Is there any rule of using will,shall,should, could and would with has/have and had?  I  know that we should never use had with will because will is a future tense but the others I am not sure?  correct: I will have lunch with her tomorrow wrong: I will had lunch with her tomorrow   similarly what will happen with shall, should, could and would? I asked an another collegue of  mine and he told me we should never use had with will, shall, should, could and would.

What is the difference between      How could it had happened   and      How could it have happened   It would be better if anyone can show its usage in some kind of situation.


Prove that if H has finite index n then there is a normal subgroup N of G with $N \subset H $ and [G:N]$ \le $n!.  I tried to solve the problem but could not done exactly. Since [G:H]=n , Let A={$a_i H$:i=1,2,..,n}. Consider the left multiplication group action on A .Then kernal of the action is intersection N= $\cap a_iHa_i^{-1}$ i=1,2..,n.  Then N is the largest normal subgroup of G contained in  H. Now it is clear that $[G:a_iHa_i^{-1}]$ =n for all i.{by orbit stabliser theorem}.Now how to find [G:N]? yes I got it. By Caley's theorem G/N is isomorphic to a subgroup of $ S_{A}$ .Therefone [G:N] divides n!.

Let $G$ be a group and $H$ be a subgroup of $G$ with finite index. I want to show that there exists a normal subgroup $N$ of $G$ with finite index and $N \subset H$. The hint for this exercise is to find a homomorphism $G \to S_n$ for $n := [G:H]$ with kernel contained in $H$.   The standard solution suggests to choose $\varphi$ as the homomorphism induced by left-multiplication $\varphi: G \to S(G/H) \cong S_n$. I'm not 100% sure if I understand this correctly. What exactly does $\varphi$ do? We take $g \in G$ and send it to a bijection $\varphi_g: G/H \to G/H, xH \mapsto gxH$? If so, how can I see that its kernel is contained in $H$? Also, the standard solution claims its image is isomorphic to $G/N$ and thus $N$ has a finite index in $G$, how can I see that the image is isomorphic to $G/N$?  Thanks in advance for any help.


In my top bar, only the time is shown. How can I also see the date there?

On previous versions I had the date displayed. Now it just shows the current day but not the day's number or the month.   Is there a way to customize the clock or tray/taskbar more in GNOME shell on Ubuntu 17.10 and later?


Is it possible to use JQuery to hide the input elements plus the text after the input? The code is generated, so I cannot change the text, wrap it in a span or alter it in any way.  Event Location *
 <input type="radio" name="a22" id="a22_0" value="Lafayette  LA">Lafayette LA
 <input type="radio" name="a22" id="a22_1" value="Houston TX">Houston TX
 <input type="radio" name="a22" id="a22_3" value="San Antonio TX">San Antonio TX

I would like to get all descendant text nodes of an element, as a jQuery collection. What is the best way to do that?


I am new with blender program. I have a need to render animation for a inventor model I have.  I got stl. file from inventor which is an assembly. My problem is that I need to color that model before rendering ( In inventor model is painted but when I import it to blender its in default grey).  When I apply coloring in blender it affects whole assembly, which is not good for me, I have some parts that I need to paint in different color.  My question is how to separate those part? As for now I see that assembly as one part and anything I do will affect it whole?  Thank you in advance.

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.


Is it incorrect to use "and so" to link an antecedent and a consequent, when "so" alone would do it?  Note: there is an existing question with a similar title () in the EL&U database, but it doesn't address the same issue. That question is about repeating some words from the antecedent. I'm asking about the appropriateness of "and so" itself.    The fact that it is fine to say "...and so do I," is because 'so' is used as an adverb. Or "...and so it goes." Both of these are 'so' meaning 'this way'. "I found a dollar, and so I picked it up," is using 'so' as a conjunction. It's the usage in this last example that I'm asking about.  I was late, and I got fired. I was late, so I got fired. I was late, and so I got fired.    I feel in my deepest soul of souls, or at least I kind of suspect, that this use of "and so" is technically incorrect, despite being incredibly common and almost no one having specifically asked this question until now. There are other questions regarding "and so," but not questioning whether this combination is itself proper. Did this come from spoken English, when someone says "and" to continue a story before realizing that "so" is more descriptive?    I can't think of another case of two coordinating conjunctions next to each other. Subordinating and coordinating, yes: "I was late, and, because the boss saw me, I got fired." or even: "I was late, and, so it wouldn't happen again, I got fired." But these are different than my question.    A happened, and so B happened. Too many conjunctions!    Edit: This is not the same question as the suggested duplicate "Use of 'and so'", which I obviously saw before posting this, as I mentioned that I searched for duplicates before asking. That question was to a particular aspect of how to use "and so". I am asking if and why and how "and so" is justified at all. The other person did not ask whether "and so" is correct in itself.    The question marked as duplicate is, word for word: If "and so" connects predicates such that the second is the result of the first, do we need to repeat the same words in the second?  My question is: Is it not in fact incorrect to use "and so"?

If "and so" connects predicates such that the second is the result of the first, do we need to repeat the same words in the second? For example,      It does not exist locally and so globally.   or     It does not exist locally and so does not exist globally.


I'm having a problem trying to find the simplest way of proving this, which has most probably been solved a hundred of times but I am unable to find a good reference.  I have two groups, $(\mathbb{R},+)$ and $(\mathbb{R}_{>0},\times)$. I am trying to prove that the only class of isomorphisms between them is the class $F = \{f: f(x) = \exp(\alpha x), $ for all $\alpha \in \mathbb{R}_{>0}\}$. Existence is easy to prove: what I'm having trouble with is a clean algebraic uniqueness proof.  Does anyone know the proof or a reference containing this proof?  Thanks in advance!

If so, how might I be able to prove it?  EDIT: OK, thanks to many answers especially spin's and Micah's explanations. All of the answers were extremely helpful in understanding -- I have accepted Micah's because it seems the most complete, but all answers provide helpful additions/perspectives! I have tried to summarize:     $\phi$ is an isomorphism between the groups if and only if $\phi(x) = e^{f(x)}$ where $f$ is an isomorphism from $(\mathbb{R},+)$ back to $(\mathbb{R},+)$.   Of course there are lots of such $f$, especially when we take the Axiom of Choice.  However, it seems from the answers and Micah's link () that the only "nice" solutions are $f(x) = cx$ for a constant $c$. It seems that all others must be "highly pathological" (in fact $\{(x,f(x))\}$ must be dense in $\mathbb{R}^2$).  A remaining question is, how strong is the statement     All such isomorphisms have the form $e^{cx}$ for some $c \in \mathbb{R}$   or its negation? Or what is required for each to hold?  One answer seems to be that supposing the reals have the  is sufficient to rule out other solutions (as is assuming every subset of the reals is measurable, assuming the , and it holds in ). For more, see , , and .


Where does the logins users are stored in the SQL server “in which data base “  In some softwares that requires the admin to create users/password for his users such as ArcGIS server the logins information are stored in a separate database so that the admin takes periodically backups just in case if the server was down to avoid losing the usernames and passwords. In the SQL server 2012 how can I manage to back up my logins since the moved the database form one machine to another preserves the users but the users cannot connect to the SQL server due to the loss of logins.

