I recently posted a version of the twin paradox with a twist but here I'd like to propose a new thought experiment all together. Take two clocks, A & B, and place A 1 AU away from B. Once the clocks are separated and stationary relative to each other sync them up again; to do so send a light pulse from A to B, and when the pulse reaches B the clock will start ticking while A waits the exact amount of time it takes light to reach B to start ticking. The idea is to have two clocks that are in sync but separated by a large distance, and I imagine there are multiple ways to do this. Now take a third clock, clock C, which is also synced with A and B and have it travel the distance between A and B at .866c so that time runs at 1/2 the rate for clock C. However to Clock C, A & B would be running at half speed. When it arrived at B though we'd be able to compare the elapsed times and say for sure whether C or A & B had in fact been running slower, even though special relativity dictates both viewed each other as running slower and both are correct. The only decent explanation I can think of is that for C, simultaneity between A & B is broken rendering B's readings inaccurate, but that still leaves us in a very bizarre place as ultimately to C, B should read half the time and to B, C should read half the time.  *Note: Please don't try and use acceleration to explain the disparity, it is a common misconception that acceleration resolves the twin paradox when its actually that acceleration is used to confirm the change in reference frames. To avoid that conundrum all together you can imagine that clock C was already up to speed when it passed A and synced itself up with A as it passed C. Furthermore we can imagine C never actually slowed down when it passed B, rather it just took the reading from B to compare. This way C is in one inertial frame for the entire duration of the experiment.

So I've been doing a lot of reading about the twin paradox and have encountered several different explanations that strive to resolve it. First off let me start by saying general relativity is not an adequate explanation and in fact has nothing to do with resolving the paradox. (That much has been made clear to me from what I have read, as it has been pointed out that believing general resolves the paradox is a common misconception) To drive that point home let me propose a slight variation on the twin paradox that removes acceleration all together.   Some ancient race of aliens long ago set up an experiment for us without our knowledge to help us understand space time. The experiment contains two space craft with clocks on board separated by a very large distance. The first clock, clock A, was accelerated to .866 speed of light millions of years ago (Thus time runs at half speed) and is set on a trajectory to fly past earth. As it flies past earth it resets its clock to 0 and continues on its way. (The aliens also left behind a clock on Earth, clock C, that starts ticking the moment Clock A passes earth and resets itself to 0) The other clock, clock B, was also accelerated to .866 the speed of light long ago and is on the same trajectory as clock A but in the opposite direction so that it heads towards Earth. The two ships and their respective clocks pass each other at a distance of four light years away from earth at which point clock A transfers its time reading to Clock B. Clock B flies past earth and relays its time measurement so as to be compared to Clock C. The time reads half the time elapsed by Clock C, but how could this be possible if time dilation is always symmetrical?


I tried to rename Microsoft Edge folder.  Doesn't work because I am not given the option of becoming administrator.  Any other ideas?

Is there any possibility to completely disable the new Edge browser? The old IE could be disabled in Settings → Default Programs, but in Windows 10, the checkbox is missing for Edge.  Is there any way to get rid of Edge, or at least to disable all entry-points?


I need to build out a new server with long term support.  Ubuntu 14.04 LTS is in Final Beta. See .  I'm OK with using a Final Beta before the Release build is released. But I'm not clear if there's an upgrade path from the alphas and betas to release. (If there's no upgrade path, I'd prefer not to use it since this includes a mailbox migration).  Question: will there be an upgrade path from 14.04 Final Beta to 14.04 Release?  Note: this could be a duplicate of  If the process for 14.04 is the same as previous, then its a duplicate. However,  does not appear to discuss it.

I installed an Ubuntu alpha or beta and have been keeping it up to date.   So, Should I presume that my system has automatically updated to the next alpha or beta, and will be running the official release when it's finished?


So what I mean precisely: take $(\mathbb{R}, \mathcal{T}_{eucl})$ can we find a function $f$ for every closed $A, B \subset \mathbb{R}$ such that $A \subset f^{-1}(\{0\})$ and $B \subset f^{-1}(\{1\})$ and $f'$ is continious?  I think this makes sense because we can find a continious function $f$ such that this is true, and then redefine $f$ in a small neighboorhood around a point where $f'$ is not continious such that it is smooth, but I can't proof it, and I can't find mentoin anywhere on the internet, so I'm wondering whether this is actually true.

The smooth version of Urysohn's Lemma is      Let $A,B$ be two disjoint closed subsets in $\mathbb{R}^n$ with one of them compact, then there exists a smooth function $f: \mathbb{R}^n\to [0,1]$ such that    $$f(A)=0\qquad f(B)=1$$   For a proof, for example , see .   I'am stuck on the following problems in the smooth version    How about the counterexamples without the condition that "one of them is compact"?  Can we make more strict conclusion that $f^{-1}(0)=A$ and $f^{-1}(1)=B$? Note that it implies $f(A)=0$ and $f(B)=1$.    Without the requirement of smoothness, we can release the condition of compactness and make more strong requirement of inverse image, since we can simply take $f(x)=\frac{d(x,A)}{d(x,A)+d(x,B)}$. Clearly, it is not smooth in general.   The idea of the above link does not holds even for the following regular figure.


I Travelled from DEL to EWR in Jan 2021. After Immigration in EWR, I found out that my passport is not stamped. I cross-checked the i-94 and It was updated. I'm sure that I won't face any issues in USA immigration in the future because of the valid i94 and travel records. But I'm worried about Indian Immigration. Can anyone please let me know should I get a stamped or will I face extra scrutiny with Indian Immigration? It would be really helpful to get input from people who have undergone this situation. Thank you

I recently traveled from India to USA. I am on H1B. I entered USA on 29th December 2016. As my Visa extension is due in August 2017, I was gathering documents for Visa Extension. It was required to provide a scanned copy of passport page with all entry and exit stamps.  Myself and my wife both travelled back from India. My wife's passport has a entry stamp with date as 29th December 2016. But the same is missing from my passport. I guess the officer missed putting the entry stamp on my passport. My I 94 reflects the correct date of entry as 29th December. Somehow I still have my boarding pass from this trip (usually I throw them once trip is complete).   Want to know what could be implications of missing entry stamp when I travel to India next time (somewhere towards early next year)? Does this impact my H1B Visa extension ? Also what can I do to correct this information on my passport?


I have the following snippet         cout.precision(30);         long double d = 85952643841691072928.0;         cout << d << endl;  The print statement outputs  85952643841691074560. Why are the last 4 digits before the decimal incorrect? A long double should be capable of handling a number of this size?

Consider the following code:   0.1 + 0.2 == 0.3  ->  false   0.1 + 0.2         ->  0.30000000000000004   Why do these inaccuracies happen?


As a scenario say, If we suddenly push the ground and release the pressure we will jump off but where does the force coming from?

My father explained to me how rockets work and he told me that Newton's Third Law of motion worked here. I asked him why it works and he didn't answer. I have wasted over a week thinking about this problem and now I am giving up. Can anyone explain why Newton's Third Law works? For reference, Newton's third law:  To every action there is always opposed an equal reaction: or the mutual actions of two bodies upon each other are always equal, and directed to contrary parts.


When I try to make faces from non manifold edges the edge of the model is darkens.      I see the same affect on Unity 3D when I import .blender files. When I add a material to the model the affect doesnt change and the color of the corners stays darkened. How can I prevent this?

I'm currently working on a model of an X-wing that I'm intending for use in a game and running into a bit of trouble with the shading of the mesh. The upper nose is rounded off where the sensor cone attaches, but at the point it reaches the canopy frame it flattens out and meets at a corner.  Everything is fine and dandy when the sides are modeled:    but once I close it off and add the top of the nose, the shading goes to hell:    As you can see, the smoothing gets confused at the lip of the cockpit.  I've tried a couple different means of getting around this, none of which looks right while maintaining the correct shape. The transition from the rounded to flat is a fairly important part of the ship's character, so I don't want to discard the contours, either.  Any tips or suggestions on modeling this area?  Addendum:  If I eliminate that second angle where the canopy frame meets the fuselage as marked in red:    this also fixes the smoothing. However this is not a solution, as the angle is a part of the design. It DOES give me another thought on fixing, but I won't be able to test it until I get home.


I'd like to see the SE term "unupvote" be changed to an actual word.  This may seem like petty pedantry, .  Let's at least make things make sense.  Some suggestions:   undo un-upvote upvote undo

It seems like maybe cancelled downvote might be less...weird?


I was the given the follow definition     Definition: If $D$ is simply connected space then each cycle is homologous to zero   So it we look at a point, let say $p$ in the middle of the ring and on the paths one that is clockwise and the other which is anti-clockwise the cycle is zero, but because we can take $2$ paths that sum up to $\neq 0$ then a ring is not simply connected space?

I don't have complex analysis at my beck and call, and I only have a low level of knowledge in topology, but I need to prove that this metric space (for any real $r$ and $R$ with $r < R$)$$ X = \{ (x, y) \in \mathbb{R}^2 \ | \ r \leq x^2 + y^2 \leq R \}$$  with the Manhattan metric $d((x_1, y_1), (x_2, y_2)) = |x_1-x_2| + |y_1-y_2|$ is not simply connected.  I've already prooven that it's path connected, and now I need to show there are some points $P$ and $Q$ with two paths between them such that one cannot be continuously 'morphed' into the other.  $ \ $  What I have so far is as follows:  I take $P = (0, r)$ and $Q = (0, -r)$, with $f_0$ being a path from $P$ to $Q$ going clockwise around the circle radius $r$ and $f_1$ being much the same but going counterclockwise.  Now I assume there is a function $g : [0, 1]^2 \to X$ such that:   $g(s, 0) = f_0 (s)$ $g(s, 1) = f_1 (s)$ $g(0, t) = P$ $g(1, t) = Q$   To get the final result, I need to show that this function cannot be continuous, but for the life of me I cannot.  For some context, these are the topics which have been visited during the course, roughly in order of recentness.   Multiple connectedness Simple connectedness Pathwise connectedness Interior points Boundary points Open sets Compactness Complete metric spaces Bounded metric spaces Totally bounded metric spaces Closed sets Closure of a metric space Limit points Cauchy sequences Convergence Continuity Metric space quivalence Metric equivalence   Edit: I might have an argument that works, though it's far from rigourous. We can shrink $R$ to be as close to $r$ as we want, so we can essentially constrain the annulus down to a circle and thus force any path from the left side of the circle to the right side to go through $P$ or $Q$.  So holding $s \in (0, 1)$ constant and varying $t$ must produce a path through $P$ or $Q$ for any $s$. If for some $s$ it passes through $P$ and for some other $s$ it passes through $Q$, then there must be $s_0$ such that $\forall \epsilon >0  \ \exists \delta \leq \epsilon$ st. $s_0$ produces a path through $P$ and $s_0 + \delta$ produces a path through $Q$.  Now we can consider the path $g(s, \frac{1}{2})$, and note that it must have a discontinuity at $s_0$.  Now consider the case where all $s$ produce paths through only one of $P$ or $Q$. WOLOG: $P$. Now, at $t = \frac{1}{2}$, $s$ arbitrarily close to $1$ are mapped away from $Q$, but $1$ is always mapped to $Q$ by definition, so $g(s, \frac{1}{2})$ has a discontinuity at $s=1$. Therefore $g(s, t)$ is not continuous.  This argument is definitely iffy to me, if no one has their own argument (using sufficiently low level concepts), then criticism on the above would be appreciated.


