emails to our customers (new account confirms, etc).   My server is known as prod01.bidrodeo.com and resolves to 97.107.134.38 .  For reverse DNS, 97.107.134.38 resolves to prod01.bidrodeo.com . However, all our email addresses are in the form of user@bidrodeo.com. Should I make the reverse DNS point to bidrodeo.com instead?   My emails are getting delayed or rejected by certain systems and i am not sure if my reverse DNS is not set up correctly.


Sorting linked list as numbers are added

I am trying to create a sorted linked list that sorts as new numbers are added in Java. The way I would like the program to work is to insert the new node in the correct place so that it is sorted. However, I keep getting a NullPointerException.  Here is my code:  public void Add(int d){         Node newNode = new Node(d);         if(first == null){             first = newNode;             return;         }         Node cur = first.next;         Node prev = first;         if(newNode.data > prev.data){             newNode.next = first.next;             first = newNode;             return;         }         while(cur.next != null){             if(cur.data < newNode.data && prev.data > newNode.data){                 newNode.next = cur;                 prev.next = newNode;             }             cur = cur.next;             prev = prev.next;         }         cur.next = newNode;      }   I have no idea why it does not work.


Why is "what can I ask about here" not the first entry in the help center?

On a lot of sites, the first section of the Help Center looks like this:    When I go to a site's help center it's almost always to find out what's on-topic there, because I'm considering asking or migrating a question.  Leading with what not to ask seems odd to me, and I suspect that to someone not already familiar with SE it could be a little off-putting.  It's not always like this, though; here on MSE we get this, which I've seen on some other sites too:    That ordering makes a lot more sense to me.  It's also consistent with the tour.  (Maybe "how do I ask a good question?" should also be "above the fold", in the top five somewhere.)  Why the difference?  Can we either make the order consistent across the network and more logical, or give users or moderators the ability to change the order on their sites?


Suppose I have called a function as, const data = await someFunction()  I want to calculate execution time of this function. For this I tried as, let startTime = Date.now(); const data = await someFunction() let endTime = Date.now();  And I calculated difference between endTime-startTime and the result I get i think is in millisecond and converted it to second. I would like second opinion on this whether this is one of the option to calculate or is there some more better method which can give me execution time in second.


Example: It is I who is/am the best player of this team. which option is correct is or am plz also explain what is antecedent here


I need to do the small animations in Ubuntu 12.04 Please let me know what type of animation software are available for Ubuntu 12.04?  If I can install the Adobe Flash Professional to my Ubuntu 12.04 is better.


How to create an instance just by generic type T

I want to create an instance just by defining the type for a generic class  public abstract class Base<T> {     private final T genericTypeObject;      protected Base(){           //Create instance of T here without any argument      } }   So that I just can call the default constructor:  public class Child extends Base<SomeClass>{     public Child () {         super();     } }   and the Base-class implementation will create me an instance of the GenericType.


Prove that bilinear form can be presented as product of linear forms if and only if it has rank one

Let $f: V \rightarrow F$ a bilinear form such that $f \ne  0$. Prove that $f$ can be presented as a product of two linear forms $f(X,Y) = \left(\sum\limits_i^nb_ix_i \right)\ast \left(\sum\limits_j^nc_jy_j\right)$ if and only if $rank(f)=1$   I saw this question and it's answer:   But the answer seems to ignore the fact that $rank(f)$ must be $1$. I don't know how to use that fact to solve this.  Thanks in advance


why do we relate spin with angular momentum operator in quantum mechanics?

In fact angular momentum is the generator of rotation around an axis. If the axis passes through the center of mass of the object then it is spinning. spin in QM can be a property of point particle(such as electron) that can't rotate around it self.


Is it correct to use the suffix -ian when referring to names?

Oftentimes when reading academic texts I will come across the suffix "-ian" as a way to denote ownership.  While I find it fitting syntactically (it "feels" right), I don't remember ever learning it specifically in school, etc.  For example:     Wilsonian (Wilson's) moral diplomacy is widely regarded as a failure.      Carverian (Carver's) Minimalism marked a rebirth of the realist movement.   So, here are my questions:   Is this syntax correct? If so, What mood does it give off?  Does it offer an academic tone, etc.? Is it possible to use this with any name, or just a few popular ones?  Can I say "Flafla2-ian"?   Thanks in advance.


Question mark after a comma and a second sentence?

A non-English native friend has just said that an English speaker told him the question mark should NOT be used after a pair of sentences separated by a comma. Something like this: "Could someone else have done that, as she was on holidays" I am also a non-native speaker and am not a language expert but I find this construction quite strange. I would use the question mark here, even if the second sentence is not interrogative. From my point of view, the question is in the first sentence but the second does not act as a separate statement. Help? Many thanks for your thoughts.


The elements in the composite field $FK$

Where $F$,$K$ are two fields. What does the element in the composite field $FK$ look like? All the elements are generated by the elements of $F$ and $K$? (combination of the elements of $F$ and $K$) I think $FK$ is pretty close to the free product of $F$ and $K$; is $FK \subsetneq F*K$? Thank you!


I often see "replace with" and "replace by" used interchangeably, but this doesn't sound right to me:     I replaced that component by this one.   I would use "with" in such a sentence. "By" only seems reasonable in passive, although "with" sounds like it would there work too:     That component was replaced by this one.   That component was replaced with this one.   In my native language, the equivalent of "replace by" can only be used in passive, and even then it's a bit weird unless a person is the object replacing something – perhaps this affects my judgment?  Web searches haven't come up with anything conclusive; the results are contradictory and speculative at best.  Are "replace with" and "replace by" interchangeable in active context? What about passive? Are there stylistic reasons to prefer one over the other?


How to create an iso from current installation

I installed Ubuntu 14.04.1 on one of my laptops and now I want distribute that exact installation to a few of my friends. I tried making an iso with Gparted on a live session but it makes a 500 GB file (I've only used around 8 GB) .   Thanks in Advance !


Javascript private methods: function expression vs function declaration

A common method of creating private methods (of sorts) in javascript is this:  Class = function (arg0, arg1) {     var private_member = 0;     var privateMethod = function () {         return private_member;     }; }   The above example could also have been done with a function declaration instead of a function expression:  Class = function (arg0, arg1) {     var private_member = 0;     function privateMethod () {         return private_member;     } }   In what ways are these two ways of declaring a private method different? (Outside of one being an expression and the other being a declaration)  For example, the expression obviously generates a new function everytime the constructor gets called. Does this happen with the function declaration aswell, or does it only get evaluated once because function declarations are evaluated at parse time? (As opposed to function expressions which are evaluated at execution time, you get the idea.)  EDIT: I'm aware that javascript doesn't really have private methods. I'm using the the term loosely.  EDIT: Not a duplicate of , if anything a duplicate of . My question isn't about the difference between function expressions and function declarations in general, but their differences specifically in regards to "private members" in javascript "classes".


How do I get my Median Program to work (part 2)

I am trying to make a median program. This is my code.  def median(list=[]):     x = 0     list = sorted(list)     if len(list) % 2 == 0:         b = int((len(list)/2))         print b         c = int(len(list)/2)         x = [list[b-1],list[c]]         print x         x = float((x[0]+x[1])/2)         print str(x)     else:         print list[((len(list)//2))]   When I run it, I get this  >>> median([1,2,3,4]) 2 [2, 3] 2.0   What is happening?  Please note: I do not want any advice on ways to do it better, I just want help.


Why didn't Sauron make the rings himself?

So Sauron had to trick the elves/Celebrimbor into making tainted rings for him. The reason he couldn't just cut out the middle man and make them himself, using his fair physical form, was because........?


Sous vide effectiveness without using a vacuum sealer?

I frequently use the water displacement method to seal ziploc freezer bags when I sous vide. I can get maybe 99% of the air out, but technically the bag is not under vacuum. If I clip the top of the bag to the side of my container, any air pockets that emerge collects at the top, and the meat is entirely in contact with the bag and immersion bath. Alternatively, if I seal the bag with a marinade, there are no pockets of air between the meat and the immersion bath.   I can't imagine that the temperature transfer can be any more effective when vacuum sealed. So why does a site like SeriousEats still suggest that a vacuum sealer is needed for best results with longer cooking times?    update from   In the context of food storage in plastic bags, SeriousEats claims, "excess air causes oxidation that can develop into off flavors or promote spoilage." But I never sous vide for the freezer, it gets served when done.   There was a comment that asked if food contamination might occur for cooking times longer than 48 hours, but it was never answered.   What is the science behind this statement? How much residual air is "too much"?   If the bag remains submerged, does not leak, and the food in full contact with the water bath, is that enough to duplicate the benefits of a true vacuum seal?  update 2  Also, what is the scientific impact of trapping small amounts of residual air in a pocket above the water bath?  This assumes that there is still a very strong thermal coupling between the water bath and sous vide item.   In the photo below, you can see at least a 2inch gap between the air pockets above water level and the actual short ribs. From a heat transfer perspective, I can't imagine that a vacuum sealed bag can perform significantly better—certainly not relative to a 48hr cook time. Is there a possibility of bacterial contamination?


UK Plab Visa Refusal due to bank deposits even though affidavit provided for the deposit

I have successfully cleared PLAB1. My visa appointment to appear for PLAB2 was on 18 Dec 2018. My visa was denied under section 4.2 a,c and e. My brother (he is working in the US with a reputed company) is acting as my sponsor and I have submitted supporting letters from him as well. I work part time as a duty doctor in Bangalore with an annual salary of 250,000 INR.  For personal funds, I had shown around 250,000 INR in my bank account.  I had transferred a sum of 100,000 INR to my bank account through a cheque from my father's account on 13 Dec 2018. In order to explain this amount, I had attached a notarized affidavit explaining this amount as a gift from my father and mentioning that the gift is irrevocable. I had also mentioned the cheque number in the affidavit and mentioned that the amount is from my father's savings.  The visa officer has specifically called out the deposit of 100,000 INR in the refusal citing that we have not explained the source of these funds.  Now my questions are,    Do you think the visa officer overlooked the legal affidavit we had attached? Is there something else we can do to explain the 100,000 INR deposit apart from the affidavit? Should I re-apply with further explanation for the deposit?   We still have the balance in my amount and it is almost 1 month since the deposit.