I moved a database from SQL Server 2005 to SQL Server 2012. Is there any way of restoring all the logins on the new server?


How do you get the portal in act 2 in the center of the desolate sands to work? If you press the stone to the left of it it does nothing... What do you do to get it to actually do something?

What are the 10 possibilities for Wheel of Misfortune?  And what is the best way to farm them?


I found this sentence in a university test: "the process....gradually", and I was supposed to fill the gap with either the present simple or the present continuous form of the verb "to stabilize". Without context I really didn't know which tense I had to use. I ended up using the present continuous tense because I thought it made a bit more sense. So, is it correct to say "The process is stabilizing gradually"? I do know that adverbs should be placed after the verb "to be", therefore from a grammatical standpoint "the process is gradually stabilizing" is probably the better sentence of the two. It seems to me, though, that in this case putting the adverb at the end of the sentence does not sound terrible.

What would be the right position of "substantially" in the following:     1). Before verb: These optimal values substantially contribute to the success of the methodology.      2). After verb: These optimal values contribute substantially to the success of the methodology.   Here is my issue:  Fact1: When I use Google Ngram, I get , 0 occurrence of option 1.  Fact2: I found an excellent Grammar book that discusses Adverbs, their types and prefered positions. The author defines some rules that I'll summarize as follows:   Connecting adverbs, eg: however, then,..., Position: Beginning of clause. Indefinite frequency, eg: always, usually,..., Position: Mid position (after auxilary verb, before other verbs) sometimes beginning of clause. Focusing adverbs, eg: mainly, only,..., Position: Mid position. Adverb of certainty, eg: clearly, obviously, Position: Mid position. Adverb of completeness, eg: almost, nearly,..., Position: Mid position. Adverb of manner, eg: fast, slowly, nicely,..., Position: End clause, mid and beginning. Adverb of place, eg: upstairs, around, Position: End clause, sometimes beginning. Adverb of time, eg: daily, weekly, ... Position: Mostly end clause, sometimes beginning and mid position.   I think that "substantially" is an adverb of completeness. Therefore, the right position is before the verb "contribute" (option 1). However, Google Ngam indicates that option 1 is not widely used.  What do you think? Any suggestions?


Yes, the books might have been written on this but not being a technical person, I'd like to understand in short and easy to understand language - How to interpret a histogram to know whether the photo is under or over exposed?

I realize that an image histogram is a graphical display of an images tonal distribution (i.e. horizontal darks to lights, vertical pixel distribution), but how does one really use it and why? I mean, can't you determine everything you need just by looking at the image?


I'm designing a custom headboard for our bed and I want to install electrical into the cubbies I am making in the headboard (primarily for cell phone charging). In my current design, the electrical box would be installed into a cut out 2x4.  I've attached two sketchup models for reference. My primary question is this: Are there any U.S. electrical codes or even best practices I need to be aware of in regards to where and into what material I can install an electrical box? The only thing I could find was that a box can protrude through up to 1/2" of drywall, so I'm wondering if that means that attempting to protrude through a larger (flammable) piece of material like this is against code. If you have any other related advice/caution about running electrical into furniture, that would be welcomed as well. Thanks!  EDIT: In my design, this 2x4 could be changed to a different material, but initially I was trying to keep the structure to 2x4s and plywood for simplicity. I could switch to a thinner material if that would help me to be in compliance.  ,

Having electrical outlets, USB charging ports, night lights, etc would be nice to have on some pieces of furniture, like side tables. Several receptacle manufacturers make combination fixtures with USB and power, for instance, or power plus a night light.   I've thought about nailing an electrical box to a (hidden) portion of the table and putting one of those receptacles in it, but what things do I need to consider doing this? Is it as simple as it sounds,  and then just fashioning some kind of plug out of 12/2 or 14/2 wire? Does the answer change if the box is concealed (though still accessible) vs it being completely visible?


I believe this was a childrens book. I would have read it about 10 years ago.  The main character was a girl who could change her appearance when concentrating on herself in the mirror. This is later explained as her shifting around in more than three dimensions. She at some point tries to point at something she sees in a higher dimension, and another character says her arm turns red and disappears. She at one point finds a hypersphere that she can "fold" into higher or lower dimensions that she carries around with her which helps her use her powers.   She is part of a group of four children with different such power that start out trapped in a house and unaware of their powers and origins. They work differently, one boy turns into a metallic dragon-like creature and is then semi-killed/reborn via magic bacteria/nanomachines.

The series had three books.  A universe of Greek gods/goddesses, set in modern time.    The gods steal Titans and force them to assume the form of infants/children, and raise them as mundanes in a boarding school type situation.  The protagonist is a young woman who discovers she can travel through the fourth and fifth dimensions as her power.  Her companions: a fey, can travel by unseen ways to various locations; a boy-shaman raised under the traditions of science, can cause anything he wants to happen simply by wishing it and tries to recreate the Michelson–Morley experiment. She ultimately discovers the true nature of the universe she is in and that the deities all follow some sort of rock-papers-scissors system where each deity has a corresponding type which he is weak to, and strong against.  What is the name of this series?


It looks like there are companies that sell the lists of domain names, yet their lists are incomplete, and each company has a different amount of entries for a particular TLD.  Why so much conspiracy about the complete list of existing/registered/active domain names? Why isn't it just available online for everyone (of course, without any additional data, just domain names)?  And the main question is - is there a right technical way to build such a list on my own?  If I understand correctly, registrars are accredited for each TLD, and then they are responsible to host zone files.  So, if one is to build the complete list, they would need to get a complete list from all registrars and join them together.  Sounds simple, yet there are no such lists available. So why is it so and how to do it properly on my own from the technical point of view?

Where can I find a list of domain names that I can download in a text file? I looked around and I found many sites with lists of expired domain names or domain names that will expire soon, but that's not what I need, I need a list of CURRENTLY REGISTERED domain names. The closest I found was this site (hxxp://www.list-of-domains.org/), but what I'm looking for ideally is just a plain list of registered domains and not some web links split across many pages full with ads and no text file. I know it's possible, after all how do these sites get the list of domains that they use? Where can I find such a list?


I overheard some of the kids in one of my programming classes discussing this. I am curious as to what the answer is. What do you guys think?

I remember an episode in Star Trek TNG (probably first season) where Data is describing some of his internal workings. Among them, he lists that he is equipped with "12 quadrillion" bytes for memory storage. If my math is right that is 12 petabytes.  It seems to me that is severely short for the amount of data he collects every single day.  I found this related question:    However, it seems that Data likely did not back up anything that he learned. I do remember him stating a few times that he forgets nothing.  So this is the question: Is 12 PB enough storage for an android like Data (assuming none of it is taken up by OS and programs)?     Consider some of the implications about massive amounts of data on .    Well, I just found  which says it is 800 quadrillion bits! That is quite a bit more (pun intended) but I am certain that the episode I am thinking of said 12.