Prove: $$F^2_{n+1} - F_nF_{n+2} = (-1)^n$$ I do understand where does $$F^2_{k+2} - F_{k+1}F_{k+3} = $$ come from. But then it distributes as follows: $$=F_{k+2}(F_{k+1} + F_k)-F_{k+1}(F_{k+2} + F_{k+1})=$$ $$=F_{k+2}F_k - F^2_{k+1}=-(F^2_{k+1}-F_kF_{k+2})=-(-1)^k=(-1)^{k+1}$$ I see no pattern. Can someone explain this transition

I was looking at the decomposition of Fibonacci numbers using the definition of $F_n = F_{n-1} + F_{n-2}$, and noted the pattern in the coefficients of the terms were Fibonacci numbers. It appears to hold, and I believe it's true, but I haven't seen a proof for it. Does one exist?  $F_n = 1F_{n-1} + 1F_{n-2}$ $F_n = 2F_{n-2} + 1F_{n-3}$ $F_n = 3F_{n-3} + 2F_{n-4}$ $F_n = 5F_{n-4} + 3F_{n-5}$ etc  This can be generalized to $F_n = F_xF_{n-(x-1)}+F_{x-1}F_{n-x}$


If $\lambda_1, \cdots, \lambda_n, \cdots$ are positive real numbers such that $\displaystyle\sum_{k=1}^{\infty}(\lambda_1+\cdots+\lambda_k)=+\infty$, we can affirm that $\displaystyle\sum_{k=1}^{\infty}\frac{\lambda_k}{(\lambda_1+\cdots+\lambda_k)^2}$ converges?  I try use some comparison test, but I have not success. Can someone help me? Thanks.

Assume that $0 < a_n \leq 1$ and that $\sum a_n=\infty$. Is it true that  $$ \sum_{n \geq 1} \frac{a_n}{(a_1+\ldots+a_n)^2} < \infty $$ ?  I think it is but I can't prove it. Of course if $a_n \geq \varepsilon$ for some $\varepsilon > 0$ this is obvious.  Any idea? Thanks.


I need to show one attribute referring to two different instances of the same attribute.   I have a set of tables such as Branch, Address, Property_for_rent, State. I need to show properties data including the branch_state and the property_state. These two attributes come from the table state row name. My problem is that I haven't found a way to join the table state two times referring to two different instances. I already tried Full Join but sql doesn't recognize one copy of my table state, Union doesn't work because if I split the query into to I won't have the same amount of columns.  need to join this two queries:  SELECT p.property_no, p.prop_type, p.rooms, p.rent, s.name AS property_state, staff_no FROM state s JOIN address a ON s.state_id = a.state_id JOIN property_for_rent p ON a.address_id = p.address_id ORDER BY rent ASC;     +-------------+-----------+-------+------+----------------+----------+ | property_no | prop_type | rooms | rent | property_state | staff_no | +-------------+-----------+-------+------+----------------+----------+ | PR200       | Flat      | 3     |   24 | Nevada         | SQ523    | | PR901       | Flat      | 7     |   31 | Vermont        | SL569    | | PR806       | House     | 3     |   54 | Minnesota      | NULL     |     SELECT branch_no, z.name AS branch_state FROM branch b JOIN address a ON b.address_id = a.address_id  JOIN state z ON a.state_id = z.state_id;     +-----------+----------------+ | branch_no | branch_state   | +-----------+----------------+ | B424      | Kentucky       | | B947      | Massachusetts  | | B942      | South Carolina | | B714      | North Dakota   |   branch_state and property_state are alias for the name attribute in the state table.

I have 2 tables. One (domains) has domain ids, and domain names (dom_id, dom_url).  the other contains actual data, 2 of which columns require a TO and FROM domain names. So I have 2 columns rev_dom_from and rev_dom_for, both of which store the domain name id, from the domains table.  Simple.  Now I need to actually display both domain names on the webpage. I know how to display one or the other, via the LEFT JOIN domains ON reviews.rev_dom_for = domains.dom_url query, and then you echo out the dom_url, which would echo out the domain name in the rev_dom_for column.  But how would I make it echo out the 2nd domain name, in the dom_rev_from column?


I have ubuntu 14 iso and also have successfully installed it alongside win8(uefi, and it was fairly difficult). now I am able to boot into both as needed.  But i want a os that i can carry around in an usb, along with user files. how can I install this ditro as live? is it even possible?  I am a total newbie to linux and having linux in my hdd is not motivating me to make the most out of it. if it was portable i would be a lot more interested.  thank you.

How do I make an Bootable Ubuntu USB containing the the latest version of Ubuntu?  For completeness, how would I be able to do this on Ubuntu, Windows, OS X or another Linux distro?


Hey guys I need help on solving the following problem Find all the functions for which : $$f(x^{2})-f(y^{2})=(x+y)(f(x)-f(y)):\forall x, y\in\mathbb{R}$$ I started with taking $x=y$, and there you see that the both sides are equal to $0$, therefore the solution is the function $y=x$, but after that I can't prove that that is the only solution (if it is the only). Would appreciate some help, thanks.

Find all functions $f$ that assign a real number $f(x)$ to every real number $x$ such that $$(x+y)f(x)+f(y^2)=(x+y)f(y)+f(x^2)$$  I've tried subbing in heaps of values but I keep getting things like $f(0)=f(0)$ and other such useless results.  Any help would be hugely appreciated.


How do I download Ubuntu so that I may install it on another computer that presently does not have an operating system?

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


Using induction or otherwise, show that the polynomial  $$P_{n}(x)=1+x+\frac{x^{2}}{2}+\cdots+\frac{x^{n}}{n!}$$  has exactly one real zero if $n$ is odd and none if $n$ is even.  I believe the key here is that $P_{n}'(x)=P_{n-1}(x)$, but I cannot see how to apply this to the problem.

Find the number of real roots of $1+x/1!+x^2/2!+x^3/3! + \ldots + x^6/6! =0$.  Attempts so far: Used Descartes signs stuff so possible number of real roots is $6,4,2,0$ tried differentiating the equation $4$ times and got an equation with no roots hence proving that above polynomial has $4$ real roots. But using online calculators I get zero real roots. Where am I wrong?


I want to install Windows 10 and I want to keep Windows 7 since it'll take time to get used to W10. I also have Linux Mint. The problem is that my computer is 5+ years old Dell laptop, from what I learned here, my HDD doesn't support more than 4 primary sections.    Please help me figure out a solution. Can I delete 3,81 Linux swap partition without damaging any of the systems and create another partition for W10? Should I delete the recovery partition? Which one is less risky?  In short, what are my options to install 3rd OS on this HDD?

I have a Fedora 18 system installed on my hard disk, but upon installation I created 4 partitions for boot, swap, root and home, and now I want to install Windows on some unallocated space (I need it, don't judge me :D) but I'm limited to 4 primary partitions. Is there anyway I can change one of them do logical, or something else to empty one partition?  I can free up to 300 GB, which can hold all 4 partitions easily, in the extended partition that holds only home, if it is possible moving.  fdisk -l /dev/sda  Disk /dev/sda: 500.1 GB, 500107862016 bytes, 976773168 sectors Units = sectors of 1 * 512 = 512 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes Disk identifier: 0x000668e4  Device    Boot      Start     End       Blocks   Id  System /dev/sda1 *         133120    1026047   446464    83 Linux /dev/sda2           1157120   8202239   3522560   82 Linux swap / Solaris /dev/sda3           8333312   113059839 52363264  83 Linux /dev/sda4           113190912 894853119 390831104 5  Estendida /dev/sda5           113324032 894722047 390699008 83 Linux   Of course, without excluding existing partitions/files.


I making a simple mesh of two different materials as shown in the figure, the question is how can I differentiate both of them in Blender?

How do you add more than one material to a mesh?   I have tried adding two materials to the object, and then assigning one of the materials to a vertex-group, but I could not find a place to assign it.  I am making a striped bouncy ball that I want to deform, so adding a different material by separating the mesh into different objects would not be ideal.


It is easy to give an example of a polynomial of degree 3 with integer coefficients having:   (a) three distinct rational roots,  (b) one rational root and two irrational roots.  But for a while I am trying to construct one that all its roots are irrational but I can't. It seems that it is not possible at all?   Also, can a polynomial with integer coefficients of degree 3 have two rational roots and one irrational root?

I am looking for an equation     $$x^3+ax^2+bx+c=0, \qquad a, b, c \in \Bbb Z,$$   of degree $3$ that has $3$ different roots.  For an equation of degree $2$ it is easy---for example $x^2-2=0$---but I can't find an example for degree $3$.  if there is a method for finding this kind of Equation I will be grateful.


Using Beaglebone.  Need to run dd to backup an image and then restore it.   dd bs=64K if=/dev/sdX of=/dev/mmcblk1/myImage.img   But I don't see any sdX, where X is a number.  So, what should be the input file path for a full backup?

Given HDD 1TB with a two partitions: one is small ~24GB (for Ubuntu) and all the rest is the second partition with about 10% occupied space for multimedia files.  I want to duplicate it as fast as possible. I boot from USB stick. The second disk is /dev/sdb.  sfdisk -d /dev/sda > a sfdisk /dev/sdb < a   Then I copy bytewise the small partition:  dd if=/dev/sda1 of=/dev/sdb1 bs=4M status=progress   It takes about two minutes. Then I want to copy in optimal manner contents of the second partition. Just filesystem w/ file attributes:  rsync -avHAX /media/ubuntu/sda2dir /media/ubuntu/sdb2dir   After that I tried to boot from second HDD and can't.  How to copy MBR and other crucial information?  dd if=/dev/sda of=/dev/sdb takes about 1h20m for 1TB HDD. It is not acceptable. And seems also not works.


I’m now writing a masters thesis in mathematics. I’d like to introduce basic definitions and theorems in the beginning. By basic I mean truly basic, like the definition of a connected graph and the theorem about Eulerian paths (such a path exists if and only if even degrees).   The lecture notes written by my professor is really nice so I’d like to use his definitions (I’ll cite, of course). In this case can I cite his lecture notes?

When learning a new subject, I would frequently use lecture notes found somewhere in the Internet. When writing a paper (or a master thesis, as in my case, but the rules should be similar, I believe) one should give some reference for used results which are not common knowledge, if I understand correctly. This make me wonder: what do I do if I want to reference a result I found in some notes?  The natural thing to do would be to just add these notes to bibliography. What format would be preferable for this? Note that there will generally not be much publishing information, perhaps not even a definite year and place. (A BibTeX template would be .)  Secondly, is it OK to cite such materials as a reference?