The question is: Suppose that T is a self-adjoint operator on a finie-dimensional inner product space and that 2 and 3 are the only eigenvalues of T. Prove that $T^2-5T+6I = 0$.   To prove this question, can I take the inner product of $(T^2-5T+6I)v$ and $Tv$, where $Tv = 2v$ and $v \neq 0$, and then show that the inner product of those two vectors is equal to $0$? Since $v \neq 0$, would that imply that $T^2-5T+6I = 0$? Or am I coming at this question completely wrong?   Thanks.


In an alternating current, do electrons flow from the source to the device?

If electrons in an alternating current periodically reverse their direction, do they really flow? Won't they always come back to the same position?


Blender 2.8 volume over transparent background not showing in rendered image

I made this planet with a volumetric shader for the atmosphere    Left you see the atmosphere rendered in viewport mode Right you see it just rendered out but now the volumetrics are missing  Any guesses?


"Use of \@startpbox doesn't match its definition." Error on a Table

I am getting the following error during compilation "Use of @startpbox doesn't match its definition." for all my tables in tabular and tabularx environment.  The relevant portions of my document include:  \documentclass[12pt]{article} \usepackage[table]{xcolor} %Reason for the error \usepackage{geometry,tabularx,multirow}  \begin{document} \noindent\begin{tabular}{l c p{6cm}} \textbf{Name} & : &  \\ \textbf{Registration Number} & : &  \\ \textbf{Department} & : & Civil Engineering \\ \textbf{Date of Joining} & : &  \\ \textbf{Date of Upgradation (if any)} & : &  \\ \textbf{Specialization/Stream} & : & \\ \textbf{Area of Research}  & : &  \\ \textbf{Category of Admission} & : &  \\ \textbf{Guide} & : &  \\ \textbf{Co-Guide(s)} & : & \\ \textbf{Date of DC Meetings} & : & \\ \end{tabular}  \end{document}   This error occurred after I updated all the packages. Any help is appreciated.


If $\{a_n\}$ is a convergent sequence of real numbers, then $ \lim_{n \to \infty} n(a_{n+1} - a_n) = 0$

The question is as follows:  If $\{a_n\}$ is a convergent sequence of real numbers, then $\lim_{n \to \infty} n(a_{n+1} - a_n) =0 $.  I have been thinking about this question since yesterday but I am unable to prove it. $a_{n+1} - a_n \rightarrow 0$ if $\{a_n\}$ is convergent, but there is also a term of $n$ which is creating trouble for me. I verified this with examples like $a_n = 1/n$ and $a_n =1$ but can't get any idea on how to prove it. Please help me, any idea will be appreciated.


Why is public transport from/to the airport so expensive?

In the different places in the world, I always have the feeling that public transport from/to the airport is really expensive for what you actually get.  Here are a few prices for a couple of airport and additional information to be able to compare (I wanted to create a nice table but didn't find how to do it) :   Sydney Domestic Airport Station   15.90 AUD one way using  6.3 km to Sydney Central Station by car (from ) Sydney Central to Ashfield seems to be the same distance and costs 3.60 AUD (8.4 km) using   Sydney International Airport Station   16.70 AUD one way using  9.2 km to Sydney Central Station by car (from ) Sydney Central to Croydon seems to be the same distance and costs 3.60 AUD (9.44 km) using   Melbourne Tullamarine Airport   17 AUD one way, $28 return using  24 km to Melbourne Southern Cross Station by car (from )  Paris Charles-De Gaulle    : 9.25 EUR (RER) ; 10 EUR (Roissybus) 30 km to Chatelet les Halles by car (from )  Paris Orly    : 6.50 EUR (RER+BUS) ; 10.90 EUR (Orlyval), 7 EUR (Orlybus) 17 km to Chatelet les Halles by car (from ) Chatelet les Halles to Villeneuve-Saint Georges seems to be the same distance and costs 4.10 EUR using   London Gatwick   19.90 GBP using , a bit cheaper using other slower rail companies 43km to London Victoria  by car (from )    Why is the price so high ? If there's something which is to be paid to the airport when going there, why isn't it included in the airport taxes on the flight ticket prices?  I find the even weirder when it makes the cab/taxi, despite its price being increased too, cheaper than the train/bus/shuttle for a couple of passengers.  Also, as an additional question, is this price difference higher/lower in different part of the world?


Is there a way to mirror a directory structure and files there contained with rsync,  giving out facade zero length files?   I mean, mirroring dirs (-d flag I think) exactly as they are, while not copying the files and substituting them some sort or symlink(?) or something like an empty file with his name and attr and no size? In short I want to mirror an env entirely while minimizing uninportqnt files size.


Let $X$ be topological space and $A\subseteq X$.   If $E\subseteq X$ is connected, $E\cap A\neq\emptyset$ and $E\cap(X\setminus A)\neq\emptyset$ then $E\cap\partial A\neq\emptyset$.  Assume that $E\cap\partial A=\emptyset$.  If $E\cap\partial A=\varnothing$ then $E=(E\cap\text{int}(A))\cup(E\cap\text{ext}(A))$, i.e. a union of disjoint sets open in $E$.   Also the sets are nonempty because: $E\cap\text{int}(A)=E\cap A\neq\varnothing$ and $E\cap\text{ext}(A)=E\cap A^c\neq\varnothing$.  This contradicts that $E$ is connected.  Fixed.


I am going through the following subroutine:  sub new{     my $self  = shift;     my $class = ref($self) || $self; }    Here, I don't understand what does shift is used for? What I understand from googling is that, shift returns and deletes the leftmost value of the array. But still I am not sure.  Another question, what does ref is used for? Google says it acts as typeof function that returns the type like scalar, array, hashes.  Still I am not sure about my understanding. Can someone please clarify?


Just as  would be interesting, I think it could be interesting to see the inside of embassies too. Let's say I was going to be in London for a week and wanted to see the inside of the US embassy in London.  Looking at the , I guess I could do something like...  print out the form to  and try to have them notarize it, but if I didn't actually have US savings bonds that needed to be re-issued it seems like that would be a bit scammish. It also seems like the US embassy might wonder why I couldn't just wait a week and do it when I got back to the states.


Constructing a continuous linear functional

Let $C$ be the Banach space of complex continuous functions on $[0,1]$, with the supremum norm. Let $B$ be the closed unit ball of $C$. Show that there exist continuous linear functionals $\phi$ on $C$ for which $\phi(B)$ is an open subset of the complex plane; in particular $|\phi|$ attains no maximum on $B$.  I had tried it several times but I am not able to generate such a linear  continuous functional on the given space. Any type of help will be appreciated. Thanks in advance


What is the difference between Ring, Field and Groups in abstract algebra?

Groups, rings, fields all seem similar to me. I don't get the difference between them.    What is the difference between them algebraically and graphically? Please give suitable example.


For example, if I say $f(x) = \ln \left\{ x \right\}$ where $ \{ \cdot \}$ denotes the fractional part function. Is there any way to know the codomain of this function?   And Now if I define $f : \mathbb{R} \to \mathbb{R}$, now the codomain is $\mathbb{R} $. So is it safe to say, codomain could be anything we want so long as it contains range, if there isn't a codomain already given?  So, $ \sin : \mathbb{R} \to [-1,1]$ is as correct as writing $\sin : \mathbb{R} \to \mathbb{R}$?  So I take it that if domain and codomain aren't given, then I could also say Codomain $\equiv$ Range?  EDIT : What I'm trying to ask is, if it's only a matter of codomain, then every function can be called surjective and conversely every function can be called into function? Which makes it all ambiguous.  I have so many confusions with co-domain, but can anyone just explain me these for the time being? Help is appreciated :)


Proving $r \binom{n}{r}=n\binom{n-1}{r-1}$ combinatorially. (Advice on combinatorial proofs in general?)

How do you combinatorially prove the following? $$r \binom {n}{r} = n \binom  {n-1}{r-1}$$  I find it easy to prove such equalities algebraically, but have a hard time finding the right combinatorial intuition. Any advice for coming up with combinatorial proofs myself?


If $f$ is continuous, nonnegative on $[a, b]$, show that $\int_{a}^{b} f(x) d(x) = 0$ iff $f(x) = 0$

If $f$ is continuous, nonnegative on $[a, b]$, show that $\int_{a}^{b} f(x) dx = 0$ iff $f(x) = 0$  "$\Rightarrow$" Assume by contradiction that $f(x) \neq 0$ for some $x_0 \in [a, b]$. Without loss of generality, assume that $f(x_0) > 0$. Since $f$ is continuous, $\exists \delta > 0$ such that $f(x) > 0,  \forall x \in (x_0 - \delta, x_0 + \delta)$. Since $f$ is continuous on $[a, b]$, then it is Riemann integrable. Therefore $\int_{a}^{b} f(x) dx = \sup L(f, p)$ for some partition $p$. Now what I want to do is to show that the lower sum, $L(f, p) > 0$, in that case its supremum is $>0$, and that contradicts the condition that $\int_{a}^{b} f(x) dx = 0$. However, I don't know how to articulate it.  "$\Leftarrow$" If $f(x) = 0, \forall x \in [a, b]$, then $\int_{a}^{b} f(x) dx = \int_{a}^{b} 0 dx = 0$


The company halted, and there was not a heart among them that did not quail, unless it were the heart of Legolas of the Elves, for whom the ghosts of Men have no terror.   Given Elladan and Elrohir were in the company, are they fearful of the shades of men or am I reading to much into the passage?


When I use the WGS 84 CRS the Chukotka peninsula east of the 180 meridian is shown on the left of the map. If I project (on-the-fly) the map using a Lambert Azimuth projection, the Chukotka peninsula is shown as a whole, but the 180 meridian is shown as a line through the peninsula.  Can someone please tell me how I can either:    project my map so that the 180 meridian is not shown, or  tell me how I can hide the meridian in the vector layer, or merge the two polygons (there does not seem to be a Merge option in QGIS, unlike ArcGIS)   The syntax I am using is:  +proj=laea +lat_0=55 +lon_0=40 +x_0=4321000 +y_0=3210000 +ellps=GRS80 +towgs84=0,0,0,0,0,0,0 +units=m +no_defs   I am using QGIS 2.14.1 on Windows 10.


Vertical alignment in tabularx X column type

I'd like to create a new column type which works exactly like a X column from tabularx but that also has the text vertically centered. I tried with the newcolumntype command but I can't figure out where to put the second column type? Example:  \newcolumntype{n}{>{\centering\arraybackslash}X}   Where should I put the mto specify that the cells content should be vertically centered?


why a set of all $2 \times 2$ matrices can be a vector space?