I get a phone call on my iPhone which is paired with QC35 headphones. At the point that the call starts, my mac starts iTunes and starts to play music through the same headphones I'm taking the call on.  I've tried disabling iTunesHelper but this continues to occur. Completely ridiculous out of the box behaviour.

Recently I have been having these issues with my MacBook and iPhone wherein if I press the play/pause button on my MacBook to stop iTunes it "mutes" all audio and switches to my connected iPhone.  Only when I reset my QC35 does it reset and behave correctly (where in pressing the button stops iTunes but leaves audio connected to my MacBook).  Any ideas how I can solve this permanently or can someone guide me in the right direction?  Update  Little late but thought I'd add an update. I simply contacted Bose and they ended up replacing my headphones and even gave me the gen 2 headphones


I just finished my application, and thought I checked it over pretty well  submitted, and printed.   I just did another check to realize I entered my mother's year of birth wrong. It's certainly not 2017. Lol   How shall I proceed? Is it advisable to correct neatly with pen, straight line through? Perhaps include a cover letter just stating my clerical mistake? Do I just mention this to the ECO?   My appointment is in three days... Help!

I am applying for an EEA national permanent visa and the planned date of arrival is not correct on the application form submitted. Am I able to cross it out and write in the new one? I am from Spain and submitted the application to the British Embassy.


First let me be clear here， I thoroughly understand that economy in general is very convoluted and volatile. I am not expecting myself to somehow do well especially in practical terms in a short period of time or any foreseeable future really. I only want to pick it up as I enjoy learning and recently I really start to gain interest in some of the papers I come across on econometric. I enjoy learning things especially things that are less well understood. My education background is a PhD in ontology; however, my current job mostly works with fields like convex analysis, mostly real-time machine learning and things to do with said field (probability, information, topology, linear algebra vector calculus discrete math lie group etc etc).  My understanding of stochastic statistics would be weaker than many who work in the field, I read these are much more prominent in financing than things I am familiar with. But I am happy to put in some time and get a better grasp of it.   My question however is from my background of education, what are the good list of books to read in regard to learning stock trading? I do have a day job so it wouldn't be very unlikely for me to take any course in it. However, I do get a lot of free time even when I am working so I am happy to put in more then 5 to 6 hours a day for the near future. As I said I am not looking to make a dim anytime soon I just want to learn and understand. I also am very accustomed to read very heavy books with limited language expression capabilities, so you don't have to worry there, haha.

Despite being STEM person, I always wanted to learn how stock & financial markets work. I always wanted to know how those stocks work, what are those bonds e.t.c.  The only struggle I am having, is the absence of the book, which describes market in a mathematical way. I mean, after all these years, I get used to books which have a little of text and a lot of formulas.   So, what are some good books on stocks, bonds, derivatives, theories behind them, decision making e.t.c., which are mathematical?


Obviously Malfoy was sent to kill Dumbledore. But wouldn't it just have been easier to kill Harry? Why did Voldemort only have him kill Dumbledore, when there were countless opportunities to do them both off at separate times?

I was watching the Harry Potter and The Half-Blood Prince movie recently and when Harry tries to take down Snape at the end      (after Snape kills Dumbledore)    it was a perfect opportunity for the Death Eaters to take Harry to Voldemort.   Why didn't the fleeing Death Eaters take Harry right then? Was it too much of a risk for them to take him?


I like to run some scripts from mxd. Very often I am using Make Feature Layer tool to facilitate queries.  Tool help says: “Creates a feature layer from an input feature class or layer file. The layer that is created by the tool is temporary and will not persist after the session ends unless the layer is saved to disk or the map document is saved”.  Question:  How to remove newly created layer without closing mxd?   Note arcpy.mapping.RemoveLayer is not working on layer created that way or maybe I am doing something wrong here

I have an ArcPy based script where I'm trying to intersect two layers where one layer must have its centroid in the other layer.   Since I need to know that one layer (feature_layer below) includes the centroid of the other, I'm using the arcpy.SelectLayerByLocation_management() tool.   I do not have a Map Document (*.mxd) open so in order to do this, I have to use  to feed into it.   The documentation notes that the feature layer will disappear when the program exits, but I need it to disappear sooner since I have it in a loop similar to below  for feature_class in large_list_of_feature_classes:     some_function(feature_class)  def some_function():     feature = "{path to feature class}"     feature_layer = "feature_layer"     HUCs_layer = "all_HUCs" #HUCs being Hydrologic Unit Codes      arcpy.MakeFeatureLayer_management(feature, feature_layer)     arcpy.MakeFeatureLayer_management(feature, HUCs_layer)           arcpy.SelectLayerByLocation_management(HUCs_layer, "HAVE_THEIR_CENTER_IN", feature_layer, selection_type="NEW_SELECTION")      arcpy.CopyFeatures_management(HUCs_layer, selection_name)   I'm looking for a function to remove feature layers and I haven't been able to find one.   I realize I could put some sort of count in there or something to make each one unique within the scope of the program, but that's not ideal unless there is no way to remove feature layers.


I want to replace the floors in the lower floor of my home.  I'm estimating about $8000 worth of work, installed.  My wife has been looking into engineered floors.  I have never been a huge fan of engineered, because I am under the impression that long term durability is not there. We have big pets and children. The chances of needing the floor stripped and refinished in under a decade is extremely high.  Can you even refinish an engineered floor?

Are there any downsides to engineered hardwood? I'm looking to install hardwood in dining room and kitchen areas.


Please, in which LaTeX package can I find the symbol between $s$ and $\langle n\rangle$ below ?

I know what my symbol or character looks like, but I don't know what the command is or which math alphabet it came from. How do I go about finding this out?


We use @username in comments and other places to refer to others here on stack exchange communities , so I guess  it would be good if @username automatically points to the profile to user 'username'.

Stealing this from OSQA (see here for ) - I suggest that whenever the system identifies a username prefixed by @ (e.g. @ripper234), this text is turned into a link to that user's profile: .


According to  , the earth does not fall down because of the gravitational force of the sun.   At the same time , earth's repulsive force , acts as a resistance to the gravitational force of the sun.   This theory is not satisfying because it doesn't hold good for mercury.   Mercury's mass is negligible when compared to sun.  So sun should have swallowed mercury already.  Is there a better theory to why the earth doesn't fall.

Why doesn't the Moon fall onto the Earth? For that matter, why doesn't anything rotating a larger body ever fall onto the larger body?


Evaluate $\sum_{k=1}^\infty \frac{k^2}{(k-1)!}$   I sense the answer has some connection with $e$, but I don't know how it is. Please help. Thank you.