I have an external hard drive with Windows 8 installed on it. Ubuntu cannot mount this drive.  Failed to mount '/dev/sdb5': Operation not permittedThe NTFS partition is in an unsafe state. Please resume and shutdown Windows fully (no hibernation or fast restarting), or mount the volume read-only with the 'ro' mount option.   I'm not using this Windows installation right now, so I don't mind deleting it. What can I do to fix this? Do I have to delete some partitions in the drive? If so which ones? Or is there an easier way?  Thanks.  Edit: I forgot to mention that the Windows installation is broken so I have no way of booting into it and shutting it down properly. Also, the main partition of the HDD (not the windows partition) has important data.    Final Update (Solution):

Whenever I boot Ubuntu, I get a message that it cannot mount my windows partition, and I can choose to either wait, skip or manually mount.  When I try to enter my Windows partition through Nautilus I get a message saying that this partition is hibernated and that I need to enter the file system and properly close it, something I have done with no problem so I don't know why this happens.    Here's my partition table, if any more data is needed please let me know.     Device Boot      Start         End      Blocks   Id  System /dev/sda1            2048    20000767     9999360   83  Linux /dev/sda2        20002814   478001151   228999169    5  Extended /dev/sda3   *   478001152   622532607    72265728    7  HPFS/NTFS/exFAT /dev/sda4       622532608   625141759     1304576   82  Linux swap / Solaris /dev/sda5        20002816   478001151   228999168   83  Linux


$N$ and $K$ are submodules of $M$ with $I=Ann(N)$ and $J=Ann(K)$, then show that annihilator of intersection of $N$ and $K$ contains $I+J$. Give example to show that the inclusion may be strict.

Let $N$ and $K$ be sub-modules of $M$ with $I=\operatorname{Ann}(N)$ and $J=\operatorname{Ann}(K)$. Show that $I+J$ is a proper subset of $\operatorname{Ann}(N \cap K)$.


I am trying to set up a wifi hotspot using my iPhone XR running iOS 13, which I wish to connect to using my Windows 7 Pro laptop. On the iPhone I go to Settings | Personal Hotspot and switch on, and I have set the name and password of the network. Then on the laptop I can see the name of the network, and I can connect to it.  The problem is that it's showing on the laptop as unconnected to the internet even when the iPhone is definitely connected to the internet because I can browse the web with it. What settings do I need to change?

After upgrade to iOS 13 from 12.4, I noticed that personal hotspot isn't working anymore over Wi-Fi (via USB is ok).  Tested on two computers with Win7. The PC can connect to Wi-Fi, but no valid IP (IPv4) is assigned and no connection is working to internet.


I am reading data from the following csv file:  X   Y   Z 0.1 50  6.951 0.1 60  12.774 0.1 65  17.454 0.1 70  27.842 0.2 50  7.908 0.2 60  12.218 0.2 65  15.601 0.2 70  25.811 0.3 50  9.294 0.3 60  13.184 0.3 65  18.021 0.3 70  27.465 0.4 50  10.817 0.4 60  14.819 0.4 65  17.288 0.4 70  28.82 0.5 50  10.755 0.5 60  15.15 0.5 65  18.997 0.5 70  26.2   This is how I am trying to construct the plot:  \documentclass{article} \usepackage[utf8]{inputenc} \usepackage{pgfplots} \usepackage{tikz} \usepackage{pgfplotstable} \pgfplotsset{compat=newest} \usepgfplotslibrary{patchplots} \begin{document} \begin{tikzpicture} \begin{axis}[grid=major] \addplot3 [surf,shader=faceted, samples=25,domain=0:2,y domain=0:1]  table[x=X, y=Y, z=Z, col sep=comma] {3dData1.csv};  \end{axis} \end{tikzpicture} \end{document}   It generates the following:   It doesn't generate  surface plot.  How can I make it surface plot?


I am currently borrowing New Leaf from my step sister and I have now bought a copy of Animal Crossing: New Leaf for myself.. I am NOT the mayor on her game card, when I transfer my save data from her town to my new town, would i automatically become mayor? Or will I need to start a whole new game in order to become mayor?

I rent (and still have) Animal Crossing: New Leaf. Since I might buy it later, and I have gotten pretty far into the game, is there a way for me to keep the save so when I buy the game later I can use the same save?


The footer space stands in the middle of the page at the inside pages and in the mobile and desktop view. Please refer to the inside pages. site:       /*  10.0 ===== Footer =====   */  /*   -- "Footer" section (These are the styles for the Footer section) --   */    .site-footer {     padding: 30px 0 0px; }  .footer-branding:hover img {     opacity: 0.5;     transition: all 0.3s ease 0s;     -webkit-transition: all 0.3s ease 0s;     -moz-transition: all 0.3s ease 0s;     -ms-transition: all 0.3s ease 0s;     -o-transition: all 0.3s ease 0s; } .footer-branding {     margin-bottom: 15px; } .site-footer .widget-area {     clear: both;     padding: 75px 0 30px;     position: relative; } .widget-area .widget {     margin: 0 0 30px; } .widget-area .inline-social-icons{     padding-bottom: 20px;     text-align: center; }

I have a simple 2-column layout with a footer that clears both the right and left div in my markup.  My problem is that I can't get the footer to stay at the bottom of the page in all browsers.  It works if the content pushes the footer down, but that's not always the case.


I have A200 Creative speakers with 10.5 V, 1 A transformer which not working, and i can buy 12V-1A transformer only. Is 1.5 V accepted tolerance for the amplifier power supply?

Power supplies are available in a wide range of voltage and current ratings.  If I have a device that has specific voltage and current ratings, how do those relate to the power ratings I need to specify?  What if I don't know the device's specs, but am replacing a previous power supply with particular ratings?  Is it OK to go lower voltage, or should it always be higher?  What about current?  I don't want a 10 A supply to damage my 1 A device.


While the normal pronunciation of "cursed" is in one syllable, I have seen it used as a two-syllable word, "curs-ed". The Cambridge dictionary lists this pronunciation as an alternative in UK only:   Is the two-syllable version valid for use in modern poetry, or is it restricted to real or simulated Early Modern text, like thee/thou usually are?

'Cursed' can be pronouced '/kɜːrst/' or '/ˈkɜːrsɪd/'. As far as I am aware, when used as the past tense of the verb 'to curse' it is always the former ('He stubbed his toe and cursed'). When used as an adjective the former is used for the predicative ('This house is cursed') but either can be used for the attributive ('This cursed house'); to me , as a native English speaker, /ˈkɜːrsɪd/ has an old-fashioned feel; most of the examples I can think of are Shakespearean or religious. When should each of these pronunciations be used for 'cursed' as an attributive adjective? Nowadays, is /ˈkɜːrsɪd/ simply used when someone wants something to sound dramatic and portentous, or is there more to it than that?  The ,  and  definitions each list both pronunciations but don't provide guidance on when to use each; the , interestingly, claims the first pronunciation is used when something is literally under a curse, while the second is for metaphorical usage (describing something unpleasant or annoying). This would be a nice straightforward rule but it doesn't sound correct to me.  (This question was prompted by one over on 'Science Fiction and Fantasy' about ).


I recently saw the synonyms for Formal on Google and was wondering why standoffish is apart of it? Because being formal is being polite, while standoffish is unfriendly. What makes these two words synonyms oh and also here is a picture

In the dictionary reserved means - not revealing emotions and formal means - prim or stiff. I saw they were synonym in the Google dictionary. What makes these two words similar, I wonder?


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


I'm a 19 year old student and I have a part-time job as a programmer.  I make 20 euros an hour and I work about 10-15 hours a week, depending on school responsibilities.  I earn 800 euros a month, sometimes more.    My monthly expenses are  about 500 euros.  If I deduct another 150 a month for unexpected expenses such as a broken washer, I'm left with 150 euros to spend on whatever.  I'm aware that 150 euros a month for unexpected events is not a lot but I have  enough money saved up so that I won't run into any trouble if I have  multiple unexpected expenses. So I thought I would continue to slowly add more money to the unexpected expenses pile.  What would be the best way to use my left over money? Should I invest the money or should I just save it on my bank account?  If the answer is invest,  since I've never done this before, could you please recommend a book or an article that I could use to inform myself on how to invest?

I am young, just started my career, and looking to begin investing so I can make my money work for me. I'm still living like I did in college (occasional purchase on myself, but most of it goes into savings) and I would like to take the extra money and invest it.   What would you suggest are the best options for me to begin? I was considering getting a personal investor [a financial advisor] for perhaps a year or so, but I've heard that they really are not worth the money. I wanted to get the input of the great minds here.


Is there a simple command (like uname -r to know my kernel version) to know if I need to download a AMD-64.deb package or a x86_64.rpm one ?  For example, for downloading printer drivers, I need to decide which one to take.  Sorry, if this is a dupe, I've seen many questions around this matter, but didn't find how to know what is my processor.

When running uname -a, I get as output   41-Ubuntu SMP Mon Aug 13 17:59:54 UTC 2012 i686 athlon i386 GNU/Linux   Can someone please explain to  me why both i386 & i686 ?    What exactly is my PC architecture and what version of Ubuntu am I using (32bit or 64bit)?


I'm trying to map some non numerical values in a pandas dataset that contains information from passengers that were on the Titanic. Right now I'm trying to map the ports where passengers embarked from. There are 3 ports and I'm trying to map them by adding a column for each port. 0 if they embarked from that port 1 if not.  I tried doing something similar with sex. I added another column with a 0 if the sex was male and 1 if the sex was female. That worked, but when I try doing this with the ports I get a "'float' object is not subscriptable" error.  import pandas as pd #opening the data train_path = #path to data set passengers = pd.read_csv(train_path)  #creating a copy passengers_copy = passengers  #mapping sex passengers_copy['SexBin'] = [0 if x[0] == 'm' else 1 for x in passengers_copy['Sex']]  #trying to map the first port passengers_copy['EmbarkedS'] = [0 if x[0] == 'S' else 1 for x in passengers_copy['Embarked']]

Which types of objects fall into the domain of "subscriptable"?


I have an iPad 3rd Generation, it's called the New iPad, and I don't know how can I sync with my PC. I'm now using Ubuntu 12.04.3 LTS.   Thanks a lot!

If Ubuntu can't do this natively, are there any workarounds?


I just wanted to make sure about an issue.  Let $m, p= \text{prime}∈ ℕ-\{0\}$ If $$m≤p^k,$$ does the following exist? $$\gcd(m,p)≠1⟺ \gcd(m,p^k)≠1$$ and does the restriction $$m≤p^k$$ matter to the existence? Thanks in advance!!!