I am sorry this is a stupid question, but I am really confused about why $2 \times 2$ matrix is not a vector, but all $2 \times 2$ matrices can be a vector space? According to the definition, the each element in a vector spaces is a vector. So, $2 \times 2$ matrix cannot be element in a vector space since it is not even a vector.


My Xterm always print:      tony@tony-ThinkPad-Edge-E540:~$      I want it to print only   ~$   How can I do that?


Is it (theoretically) physically possible to project an image into thin air?

Is there some law of physics that strictly prohibits the projection of 2D or 3D images into thin air (such as holograms in movies) or is a solution to achieve this still up for grabs by an eventual discoverer?


I recently started in unity and for making models, i went for blender. I was watching tutorial, but the guy was having a totally different interface from mine. I wasnt even able to find some stuff. I am using 2.82. The video is from October 2018. Here is the video:    Here is my photo:   I don't know if i have to arrange my panels in a certain way, or it is from the version.


How to get unbanned after a question-ban?

When I try to ask a question, I see the below message:     Sorry, we are no longer accepting questions from this account. See the Help Center to learn more.   Is it possible to reverse this ban?


How do I format my section/subsection titles without changing the cross-referencing result

I am using some code recommended by the editor of a journal.  However, the \renewcommand line for \thesubsection and \thesubsubsection seems to be causing a problem with the cross-referencing function \ref.  When I reference a subsection (e.g., 'II.A') it only displays "A" or a subsubsection (e.g., 'II.A.1') I just get "1".  Is there a way to fix this code so that it properly references the subsections with the section number included.  \documentclass[12pt, titlepage, reqno]{article}  %load packages \usepackage[margin=1in]{geometry} %overwrites 1.5" default margins   from    article class \usepackage{graphicx}% Include figure files \usepackage{dcolumn}% Align table columns on decimal point \usepackage{amssymb,amsmath,amsfonts}% popular packages from the American Mathematical Society \usepackage{bm}% Bold Math package \usepackage{array} \usepackage{color} %colored text \usepackage{float} \usepackage{setspace} \usepackage[super,comma,sort,compress]{natbib} \usepackage{latexsym} \usepackage[mathscr]{eucal} \usepackage{enumerate} \usepackage{titlesec} %for formatting section titles %\usepackage{appendix}   %% SECTION TITLE FORMATTING \renewcommand{\thesection}{\Roman{section}} %numbering \titleformat{\section}   {\normalfont \bfseries \raggedright \uppercase}   {\thesection.} %numbering   {0.5em}{}  \renewcommand{\thesubsection}{\Alph{subsection}} %numbering \titleformat{\subsection}   {\normalfont \bfseries \raggedright}   {\thesubsection.} %numbering   {1em}{}  \renewcommand{\thesubsubsection}{\arabic{subsubsection}} %numbering \titleformat{\subsubsection}   {\normalfont \bfseries \itshape \raggedright}   {\thesubsubsection.} %numbering   {1em}{}


Clicking ISO does nothing in the 'Make Startup Disk'. Cannot make a USB Boot Drive that I need for work

Ubuntu 16.04 LTS Im using ubuntu for the first time. I tried to install Windows 7 onto my new pc using a usb boot i made on my vista 32bit laptop, but it wasnt detecting any hard drives to install on.  I made a ubuntu boot drive instead with the same usb, but I know nothing about Ubuntu. Whenever I select the Win 7 ISO from the file browser in Make Start Up Disk nothing happens at all. I want to try making a new iso boot on a new usb stick using a different program. My laptop has since died. Ive been trying for hours, but my dyslexia is getting the better of me. Please write to me simply, thank you!


How can I access these functions on the derived class?

class A has a member function fx1 class B has member function fx1 class Z is derived from class X and class Y.  If obj is an object of class Z, How will you access these functions.


What is the Difference between Geometric and Geographic columns?

I am a beginner in GIS and Learning PostGIS. I came across this two terms Geom and Geog, Could anyone explain in brief. What is the best to use with map data and Do all functions support both Geom and geog.


Show that $\lim_{n\to \infty}\int_{[0,\infty]}\left(1+\dfrac{x}{n}\right)^n\exp(-ax)=\dfrac{1}{a-1}$

Establish the following limits:  $\lim_{n\to \infty}\int_{[0,1]}\dfrac{n^2x^2}{\exp(nx)}=0$ $\lim_{n\to \infty}\int_{[0,1]}\dfrac{1+nx}{(1+x)^n}=0$ $\lim_{n\to     \infty}\int_{[0,\infty]}\left(1+\dfrac{x}{n}\right)^n\exp(-ax)=\dfrac{1}{a-1}$ (In the last part, assume $a>1$.)  The first two were relatively simple to do. Just do tabular integration for each and then take the limit and you are done. However the third one is giving me a hard time to show that the statement is true. I first integrated and found this large complex expansion. But this seems too complicated. Can I get some suggestions?


pgfplots: x label at sixth decimal number

As suggested by similar topics on this site, I followed the procedure to write the x labels in decimal form. However, they continue to appear in scientific form. These are decimal numbers of the order of 10 ^ -3: perhaps it is a pgfplots limit?  \documentclass{article} \usepackage[T1]{fontenc} \usepackage{lmodern} \usepackage{amsmath,amssymb,amsfonts,systeme,mathtools}  \usepackage{chemfig} \usepackage[version=3]{mhchem} \usepackage{pgfplots}  \begin{document}  \begin{figure} \centering \begin{tikzpicture}   \begin{axis}[   legend pos=outer north east,   legend cell align={left},   grid, grid style=dashed,   ymin=1.50,ymax=2.75,   ytick={1.50,1.60,1.70,1.80,1.90,2.00,2.10,2.20,2.30,2.40,2.50,2.60},   xtick={0.0030,0.0031,0.0032,0.0033,0.0034},    xmax=0.0035,xmin=0.0030,   axis lines = middle,   set layers,                   % <---     x tick label style={         /pgf/number format/.cd,             fixed relative,             precision=5,         /tikz/.cd,         rotate=90     }   ]   \addplot[color=orange,mark=*,mark options={solid,draw=orange,fill=orange},smooth]     coordinates {     (0.00341,2.67)(0.00335,2.44)(0.00330,2.24)(0.00324,2.06)(0.00319,1.88)(0.00314,1.72)(0.00309,1.56)     };     \addlegendentry{$x_1 = 0.3$};   \end{axis} \end{tikzpicture} \end{figure}  \end{document}


Hai all I am using Hibernate, java and Sql server for creating an application. And while doing this I have come across a problem where Union is not supported by HQL. For me the following code works in native SQL but it is not working when I am dealing with HQL.  SQL  select inttestid,testname from LAB_TEST_SERVICES where inttestid in(select inttestid from dbo.LAB_SPECIMEN_MAPPING union select intprotestid from LAB_PROFILE_TEST_LIST) and inttestid not in(select inttestid from LAB_TARIFF_MAPPING);   HQL  String h = "From SERVICES_TYPE_POJO lst where lst.inttestid in(select smp.inttestid from SPECIMEN_MAPPING_POJO smp union select ptl.intprotestid from PROFILE_TEST_LIST_POJO ptl) and lst.inttestid not in(select tmp.inttestid from TARIFF_MAPPING_POJO tmp)";   Can anyone help me with changing the SQL to HQL. Thanks in advance.


Hi I'm having a lot of trouble with this: I need to find the limit of the following sequence: $$ k \in \mathbb{N}, \lim _{n \rightarrow \infty} \frac{1}{n^{k+1}}\left(k !+\frac{(k+1) !}{1 !}+\cdots+\frac{(k+n) !}{n !}\right) $$ There's a hint that I should use the following formula: $$ (1-q)\left(1+q+\cdots+q^{N}\right)=\left(1-q^{N+1}\right) $$


Why is $\cos(\theta) < \dfrac{\sin(\theta)}{\theta}$ for $\theta \in (0,\dfrac{\pi}{2})$

I read that $ 0 < \cos(\theta) < \dfrac{\sin(\theta)}{\theta} < \dfrac{1}{\cos(\theta)}$ for $\theta \in (0,\dfrac{\pi}{2})$. I am confused about the middle part. I don't find it intutive (even from the graph). Please explain me why this is so.


I have this challenge, that i've found out that i'm not the only one in the WEB with the same issue, nevertheless, there are no solutions yet.  I'm trying to remove shortcodes from my custom post types excerpts.  here is my example:   in sidebar there's the "in the neighborhood" widget that shows images with excerpts... some are showing this issue.  Any tips?  Thanks in advance


I would like to have three screens connected to my Mac Mini, so far I have one screen connected via HDMI and one screen connected via thunderbolt. The only ports I have left are USB and firewire, would there be any way for me to connect a third monitor?


Radius of convergence greater than 1 if $f$ is analytic in $\left\{|z| < 1 \right\} \cup{} \left\{1 \right\}$ and $a_n \ge 0$

We are doing Laurent series, singularity & Identity theorem at the moment, and I've been struggling to find a lead on this one. $f = \sum_{n=1}^{\infty} a_nz^n$ is analytic in $\left\{|z| < 1 \right\} \cup{} \left\{1 \right\}$ and $a_n \ge 0$, and I am supposed to prove that the convergence radius is greater than 1. I've tried to prove that since I can input 1 into the equation and $f(1)$ is a value, than the sum $\sum_{n=1}^{\infty} a_n$ converges, but that only proves the radius is greater or equal to 1. Feel like I should probably use one of the things I mentioned above, but haven't really been able to find how. Would love even a hint! Thanks :)


Runing      echo "zyc.txt" | openssl dgst -sha512      (stdin)= 11aa472bf4c97ffb1fae06a3f7175127da084c5dfb840038ee308b37136330e5b6a56cc053c62881f10aec88948d8addb1d4844496cdb08e4067b4fd4601330e   or     echo "zyc.txt" | sha512sum 11aa472bf4c97ffb1fae06a3f7175127da084c5dfb840038ee308b37136330e5b6a56cc053c62881f10aec88948d8addb1d4844496cdb08e4067b4fd4601330e   Output is wrong, hash should be     DDD2379F9A1ADF4F0AFA0BEFAFDB070FB942D4D4E0331A31D43494149307221E5E699DA2A08F59144B0ED415DEA6F920CF3DAB8CA0B740D874564D83B9B6F815   Here is info on my computer     Linux MobileSpace 4.14.0-3-amd64 #1 SMP Debian 4.14.17-1 (2018-02-14) x86_64 GNU/Linux   sha512sum --version sha512sum (GNU coreutils) 8.28 Copyright (C) 2017 Free Software Foundation, Inc. License GPLv3+: GNU GPL version 3 or later  <http://gnu.org/licenses/gpl.html>. This is free software: you are free to change and redistribute it. There is NO WARRANTY, to the extent permitted by law.  Written by Ulrich Drepper, Scott Miller, and David Madore.   Is this a bug or am I doing it wrong?