For some series, it is easy to say whether it is convergent or not by the "convergence test", e.g., ratio test. However, it is nontrivial to calculate the value of the sum when the series converges. The question is motivated from the simple exercise to determining whether the series $\sum\limits_{k=1}^{\infty}\frac{k^2}{k!}$ is convergent. One may immediately get that it is convergent by the ratio test. So here is my question:     What's the value of $$\sum_{k=1}^{\infty}\frac{k^2}{k!}?$$


I have a table that looks like the following   COLUMN_A|| COLUMN_B || ====================== NAME1   ||    1     || NAME2   ||    1     || NAME3   ||    1     ||   NAME4   ||    2     ||   NAME5   ||    2     ||   NAME6   ||    3     || NAME7   ||    3     ||     I want to concatenate COLUMN_A depending on COLUMN_B. If values of COLUMN_B are same, then COLUMN_A should be concatenated seperated by a comma.  Expected result  NAME1, NAME2, NAME3 NAME4, NAME5 NAME6, NAME7

I'm trying to migrate a MySQL-based app over to Microsoft SQL Server 2005 (not by choice, but that's life).  In the original app, we used almost entirely ANSI-SQL compliant statements, with one significant exception -- we used MySQL's group_concat function fairly frequently.  group_concat, by the way, does this: given a table of, say, employee names and projects...  SELECT empName, projID FROM project_members;   returns:  ANDY   |  A100 ANDY   |  B391 ANDY   |  X010 TOM    |  A100 TOM    |  A510   ... and here's what you get with group_concat:  SELECT      empName, group_concat(projID SEPARATOR ' / ')  FROM      project_members  GROUP BY      empName;   returns:  ANDY   |  A100 / B391 / X010 TOM    |  A100 / A510   So what I'd like to know is: Is it possible to write, say, a user-defined function in SQL Server which emulates the functionality of group_concat?   I have almost no experience using UDFs, stored procedures, or anything like that, just straight-up SQL, so please err on the side of too much explanation :)


I want to know how can I set a "selector layer" (L.Control.Layers) outside the container in Leaflet. Like this screenshot of an OpenLayers application:

Can someone tell me how I can place controls outside of the map content with Leaflet?  In this case, I just want to place the layer switch control outside the map object.


For security reasons we are establishing SSO login to the entire org but we are facing an issue coming to Data loader CLI users. In CLI the username and password are provided in the process-conf files, how can SSO be enabled and used for the Data Loader CLI users without providing the Username and password in the conf files? Thanks in advance.

Hi is there a way to Sign in in Data Loader when is Single Sign On activated in my organization? If so what would be the steps?


Let ($\Omega$, $\cal{F}$, $\mu$) be a probability space and $f\in L^1(\Omega)$. Prove that  $$\displaystyle\lim_{p\to 0} \left[ \int_{\Omega}|f|^pd\mu \right]^{\frac{1}{p}}=\exp \left[ \int_{\Omega}\log|f| d\mu  \right],$$  where $\exp[-\infty]=0$. To simplify the problem, we may assume $\log|f|\in L^1(\Omega).$

The $L^p$ norm in $\mathbb{R}^n$ is \begin{align} \|x\|_p = \left(\sum_{j=1}^{n} |x_j|^p\right)^{1/p}. \end{align} Playing around with WolframAlpha, I noticed that, if we define the "scaled" $L^p$ norm in $\mathbb{R}^n$ to be  \begin{align} \| x \|_p = \left(\frac{1}{n}\sum_{j=1}^{n} |x_j|^p\right)^{1/p} \end{align} then \begin{align} \lim_{p \to 0} \|x\|_p &= \left( \prod_{j=1}^{n} |x_j| \right)^{1/n}, \end{align} which is the geometric mean of the coordinates' absolute values. This is interesting maybe because the $L^p$ norm doesn't have a nice limit at zero.  My questions:   How do I prove this? Is this definition of "scaled $L^p$ norm" interesting, or known by another name, or used anywhere? Is there any interesting reason to define the $L^0$ norm as the geometric mean, as above? Further reading?   Thanks!


Prove that for all real numbers $x,y,z$: $$\frac{1}{x}+\frac{1}{y}+\frac{1}{z}=\frac{1}{x+y+z}\implies \frac{1}{x^5}+\frac{1}{y^5}+\frac{1}{z^5}=\frac{1}{(x+y+z)^5}.$$

Suppose that $\displaystyle\frac{1}{a}+\frac{1}{b}+\frac{1}{c}=\frac{1}{a+b+c}$ . Then , prove that $\displaystyle\frac{1}{a^5}+\frac{1}{b^5}+\frac{1}{c^5}=\frac{1}{a^5+b^5+c^5}.$  Attempt :  From the given relation , $\displaystyle \frac{a}{b}+\frac{b}{a}+\frac{b}{c}+\frac{c}{b}+\frac{a}{c}+\frac{c}{a}=-2$.........(1)  Now I want to calculate , $\displaystyle \frac{a^5}{b^5}+\frac{b^5}{a^5}+\frac{b^5}{c^5}+\frac{c^5}{b^5}+\frac{a^5}{c^5}+\frac{c^5}{a^5}$. I tried by expanding pair of terms and putting the value of (1), but it can't help...


Today, we had a math class, where we had to show, that $a_{100} > 14$ for  $$a_0 = 1;\qquad a_{n+1} = a_n + a_n^{-1}$$  Apart from this task, I asked myself: Is there a closed form for this sequence? Since I didn't find an answer by myself, can somebody tell me, whether such a closed form exists, and if yes what it is?


On Windows I use Adobe Acrobat. With that I can create, edit pdf's or just fill in documents. There are programs available for making/editing pdf but they don't work that well.  So I am hoping you know a good one that has similar functions as Acrobat. I would switch to Windows right now but my primary notebook is out for repair so I have to do it with my old notebook witch only has Ubuntu to try it out and learn a little bit more

I know that there is a very similar question, but I'm not interested in highlighting. What I'm looking for is some tool in Linux to edit pdf files. I've tried pdfedit which did the work for me, but if freezes after a few edits. I've tried this tool under Ubuntu 9.10 and under KDE Fedora 14 and the same thing happens. I've tried Okular but the notations are too big to fill out exercises from pdf workbooks.    Is there any tool that suits this job? I don't care whether it is open source or I have to pay a reasonable price for it.


Loki is by-birth a blue frost giant. A frost giant's appearance isn't like that of Asgardians/Humans.  In Thor movie, Casket of Ancient Winter was able to transform Loki to original form temporarily. And, Loki was surprised with this. Meaning, Loki wasn't actively transforming his appearance using his imagery tricks. Plus, his imagery tricks don't work when his concentration is lost. But yet, we can see his Asgardian appearance everytime. Means, it's not his imagery trick.  How is Loki's default appearance like Asgardians/Humans?

Apologies for the slightly vague title.  It is revealed during Thor that      Loki was taken as a baby and is actually the son of Laufey, king of the Frost Giants.   Is there any explanation as to why he doesn't look like the rest of his race?


When I read tutorials about uninstalling Ubuntu on dualboot, it always says that I need to fix the bootloader. But, if my Windows Update would overwrite the grub bootloader and it just boots to Windows 10 instantly when launching the computer, do I still need to make all these changes to the bootloader by myself or I just need to remove Ubuntu partitions? Thank you for every answer.

I wish to remove Ubuntu and I'm not quite sure how. I know it has something to do with partitions. I have 3 partitions. 1. OS [683 GB]  2. Recovery [14 GB] 3. Ubuntu 12.04 LTS (E:)  I know it says Ubuntu but when I installed Ubuntu I think I put 14 gigabytes for it so I think its the recovery one but I'm not sure. I could have sworn I put more than 700 megabytes for it.  I have googled this and I can't seem to find an answer. Any help would be nice.