I have just began learning number theory and I wanted to prove the following statement:   'if $x$ is coprime with each $p_i$ then $x$ is coprime with $p_1...p_n$'   This was actually a statement from a proof within CRT and they also had the condition that $p_i$ are pairwise coprime but I am not sure if that was used in proving the above statement.  Here is my attempt.  Suppose for a contradiction that $x$ is coprime with each $p_i$ and $x$ is not coprime with $p_1...p_n$, then there exists a prime number $q$ such that $q\mid x$, $q\mid p_1...p_n$. By the property that $q$ is prime we must have $q\mid p_i$ for some $i$. Hence $\operatorname{hcf}(x, p_i)\geq q$ for that specific $i$ and so there is a contradiction.   As I said, since I didn't use at all the pairwise coprime property of $p_i$, I am not sure if my proof was correct, could someone please let me know if there were any flaws in my argument?


Can someone explain to me what's going on here?  Script:  #!/bin/sh SKIP="unity-launcher|unity-panel|unity-dash|Hud|XdndCollectionWindowImp|Desktop" WINS=() wmctrl -l | grep -Ev " (${SKIP})" | cut -d \  -f 1 | while read window; do     WINS=( ${WINS[@]} $window )     echo "Found window: $window; New size: ${#WINS[@]}" done echo "Total window count: ${#WINS[@]}" echo "Window IDs:" for i in "${WINS[@]}"; do     echo "  $i" done   Output:  Found window: 0x0380000a; New size: 1 Found window: 0x038002ae; New size: 2 Found window: 0x03800a33; New size: 3 Found window: 0x03000001; New size: 4 Found window: 0x04c00004; New size: 5 Total window count: 0 Window IDs:   Expected:  Found window: 0x0380000a; New size: 1 Found window: 0x038002ae; New size: 2 Found window: 0x03800a33; New size: 3 Found window: 0x03000001; New size: 4 Found window: 0x04c00004; New size: 5 Total window count: 5 Window IDs:     0x0380000a     0x038002ae     0x03800a33     0x03000001     0x04c00004   Essentially, at the end of the while loop, the WINS array is getting reset somehow, and I have no idea why.  Is there some weird scoping thing in bash I'm unaware of?

Why do I get different values for $x from the snippets below?  #!/bin/bash  x=1 echo fred > junk ; while read var ; do x=55 ; done < junk echo x=$x  #    x=55 .. I'd expect this result  x=1 cat junk | while read var ; do x=55 ; done echo x=$x  #    x=1 .. but why?  x=1 echo fred | while read var ; do x=55 ; done echo x=$x  #    x=1  .. but why?


I need to execute some tests on a script of mine which requires a lot of CPU cycles. Is there a way to kill the GUI? I tried but it always restarts by itself.

I need to enter the command line alone with no GUI to install the official NVIDIA drivers. I'm trying to get my computer to work over HDMI and someone on Youtube shows how but you have to be in the Nvidia settings program.


I am trying to launch PlayOnlinux on 64bit Ubuntu 16.04 with installed cuda-8.0 and binary NVIDIA drives from cuda run file.  I got constant problems with OpenCL libraries. One that I cannot fix by now is associated with PlayOnLinux. When I launch it, it shows an error:  " PlayOnLinux is unable to find 32bits OpenGL libraries "   If I launch ldconfig -p | grep libGL.so.1 I got the following output:  libGL.so.1 (libc6,x86-64) => /usr/lib/x86_64-linux-gnu/libGL.so.1 libGL.so.1 (libc6,x86-64) => /usr/lib/x86_64-linux-gnu/mesa/libGL.so.1 libGL.so.1 (libc6,x86-64) => /usr/lib/libGL.so.1 libGL.so.1 (libc6) => /usr/lib/i386-linux-gnu/mesa/libGL.so.1   To clarify problem:  I have installed wine:i386 prior playonlinux instalation. As well, I tried to reinstall the following:  sudo apt-get install --reinstall libgl1-mesa-glx:i386 libgl1-mesa-glx:amd64 libgl1-mesa-dri:i386 libgl1-mesa-dri:amd64 xserver-xorg-core  As was mentioned in one of the topics, modifying /etc/ld.so.conf.d/i386-linux-gnu_GL.conf could help. The syggestion was to put link to /usr/lib32 instead of /usr/lib/i386-linux-gnu/mesa/ which I have in my case.  I do not have folder /usr/lib32 on my system, only /usr/lib. Thus, I cannot re-link libGL.so.1 (libc6).  So any suggestions what is missing and how can I link 32bits libs correctly?  P.S. I am interested in keeping cuda-8.0 and binary NVIDIA drivers on my system.

When I open a fresh instalation of playonlinux, it gives 2 dialog box as mentioned in title:     playonlinux is unable to find 32bits OpenGL library   playonlinux is unable to find 64bits OpenGL library   I am using Ubuntu 12.04 (and new to it) and would like to know how to solve this problem  EDIT TERMINAL OUTPUT  ~$ playonlinux [main] Message: PlayOnLinux (4.1.8) is starting [clean_tmp] Message: Cleaning temp directory Xlib:  extension "GLX" missing on display ":0". Xlib:  extension "GLX" missing on display ":0". [Check_OpenGL] Warning:  Xlib:  extension "GLX" missing on display ":0". Xlib:  extension "GLX" missing on display ":0". [Check_OpenGL] Warning:  [main] Message: Filesystem is compatible [install_plugins] Message: Checking plugin: Capture... [maj_check] Message: Web version : 1349866727 [maj_check] Message: Current local version : 1349563245 [maj_check] Message: Updating list [install_plugins] Message: Checking plugin: ScreenCap... [install_plugins] Message: Checking plugin: PlayOnLinux Vault... /usr/share/playonlinux/bash/startup_after_server: line 38: [: : integer expression expected /usr/share/playonlinux/bash/startup_after_server: line 38: [: : integer expression expected [POL_Config_Write] Message: Config write: LAST_TIMESTAMP 1349866727   EDIT Nvidea print screens   What it says:


I am using different Likert Scales in questionnaire. Three dependent variables have Likert scales of 4 points, 2 points and 2 points. Three independent variables have 3 points scales. One moderating variable has 3 points Likert Scale whereas the other moderating variable has three questions with 4 points, 3 points and 3 points scales. If I use average of each variable in statistical analysis to find correlation, regression and moderated regression, is it allowed and results are considered valid or not?

Let's say I have some self-report items measured on a 5-point Likert scale (Strongly Disagree to Strongly Agree) and other items measured on a 4-point Likert scale (Never, Rarely, Sometimes, Often). Can anyone point me to literature (or practical advice) on combining these items into a composite scale? Let's assume for the sake of argument that we have some empirical evidence that items should be combined.  Some ideas:  1. Sum raw scores  Pro: Easy  Con: Max responses on the 5-point scale (originally 4's) drive up the total scale score more than max responses on the 4-point scale (originally 3's).  2. Rescale and sum  Put all of the items on a 0-1 scale and sum. So the 4-point items (0,1,2,3) would be multiplied by (4/3)/4 and the 5-point items (0,1,2,3,4) would be multiplied by 1/4, resulting in possible values of (0,.33,.66,1) and (0,.25,.50,.75,1), respectively. This way max responses on the 5-point scale (originally 4's) would not drive up the total scale score more than max responses on the 4-point scale (originally 3's).   Pro: Items would have equal weighting. (could be a con, depending on your perspective).  Con: Ignores differences in variability between items on different metrics?   3. Standardize and sum  A related approach would be to standardize all of the items (z score) and then sum.  Pro: Addresses differences in variability between items on different metrics  Con: Total scale score becomes less interpretable and sample-specific. The latter makes it hard to benchmark as a measure to be used in other settings/other samples.  4. PCA or other data reduction   4a. EFA to get factor loadings. Multiply scaled items by factor loadings.  4b. PCA to get score of first principal component.  Pro: Items weighted by influence.  Con: Same as #2. EFA-derived scores could vary a lot depending on rotation/extraction choices. Some would not advise on ordinal data.    Overall: I like #2 because it seems easier to compare results across different samples. Thoughts? Alternative ideas or concerns about the ideas presented?


I have a Blender project with planes with image textures on them, but the images aren't being loaded. I'm pretty sure I have the images as well, but the person who uploaded all this apparently didn't keep the original folder structure. Where can I see (or edit) the file location for the images?  Note that I'm a new user.

Menu command File > External Data > Report Missing Files gives output such as:  Warning: Path '/foo/sometexture.jpg' not found   How do I discover which materials use that texture?  Or, is there a way to get a list of materials that have missing textures?  Update: I'm specifically interested in Cycles materials.


It used to be off the top bar, now its gone  Where has it moved?  EDIT:  It moved onto the profile page !  Right side same row as your name in profile:    Thank you

Can't find the Privileges link any more.   is no longer valid.  Can someone please tell me where it's hiding now?


For some reason I'm not able to have a top alignment of figures using subfigure and the environmental option [t]. I have search the internet for solutions and found them pretty complex for such a simple and general problem... What is the simple solution?  \documentclass[11pt]{article} \usepackage[draft]{graphicx} \usepackage{caption} \usepackage{subcaption}  \begin{document}  \begin{figure}[h!] \centering  \begin{subfigure}[t]{.49\linewidth} \centering \includegraphics[width=1\textwidth]{calCurve.pdf} \caption{Caption 1} \end{subfigure}% \begin{subfigure}[t]{.49\linewidth} \centering \includegraphics[scale=0.7]{anova.pdf} \caption{Caption 2} \end{subfigure}% \end{figure}  \end{document}

This is a follow-up to an earlier question regarding .  Having achieved the left-alignment goal, I would now like the caption of the subfigure to be bottom-aligned, while having the subfigure itself be top-aligned. As an example, in the figure below, subfigures (a) and (b) would share an uppermost edge, and their captions would share a lowermost edge, and similarly for subfigures (c) and (d). This is most appropriate for the overall layout style of my document and also the content of the subfigures themselves.    \documentclass{article} \usepackage[font=footnotesize]{subcaption} \usepackage[draft]{graphicx}  \begin{document} \begin{figure}[!ht] \captionsetup[subfigure]{justification=justified,singlelinecheck=false} \centering \begin{subfigure}[b]{0.3\textwidth} \includegraphics[scale=0.8]{fig/workflow-S} \caption{workflow $S$} \end{subfigure} \begin{subfigure}[b]{0.5\textwidth} \includegraphics[scale=0.8]{fig/workflow-S-run} \caption{run of $S$} \end{subfigure} \vskip 8pt \begin{subfigure}[b]{0.3\textwidth} \includegraphics[scale=0.8]{fig/workflow-S'} \caption{workflow $S'$} \end{subfigure} \begin{subfigure}[b]{0.5\textwidth} \includegraphics[scale=0.8]{fig/workflow-S'-run} \caption{run of $S'$} \end{subfigure} \caption{Here's a figure} \end{figure} \end{document}   I've experimented with the minipage settings for subfigure, specifically using [t] instead of [b], but it seems to have no effect. I'm unsure as to whether a position of [t] would produce the right effect anyway, or whether it would shift the captions up as well.  Why is [t] not working here, and what's the right way to produce the layout I need?   The solution should generalise to an arbitrary number of subfigures per row, subfigures which are text or tables rather than images, and should not require any hard-coded sizes.