Prove the von Staudt-Clausen congruence of the Bernoulli numbers

I need to prove that:  If $p$ is prime greater than or equal to five, then $pB_{p-1}$ belongs to the p-integers and more over:  $$pB_{p-1} \equiv -1 \pmod p$$ Hint:Put $N=p$ in the Faulhaber´s formula: $S_{j}(N-1)=  \displaystyle\sum_{k=o}^j \frac{1}{(j-k+1)}{j \choose k}N^{j-k+1}B_{k}$ and reduce everything mod p and use the Fermat´s little theorem.  But I do not know how to reduce this:  $S_{j}(p-1)=  \displaystyle\sum_{k=o}^j \frac{1}{(j-k+1)}{j \choose k}p^{j-k+1}B_{k}$ to mod p,and I have problems trying to prove that $pB_{p-1}$ belongs to the p-integers, Can you help to prove the theorem please, Thank you.


When writing an integral, it seems like something should be done to separate the "d", as in \int f(x) dx, so as not to confuse it with a variable. I've seen it left as-is, bolded, and straightened. Even among those options there are several ways to accomplish each task; e.g., I could do a \mathrm or a \operatorname. What is the preferred method of dealing with the "d"?


Want this cut-out part to be seperate object, how?

I have cut out this selected piece with a knife and i want it to be a part of its own in the right colon (scene section). Right now its still part of the cube around of it. What is the option for this?


What GRE verbal score is needed for a non-native English speaker to get into math or applied math PhD programs in the USA?

I am an international student whose native language is not English. I am planning to apply for a Phd program in math or applied math in US in the future and general GRE test is a requirement.   From most posts , I know I should put more attention in related research experience and GRE test only matters when it's low. But I am wondering what it means exactly. I know most universities have a minimum score for TOEFL speaking session but didn't find any information about GRE general test.  My classmates told me that based on previous record, in order to get admitted by a top program (top10 or 20), both verbal (V) and quantitative (Q) can't be bad. For Q I should aim at 140 but they are not sure about V. I also checked some forums such as mathgre. I found a lot of local applicants got verbal score higher than 135. To achieve that, I must put a lot of effort which will reduce my time about research significantly.  Hence I want to know what kind of gre general score is acceptable for international applicants who plan to apply for top theoretical phd programs? Based on my understanding, most programs usually higher GRE subject score for international students, will you usually have different language requirements for local/international students (except toefl) when you review the application materials?


Why are many of my flags still waiting for review?

I have included an image of my flagging history below:    Of the 51 flags still waiting for review, 40 have been in this waiting state for more than a month. What could cause this?


Proving the Rietz-Fischer Theorem for $p = \infty$

Rietz-Fischer Theorem: Let $E$ be a measurable set and $1 \le p \le \infty$.  Then every rapidly Cauchy sequence in $L^p(E)$ converges both with respect to the $p$-norm and pointwise almost everyone on $E$ to a function in $L^p(E)$.  Question: How does one prove this in the case that $p = \infty$?  Every proof I have seen thus far seems to assume that $p \in [1,\infty)$.  For example, the  makes this assumption and then concludes by remarking "the case $p = \infty$ reduces to a simple question about uniform convergence".  Upon thinking about this for a bit it's not obvious how to proceed.


When I try to install Software Center it says:  The following packages have unmet dependencies:   gsettings-desktop-schemas : Breaks: gnome-settings-daemon (< 3.19.92) but 3.18.2-0ubuntu3.1 is to be installed                              Breaks: mutter (< 3.31.4) but 3.18.3-0ubuntu2 is to be installed  perl-base : Breaks: debconf (< 1.5.61) but 1.5.58ubuntu1 is to be installed              Breaks: debconf:i386 (< 1.5.61)  software-center : Depends: python-apt (>= 0.8.3ubuntu4) but it is not going to be installed                    Depends: python-aptdaemon (>= 0.40) but it is not going to be installed                    Depends: python-aptdaemon.gtk3widgets but it is not going to be installed                    Depends: python-oneconf (>= 0.3) but it is not going to be installed or                             oneconf (< 0.3) but 0.3.9 is to be installed                    Recommends: software-properties-gtk but it is not going to be installed E: Error, pkgProblemResolver::Resolve generated breaks, this may be caused by held packages.


Compositor Problems when working with alpha over and blur nodes

I am doing an animation. The images I have attached show 2 different render layer view node results.    Image one shows a cube on layer 1, and 2 icosphere on layer 2. I have layer 2 set to fast blur. I have to use transparent film and therefore I use the Alpha over nodes in composition.  Image two shows a cube and 1 icosphere. Image 1 should not be showing 2 icospheres, as the left most one is behind the cube.    Image 2 is from the same render result, and is correcting showing only 1 icosphere. However, that icosphere should be blurred as it is on layer 2. It seems for whatever reason I can not have both the correct composition effect and also have every object's visibility render correctly. I can only either have everything work fine, with no composition, or composition with every emission object showing through every other object in the scene.   I am aware that masks would solve this problem, but because of the complicated setup of object materials and particles, masking produces these very strange and suddenly appearing artifacts. Material Indexing also produces odd artifacts and does not consistently effect the appropriate materials.   This is also a new problem, I did not have this issue in the last blender version. So, material indexing is out, masking is out, object indexing is out.       I want to use the compositor to blur certain layers, but every emission object in the scene shows through. It shows through as though it was on x-ray, regardless if it is behind another or inside another object. The first image is an example of this, the left icosphere is behind the cube, and should not be visible. That is the problem. Why is it visible when it shouldn't be?


Can I force WordPress to use  instead of ?

For example,  Did you know that hot was used to mean " sexually attractive" as long ago as 1450? (Though it seems that in earlier use, it more commonly meant "sexually attracted".)   The second use of  in the above is correct: I want to emphasise the suffix -ed. However, the first use is incorrect. I want to use italic type to indicate the “use/mention distinction”. This is the proper preserve of the  tag. But WordPress autoconverts  to . Is there any way to get around this?


I would like to find out on the console if my processor is 64 bit capable.  I can find out that I have installed the 32 bit version of Ubuntu with  uname -a   If it doesn't contain 64 at all, then I know I have a 32 bit kernel.  But how can I find out if I could install the 64 bit version as well?


How to access the internet during a road trip in the USA?

I'm traveling from Europe (Belgium) to USA soon. While on a road trip from New Orleans to Miami, I'd like to access the internet without paying exorbitant amounts of money on roaming fees. I was thinking about getting a pre-paid SIM card from an American provider to lower the costs.  It seems hard to order a pre-paid SIM from an American provider without an address in the USA. What are my options?


I have a bsnl broadband connection. I don't see any settings for broadband in Ubuntu, and I can't just connect automatically -- "wired connections" shows no connection.  I see an option for mobile settings, but that doesn't work for this case.  Where do I need to look to get the broadband connection to work?


VT1001 talking thermostat has started saying “two sixty four”

I have a energy star rated VT1001 talking thermostat installed sometime in the early to mid 2000s.  This morning it began to periodicall speak the words “two sixty four” (264). I cannot find anything to explain to me what this means.  I have located and obtained a user manual for a smilar thermostat from the same manufacturer but this gives no explanation.  When this occurs then the light button no longer iluminates the lcd display.  However, pressing the report button does illuminate the display and immediately produces the phrase 264 as discribed above.  Can anyone here tell me what this message means?


Tag wiki edits do not show up in reputation tab on Android App

The tag wiki edits do not show up in reputation tab on the Android App.   App Version: 1.0.89 Device Manufacturer: samsung Device Model: SAMSUNG-SM-G928A   OS Version: 6.0.1 (G928AUCU3CPHA)


If I touch an object, am I touching the atoms on its surface?

If I hit an object with a pen for example, does the pen touch the atoms on the surface of the object? Won't it damage the atoms? If I can't touch it, then where does the sound come from?


How to get click event on cell in a table after dynamically generated?

First the error which i am recievieng is undefined is not a function. I am generating a table on ajax call by button click. The problem is that the click event on cell is not performing.  my code is like   $(document).ready(function () {     $('#btnCall').click(function () {        $.ajax({....           success: function (data) {              //Here i am creating a table with id = myTable           }        });    });     //After ajax call completed i am using this     //but this is not happening    //i want to show alert when cell clicked of the table     $("#myTable tr td").click(function(event) {          alert(event.pageX);          alert(event.pageY);     }); });


I need to process a file like below in the bash script:  input.txt:  host1 53 host1 123 host2 0 host1 222 host3 1 host1 85 host1 25 host1 13 host3 8 host2 90   I need to get in the results only one line for each host based on maximum value in column 2:  output.txt:  host1 222 host2 90 host3 8   Any ideas?


I'm trying to figure out a good workflow for developing scripts and add-ons in Blender. Here's what I'm currently doing as I try my luck with a PyNode add-on:   Open blender Create a text editor panel Open my script (external text file) Edit my script in a nice external editor Reload the script Save the .blend file Run the script   Now that I can see what my code does, this Blender instance has been modified, so I can't (make changes to my script and) run my script again. So I do this:   Close blender Open blender with the .blend from step 6 and repeat steps 4-7, over and over and over..   Is there a better workflow for this sort of thing?


I've this project:    I'm beginner so I don't know how can I do that, I want to edit surface to align with the road. Like that:   Am I able to do that without editing every vertex?


I understand residuals intuitively in terms of linear regression as "the error in prediction". Mathematically I've seen residuals given by  $$\epsilon = y - \hat{y}$$  where $y$ is the true value and $\hat{y}$ is the estimated value.  But what are residuals with respect to PCA? Once we apply PCA to a matrix say, we are reducing its dimension by finding the directions with the most variation and projecting the data onto these directions (the principal components). I would guess that the residual here is the amount of variation left "unexplained" by the dimensionality reduction. But I haven't seen a formal definition for this so I can't be sure. Is there a more formal definition or better intuitive understanding to PCA residuals?


How to prove that the set $\{\sin(x),\sin(2x),...,\sin(mx)\}$ is linearly independent?