I'm making a cube-world-game like Minecraft. And to render it I've splitted it in 16x16x16 blocks regions (also known as chunks in mc) and then, on rendering, I take all the chunks in the rendering distance area and foreach of them I iterate all blocks and draw them.  It's so slow.  Then I tryed to remove hidden blocks and draw only visible faces of blocks. I made a VBO that store a face and then using model matrix I rotate it to make the other sides of the block. Finally I added a camera frustum test that checks if the block is visible from the camera.  I didn't code yet all these things, that's just a reasoning.  Are these optimization good or could I add something else?  P.S: I've seen that minecraft use a "display list" foreach chunk and not use a VBO for a face (I've didn't understand the code well since part of it is obfuscated) and each loop get just the rendering distance chunks and draw them using the display list stored. How's possible making a display list with all the shape of the chunk? There's another thing that does the same thing of the display list but it's not deprecated (I though VBO but I'm not sure)?

I'm writing my own clone of Minecraft (also written in Java). It works great right now. With a viewing distance of 40 meters I can easily hit 60 FPS on my MacBook Pro 8,1. (Intel i5 + Intel HD Graphics 3000). But if I put the viewing distance on 70 meters, I only reach 15-25 FPS. In the real Minecraft, I can put the viewing disntance on far (= 256m) without a problem. So my question is what should I do to make my game better?  The optimisations I implemented:   Only keep local chunks in memory (depending on the player's viewing distance) Frustum culling (First on the chunks, then on the blocks) Only drawing really visible faces of the blocks Using lists per chunk that contain the visible blocks. Chunks that become visible will add itself to this list. If they become invisible, they are automatically removed from this list. Blocks become (in)visible by building or destroying a neighbour block. Using lists per chunk that contain the updating blocks. Same mechanism as the visible block lists. Use nearly no new statements inside the game loop. (My game runs about 20 seconds until the Garbage Collector is invoked) I'm using OpenGL call lists at the moment. (glNewList(), glEndList(), glCallList()) for each side of a kind of block.   Currently I'm even not using any sort of lighting system. I heard already about VBO's. But I don't know exactly what it is. However, I'll do some research about them. Will they improve performance? Before implementing VBO's, I want to try to use glCallLists() and pass a list of call lists. Instead using thousand times glCallList(). (I want to try this, because I think that the real MineCraft doesn't use VBO's. Correct?)  Are there other tricks to improve performance?  VisualVM profiling showed me this (profiling for only 33 frames, with a viewing distance of 70 meters):    Profiling with 40 meters (246 frames):    Note: I'm synchronising a lot of methods and code blocks, because I'm generating chunks in another thread. I think that acquiring a lock for an object is a performance issue when doing this much in a game loop (of course, I'm talking about the time when there is only the game loop and no new chunks are generated). Is this right?  Edit: After removing some synchronised blocks and some other little improvements. The performance is already much better. Here are my new profiling results with 70 meters:    I think it is pretty clear that selectVisibleBlocks is the issue here.  Thanks in advance! Martijn  Update: After some extra improvements (like using for loops in stead of for each, buffering variables outside loops, etc...), I now can run viewing distance 60 pretty good.  I think I'm going to implement VBO's as soon as possible.  PS: All source code is available on GitHub:


How can I select all ids and values in one row, group by condition?  For example:   | id | value | condition | -------------------------- | 1 | value1 |     0     | | 2 | value2 |     0     | | 3 | value3 |     1     | | 4 | value4 |     1     |   Result:  | ids  |     values     | condition | ------------------------- | 1, 2 | value1, value2 |     0     | | 3, 4 | value3, value4 |     1     |

How do I get:  id       Name       Value 1          A          4 1          B          8 2          C          9   to  id          Column 1          A:4, B:8 2          C:9


Let $f : [0, 1] \to \Bbb{R}$ be a continuous function such that $f(x^2) = f(x)$ for all $x \in[0, 1]$.   Which one of the following is not true in general?   A) $f$ is constant  B) $f$ is uniformly continuous   C) $f$ is differentiable   D) $f(x) \ge 0 \forall x \in[0, 1]$   If I take $f(x) = -C$ ($C$ is positive constant) then clearly it shows that option D is not true in general.    But I want some theoretical approach to this question if there is any.  Like is there anything special about the functions satisfying $f(x^2) = f(x)$?

Problem: Given $f:[0,1] \rightarrow \mathbb{R}$ ($f$ continuous ) and $f(x^2) = f(x)$ $\forall x \in [0,1]$. Show that function $f$ is a const.


I'm facing a problem with QGIS and have no clue what I'm doing wrong here. I've tried everything I know of.  I have polygon layer in CRS 2180. I add another layer that should be overlapping perfectly - and it does.  When I simply drag the layer to QGIS it fits perfectly fine, but when I change that new layer CRS to 2180 (THE SAME CRS THAT IM WORKING WITH) it goes somewhere far far away. I don't get it. Both layers are in the same CRS and they don't fit but when they're in different CRS then they fit. What am I doing wrong here?  I need them to be in the same CRS because otherwise the clip function doesn't work and I want to clip these new layers to only fit my original layer.

I have a series of layers of lines (shapefiles) in My Project. The CRS of some are different and to merge them they all must have same CRS.  When I use Processing/Toolbox/Qgis_algorithims/Reproject_layer the reprojection only works if it is allowed to save to temporary file somewhere (it will not change the CRS when I reproject if I try to save and replace it in My Project directory);   I must remove the original from the layer list and reproject the temp file (without changing the CRS) to get it into my project and name it appropriately.  Is there a better way to reproject a layer in Qgis?


I have a program I'm thinking through right now and doing tons of investigating on.  One of the stipulations with the program is that I want it so it can only run on Linux.  I DO NOT want the program to be usable on Windows or Apple...Linux only.  I have my reasons.  I know you can use certain modules(tkinter...root.mainloop()), ie, that will cause a program to not run in Windows if you leave certain things out.  Is there a way you can accomplish the same task without using any particular module...just 'base code'?

Possible Duplicate:          As the title says, how can I find the current operating system in python?


Is loading the images from other sites into mysite is good?  Will it affect my website in anyways like speed, seo, copyright?  please don't mark this ques as off topic or duplicate. I need a clear understanding on this.

What exactly is hotlinking? And why do people say you shouldn't do it?


I am really confused about the use of tensors in special relativity. I'm not sure if I understood what is a covariant and a contravariant tensor and vector. I am looking for a book of relativity that teach this.

I am looking for a textbook that treats the subject of Special Relativity from a geometric point of view, i.e. a textbook that introduces the theory right from the start in terms of 4-vectors and Minkowski tensors, instead of the more traditional "beginners" approach. Would anyone have a recommendation for such a textbook ?  I already have decent knowledge of the physics and maths of both SR and GR ( including vector and tensor calculus ), but would like to take a step back and expand and broaden my intuition of the geometry underlying SR, as described by 4-vectors and tensors. What I do not need is another "and here is the formula for time dilation..." type of text, of which there are thousands out there, but something much more geometric and in-depth.  Thanks in advance.