I've had my Galaxy Note about 18 months. It's progressively getting slower and slower to respond to user input. Any tap has an unpredictable delay, up to a few seconds. Even typing has a noticeable lag to it. I frequently accidentally tap things twice because there's no response to the first tap.  Is there anything I can do? I'd happily completely wipe and start over at this point. It's at the stage where I barely use it for things like quickly looking up stuff on the net - it's just too tedious.  It's the stock Samsung Android 4.1.2. 350 MB free on the internal storage out of 2GB, 830MB free out of 11GB on the USB storage, and 1.7/14.7GB free on the memory card.  Any suggestions gratefully received.

Everything was working fine for a long time. But suddenly the device is getting slower than usual (e.g. apps react slowly when starting an action -- like the RSS reader takes "ages" to open an article). Also, several apps start crashing: force-closes as well as unexpected restarts. Sometimes this even involves some automatic reboot of the device.  Is there anything I can do, besides doing a factory-reset? Preferably it should work on un-rooted devices.  Remark: not all described problems may occur together, so on one device e.g. there might be no automatic reboot involved. Question remains the same, nonetheless.


In QGIS 2.13.2 I have a google map and a shapefile. Now I want to print it with all the necessary items, but I have a big problem with the coordinates. First of all, the coordinates just appear when I use the WGS84 / Pseudo Mercator (EPSG: 3857). If I try to use the normal WGS 84 nothing appears. Why is that?  The other problem is, that my coordinates show something completely different than they should be. I looked them up and its somewhere in Africa, although I need the coordinates for a place in Germany. Did I make a mistake with georeferencing the shapefile?

I'm having trouble with the OpenLayers Plugin of Qgis and the map composer:  If I create an OSM-background layer and if I want to export this, the OSM-Layer looks perfectly all right in the normal qgis program window. But in the map composer and after export the layer has shifted relatively to my other shape layers (EPSG:32633 - WGS 84 / UTM zone 33N).  The second thing is that the output resolution of the exported osm-layer is very, very poor.   A really bad way of getting around this whole trouble would be to increase the screen resolution and make a screenshot of the map composition window of qgis. But I don't think this would be very professional. It also would cause a lot of pain :)   I'm using Qgis 1.8.0-Lisboa under Linux. The openlayers plugin is version 0.92.


i am trying to compile a work in Texmaker, but when doing so, the console returns:  Package biblatex Warning: No "backend" specified, using Biber backend. (biblatex) To use BibTeX, load biblatex with (biblatex) the "backend=bibtex" option.   I really do not know what does it means.  My preamble is the next:  \documentclass[12pt,twoside]{report} \usepackage[utf8]{inputenc}  \usepackage{fancyhdr} \pagestyle{fancy} \usepackage{csquotes} \usepackage{biblatex} \addbibresource{bibtex.bib}

I am trying to compile a simple tex file but I get this warning and no bibliography printed out:  Package biblatex Warning: No "backend" specified, using Biber backend.   I am using Kile on Ubuntu 14.04. While the same exact file on another pc with Ubuntu 12.04 is correclty working. What is the problem? How can I solve it?  Here is my MWE:  \documentclass[a4paper,11pt]{article} \usepackage[utf8]{inputenc} \usepackage[italian,english]{babel} \usepackage[T1]{fontenc} \usepackage{booktabs} \usepackage[font={small}, labelfont=bf, hypcap=true]{caption}[2004/07/16] \usepackage[unicode,colorlinks=true]{hyperref}  \usepackage[babel]{csquotes} \usepackage[style=authoryear-comp,maxcitenames=1,maxbibnames=99,sortcites=true,firstinits=true,doi=false,url=false,isbn=false, hyperref]{biblatex}%style=numeric-comp,sorting=none,backend=biber  \renewbibmacro{in:}{% elimina il in nella biblio   \ifentrytype{article}{}{%   \printtext{\bibstring{in}\intitlepunct}}}   \renewcommand*{\bibfont}{\small}  \bibliography{biblioTC}  \title{My paper title} \author{Me}  \date{}  \begin{document}  \maketitle  \newpage  \section{Test}  Lalalalalalalalalala \cite{Colitti2014}.  \newpage \phantomsection\addcontentsline{toc}{section}{\refname}         \printbibliography  \end{document}


Hereby i have included my WMS layer displaying code.I referred many sites i can't able to get WMS getfeature info.Please anyone help me how to get WMS layer feature info give source code please           WMS - GetFeature                                                              var osm, map, state_boundary;     var state_code;     var vectorLayer, vectorSource, featureRequest;          // set up the map         osm = new ol.layer.Tile({     // basemap layer             title: 'OSM',             type: 'base',             source: new ol.source.OSM()         });         state_boundary = new ol.layer.Image({              title: 'india',             source: new ol.source.ImageWMS({             url: 'http://localhost/geoserver/workspace/wms?',                 params: { 'LAYERS': 'workspace:IndiaState' },                 serverType: 'geoserver'             })         });          map = new ol.Map({             layers: [osm, state_boundary],             target: 'map',             view: new ol.View({                 center: ol.proj.transform([78.188860, 23.176633], 'EPSG:4326', 'EPSG:3857'),                 zoom: 5             })         }); </script>

I have a map a at the link below:    I added one of my GeoServer WMS layers to the map, now I try to add the attributes window pop up on click. I found to examples on the OpenLayers 3 homepage, but I cannot put together a working code...      Is there any chance to have a working sample somewhere?


Let $f(z)$ be a complex valued function which can be represented by $$f(z)=u(x,y) + iv(x,y).$$ If $f(z)$ is differentiable, show that $$\left|f'(z)\right|^2=\left(\frac{\partial u}{\partial x}\right)^2+\left(\frac{\partial v}{\partial x}\right)^2.$$ I am a beginner in complex analysis, so bear with me. In my solution, it is given that $$f'(z)=u_x + iv_x=\frac{\partial u}{\partial x} + i \frac{\partial v}{\partial x}$$ and things follow from here. My doubt is, how does the above came into picture. As far as i know, $f(z)$ is a complex valued function with real part as $u(x,y)$ and imaginary part being $v(x,y)$ which are both functions of $x$ and $y$. How does one calculate the derivative of $f(z)$ by taking partial derivative with respect to $x$ only? Any help would be appreciated from the community.

This might look funny but this is disturbing me for quite a while, that is,  why $$f'(z)=u_x+iv_x.$$ Why the partial derivatives $u_y$ and $v_y$ are being ignored? From the following limit: $$\label{1} f'(z)=\lim_{h\to0, \>h\in{\mathbb R}}{f(z+h)-f(z)\over h}={\partial f\over\partial x}(z)=u_x(x,y)+iv_x(x,y)\ ,\tag{1}$$   I can understand that the infinitesimal $h$ is real and this corresponds to increment in $x$ variable only, but why the variable $y$ is being ignored? If this is the case, then won't the limit \eqref{1} would only be defined in the horizontal neighborhood of $0$, without considering increments in vertical or any other direction in complex plane?


I know the number of normal subgroup in $D_3$ and $D_4$ but I don't know the number of normal subgroup of rest of the Dihedral group like $D_{16}$ or $D_{60}$.  I want to know is there any formula for finding number of normal subgroup in $D_n$.  If there is no formula for that then how could we able to find that as I'm a beginner please help.

In relation to , I am curious about what exactly are the normal subgroups of a dihedral group $D_n$ of order $2n$.  It is easy to see that cyclic subgroups of $D_n$ is normal. But I suspect that case analysis is needed to decide whether dihedral subgroups of $D_n$ is normal.  A little bit of Internet search suggests the use of semidirect product $(\mathbb Z/n\mathbb Z) \rtimes (\mathbb Z/2\mathbb Z) \cong D_n$, but I do not know the condition for subgroups of a semidirect product to be normal.  I would be grateful if you could suggest a way to enumerate the normal subgroups of $D_n$ that does not resort to too much of case analysis.


My not an answer flags for the below answers were declined "a moderator reviewed your flag, but found no evidence to support it".                       Was it a mistake to flag the above answers? Description for the flag I used says:     This was posted as an answer, but it does not answer the question. It should possibly be an edit, a comment, another question, or deleted altogether.

Related:  (not a dupe, that's a feature request and was closed as a dupe of another one)        (old) post does indeed say that Link-only answers can be flagged as NAA, but there are a lot of posts like  which define Not An Answer is a way that it doesn't apply to link-only answers.  Can we get some up-to-date consensus on this? That link only answers are not allowed is .


Let $ x_1 = 1$ and $$ x_{n+1} = x_{n} + \sqrt{x_n^2 + 1}$$ Find the limit $$\lim_{n\to \infty} \frac{2^n}{x_n}$$  This is what I've found so far:   $$ x_{n+1} - 2x_n = \sqrt{x_n^2 + 1} - x_n = \frac{1}{\sqrt{x_n^2+1}+x_n} = \frac{1}{x_{n+1}}$$  How should I proceed?

Be $(x_n)_n\ge 1 $  such that $x_1=1$ and $x_{n+1}=x_n+\sqrt{x_n^2+1}$ for every $n\ge 1$. Prove that the sequence $y_n=(2^n/x_n)_n \ge 1$ is convergent and find it s limit.  Being positive and decreasing, $y_n$ is clearly convergent. But finding it's limit really put me intro trouble. Any help?  Thank you!


I'm using \DeclareMathOperator*{\argmin}{argmin} for getting the argmin parameter. Every thing is Ok expect if I type it inside algorithmic table, it fails to show the correct output. In the below picture, the scenario is shown    The code for this picture is   \documentclass{article} \usepackage{algorithm,algpseudocode,float} \usepackage{amsmath}  \DeclareMathOperator*{\argmin}{argmin}   %----------- \makeatletter \newenvironment{breakablealgorithm}   {% \begin{breakablealgorithm}    \begin{center}      \refstepcounter{algorithm}% New algorithm      \hrule height.8pt depth0pt \kern2pt% \@fs@pre for \@fs@ruled      \renewcommand{\caption}[2][\relax]{% Make a new \caption        {\raggedright\textbf{\ALG@name~\thealgorithm} ##2\par}%        \ifx\relax##1\relax % #1 is \relax          \addcontentsline{loa}{algorithm}{\protect\numberline{\thealgorithm}##2}%        \else % #1 is not \relax          \addcontentsline{loa}{algorithm}{\protect\numberline{\thealgorithm}##1}%        \fi        \kern2pt\hrule\kern2pt      }   }{% \end{breakablealgorithm}      \kern2pt\hrule\relax% \@fs@post for \@fs@ruled    \end{center}   } \makeatother  \begin{document}   $$ a = \argmin_s $$  \begin{breakablealgorithm}   \caption{XXXXXXXXX}   \begin{algorithmic}[1]     \State{$\text{A} = \argmin_s B$} \end{algorithmic} \end{breakablealgorithm}    \end{document}   My question is now why it doesn't work properly inside the algorithm.