Could you help me to show that the functions $\sin(x),\sin(2x),...,\sin(mx)\in V$ are linearly independent, where $V$ is the space of real functions?  Thanks.


What should I do after a suspected compromisation of my system?

I run a Debian Stretch box. I had mistakenly forgot to delete a guest account I opened for a, well, guest of mine, and I suspect my system may have been compromised using that account. I'm not entirely sure, but I saw a few processes belonging to guest taking up CPU time - some sshd's and a /sbin/syslogd instance (which kind of scared me).  So, I killed the processes and removed the user, good for me. But - what would be a good idea to also do? Something specific to look for in the logs? Reinstallation of packages? Nuke the thing from orbit?


till vs. until in "from Apr. 21st till/until Apr. 28th"

Possible Duplicate:          Please kindly advise me on the correct usage of till/until when talking about period of time. For example:     This offer is valid from Apr 21st until/till Apr 28th.   Also, I would be grateful if you could tell me what variants are possible if I want to squeeze this phrase into a small area? How can I make it shorter? That is, what parts can be omitted? The suffixes (st, th)?  For example:       Apr 21 - 28


We are trying to redirect our site from http to https only. Everything we have tried in .htaccess has resulted in a redirect loop. If we manually type the "https://" in front of the url, our page returns jQuery error!. So I suspect it has something to do with not all the requested resources are being requested over https?  Our htaccess file:  RewriteEngine on  RewriteCond %{HTTPS} !=on RewriteRule ^/?(.*) https://%{SERVER_NAME}/$1 [R,L]  # change rewrite base if not in root RewriteBase /  # api RewriteRule ^(api)($|/) - [L]  # index.php RewriteRule ^index.php$ - [L] # pass-through RewriteRule ^(css|js|site)/.*$ - [L]  # redirect errors ErrorDocument 400 /error/400/ ErrorDocument 401 /error/401/ ErrorDocument 403 /error/403/ ErrorDocument 404 /error/404/ ErrorDocument 500 /error/500/ RewriteRule ^error/(.*)/$ index.php?page=error&eid=$1 [L]  # login RewriteRule ^login$ login/ [R] RewriteRule ^login/$ index.php?page=login # logout RewriteRule ^logout$ logout/ [R] RewriteRule ^logout/$ index.php?page=logout # ip requests RewriteRule ^request_ip$ request_ip/ [R] RewriteRule ^request_ip/$ index.php?page=request_ip # IE fix RewriteRule ^login/dashboard/$ dashboard/ [R] RewriteRule ^logout/dashboard/$ dashboard/ [R]  # upgrade RewriteRule ^upgrade$ upgrade/ [R] RewriteRule ^upgrade/$ index.php?page=upgrade # install RewriteRule ^install$ install/ [R] RewriteRule ^install/$ index.php?page=install  # dashboard RewriteRule ^dashboard/$ index.php?page=dashboard  # widgets RewriteRule ^widgets/(.*)/$ index.php?page=widgets&subpage=$1  # subnets RewriteRule ^subnets/(.*)/(.*)/ipdetails/(.*)/$ index.php?page=subnets&section=$1&subnetId=$2&ipaddrid=$3 [L] RewriteRule ^subnets/(.*)/(.*)/changelog/$ index.php?page=subnets&section=$1&subnetId=$2&sPage=changelog [L] RewriteRule ^subnets/(.*)/(.*)/(.*)/$ index.php?page=subnets&section=$1&subnetId=$2&sPage=$3 [L] RewriteRule ^subnets/(.*)/(.*)/$ index.php?page=subnets&section=$1&subnetId=$2 [L] RewriteRule ^subnets/(.*)/$ index.php?page=subnets&section=$1 [L]  # folders RewriteRule ^folder/(.*)/(.*)/$ index.php?page=folder&section=$1&subnetId=$2 [L] RewriteRule ^folder/(.*)/$ index.php?page=folder&section=$1 [L]  # vlans RewriteRule ^vlan/(.*)/(.*)/$ index.php?page=vlan&section=$1&vlanId=$2 [L]  # vrfs RewriteRule ^vrf/(.*)/(.*)/$ index.php?page=vrf&section=$1&vrfId=$2 [L]  # changelog override RewriteRule ^tools/changelog/(.*)/(.*)/$ index.php?page=tools&toolsId=changelog&cfilter=$1&climit=$2 [L] RewriteRule ^tools/changelog/(.*)/$ index.php?page=tools&toolsId=changelog&climit=$1 [L] # search override RewriteRule ^tools/search/(.*)$ index.php?page=tools&toolsId=search&ip=$1 [L] # devices override RewriteRule ^tools/devices/hosts/(.*)$ index.php?page=tools&toolsId=devices&deviceid=$1 [L] # tools RewriteRule ^tools/(.*)/$ index.php?page=tools&toolsId=$1 [L] RewriteRule ^tools/$ index.php?page=tools&toolsId=showAll [L]  # admin RewriteRule ^administration/manageSection/sectionChangelog/(.*)/$ index.php?page=administration&adminId=sectionChangelog&sectionId=$1 [L] RewriteRule ^administration/(.*)/$ index.php?page=administration&adminId=$1 [L] RewriteRule ^administration/$ index.php?page=administration&adminId=showAll [L]   Manually putting https in the url (with no modification to htaccess) produces the following:     It should look like the following:


Could someone provide an intuitive explanation for contour Integrals?

So my core understanding of what a contour integral is may be wrong so the question I'm attempting to ask is what is the complex output value of a contour integral 'defining'. I understand well enough that for closed paths not containing singularizes, the contour integral will equal zero and that if it does contain singularities the it may produce a complex valued output given in the form of $\displaystyle 2\pi i\ f( a)$ for cases that can be evaluated using the Cauchy integral formula. I have no trouble evaluating them mathematically but I have zero idea about why it's even useful to compute a contour integral. If not defining an 'area', what is it actually telling us? How do we use that information? Is their a good visual explanation for why a contour integral is non zero for contours around a singularity?


If I'm using an <a> tag click event to trigger an ajax call, and I don't want the link to physically go anywhere, what is the correct value for the href attribute?   Is it '#' or just leave it empty?  (I understand the accessibility issues that this brings).


If I'm moving at half the speed of light $c/2$, and another object with $c/2$ in the opposite direction, will I move with speed of light?

... c/2-(-c/2)=c relative to the other object?  (title character limit)  Alternatively  If my speed is c/n to the object behind me, which also has c/n to the one behind it and so on I should have a speed of c to the observation of the nth or so object behind. If n is a large number none of the objects are moving unreasonably fast themselves. There's a bunch of stuff in the universe so there should be an object moving with c with respect to another, maybe even faster.  And if this is wrong does it mean that c is the maximum relative speed something can reach, so there's a region of possible speed differences that are possible such as (x,x+c), so everything in the universe is limited to a speed "range"?  I barely know anything about relativity and this might be a little ignorant of a question, but I don't know a way to efficiently research something like this other than asking people.


I have a section in a form of inputs, quanitity, price and tax.  I can add them together for 1 row fine, where I get stuck is per additional row.  JSfiddle:   html:

    <select class="form-control" name="prod_name[]">     <option value="x">Platinum subscription</option>    </select>

    <input type="text" name="quantity" class="form-control" />

     <input type="text" name="price" class="form-control" />

     <input type="text" name="tax" class="form-control" />

&pound; 0

     Remove

  <button class="btn btn-lg add_product_button">Add product</button>
   JS  $('[name="tax"]').on('input', function() {  var quantity = $('[name="quantity"]').val();  var price = $('[name="price"]').val();  var tax = $('[name="tax"]').val();  var subtotal = quantity * price;  var tax_total = (subtotal / 100) * tax;  var total = subtotal + tax_total;  $('.total').text(total); });   My amended code (which doesn't work) is:  $('.prod-new-row').each(function() {  $('[name="tax"]', this).on('input', function() {   var quantity = $('[name="quantity"]').val();   var price = $('[name="price"]' ).val();   var tax = $('[name="tax"]').val();   var subtotal = quantity * price;   var tax_total = (subtotal / 100) * tax;   var total = subtotal + tax_total;   $('.total').text(total);  }); });   Thanks in advance for any pointers.


Denoising is giving my strange artifacts

I have this material, that is a subsurface and because some reason when the denoise is applied it gives my really strange artifacts only in the red parts(the oxidized metal is other object).


Test the convergence of the series   $\frac{1}{3}+\left(\frac{1}{3}\right)^{1+\frac{1}{2}}+\left(\frac{1}{3}\right)^{1+\frac{1}{2}+\frac{1}{3}}+\cdots$   The $n$-th term of the series is $t_n=\left( \dfrac{1}{3}\right)^{1+\frac{1}{2}+\frac{1}{3}+\cdots+\frac{1}{n}}$.    Now, $\dfrac{t_{n+1}}{t_n}\to1$ as $n\to \infty$. Thus D'alembert ratio test fails. How can I check convergency?  Added: The given solution is quite complicated. I am looking for a simpler one.


My question is: given an abelian group $G$ with addition $+$, is there some natural multiplicative structure that arises so that we can define a ring $(G, +, \cdot)$. For instance, multiplication on $\mathbb{Z}$ and $\mathbb{Z}_n$ are entirely determined by addition, since it must be that $ma = a + \ldots + a$, where the addition is $m$ times.  For finitely generated abelian groups $G$, we know that its representation according to the Fundamental Theorem of Finitely Generated Abelian Groups is  $$G = \mathbb{Z}_{p_1^{r_1}} \times \ldots \times \mathbb{Z}_{p_n^{r_n}} \times \mathbb{Z} \times \ldots \times \mathbb{Z}$$  Since each of those factors has a natural ring structure, we can define a ring structure on $G$ as the product of these ring structures. That leaves the question: can we define a "natural" ring structure on infinitely generated abelian groups $G$?


Is there a "first" pureblood in the Harry Potter Universe?

I was reading the question and answers found  and I realized something. Distinction between half-bloods and pure-bloods were done using Third Reich rules for Jews. Well in order for magic to exist a "first" Wizard (or witch) should exist. The specific first was muggle born. Given that the first was alone his/her children would be half bloods. If he/she was not alone (let's say another one was created from another family) their children were both descendants of muggle borns.   So in theory all magicians in the magic world are descendants of muggle borns. Unless In the whole harry potter universe exists a "creation/evolution" theory in which the first wizard/witch descended from a different kind of species (or created by god alongside adam and eve even though I do not accept the creationists theory IRL, I would accept it in mythology).  Is there a canon answer to this? Are all Wizards descendants of Muggle borns?