I am reading a book and they state that "in a group of 23 people, the probability is 50.7% that two people share the same birthday"  How can this be?  Could somebody point to me how to calculate the 50.7% figure?  Many thanks in advance

I recently read about the Birthday Paradox which states that in a group of 23 people, there's a probability of 50% that 2 people share their birthday, probability wise.  I calculated and don't think it's possible that it's true in any case (unless my math is wrong). So, can anyone please tell me how to prove or disprove it mathematically ?


I'm just curious how python know beforehand that a variable is local and not reference the global variable instead. Please have a look on two versions of the code.  eggs = 'global' def spam():     print(eggs)     eggs = 'local' spam()   While, if i comment eggs = 'local', python refer to global variable.   eggs = 'global' def spam():     print(eggs)     # eggs = 'local' spam()   Please help me with understanding as to what i'm missing.  Edit: Found the answer here:

The following code works as expected in both Python 2.5 and 3.0:  a, b, c = (1, 2, 3)  print(a, b, c)  def test():     print(a)     print(b)     print(c)    # (A)     #c+=1       # (B) test()   However, when I uncomment line (B), I get an UnboundLocalError: 'c' not assigned at line (A). The values of a and b are printed correctly. This has me completely baffled for two reasons:   Why is there a runtime error thrown at line (A) because of a later statement on line (B)? Why are variables a and b printed as expected, while c raises an error?   The only explanation I can come up with is that a local variable c is created by the assignment c+=1, which takes precedent over the "global" variable c even before the local variable is created. Of course, it doesn't make sense for a variable to "steal" scope before it exists.  Could someone please explain this behavior?


I am seeing some strange behavior when using \pgfuseshading in xelatex: compared to pdflatex, the gradient is shifted to the right by an unspecified amount. Example: % !TEX TS-program = xelatex  \documentclass{article}  \usepackage{geometry}  \geometry{   paperwidth=8cm,   paperheight=4.5cm,   margin=0.5cm }  \usepackage{tikz}  \pgfdeclarehorizontalshading{shading}{3cm}{%   color(0pt)=(red);   color(\paperwidth)=(blue)}  \begin{document}   \noindent A \dotfill A\\   \pgfuseshading{shading} \end{document}  Produces  using xelatex but  using pdflatex. I am running TeXLive 2020 with the latest updates (as of today). Interestingly, I do not see this behavior on another computer with an older version of TeXLive (2019). Is this a bug? Can I fix it locally in my document?

Beamer item balls go missing while compiling in XeLateX since yesterday's TeXlive update, however, the same code works with pdfLaTeX. Any solution, please. Here is my MWE: \documentclass{beamer}  \setbeamertemplate{itemize item}[ball] \setbeamertemplate{enumerate item}[ball]  \begin{document}  \begin{frame} \frametitle{A tested title} text \begin{enumerate}     \item this is an item \end{enumerate} text3 \begin{itemize}     \item this is an item \end{itemize} \end{frame} \end{document}


The formal definition I was given in my analysis papers was that in order for a function $f(x)$ to have an inverse, $f(x)$ is required to be bijective. Nevertheless, further on on the papers, I was introduced to the inverse of trigonometric functions, such as the inverse of $sin(x)$. But $sin(x)$ is not bijective, but only injective (when restricting its domain).  As you can see the topics I'm studying are probably very basic, so excuse me if my question is silly, but ultimately does a function need to be bijective in order to have an inverse? If this is the case, how can we talk about the inverse of trigonometric functions such as $sin$ or $cosine$?

I know that if one inverse function want to exist main function must be injective, yet, does it really need to be surjective as well?if so, why?


says     It appears that space was created in the Big Bang, 13.8 billion years   ago   This seems a little off to me: can we say something has been created if there was no before it had already been created?     The visualizations often seen of the Universe growing as a bubble into   nothingness are misleading in that respect. There is no reason to   believe there is anything "outside" of the expanding universe into   which the Universe expands.   Neither do I understand this on  either: it assumes that nothingness is something outside what exists. Nothing is not a ham sandwich.  Anyway my actual question is: can space be created and destroyed - or does an expansion or crunch leave the extent "space" itself the same?

TV documentaries invariably show the Big Bang as an exploding ball of fire expanding outwards. Did the Big Bang really explode outwards from a point like this? If not, what did happen?


I just joined this community and posted . But after some few minutes, i realised it's been on hold. Is there anything i said that was inappropriate?

Questions can be closed or marked as duplicates.  What does it mean for a question to be "closed"? What does it mean for a question to be marked as a "duplicate"? Who can close a question? What are the reasons for closing a question ? Is closure the end of the road for a question? When are closed questions eligible for deletion?   Related        For more information, see "" in the .


Where is the correct place to store user-local executable files?  echo $PATH gives  /usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/games   It doesn't include eg. $HOME/bin  Would $HOME/bin be advisable? Or $HOME/opt/bin ....  I guess I would have to add that to my .profile too?

Occasionally I install applications manually, rather than using apt or another package manager.   What location (/usr/, /usr/local/, /opt/, /home/, etc.) is suggested by "best practices" for the installation of user applications?


I am planning my new mobile development working station consisting of a Notebook and a Tablet as second monitor.  Notebook OS: Windows 8.1 Tablet OS: Ubuntu (14 LTS)  I have asked  how I can achieve to simulate the Ubuntu Tablet as second monitor on Windows.  Now I want to know: how can I achieve using the Windows Notebook display, keyboard and mouse for controlling the Ubuntu OS that runs on the tablet. Like a VNC Session started on Windows (targeting the Ubuntu tablet), but instead of mirroring a display, I want to use it as an extension.  Therefore when I start the program on Windows and connect to the tablet, Ubuntu should see an additional monitor.

I've noticed people using a product for Windows and Mac called  which lets you use your Android or iPad as a secondary display. This seems like a great idea, and something that could be done on Ubuntu. Unfortunately, I've got no idea how to get started.  How could you re-create this setup on Ubuntu?


Is there any way to determine a file's size without having to open it, as provided in the Java platform API (no 3rd party libs)? Also, I need the 64-bit size (which I assume Java would provide to begin with).

While googling, I see that using  can be slow.  has a  method that is available as well.  Is there an efficient way in java to get the file size?


My first time trying to use Ubuntu. I clean installed the Ubuntu 12.10-beta2 on an old Dell Dimension 4600 today. Install seemed to go fine, but after restarting and entering the requested passwords I'm taken to a purple screen with no panels, launchers or anything else--just a purple screen. I'm able to access the terminal from the screen with ctrl-alt-t, but I'm not sure at this point in my Linux training how to search for errors. Also have no Internet connection (I'm typing this on a mac), but I'll have to deal with that later. Would appreciate any suggestions.

When I login, nothing happens.   I am presented with my desktop wallpaper.    No Dash, no Launcher, nothing.


I'm trying to come up with a js object minification function, one that would take an object and turn it into something like "VS4g3as" or whatever. The unminification would require the object prototype since I'm only storing the values.   Anyways, question is that if I run a for-in loop on an object like "for (var key in object)...", are the keys returned guaranteed to always be in the same order regardless of browser, platform, weather or whatever?   I'm trying to decide whether or not I need to enforce some kind of ordering like alphabetical.