I'm very familiar with how symbols display differently in inline mode (with $ ... $) vs. how display math shows them (with \[ ... \] or $$ ... $$).  Two examples would be with limits  $\lim_{n\rightarrow \infty}f(x)$   vs.  \[ \lim_{n\rightarrow \infty}f(x) \]   and with sums  $\sum_{n=1}^{x} n^2$   vs.  \[ \sum_{n=1}^{x} n^2 \]   My Question is:     How do you display these things in inline mode (with all the nice inline formatting) as if they were in display mode ?   The inverse -- how to display things in display mode as if they were in inline mode -- is also of interest.


Can someone explain why these two different code samples give different outputs? I'm confused on why the first sample appends "sunny" and "cloud" to all months, which is not what I want. I want the output of the second sample. However, I want to assign the variable "forecast", not its value to weatherReport["months"][month]. Is there a way to get the output of Sample 2 this way?  Sample 1:   weatherReport = {"months": {}}   forecast = []  months = ["January", "February", "March", "April", "May", "June", "July", "August", "September", "October", "November", "December"]  for month in months[1:]:     weatherReport["months"][month] = forecast  weatherReport["months"]["June"].append("sunny") weatherReport["months"]["December"].append("cloudy")  print weatherReport   Output for Sample 1:  {'months': {'February': ['sunny', 'cloudy'], 'October': ['sunny', 'cloudy'], 'March': ['sunny', 'cloudy'], 'August': ['sunny', 'cloudy'], 'May': ['sunny', 'cloudy'], 'December': ['sunny', 'cloudy'], 'June': ['sunny', 'cloudy'], 'September': ['sunny', 'cloudy'], 'April': ['sunny', 'cloudy'], 'July': ['sunny', 'cloudy'], 'November': ['sunny', 'cloudy']}}   Sample 2:  weatherReport = {"months": {}}   forecast = []  months = ["January", "February", "March", "April", "May", "June", "July", "August", "September", "October", "November", "December"]  for month in months[1:]:     weatherReport["months"][month] = []   weatherReport["months"]["June"].append("sunny") weatherReport["months"]["December"].append("cloudy")  print weatherReport   Output for Sample 2:  {'months': {'February': [], 'October': [], 'March': [], 'August': [], 'May': [], 'December': ['cloudy'], 'June': ['sunny'], 'September': [], 'April': [], 'July': [], 'November': []}}

I needed to create a list of lists in Python, so I typed the following: my_list = [[1] * 4] * 3  The list looked like this: [[1, 1, 1, 1], [1, 1, 1, 1], [1, 1, 1, 1]]    Then I changed one of the innermost values: my_list[0][0] = 5  Now my list looks like this: [[5, 1, 1, 1], [5, 1, 1, 1], [5, 1, 1, 1]]    which is not what I wanted or expected. Can someone please explain what's going on, and how to get around it?


My reputation was 89, then I posted a 50pt bounty on a question.  Now with a reputation of 39, I cannot comment on that same question.    I believe further comments may help anyone trying to answer that question. Shouldn't I at least be able to comment on my open bounties?

I think it would be very useful.  I have a question that I have an open bounty on. Putting up said bounty brought my reputation below the point where I am allowed to comment on other peoples' posts. It's so frustrating not to be able to comment and give feedback on the answers given!  Especially since it would be helpful, for them, me, and the readers, to know particularly what is good and isn't good about their answer, and therefore give some better guidelines to future answerers on how they can win the bounty.


Is it possible to know the exact dates at which Stack Exchange websites have passed each of the development stages before being launched officially? I refer to date of proposal, date of commitment, date of private beta, etc.   In the Area 51 website an approximate date is recorded (i.e. 6 years ago,..for example for Stack Overflow in Russian, this is recorded on the right column ), but I was wondering if I could find the exact dates.

Is there a way to know what date a Stack Exchange site went live? In other words what date it graduated from Area 51 to full-fledged status?


Could you please help me with this? A bit of context:     Look at this painting. In the painting you can see a little girl. So, it is a painting of a girl. A famous painter painted it. So it is a painting ___ a famous painter.   I thought we should use "of" to show that the painting depicts the person, while "by" shows who painted it, but in the test it was "of" in both cases. Is "by" acceptable /correct or not in the latter case?.

I'm not sure of the right place to ask this, but I got confused trying to understand how the computer will interpret the sentence:     This is my picture.   In actual sense, the real owner of the picture should be the photographer not the person who was photographed... or am I getting something wrong? So, it seems the confusing thing about 'picture' is determining who the real owner of the picture is. So is there a special category for these kind of nouns or an official clarification somewhere?  Thanks


I've got a lot of history in email servers in the cloud (i.e. someone else's computer). I'm looking for some way to make a local backup of all that data, preferably one I could easily access/search.  There are two products I know of that do exactly what I want but they're both Windows only MailStore and MailShelf. There's apparently also a Mac only program called Horcrux. But nothing I can find for Linux.  Thunderbird is not and could not ever be considered a backup solution. There is no way within TB to know it has completed downloading mail (even assuming it ever would). This is on its own absolutely disqualifying. It's not good enough for a backup to simply hope it's done, if it worked at all (which there is no way to check in TB). Thunderbird's cache was never designed to produce authoritative backups, it's just a convenience feature.  There do seem to be a number of Linux console tools that do the first half of what I want (imapsync, imap-backup, more?) but I'm not sure how I'd access/search the mail after the messages were down. There are also enterprise products (Piler, MailArchiva) which are probably overkill, and would be a hassle to setup anyway.  I asked this question on Ubuntu's own forum several days ago but the only solution suggested was to run a local mail server and then sync the cloud accounts to that. It might work, but it seems there should be a better way.  Is anyone out there willing to share the solution they have for this problem?

I use Thunderbird to backup my web-based email account: I open Thunderbird and copy the mail messages from the Inbox to a local folder.   Is there a way to do this automatically every day, so that I don't have to open Thunderbird all the time?  EDIT:  is very useful for GMail accounts. For non-GMail account, the getmail method should probably be used.


I just installed Ubuntu 14.04 and need to install Internet Explorer. My banks require that I use it. Any help would be appreciated. I've only found very old answers online.

I am developing one site which has chat feature in Rails. I am using Ubuntu 12.04 LTS. I need to check that the site is IE9 because the chat feature using socket io of HTML5. I want to know that how to install IE9 in Ubuntu. I have looked at Chrome and Firefox extensions but if any standalone is available then please give me suggestion.


If another member of a Quidditch team catches the snitch, does it count?

I know that if the Seeker was to catch the Snitch, that team would gain 150 points and the event would end the match.  But what happens if another player playing a different position sees the Snitch and catches it? Would it also end the game? Or would the player have to forfeit the Snitch and would it be re-released for the Seekers?


How can we prove that the following expression is a polynomial? $$   \frac{1-x^{2^{n-1}}}{1-x} $$ I've asked this question just for learning the ways different from using   $1-x^n=(1-x)(1+x+x^2+···+x^{n-1})$.

In algebra & polynomials, how do we prove that $$x-1 \mid x^n -1?$$


I have developed the lightning aura component for custom import and export feature. I need to include the time lapse since some times it is loading for longer time even though there are few records to update/insert. If i click on another tab and then come to the original tab then the results are quick but if stayed at same page then loading is take much longer time. Any suggestion why it will happen. And also as it is running for longer time i want to introduce cancel button while uploading so that if user don't want to go further then he/she can cancel the upload.How to can achieve it could you please help me. while uploading if user click on cancel then flow should exist and if there are any DML operations committed then those should be reverted back. Component page:  selected the file -> click on upload new items or update existing items then loading will start.  Here once i click on cancel button how to recall the action called by upload buttons? Please suggest.

Is there a way in lightning to keep track of enqueued server side actions and cancel them if some event happens on the client before the action completes?


I am planning to travel to Greece so I want to know if I can visit other Schengen countries with the visa and also by train from Greece after my arrival in Greece

I’m going to Germany for a semester exchange and I have a long-stay visa from Germany. Can I travel to the other Schengen states during this period with this visa or do I have to apply for a separate short stay Schengen visa?  My visa is German national visa type D. It is for a duration of 4 months, i.e., longer than 90 days. It says on the visa that the long stay visa is valid in Deutschland, which is different from my earlier visa, which I had when I visited Germany earlier; that one was a short stay visa and said it was valid in Schengen Staten.  Perhaps my current visa means that I can stay in Germany for a period of longer that 90 days can visit the other Schengen states if I don’t exceed the 90 day period.


I want to find a simple example of a property that looks like it holds for all $n \in \mathbb{N}$, but that does not. I remember reading about one that got in hold for centuries before someone found out a ridiculously big value of $n$ for which the property didn't hold, but I don't remember what the property was. I'd like if the example property was easy to explain and didn't demand many concepts outside basic knowledge of the natural numbers. Anything like that?

I just came back from my Number Theory course, and during the lecture there was mention of the Collatz Conjecture.  I'm sure that everyone here is familiar with it; it describes an operation on a natural number – $n/2$ if it is even, $3n+1$ if it is odd.  The conjecture states that if this operation is repeated, all numbers will eventually wind up at $1$ (or rather, in an infinite loop of $1-4-2-1-4-2-1$).  I fired up Python and ran a quick test on this for all numbers up to $5.76 \times 10^{18}$ (using the powers of cloud computing and dynamic programming magic).  Which is millions of millions of millions. And all of them eventually ended up at $1$.  Surely I am close to testing every natural number? How many natural numbers could there be?  Surely not much more than millions of millions of millions. (I kid.)  I explained this to my friend, who told me, "Why would numbers suddenly get different at a certain point?  Wouldn't they all be expected to behave the same?"  To which I said, "No, you are wrong!  In fact, I am sure there are many conjectures which have been disproved by counterexamples that are extremely large!"  And he said, "It is my conjecture that there are none! (and if any, they are rare)".  Please help me, smart math people.  Can you provide a counterexample to his conjecture?  Perhaps, more convincingly, several?  I've only managed to find one! (Polya's conjecture). One, out of the many thousands (I presume) of conjectures. It's also one that is hard to explain the finer points to the layman. Are there any more famous or accessible examples?


For example, suppose I have a user sysadm with password abcdefg. But when it needs to execute sudo command, the password is hijklmn.  Is this doable?

When installing Ubuntu I can create a user with an encrypted folder, what I always do. Now after the installation the login password for this user is also the sudo password. Is that how it should be? I actually would like to have a different user login and sudo password, does is make sense? Should I do that, how?