I deleted 11 rows and I want the auto increment id values to reset to 6,7,8,9 … How can I achieve that without using the update statement each row one at a time. I want to find out if there is a way to avoid this sort of issue in the beginning when creating the database.


(Markov Chains)Help finding another stationary matrix using the hint provided in the book

This is my first post here so I apologize if I format something incorrectly.  So I have a transition matrix P, $$         \begin{matrix}         .7 & 0 & .3 \\         0 & 1 & 0 \\         .2 & 0 & .8 \\         \end{matrix} $$ and I have two stationary matrices R and S respectively,  $$         \begin{matrix}         .4 & 0 & .6 \\                \end{matrix} $$ and $$         \begin{matrix}         0 & 1 & 0 \\         \end{matrix} $$  I was able to prove that they are both stationary matrices by showing SP=S and RP=R but the next question asks me to find $\mathbf another$ stationary matrix for P using a provided hint. The hint is  $$         \begin{matrix}   \\T=aR+(1-a)S, \\  0<a<1         \end{matrix} $$  I am unsure how to get a stationary matrix from that. Do I just multiply the R matrix by a and then multiply (1-a)S and then add the two resulting matrices together? If I do that then I end up with 1-a in the matrix and that just confuses me more. Sorry if this is supposed to be basic stuff, I always struggle with math :/


What algorithm does Stack Exchange use to determine if a question may be subjective?

I was asking a question in serverfault.com and this message warned me (correctly!):     The question you're asking appears   subjective and is likely to be closed   So, I'm curious if there any classifier or machine learning technique behind, or if it is just some heuristics on keywords.  Do you know?


I just installed symfony on Ubuntu 16.04 (cli) server, but I want to upgrade my php version from 7.0 to 7.2 . On Ubuntu I'm getting following unmet dependency issue while running sudo apt-get upgrade  Reading package lists... Done Building dependency tree Reading state information... Done You might want to run 'apt-get -f install' to correct these. The following packages have unmet dependencies:  linux-image-extra-4.4.0-138-generic : Depends: linux-image-4.4.0-138-generic but it is not installed  linux-image-extra-4.4.0-142-generic : Depends: linux-image-4.4.0-142-generic but it is not installed  linux-image-generic : Depends: linux-image-4.4.0-143-generic but it is not installed or                                 linux-image-unsigned-4.4.0-143-generic but it is not installed                        Recommends: thermald but it is not installed  linux-modules-extra-4.4.0-143-generic : Depends: linux-image-4.4.0-143-generic but it is not installed or                                                   linux-image-unsigned-4.4.0-143-generic but it is not installed E: Unmet dependencies. Try using -f.   how can I fix this


I took a course of Linear Algebra, but it was too basic (it only covered some elementary concepts of matrices and vectors). I am planning to purchase one of the three: Axler's Linear Algebra Done Right, Friedberg's Linear Algebra or Shilov's Linear Algebra. After one of those, I will read Hoffman's Linear Algebra, which I have learned is some advances Linear Algebra.  The topics I learned were the row echelon form, matrices operations, linear equations, inverse matrices, determinants, basic concepts of vectors, eigenvalues and eigenvectors. I want, however, to focus on the theory of it, rather than the applications (which is why I have not considered Strang's).  My Calculus course, however, has been very deep, so I consider myself able to learn proof-based mathematics books.  So, concluding, which of these three books would you recommend to me to read.


How to search through and list files that do not contain specific phrase

I am running the same job on around 1000 input files. Around 10% of these will fail, but the only way of checking this is to scroll through the output files and check if it states completed without error. To save time is there a way of using the grep command to   Search in a directory specifically through output files only (named oxxxxx), for those that do not contain the phrase completed without error, listing these oxxxx files in the terminal window.   Thank you!


how to prove this result.     $\alpha$ is limit ordinal if and only if $\beta<\alpha$ implies $\beta+1<\alpha$ for any $\beta$.   I am getting confused because of the definition of limit ordinal. it says     $\alpha=\sup\{\beta: \beta<\alpha\}=\bigcup\alpha$    for sup I am ok but for $\alpha=\bigcup\alpha$ how ??


In the Longman Dictionary I have found the following sentence:                                                                                'Try phoning Robert-he should be home by now.'                                                                                Can I say:'Try to phone Robert – he should be home by now'?Is this sentence correct?In case it is correct, do these two sentences have exactly the same meaning?


Polarizers: Linear vs Circular. How does it affect a photo?

Trying to decide which type of polarization filter I should get.  Some information I've read suggests that there is no difference and that a circular polarizer is just an ordinary linear polarizer, but a circular piece of film that can be rotated in order to adjust the phase of the filter.  Others seem to suggest that it is the result of two linear filters, aligned 90° out of phase. Like this  page, located on the Georgia State University network:      If light is composed of two plane waves of equal amplitude but differing in phase by 90°, then the light is said to be circularly polarized.    It goes on to say:     Circularly polarized light may be produced by passing linearly polarized light through a quarter-wave plate at an angle of 45° to the optic axis of the plate.   I've probably misunderstood something about the fundamentals of how it all works, or got something backwards. But was hoping someone could demonstrate the difference it makes in terms of the result it has on a photograph, rather than trying to explain with diagrams. Thanks.


I am an Indian national living in London. I need to travel to Israel for work. I will need to apply for a visa but I have been told that it will be stamped in my passport. I have read that Israel knows of the problems travellers face in other Arab countries so they issue a paper visa but the embassy in London told me that it will be stamped in. I travel often in Middle East for work and I do not want any issues in the future. Please advise.  Thanks.


Scifi novel where God invents the rules of physics as men discovers science, and gets overwhelmed by the complexity of it

Trying to find this book I read probably something like 15-20 years ago. I can't recall if it was a full book or just a short story in a collection. I think the later. It's also possible I read it in French (can't recall), but maybe it was translated. God has to come up with explanations as men discover science, creating new rules as he goes (like men are trying to understand what matter is, so he creates atoms, then men probe the atom and he comes up with quarks, etc...). God gets entangled in what is like a complex web of lies where everything must still make sense and work together, and it becomes harder and harder for him to keep track. Evil influences men so that they try to understand more and more and direct them to the fragile parts of God's design. At some point near the end, to prevent a nuclear apocalypse, god divides the speed of light in half (because E=mc2) and earth is plunged in darkness for a few minutes, until the light from the sun arrives again. The story ends with evil winning and God starting over again with "something that has a square orbit". I recall there was a drawing of a square orbit in the book (like earth orbiting the sun, but square).


Recently I've brought a caddy for my Lenovo Ideapad 510 to fit in the HDD. Currently using Samsung SSD 850 EVO 240 GB for windows.  Just few days back, I'm starting to see weird icon near the drives in explorer. And I've seen this problem after installing caddy. Even searched about it, but looks like no one is having similar problem as like me.  If somewhere have any idea, please do tell. Thanks


How to sort array containing objects by those object keys

I have such an array that I need to be able to sort by keys ASC and DESC  Array (     [0] => stdClass Object         (             [id] => 2323             [regno] => 45101008785             [regdate] => 1993-03-26         )      [1] => stdClass Object         (             [id] => 2322             [regno] => 49201003827             [regdate] => 1992-04-08         )      [2] => stdClass Object         (             [id] => 2318             [regno] => 240100720             [regdate] => 1992-10-01         )      [3] => stdClass Object         (             [id] => 2317             [regno] => 900100881             [regdate] => 1992-12-28         ) )   IE, if client sets GET parameters to ?sort_by=regno&type=asc, I need to sort this via PHP to:  Array (      [0] => stdClass Object         (             [id] => 2318             [regno] => 240100720             [regdate] => 1992-10-01         )      [1] => stdClass Object         (             [id] => 2317             [regno] => 900100881             [regdate] => 1992-12-28         )      [2] => stdClass Object         (             [id] => 2323             [regno] => 45101008785             [regdate] => 1993-03-26         )      [3] => stdClass Object         (             [id] => 2322             [regno] => 49201003827             [regdate] => 1992-04-08         ) )   How is this done?


Changing Engineering Specialisations after Undergrad

I am wondering whether it is generally possible to change engineering specialisations after completing a bachelors degree.  I'm currently completing a bachelor of engineering with honours in chemical and materials engineering. I am interested in completing a master's in aerospace engineering as I have a significant interest in aspects of jet propulsion.  I feel there would be a lot of transferable skills which may help me - i.e. thermodynamics, fluid mechanics, pumps and turbines, heat transfer, and materials; although they would be applied in a different context.  I guess my question is, as long as there are some transferable skills to your field of research, can one change specialisation without significant difficulty at the postgraduate level?


Why hydrogen's absorption spectrum have certain wavelengths dark?

Hydrogen absorption spectrum has dark lines at about 656nm, 434nm, 410nm , etc. I have been told that these are dark because hydrogen has absorbed the light of these particular wavelengths, as these wavelengths correspond to the energy difference of energy levels of hydrogen atom. But wouldn't these photons be re-emitted? And so, there shouldn't be any lines missing(dark) in the spectrum. Plz Help Me out what am I missing?


What do the numbers after skills indicate?

I have several Pidgeys, with different skill combinations:   Tackle 12 / Aerial Ace 25 Quick Attack 10 / Aerial Ace 25 Quick Attack 10 / Air Cutter 25 Quick Attack 10 / Twister 15   Note that 3 of them have a '25' value second move, while the last one is a '15' value Dragon type move. Also, Air Cutter and Aerial Ace have 4 blue bars after them while Twister has 5.  Do the bars or numbers represent the strength or charging speed of those skills? I thought maybe numbers after regular skills charge the special move bar at that rate, while the number after the special skills depletes the move bar.


How can I prove this logical statement is a tautology using logical equivalence laws.

I used a truth table and it showed that this is a tautology, although I am unsure how to prove this through logical equivalence laws.  Your help would be greatly appreciated.  Below is the logical statement.  ((p ∨ q) ∧ (p → r) ∧ (¬r)) → q


Could anybody help me install OOF 1 on my Ubuntu 16.04 virtual machine?