Does the "for…in" loop in Javascript loop through the hashtables/elements in the order they are declared? Is there a browser which doesn't do it in order? The object I wish to use will be declared once and will never be modified.  Suppose I have:  var myObject = { A: "Hello", B: "World" };   And I further use them in:  for (var item in myObject) alert(item + " : " + myObject[item]);   Can I expect 'A : "Hello"' to always come before 'B : "World"' in most decent browsers?


#include <iostream> int main() {   using namespace std;   int arr[] = {1,2,3,4,5}; //initialization    cout << -3[arr]; //line A   return 0; }   How is the output of line A -4? Thanks in advance.

As Joel points out in , in  (aka: K & R), there is mention of this property of arrays in C: a[5] == 5[a]  Joel says that it's because of pointer arithmetic but I still don't understand. Why does a[5] == 5[a]?


He is much interested in the project   He is very interested in the project.      What is the difference between these two sentences?

Please tell which one is correct. I am much interested. Or I am very Interested.  Please explain scientifically.


Trying to install from instructions on:  and I get:  $ kirby@kirby-Aspire-ES1-433:~/Downloads/rtl8192EU_linux_v4.3.1.1_11320.20140505$  sudo dkms add Error! Invalid number of arguments passed. Usage: add <module>/<module-version> or        add -m <module>/<module-version> or        add -m <module> -v <module-version>   How to do correctly sudo dkms add?  I tried also:   kirby @kirby -Aspire-ES1- 433 sudo add-apt-repository ppa hanipouspilot/rtlwifi    [sudo] password for kirby   This is ppa for Realtek drivers from Larry Finger's GitHub.    rtl8192eu is packaged from the Realtek site with some compat patches   . More info   : https   : //launchpad   . net /~hanipouspilot/ + archive /ubuntu/ rtlwifi Press [ENTER] to continue   or Ctrl -c to cancel adding it.    Hit:1 http://hr.archive.ubuntu.com/ubuntu bionic InRelease Ign     Get:2 http://ppa.launchpad.net/hanipouspilot/rtlwifi/ubuntu bionic InRelease        Get:3 http://security.ubuntu.com/ubuntu bionic-security InRelease [ 83, 2 kB ]        Hit:4 http:// hr . archive . ubuntu . com / ubuntu bionic-updates InRelease      Hit:5 http:// hr . archive . ubuntu . com / ubuntu bionic-backports InRelease Err   : 6 http   : //ppa   . launchpad   . net /hanipouspilot/rtlwifi/   ubuntu bionic Release 404 Not Found [ IP : 91.189.95.83 80 ] Get   : 7 http   : //security   . ubuntu   . com / ubuntu bionic-security / main amd64 DEP-   11 Metadata [ 204 B ] Get:8 http://security.ubuntu.com/ubuntu bionic-security/universe amd64 DEP-11 Metadata [2 452 B] Reading package lists... Done                    E: The repository 'http://ppa.launchpad.net/hanipouspilot/rtlwifi/ubuntu bionic Release' does not have a Release file. N: Updating from such a repository can't be done securely, and is therefore disabled by default. N: See apt-secure(8) manpage for repository creation and user configuration details. kirby@kirby-Aspire-ES1-433:~$ sudo apt update Hit:1 http://hr.archive.ubuntu.com/ubuntu bionic InRelease                      Hit:2 http://hr.archive.ubuntu.com/ubuntu bionic-updates InRelease              Hit:3 http://security.ubuntu.com/ubuntu bionic-security InRelease               Hit:4 http://hr.archive.ubuntu.com/ubuntu bionic-backports InRelease Ign:5 http://ppa.launchpad.net/hanipouspilot/rtlwifi/ubuntu bionic InRelease Err:6 http://ppa.launchpad.net/hanipouspilot/rtlwifi/ubuntu bionic Release   404  Not Found [IP: 91.189.95.83 80] Reading package lists... Done E: The repository 'http://ppa.launchpad.net/hanipouspilot/rtlwifi/ubuntu bionic Release' does not have a Release file. N: Updating from such a repository can't be done securely, and is therefore disabled by default. N: See apt-secure(8) manpage for repository creation and user configuration details.  kirby@kirby-Aspire-ES1-433:~$ sudo apt install rtl8192eu-dkms Reading package lists... Done Building dependency tree        Reading state information... Done E: Unable to locate package rtl8192eu-dkms   What is wrong?

I have purchased a TP-LINK TL-WN823N (EU) V2.0 device, which is a USB device that should work as a Network Interface Card, allowing me to connect my computer to wireless networks. Unfortunately, I am unable to find any wireless networks using this device using either wicd or network-manager (no networks appear in the list of networks supplied by either application).  A CD came with the device claiming "Linux support". The CD contained a URL to a corrupted archive file for downloading installation resources. I try to mask my immense frustration.  Here is the additional dmesg output I receive when I connect the device to my computer (similar content is present when I boot the computer with the device connected):  [17096.009912] usb 2-1.2: new high-speed USB device number 4 using ehci-pci [17096.103501] usb 2-1.2: New USB device found, idVendor=2357, idProduct=0109 [17096.103513] usb 2-1.2: New USB device strings: Mfr=1, Product=2, SerialNumber=3 [17096.103527] usb 2-1.2: Product: 802.11n NIC [17096.103529] usb 2-1.2: Manufacturer: Realtek [17096.103530] usb 2-1.2: SerialNumber: 00e04c000001   This is my lsusb, where the offending device corresponds to Bus 002 Device 004:  Bus 002 Device 003: ID 0a5c:5800 Broadcom Corp. BCM5880 Secure Applications Processor Bus 002 Device 004: ID 2357:0109   Bus 002 Device 002: ID 8087:0024 Intel Corp. Integrated Rate Matching Hub Bus 002 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub Bus 001 Device 004: ID 0c45:6433 Microdia  Bus 001 Device 002: ID 8087:0024 Intel Corp. Integrated Rate Matching Hub Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub   As lsusb -v:   It seems the device is working to me, but no new interface is found in 'ifconfig':  docker0   Link encap:Ethernet  HWaddr 02:42:6e:bf:92:16             inet addr:172.17.0.1  Bcast:0.0.0.0  Mask:255.255.0.0           UP BROADCAST MULTICAST  MTU:1500  Metric:1           RX packets:0 errors:0 dropped:0 overruns:0 frame:0           TX packets:0 errors:0 dropped:0 overruns:0 carrier:0           collisions:0 txqueuelen:0            RX bytes:0 (0.0 B)  TX bytes:0 (0.0 B)  enp0s31f6 Link encap:Ethernet  HWaddr 30:5a:3a:e1:96:b1             UP BROADCAST MULTICAST  MTU:1500  Metric:1           RX packets:0 errors:0 dropped:0 overruns:0 frame:0           TX packets:0 errors:0 dropped:0 overruns:0 carrier:0           collisions:0 txqueuelen:1000            RX bytes:0 (0.0 B)  TX bytes:0 (0.0 B)           Interrupt:16 Memory:df200000-df220000   lo        Link encap:Local Loopback             inet addr:127.0.0.1  Mask:255.0.0.0           inet6 addr: ::1/128 Scope:Host           UP LOOPBACK RUNNING  MTU:65536  Metric:1           RX packets:412 errors:0 dropped:0 overruns:0 frame:0           TX packets:412 errors:0 dropped:0 overruns:0 carrier:0           collisions:0 txqueuelen:1           RX bytes:31876 (31.8 KB)  TX bytes:31876 (31.8 KB)   Running 'lshw -class network' as root contains only information about the 'enp0s31f6' interface.  Additionally for sanity, my 'uname -a':  Linux home-z170a-ubuntu 4.4.0-22-generic #39=Ubuntu SMP Thu May 5 16:53:32 UTC 2016 x86_64 x86_64 x86_64 GNU/Linux   I am using Ubuntu 16.04.  My questions are:   Why are no networks present in the list for wicd or network-manager? Why is there no additional network interface created when I plug in the USB device? Is it possible to create this network interface?   Thanks for reading.