'm looking for a way to change my public IP address. You know that the one that other websites see.  I know what I'm looking for is basically a proxy server, but I don't want to use a proxy for 2 reasons:  1) It slows me down. 2) See reason   I'm using Ubuntu 9. I'm connecting to a public WiFi network (the ISP is Time Warner Cable). I'm getting my IP throug P.

I'm looking for a way to change my public IP address. You know, the one that other websites see.   I know what I'm looking for is basically a proxy server, but I don't want to use a proxy for 2 reasons:  1) It slows me down. 2) See reason #1.  I'm using Ubuntu 9.10, I'm connecting to a public WiFi network (the ISP is Time Warner Cable). I'm getting my IP through DHCP.  Thanks for any help!


Is there a back story to:     Here's the story of a lovely lady   Who was bringing up three very lovely girls   All of them had hair of gold, like their mother   The youngest one in curls        Here's the story of a man named Brady   Who was busy with three boys of his own   They were four men living all together   Yet they were all alone   Why were they all alone? Death in a war? Irreconcilable differences in former marriage(s)?   Is there a back story?

In the Brady Bunch (the TV show, not the film series), the title song establishes that the 6 new step-siblings are from Mike and Carol's former marriages (or partnerships).    What happened to Mike's former wife / partner?  What happened to Carol's former husband / partner?  Were these two others ever mentioned for any amount during any episodes, or if still alive, did they ever make any appearances or claims towards their children?  I have never watched the pilot episode / first episode, so I do not know if that episode explains it.


I'm currently using Ubuntu XFCE4 and I am trying to install elementary-desktop. Except everytime I try to install it, all it comes up with is,           E: Could not get lock /var/lib/dpkg/lock - open (11: Resource temporarily unavailable) E: Unable to lock the administration directory (/var/lib/dpkg/), is another process using it?   Could someone please help me with this? Thanks!

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


I found a pretty cool question which justified a bounty. I didn't receive a correct answer and the bounty is about to expire. Instead of extending the bounty I MUST pick an answer or half a bounty will be given away on my behalf if the answer got 2 up votes even if it is incorrect or off topic.  I will lose all the bounty regardless of up votes and correctness which also makes no sense. If I found a solution and the community found it useful why not  giving back at least the half of the reward?   It is my rep why can't I decide? I understand that other members of the community may find the answers useful but they have ways to reward answers: they can up vote or they can start their own bounty. It is unclear why their opinion matters if the bounty was mine.   The current bounty mechanism also prevents extending bounties regardless how many people saw the question and how many answers I received.   I could create a new bounty if I am not happy with the answer but it will be automatically given to an existing answer if other people found it useful and no other answer was received.   This question is not about how the bounty system work or what the FAQ says or what the current bounty is by design. It is about whether it is fair or logical to spend it on anything other than it was intended to reward.   I may disagree with the 2 up votes and since it is my rep, given up for a specific purpose it should be up to me if it is given away or not. Other members of the community should use their own reputation or the voting system to reward answers.   Extending the bounty and waiting for a better answer should be an option as well. Losing rep every time it is extended discourages rewarding answers and seems wrong.  Why it is not a duplicate of:   How does the bounty system work? – The question is not about how the system works rather than why.  Please do not auto select answers on bounty questions – This is not even a question. I am asking for a change, I want to know why the bounty system works in a certain way and what are the reasons why the alternative solution I would have used are not used.  Should we allow adding rep to bounties to extend their duration? – Extending the bounty duration would solve the issues I mentioned my question is about why it is not like that

It's possible to offer and award bounties of reputation on questions.   What is a bounty? How can I find questions that have a bounty attached? How do I start a bounty? When can I start a bounty? Why is the system requiring me to choose a bounty amount that's higher than the minimum? Can I use Markdown formatting in the bounty remarks? Can I edit the remark? How long is the bounty period? How do I award a bounty? Can I award a bounty to my own answer? Can I award a bounty to an old answer? If I offer a bounty on someone else's question, can I award the bounty to their answer? After awarding the bounty, can I remove it or move it to another answer at a later time? What happens if there's no answer after the bounty period? What happens if I feel my question is still unanswered? What is automatic awarding? Are bounty awards exempt from the 200 points/day reputation limit? How does Community Wiki mode affect bounties? How does user deletion or post dissociation affect bounties? Can I award a bounty to an answer from a deleted user or one where the author was dissociated? Can I offer a second bounty after the first one has expired? Can I raise my bounty? What happens if a bounty question is closed or deleted? Why can't I vote to close or migrate a bounty question? What happens if I delete my account while I have an active bounty? Do I keep an awarded bounty when I delete my answer? What happens if a question where I awarded a bounty later gets deleted or migrated? Can I cancel my bounty? Can I affect / divide / share part of my bounty to two (or more) users? How many outstanding bounties can a single user have?      See also:  in the Help Center


I have a simple class in here: class Info:      # __slots__ = ('name','age')     def __init__(self, name, age):          self.name = name          self.age = age      def members(self):         print(self.__dict__)  >>> Info(name= "John", age=10).members() >>> {'name': 'John', 'age': 10}  Now, I add the __slot__ to the above class: class Info:      __slots__ = ('name','age')     def __init__(self, name, age):          self.name = name          self.age = age      def members(self):         print(self.__dict__)  Info(name= "John", age=10).members()  Now, I keep getting the following error. How am I be able to access objects attributes in this case? Thanks! print(self.__dict__) AttributeError: 'Info' object has no attribute '__dict__'

What is the purpose of  in Python — especially with respect to when I would want to use it, and when not?


I read that humans are a few percent Neanderthal. So how much difference between egg and sperm is needed for there to be no offspring. That is, for there to be two different species? Is this a measurable quantity or just a random genetic mismatch?

What determines speciation at a molecular level?  At what point does a scientist determine two lineages are different enough to be considered separate species?  Does it have a margin of error?


I need to be able to find out what version of Ubuntu we are using. I have no IT person who can help anymore. Can anyone help please?

I installed some version of Ubuntu on my VMware, but I don't know what version exactly it is. How can I find it out?


Is it possible to wrap text around a circle or around a polygon? Or do I have to insert linebreaks manually to the right places?

How do insert image between text and text wrap with shapepar or other package?


not sure if its supported or not, i'm using an AMD RX Vega56 (OpenCL). using a normal map in the principled BSDF + micro displacement gets me just a blck hole.  is it supported?  thanks for the help :)

I followed a microdisplacements tutorial on Blender Guru and I was able to create a texture fine. Here is a picture.  And then I turned on Adaptive subdivision. Here is a picture of what happened.  I know that this question has been asked before but I am using blender 2.79 so it should be fixed, right? Please let me know you ideas. Thanks


I want to buy one windows server 2016 standard license. As this server will locate in Data Center, I do need to remote to access when I want to use it.  The user who manage it is only me (1 user), but sometimes I do need to remote from Mac or PC.   Should I bought RDS CAL license for this case? And Do I need to buy User CAL for adding more users?  Could you please answer me what I need to buy to complete this condition?  PS. It might seem duplicate this  , but there is some different in details. So, I ask a new question.

This is a  about Licensing.    Questions on licensing are off-topic on Server Fault.  If your question has been closed as a duplicate of this question, then this is because we want to help you understand why licence questions are off topic rather than just telling you "it just is". In all likelihood, this question will not address your question directly, it was not meant to.    I have a question regarding software licensing. Can the Server Fault community please help with the following:   How many licenses do I need? Is this licensing configuration valid? What CALs do I need to be properly licensed? Can I run this product in a virtual environment? Can I downgrade this product to an earlier version? Am I entitled to feature X with license Y?


How can I detect a client-side capsLock keypress...I have tried creating the following function that I wanted to launch when a key is pressed   <script type="text/javascript" language="javascript"> function changeCapsLock(e) {    if (typeof capsLockON != 'undefined' && e.keyCode == 20) {       capsLockON = !capsLockON;       displayMsg();          }       }   //Display the message if CapsLocks is ON, otherwise conceal the message     function displayMsg() {           if (capsLockON)                 document.getElementById('divCapsWarning').style.visibility = 'visible';         else       document.getElementById('divCapsWarning').style.visibility = 'hidden';    } }   </script> </head>  <body onkeydown="changeCapsLock(event)">    but the onkeydown event does not fire when the CapsLock is pressed?

How do you tell if caps lock is on using JavaScript?  One caveat though: I did google it and the best solution I could find was to attach an onkeypress event to every input, then check each time if the letter pressed was uppercase, and if it was, then check if shift was also held down. If it wasn't, therefore caps lock must be on. This feels really dirty and just... wasteful - surely there's a better way than this?


I would like to have a darktheme in TeXworks, So I have followed  answer. However, the default color of commands like \section is dark blue, which makes it very difficult to see (even worse for \usepackage which uses a darker blue).  Is there any way to define the special syntax coloring used within my CSS file?

I am using texworks for the first time, I want to change the background of the editor from dark to white, as the code is not visible in dark background. I am using texworks in Manjaro Linux on GNOME desktop environment. Please help me.


I will be flying from Johannesburg via Dubai to Christchurch with a technical stop in Sydney, do I need a Visa for this?

I'm travelling to New Zealand, and my itinerary mentions a technical stop in Australia.  Will I need to apply for an Australian transit visa for this?