I installed a Ubuntu virtual machine that I need to use OOF 1 (available at this link:  ), a programme for microstructural analysis from the NIST. I have never used Ubuntu in my life and after a couple of hours of trying I still don't even understand the readme file given in the download folder. Could anybody help me? Thank you very much


This is my build:   Level 1 – Warlock 1 -  otherworldy patron, pact magic  Level 2 – Warlock 2 -  eldritch invocations Level 3 – Warlock 3 -  pact boon  Level 4 – Paladin 1 -  divine sense, lay on hands Level 5 – Paladin 2 -  fighting style, spell casting, smite   If I understand correctly I am character level 5 but class level 3 Warlock and class level 2 Paladin.   This means that Eldritch Blast will make 2 ranged attacks as I am character level 5, but I do not get an ability score improvement at level 4 because I get that at class level 4.   Is this correct?   EDIT: my players have started multi classing and this is an example character I made to try to understand the rules better.   The comment that Profecincy bonus used character level and not class level is the kind of information I was looking for.   I guess my question would be close to: using the build above what do I count as level 5 for?


How to split a dictionary into "n" parts

I need to split my dictionary using LINQ expression. I need to split into two parts. Could somebody help me?  var myDictionary = new Dictionary<int, int>(); var halfOfDictionary = myDictionary.ToDictionary(...)


Drop a stone in the pond...a wave propagates radially from the source. The conservation of energy says the wave must decay proportionally to the radial distance. If I drop a steel I-beam in the pond, the same concept holds, only it can be considered a finite linear array of point sources. If the energy must still decay radially, then how do plane waves ever form?  I know we can generate them in labs and obviously express the math, but in nature, do plane waves really exist?  OK...so let's assume it was an infinitely long I-beam. Then I guess you could argue you get plane waves. But look at the assumptions: 1) infinite I-beams don't exist (nothing is infinite) and 2) you have to assume there are ZERO irregularities in the I-beam. These concepts are purely mathematical.  OK...OK....you're "zooming in" on the radial wave and it appears like a plane wave. But do you account for the fact that the wave must always be decaying in time (assume there is no external dissipation involved)?  Restating the main question...do plane waves really exist in nature? If they don't then why do they show up in theories? (Good example is plane waves hitting an open slit for diffraction studies...you started with something that is conceptual, not physical?)


Angular momentum conservation in pion decay?

I have seen the charged pion decay $$\pi^{-}~\to~ \bar{\nu}_{\ell} +\ell^{-}$$ represented with diagrams containing a $W^-$ in the $s$-channel.  The $\pi^-$ and $W^-$ have angular momentum $0$ and $1$ respectively, though. How does this process conserve angular momentum?  I see that this question has been asked before, but I haven't found an answers.


How to troubleshoot a computer not booting up when powered on?

I can turn on my computer and sometimes it will boot up just fine. After a while of use, days or even a week, when I try to turn it on, it powers up, in that the fans spins up, the power indicator light at the front comes on (although orange, it is usually green), but it will not boot, the screen remains black and never comes on.  If I leave it for a couple days, and try it again, it comes back on, and the cycle starts over.  I have no parts for that computer that I can currently swap out to test. I have tried removing the RAM or using one stick to see if it would get any further in the process, but to no avail.  I suspect I may have a motherboard or power supply problem.  What could cause a situation like this and are there any solutions?  Edit: There is no beeping when it boots, the only thing that happens is the fans spin up and the power indicator comes on orange.


Why don't Stack Exchange sites use a rich text editor?

Why does the Stack Exchange network of sites use Markdown instead of some other rich text editor like FCKEditor or TinyMCE?


Run my bash script on login and SEE terminal

i need your help :) I have some script that start on login (I set it on Application launcher preference) but i can't see terminal. One script it's easy and make light on on my CMstorm keyboard and set numlock to ON. Another script (too long) check update for every row with Internet, but i can't able to see if the process are in download mode or if script end. I would like this script open terminal and run it into the terminal, in this case i will be able to see what script are doing.  My script is in $home/Desktop/Elaborati/script1.sh I think it's necessary to create another script that lauch script1.sh in a new gnome-terminal...but I'm not able to do it.  Can you help me please  Thank you very much


I have a question regarding tension in a rope.  Consider a situation where two masses $A$ and $B$ are tied by a massless string on a horizontal plane with no friction.  Suppose we pull mass $A$ by a force $F$ then the string exerts a backward force on the block; assume $T$.  An equal amount of force is applied by the block on the string, which pulls the Block $B$ with force $T$.  The Block $B$ exerts a force backward on the string with magnitude $T$.  So far the argument seems good, but why do we stop here?  This backward force again pulls $A$ backward by the string.  The string is again pulled forward by $A$ by Newton's Third Law, which again results in the same process...Thus there are forces acting in infinite directionsbetween the boxes..?  Where is the problem in the argument?


Are there differences between the different country's editions of Cards Against Humanity?

Cards Against Humanity has different country editions, like UK, US, and AU. Are there differences between these editions other than grammar? What are those differences?


Checking what changed inside updated shapefile

I am using different shapefiles from open data in Switzerland. They have just updated the whole set. My question is: how to compared two layers (new and old version)? I would like to know the differences in geometry, as well as attributes. In the data there are points, lines and polygons and some of the sets contains a big amount of features (more than 300 000 elements). I have already checked all the simillar questions, but they all focus on creating the third layer with differences or particular layer example. What I want to know is just what has been changed. I am working with QGIS 2.14.3 and i am familiar with Python.


echo hello && $(echo "world") fails with "bash: world: command not found"

the full command is % echo hello && $(echo "world"), where % is the shell prompt. why does this fail? I've noticed that the error is the same as if I had run the command substitution directly on bash as % $(echo "world")


Maximum distance and speed for communication in StarTrek franchise

In the middle of  an alien ship is detected on long-range sensors. Worf says, that it travels with Warp 9.72 on interception course and it will take 10.53 hours to meet it.  We don't know the exact relativistic speed equivalent of Warp 9.72, but , that it is more than Warp 9, i.e. more than 1516.381 c. This speed (according to ) allowed to travel 4.152 light years in 24 hours. (4.152 / 24) * 10.53 = 1.82169 light years of estimated distance between Enterprise and that alien ship. And yet, Worf was ordered to try to hail them.  Is it really possible (in StarTrek franchise) to estabilish audio communication and "talk" to a ship, that is nearly two light years ahead and travels more than 1500 times faster than light speed?


If $n$ is an odd integer, then there exist integers $a$ and $b$ such that $n=a^2-b^2$.  Am I supposed to use induction or a direct proof?


This question  mentions that the clones still have their sex drive.  But  mentioned in the text only adopted children, he didn't actually father them.  If the clones were able to produce children they might have more cause to abandon the clone wars.  Could the clones reproduce the old fashioned way, or were they deliberately sterilized?


I read in book recently that when a glass rod is rubbed with a silk cloth, some sort of 'electrostatic interaction' take place that both of them acquires a net electric charge. It also said that the negative charge (electrons) are more mobile than the positive charge so what was going on is simply 'electron transfer' between silk cloth and glass rod. But I had read in chemistry that electrons are held tightly within the atom and breaking that bond (covalent or ionic) releases large amount of energy. Now, how come simple mechanical rubbing provide that sort of energy that electrons escape the atom? I don't know whether my understanding is correct. Please enlighten me!


How to mount /system rewritable or read-only? (RW/RO)

How can I mount the /system directory rewritable or read-only on my Android phone?


How to check which type of data stored in a variable in python?

I am very new to Python.Is there any method through which i can find out which type of value is stored in a particular variable?  In below code how to find out type of stored value in a variable?  counter = 100           miles   = 1000.0        name    = "John"      name    =10   print counter print miles print name


Canon flash plus Canon trigger on Nikon body will it work?

I was Canon user before but now I bought Nikon body . I have a third party flash along with dedicated Canon trigger and receiver and I want to use that flash remotely with those trigger can sync cable will solve my problem?


I've just answered a question wrongly, but unlike on the regular site, there's no option to delete my incorrect answer.  Although fairly minor, it would save me having to find a computer or use safari (which is far more fiddly)


Deleting symbolic links - Logics and how to

First, Happny new year all here! I'm very new to UNIX\Linux and I've mistakenly created the following Symlink:  sudo ln -s /etc/phpmyadmin/apache.conf /etc/apache2/conf-enabled/phpmyadmin.confservice   What is the right way to delete it and what is the logic behind it?:  I understand I should do unlink ***something*** command inside the folder /etc/apache2/conf-enabled/ and after I navigated to it... Therefore I ask:   why is the deletion action done based on the second path and not in the first one ... ? Usually, is something else be written there besides the file name?   I'm afraid to make damage therefore I ask this...


Using the default screenshot provided with Ubuntu 18.04, any screenshot of all my screens, or specific windows will cause the image to be saved to $HOME.  By default, the dconf value for /org/gnome/gnome-screenshot/auto-save-directory is '', which seems to be the home directory. Changing the value to either of the following has no effect:  /home/user/Pictures file:///home/user/Pictures/   Replacing user for $USER makes no difference, either.  Is there a way to work around this? Alternatively, is it possible to set a command line option to save images to a specific directory, like:  gnome-screenshot -save /path/to/save   If so, I can simply bind the print screen key as such. However, I saw no mention of such an option in the man page.  I've noticed some similar questions which are a few years old have stated there was some bug involving this. I'm not sure if the bug would have existed for that long, but I'd assume it would have been solved by now if that was the case.  Perhaps something else might be overwriting the setting? Or am I making a false assumption that gnome-screenshot is being used? I haven't installed any screenshot related packages though.


A good Linear Algebra Book for Someone with a rigorous background in it?

Tl;dr: Took a rigorous linear algebra 2 years ago, forgot most of the stuff now. Trying to resharpen my LA skills, so looking for a suitable LA book.  2 Years ago, I took a very rigorous course in Linear Algebra and Abstract Algebra. We covered content such as Groups/homomorphisms, fields, rings, vector spaces, subspaces, linear transformations, rank/nullity, isomorphisms, matrix arithmetic, representation of linear maps by a matrix, computational algorithms, dot product, inner product spaces, determinants, spectral theory, and the Cayley Hamilton theory.   The course was very proof heavy, and I came out of the course with a solid understanding about the theory of linear algebra.  Fast forward 2 years later, I am trying to resharpen my linear algebra skills. I tried reading Strang's book but I got demotivated very quickly because I felt I was benefiting very little (as I remembered most of these stuff). However, at the same time, I have forgot lots of elementary bits and pieces in the middle so I can't say I remember everything!  So I guess what I am trying to ask is, is there a suitable book for my case which still starts with the basics but picks up the pace quickly, while still covering most of the elementary content?