I have a /64 block of IPv6 addresses, and I'd like to be able to start a TCP server listening on any one of them. Currently I can bind to any static IP address, but not any others. If I try to bind to an address not statically routed (by the way, I'm not sure if I'm using the right terms), I get an error message, "bind: cannot assign requested address".  Here's from ifconfig:  eth0      Link encap:Ethernet  HWaddr 56:00:00:60:af:c6           inet addr:104.238.191.172  Bcast:104.238.191.255  Mask:255.255.254.0           inet6 addr: fe80::5400:ff:fe60:afc6/64 Scope:Link           inet6 addr: 2001:19f0:6801:187:5400:ff:fe60:afc6/64 Scope:Global           inet6 addr: 2001:19f0:6801:187:ea1e:eb99:13ae:d49a/128 Scope:Global           UP BROADCAST RUNNING ALLMULTI MULTICAST  MTU:1500  Metric:1           RX packets:1526389 errors:0 dropped:0 overruns:0 frame:0           TX packets:1622562 errors:0 dropped:0 overruns:0 carrier:0           collisions:0 txqueuelen:1000           RX bytes:280302410 (267.3 MiB)  TX bytes:266740313 (254.3 MiB)   If I try to bind to e.g. 2001:19f0:6801:187:a:b:c:d, it fails with "bind: cannot assign requested address". But if I do ip -6 addr add dev eth0 2001:19f0:6801:187:a:b:c:d, then I'm able to start the server listening on that IP address.  How can I configure Linux so that I can listen on any 2001:19f0:6801:187::/64 address? That is, I want to bind to some specific IP address without having to ip addr add it first.  Or should I just have my server ip addr add an address before binding, then maybe ip addr del it when I'm done?  Addendum: In case my problem isn't clear, I've already gotten far enough that the whole prefix is getting routed to my server so that it can, for example, respond to pings for any address with that prefix. If I start a TCP listening on "[::]:80", it will respond to requests to any IP address. What I want is to be able to listen on a specific IP address so that only requests addressed to that IP address will hit the server. Other ServerFault questions linked to are asking how to get a server to respond to requests to any IP address. I've already gotten that far. I want to be able to bind to any arbitrary address, but only one specific one. The problem is that Linux won't even let me start the server on a specific address if that particular address isn't statically assigned to an interface, and I'd like to work around that.  To be even more concrete, I can presently run a TCP echo server on my VPS on all interfaces:  ncat -l 2000 --keep-open --exec "/bin/cat"   Then from my laptop, I can connect to it using any random IPv6 address:  telnet 2001:19f0:6801:187:: 2000 telnet 2001:19f0:6801:187:abc:def:: 2000 telnet 2001:19f0:6801:187:abc:def:123:0 2000   This all works. If I start the server on a statically assigned address, it also works:  ncat -l 2001:19f0:6801:187:5400:ff:fe60:afc6 2000 --keep-open --exec "/bin/cat"   Now I can only connect to that particular IP address. So far so good.  Now I'd like to be able to start a server on some random address:  ncat -l 2001:19f0:6801:187:abc:123:: 2000 --keep-open --exec "/bin/cat"   But I get an error: "Ncat: bind to 2001:19f0:6801:187:abc:123:::2000: Cannot assign requested address. QUITTING." But if I ip -6 addr add dev eth0 2001:19f0:6801:187:abc:123::/64, then the previous ncat command works, and the server starts and only responds to connections to 2001:19f0:6801:187:abc:123::.  So can I configure Linux to let me start a server on any arbitrary address in my block without first adding it as a static address?  (Actually, my question is very similar to , although there they're talking about IPv4. There the answer is to statically add all addresses.)

I know that the ip tool lets you bind multiple addresses to an interface (eg, ). Right now, though, I'm trying to build something on top of IPv6, and it would be really useful to have an entire block of addresses (say, a /64) available, so that programs could pick any address from the range and bind to that. Needless to say, attaching every IP from this range to an interface would take a while.  Does Linux support binding a whole block of addresses to an interface?


Using SQLCMD with -o to file.  How to get rid of the (XX... rows affected) message at the end for a clean output?

I'tm trying to show in SQLcmd window the results of these queries:  SELECT SYSDATETIME() AS "date";  PRINT 'EXTRAÍDO POR:' SELECT SUSER_NAME() AS "Owner"  PRINT 'PASSWORD SETTINGS'; exec xp_loginconfig;  PRINT 'PASSWORD SETTINGS'; select * from sys.sql_logins;   And using this command in SQLcmd:  sqlcmd -S myServer -i inputpath -s, -o outputPath(like C:\log.xls) -e   So the sqlcmd output the file and does not show nothing in sqlcmd screen. How can i print these "Print" commands in the sqlcmd screen? (command promt).  When I run it on SSMS works well, like:  (1 row affected) OWNER:  (1 row affected) PASSWORD SETTINGS  (8 rows affected) PASSWORD SETTINGS  I would like to show in the prompt command this, like in the SSMS.  Thanks!


Caratheodory says that $E\subset \mathbb R^d$ is measurable if $$m^*(A)=m^*(E\cap A)+m^*(E^c\cap A)$$ for all $A\subset \mathbb R^d$. To me a more natural way would have been to define it as : $E$ is measurable if $$m^*(E)=m^*(E\cap A)+m^*(E\cap A^c)$$ for all $A\subset \mathbb R^d$. But, maybe the equality hold for all $A\subset \mathbb R^d$, even if $E$ is not measurable, that's why it wouldn't be a good definition. What do you think ?

This week I saw the definition of a measurable set for an outer measure.     Let $\mu^*$ be an outer measure on a set $X$. We call $A \subseteq X$ measurable if $$\mu^*(E) = \mu^*(A\cap E) + \mu^*(A^c\cap E)$$ for every $E \subseteq X$.   This is not the first time I've seen this definition. Unlike most other things in mathematics, over time I have gained absolutely no intuition as to why this is the definition.   The only explanation I've ever seen is that a set is measurable if it 'breaks up' other sets in the way you'd want. I don't really see why this is the motivation though. One reason I am not comfortable with it is that you require a measurable set to break up sets which, according to this definition, are non-measurable; why would you require that? Of course, you can't say what a non-measurable set is without first defining what it means to be measurable so I suppose no matter what your condition is, it will have to apply to all subsets of $X$.     Is there an intuitive way to think about the definition of measurable sets? Is there a good reason why we should use this definition, aside from "it works"?


I add a member detail from add() method , after that i go modify() to edit member detail by searching memberID, compare the stored memberID with the user entered memberID , if match then display the member detail else display invalid, so what should i create to do so?    public static void Modify(Registration [] reg){      Scanner scan = new Scanner(System.in);      System.out.print("Enter member id to search : ");      String search = scan.nextLine();      for(int i=0;i<reg.length;i++){     /*if(search == member[i].getMemberID()){     System.out.println(reg[i].toString());      }      else      System.out.println("Invalid.");*/      }}}

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


I'm getting a NullPointerException right where I call the query from my Fragment class. I'm fairly certain the issue is because I'm instantiating my ContentProvider class in my Fragment class, but I don't know how else I can call the ContentResolver if I don't have the context. I'm pretty new to Android programming and it's hard for me to get a grasp on things at first so forgive me if it's a really obvious error.  So here is part of the code,  abstract private class BaseTask<T> extends AsyncTask<T, Void, Cursor> { @Override public void onPostExecute(Cursor result) {   ((CursorAdapter)getListAdapter()).changeCursor(result);  }       protected Cursor doQuery() { // This method sets up my query call in ConstantsFragment class.      Uri uri = ConstantsProvider.Constants.CONTENT_URI;      String[] projection = new String[] { ConstantsProvider.Constants.TITLE,              ConstantsProvider.Constants.VALUE };      String selection = ConstantsProvider.Constants.TABLE + " = '"            + ("1") + "'";      String[] selectionArgs = null;      String sortOrder = ConstantsProvider.Constants.DEFAULT_SORT_ORDER            + " COLLATE LOCALIZED ASC";       Cursor result = cp.getContext().getContentResolver().query(uri, projection, selection, selectionArgs, sortOrder);       //Above is where I get my nullpointer. cp is my Contentprovider class object.       return result;      } }   I'm leaving my ContentProvider and ConstantsFragment class(which is the class that includes the above code)  below incase needed. In my ConstantsFragment class I have no completed the insert/delete methods so ignore those for now, I want to make sure my query works first.  ContentProvider class :   ConstantsFragment class:

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


how would you prove that for 135 consecutive integers $a_1,a_2,...,a_{135}$ such that for all integers $k$, $1 \leq k \geq 135$ there exists a perfect cube $z_k > 1$ such that $z_k$ divides $a_k$?  Im stuck on this question and don't even know how to start. All I know is that if $z_k$ divides $a_k$ then $a_k = mod (z_k)$

As of 22:13, the answer below does not satisfy the constraints of my question, so I'm still accepting answers.    Prove there exist 135 consecutive integers, $x_1, x_2, ... , x_{135}$, such that for each of these integers, $x_i$, there exists a number $k_i$ such that $k_i>1$ is a perfect cube where $k_i | x_i$.    I was told that I could use GCRT to help with this. I got stuck after rewriting the given statement as a system of linear congruences.


There are many methods to protect a website I know, but I was woundering if you can rate how well my methods are in the prevention of SQL-injection and database injection, and most importantly, give me suggestions on other ways to protect my website and database.  What I have in my website: (i) JavaScript + PHP form validation(dual-validation) (ii) sha512 password hashing (iii) mysql_real_escape_string all POST variables going into MySQL queries  How easy/hard are my current methods of prevention to bypass/hack? How can I improve on my current methods or addition of new methods?

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


I'm not sure where to ask a deployment question, Stack Overflow or Server Fault. It's kind of a crossover question.  I need to be able to sort out the server requirements for deploying a click once app. I thought that my server had all the required attributes, but I am having issues, which sort of implies a serverfault.com question. However it's very likely that only a .NET dev would be able to answer me.  Where do you think I should ask my question?

There are lots of questions that come up when thinking about getting software productive.   Like how to do versioning of the software, how to deploy it on client side and generally how to roll software out.  Having done this multiple times in different ways, there are still lots of open questions.  If I ask them on stackoverflow, they will get closed with very high probability. They are not to programming related, I cannot provide code, they seem to be  ideally suited for "off topic".  So: Where can I ask those questions?  -edit-  To have more concrete example of the questions that I would like to ask:   What to consider before rolling software out? How to version a bunch of assemblies without having to edit lots of config files? How to keep software on client side up to date? ...   I would really appreciate to ask those questions myself, if there is a place for it somewhere. SO seems to be no match.


I have a folder that consists of other folders (whose names are unknown), .tar archives and JPEG images. How can I remove everything except .jpeg files?

I have a directory that contains the following:  x.pdf y.zip z.mp3 a.pdf   I want to delete all files apart from x.pdf and a.pdf. How do I do this from the terminal? There are no subdirectories so no need for any recursion.


I have my below that takes entire values and outputs them into another file.  with open('candidatevalues2.txt', 'w') as outfile:     outfile.write('plate mjd fiberid FWHM erFWHM loglum loglumerr logBHmass logBhmasserr  ksvalue pvalue\n') for i in range(9):     with open('candidatevalues2.txt', 'a') as outfile:         dmpval= stats.ks_2samp(y_real[i], yfit[i])         outfile.write('{0} {1} {2} {3} {4} {5} {6} {7} {8} {9} {10}\n'.format(plate[i], mjd[i], fiberid[i], fwhm[i], fwhmer[i], loglum[i], loglumerr[i], logbhmass[i], logbhmasserr[i], dmpval[0], dmpval[1]))   The first few lines of the file show as:  plate mjd fiberid FWHM erFWHM loglum loglumerr logBHmass logBhmasserr ksvalue pvalue  590 52057 465 1710.58526651 115.154250367 42.0681732777 0.070137615974 6.81880343617 0.15451686304 0.0909090909091 0.970239478143  1793 53883 490 1736.15809558 144.074772803 40.160433977 0.0736271164581 5.7828225787 0.13016470738 0.0909090909091 0.970239478143  648 52559 335 1530.9128304 153.965617385 40.8584948115 0.110687643929 6.05420009544 0.155678567881 0.0909090909091 0.970239478143   I am wondering how do I reduce all the values to just 2 decimal places?

I want a to be rounded to 13.95.  >>> a 13.949999999999999 >>> round(a, 2) 13.949999999999999   The  function does not work the way I expected.