Let a sequence ${[a_n]}$ be defined such that $a_1=1$ and when $n\ge1$, $a_{n+1}=a_n+\frac{1}{a_n}$. Then, show that:$12<a_{75}<15$

Let a sequence ${[a_n]}$ be defined such that $a_1=1$ and when $n\ge1$, $$a_{n+1}=a_n+\frac{1}{a_n}$$ Then, show that:$$12<a_{75}<15$$ (the bracket in ${[a_n]}$ does not denote GIF, it is a general sequence)  All I got to know was that using the recursive relation we get:$$a_{75} = a_1+(\frac{1}{a_1} + \frac{1}{a_2}+\frac{1}{a_3}+\frac{1}{a_4}+...+\frac{1}{a_{74}})$$ I do not know how to proceed further. When I tried to express everything in form of $a_1$, it is becoming too messy and complicated. Like: $$a_2 = a_1 + \frac{1}{a_1}$$ $$a_3 = a_1+\frac{1}{a_1} +\frac{1}{a_1 + \frac{1}{a_1}} $$ $$a_4 = a_1+\frac{1}{a_1} +\frac{1}{a_1 + \frac{1}{a_1}} + \frac{1}{a_1+\frac{1}{a_1} +\frac{1}{a_1 + \frac{1}{a_1}}}$$ $$a_5 = a_1+\frac{1}{a_1} +\frac{1}{a_1 + \frac{1}{a_1}} + \frac{1}{a_1+\frac{1}{a_1} +\frac{1}{a_1 + \frac{1}{a_1}}}+\frac{1}{a_1+\frac{1}{a_1} +\frac{1}{a_1 + \frac{1}{a_1}} + \frac{1}{a_1+\frac{1}{a_1} +\frac{1}{a_1 + \frac{1}{a_1}}}}$$ And so on... Any hints or help would be appreciated!  This question has to be done without using induction.


Let $a,b,c$ are real number such that $a+b+c=1$. Prove that: $$\frac{a}{a^2+1}+\frac{b}{b^2+1}+\frac{c}{c^2+1} \leq \frac{9}{10}.$$


For example, I have an object with 3 properties: Name, Price and Description. I need to sort a collection of these objects. It's easy to sort by only one parameter:  var sortedList = ObjectCollection.OrderBy(x => x.Name).ToList();   But how to perform the sorting by 2 parameters (Name and Price). For example, I need to get a list like that:  ItemName1 $100 SomeDescription ItemName1 $200 AnotherDescription ItemName1 $250 AnotherDescription ItemName2 $20 AnotherDescription ItemName2 $40 Description ItemName3 $100 Description   and so on. So, the main key is a Name, but if there are several items with the same name then the second key is the price. How to do this?


We have a derivative function $f$ with for every $c$ element of $\mathbb{R}: |f'(c)|<M$. I tried to prove that prove that $\displaystyle \left|\int_{0}^{1}f(x)\mathrm{d}x-\frac{1}n \sum_{k=0}^{n-1}f\left(\frac{x}n\right)\right|\leq\frac{M}{n}$. I really have no idea how to start. I'm trying to use integral , derivative, sums ... so my paper is full of definitions but i can't use one. Can someone give me a hint how to start with this question so that i can move on. I'm really sorry i can't give a proper prove that i have already found but i'm stuck at the beginnin already.


I have been told to avoid using Environment.TickCount() as it overflows in about a month of uptime and can mess up my code, so I was wondering if DateTime.Now.Ticks() would be a safer choice for long terms ? I mean when will it overflow ?


I have a few circumstances which invlove someone being shocked with 20 watts of electricity and whether it would be deadly. So here they are:   Would 1000 volts at 20 miliamperes of AC (2MHz frequency) be dangerous or deadly? Would 1000 volts at 20 miliamperes of DC be dangerous or deadly? Would 10 Kilo volts at 2 miliamperes of AC (2MHz frequency) be dangerous or deadly? and Would 10 Kilo volts at 2 miliamperes of DC be dangerous or deadly?   Thanks for everyones help.


Who gets the "Was this post useful to you?" feedback?

I just read . I found the explanation very clear and interesting, but I don't want to create an account on that site. So, I clicked Yes by "Was this post useful to you?"  Who will get that feedback?


I am using a LM317 to create 12V into 7V which is driving a load that draws 1A. So I have to dissipate 5W from my voltage regulator. Datasheet is .  According to the datasheet Rja is 65 C°/W (Case 221A) so the heat on the chip is 65*5=325C° which is way too much obviously.     So I need to choose a heat sink but not sure how. One confusion I have is, each heat sink has a thermal resistance associated with it but I'm not quite sure what to do with that number or what to calculate next.  If I pick a heat sink with a thermal resistance of lets say 4 C°/W then does that mean the heat on the chip will simply be 4*5=20C°? So I've solved the temperature problem?


Explicit construction of a finite field with $p^n$ elements

I'm trying to understand the following explicit construction of a finite field with $p^n$ elements where $p$ is prime, $n \geq 2$:  Take any irreducible polynomial $f(X) \in \mathbb{F}_p$ of degree $n$. Then $\mathbb{F}_p[X] / (f(X))$ is a field with $p^n$ elements.  Now, I understand that if $f$ is irreducible, the ideal generated by $f$ is maximal, so $\mathbb{F}_p[X] / (f(X))$ is indeed a field.  I don't understand the following points:   Why does for every $n \geq 2$ an irreducible $f(X) \in \mathbb{F}_p[X]$ of degree $n$ exist? Why does the field $\mathbb{F}_p[X] / (f(X))$ have $p^n$ elements?   Thanks in advance for any help!


Why the C++ used in Borland is so different?

I learned C++ in my highschool on Borland C++, and used textbooks which referred to the same. So the basic C++ I know doesn't even work on most IDEs I have tried. For example, I was using hackerrank the other day and I got an error because I used cout<<""Hello!"; which is what I learned in school. But the only way the program started working was after I changed it to std::cout<<"Hello";.    I am stuck here wondering what I should do now.    I want to get back to C++ programming and this time the right way. So any suggestions?    Also, explain the difference in the above code samples and in standard way of C++ programming and Borland way of programming.


How to find the documentation for a package?

Where could I find the  Tikz Manual version 3.0.1a as a PDF file ?  More generally, how do I find the documentation for a package.


I am not sure why but when I get a string from the user, I cannot compare it in an if statement but when I try to print it, it works fine.  Part of my code:           Scanner in = new Scanner(System.in);          while (true) {              String userInput;              int rowInput, colInput;              printBoard(board);              System.out.print("Move: ");               userInput = in.next();               // shift board right on a row              if (userInput == "r") {                  System.out.print("row #: \r");                  rowInput = in.nextInt();                  moveRight(--rowInput, board);              }   Does anyone know why this isn't working as expected?


Convert String to Time Java.sql.time error

I want to convert a string to time using the parse method which is going to be inserted to database later. But I get: Incompatible Types: Java.util.date cannot be converted to Java.sql.Date. Any Solution?  String s = time.getText();     DateFormat sdf = new SimpleDateFormat("hh:mm:ss");     Date d = sdf.parse(s);


remove lines with sed that follow a particular line

I am trying to remove all (including new lines) content with sed that comes after the following text in a file (/etc/sudoers):  #includedir /etc/sudoers.d


I'm taking a course and the instructor has beveled an edge and I cannot get the same result. My bevel only bevels on segment on one side then the rest, about 4 or 5 segments bevel on the other side. Other words the bevel is not beveling evenly on the top of a cylinder. Pictures below


Beamer: how to display item one at a time BUT also hide the first item

There are many answers as to how to show item one item at a time in Beamer  But these answers do not address the case where I want to hide the first item as well (start with a completely blank slate). The first item is always displayed when you use the following code. \begin{itemize}[<+->]  ... \end{itemize}  I tried to put it in a \only<> block. However, this causes the itemize to display two items simultaneously. Is there anyway to address this problem?


Let $G$ be a self-complementary graph of order $n$, where $n ≡ 1 \pmod{4}$. Prove that $G$ contains an odd number of vertices of degree $\frac{(n − 1)}{2}$.    My approach   Let $G$ be a self-complementary graph of order n, where $n=4k+1$ i.e. $n$ is odd.   Now size of $G$ is $\frac{n(n-1)}{4}$.   Now if $V(G)=\{v_i:1\leq i \leq n\}$.   Now $\sum d(v_i)=\frac{n(n-1)}{2}$=even.   Then what can i do?


Finding $f(x)$ from a functional equation

This sum really looks scary to me. No idea how to begin. I just figured out that $f(0)$ is $0$. What's next?     Let $f:\mathbb R \rightarrow \mathbb R$, such that $f'(0)=1$ and $$f(x+2y)=f(x)+f(2y)+e^{x+2y}(x+2y)-xe^x-2ye^{2y}+4xy$$ for all real $x$ and $y$.   Find $f(x)$.   P.S: Please don't use very high level maths.


I try to use  (versions 3.0.13, 3.0.11, 3.0.10, and 3.0.9) in QGIS 3.12.1, none of them are functioning.  Your suggestion would be of great help.


How to get a toddler to start chewing and eating solids?

My son is 18 months old and still doesn't want to chew and eat solid foods. We have to blend soups and other food into purée for him to accept it. If there is even a slight solid, he will automatically push it out of his mouth with his tongue.  I have had a breakthrough with breakfast where I don't blend as much and leave it a little chunky. He ate it but still pushed chunks of soft banana that were bigger out.  Some of my friends have kids that are 4-5 months younger, who are eating chicken cutlets.  Any ideas or proven methods for getting a child to start eating solids?


This is from and exercise of probability theory:     Let $(X_j)_{j\geq 1}$ be independent and let $X_j$ have the uniform distribution on $(-j,j)$. Show that   $$ \lim_{n\to\infty}\frac{S_n}{n^{3/2}}=Z\sim N(0,\frac{1}{9}) $$   in distribution.    In terms of characteristic functions, it suffices to show that $$ \lim_{n\to\infty}\prod_{j=1}^n\frac{\sin(jn^{-3/2}u)}{jn^{-3/2}u}=e^{-u^2/18}. $$ Take $\log$ on both side one gets: $$ \lim_{n\to\infty}\sum_{j=1}^n\log\frac{\sin(jn^{-3/2}u)}{jn^{-3/2}u}=-\frac{u^2}{18}. $$ How can this limit be proved?