Currently, when editing my profile, I have two options:   Save it for just the current site, or Save it for all sites.   However, this doesn't really fit my use case: I like to keep the same profile on every site except I have a couple of sites with site-specific profiles.  This makes it very difficult for me to update my "default" profile that I use on the majority of sites:   First I have to go to the one or two sites I have a custom profile on, and copy the profile text to a text editor or whatever (and save the avatars if I'm changing my avatar). Next I edit my profile and save it for all sites. Then I have to go back to each of the custom sites and paste the profile text back in (and change/upload the avatars if needed).   It's super unwieldy.  To that end I propose a checkbox in the profile tab of each site that reads something like "Lock this profile", that is unchecked by default. When it is checked, "save profile for all communities" will not apply to that site (unless, of course, the "save for all" button is pressed from that site, in which case it should be applied, of course, to that site in addition to all other non-locked sites).  I think this would be really helpful. This is for the same type of control that  asks for but, specifically, I'd like it to be implemented as a checkbox on each site rather than some dropdown selection list of sites to copy profiles to, I think it's easier to manage that way, since you can just check the box and forget about it.

The "Save And Copy Profile To All Stack Exchange Accounts" button is quite useful for users with many accounts across the Stack Exchange network.  However, many users have profiles on certain sites that intentionally differ from the rest of the network, such as .  Can someone add an option to allow copying the profile to all Stack Exchange accounts except for selected sites?


I'm supposing we have to show that there an injective function from the set of all axiomatic proofs to the set of all natural numbers? If so, what would such a function look like?  Any help would be greatly appreciated!

I think that the number of mathematical statements is countably infinite, since each statement is a finite string of finitely many symbols, but i am not sure how to prove it. Once i prove that, i can say that a every math proof with $n$ steps is a subset of the cartesian product $A^n$ where $A$ is the set of all mathematical statement, and each element in the resulting set is a statement that is a step in the proof. Since the cartesian product of countably infinite sets is countably infinite, then the set of all proofs with $n$ steps is countably infinite, for any $n$. How can i prove that the number of mathematical statements is countably infinite, and is the rest of the proof correct?


Is using an underscore in user mentions as a replacement for a space a valid practice, and if not, then why? It feels obvious for me to do so, however the help on using @username does not say anything about this.

According to Jeff's answer, :  So you can now @reply to editors of a post even if they haven't commented.  Yet, I just tried to address the editor of a question in a comment and couldn't. No auto-completion of the name. I typed it in anyway, but it doesn't seem to have reached the editor. I tried it at another post where the same user commented and the @reply worked as expected there (auto-completion and everything). Happened with this question:  I haven't changed anything further so I wouldn't contaminate the crime scene. Edit: I ran some tests with OMG_Ponies, and he did get the messages. So, it's only the auto-complete that doesn't work as expected. And the _ in his name helped to fool me at first.


I am completely new to GIS and therefore have questions regarding how the GIS Web development should be made, because the entire concept still confuses me.  So, imagine I have a map. And by this, i mean the shape files for the layers and so on.   How i should i use this in my web application?   I have read about MapServer, OpenLayers, PostGIS, but can't quite understand how and why this all enters the question.   If i have my map, my files, shouldn't the problem be just on to represent it in the web page?

I want to start working on a web map at work to map some of our statistics by city.    I have an idea, but I'm not exactly sure where to start.   Are there any definitive resources that provide step by step guidance on how to do this?


I hope this is a question with a shorter answer than "Read a 1000 page book", but then, if that's the real situation, then hit me with it.  I am not a real DBA, I'm a software developer who is realizing we need a DBA, and yet the shop I work in has zero DBAs. However our MS SQL database design including several core stored procedures, is a giant mess. The stored procedures are slow, we suspect they have bugs, but we don't even know how they are expected to work, so we don't know how to fix them.  As a start I've decided we'll document how it's supposed to all work, then we'll start unit testing, and building up a set of unit tests that help prove that the stored procedures actually do work. The logic that they perform is a key part of our application, you could say, it's the "crown jewels" of our company's main product, and the way it works is completely undocumented.  I'm looking for the specific technical documentation that a professional DBA might expect to have existing, or might write themselves, if they had to, to understand a giant web of stored procedures that call each other.   What is the usual format for documenting a large stored procedure? Description of expected values for each In Parameter  (ie "preconditions", "postconditions", ie, for boolean parameters what changes when you turn it on or off, etc?) How does one usually document it? SQL comments only? External tooling that is specific to the purpose? External "documentation"? We have no SQL tools, other than MS SQL Management studio, but we are wondering if there is a tool that would make understanding, documenting, and testing our environment better.  Maybe that is a better way to ask my question; What tool do I need to solve our mess?   Our goal is to be able to:  A. Use the documentation we generate, or whatever tools we add to our environment, to help understand how the procedures are supposed to work, so we can then go on to create unit test coverage for the stored procedures.  B. Show the client-app developers how to properly call each of these complex stored procedures.  C. Unit test our stored procedures.

I find that most of my clients are not documenting their databases at all and I find that pretty scary. To introduce some better practice, I would like to know what tools/process people are using.   How do you document your database? (SQL-Server)  What tool do you use?  Documentation Storage Format for database schema/meta-data?   Word documents Excel spreadsheet Plain Text  Documentation process or policies?   I am not talking about reverse engineering / document a existing database, but mainly on the documentation best practices while you develop your system/database.


I have an android phone(1) on 2.3.3 and a tablet(2) on preorder that will be on 3. (And a bad gadget habit.)  Can I, when the tablet arrives, uninstall paid apps on the phone and install them on the tablet? It feels like I should be able to since I've paid for a copy of the app linked to that Google account it shouldn't matter which linked device it's on. (Why? Some stuff I've paid for will look better/be more useful on the tablet.)  I've looked online, but most people are asking about moving paid apps from broken phones (ie when they can't uninstall from the first device) or trying to run the same paid app on multiple devices which is piracy/cheap.   (1) nexus one (2) xoom

On the iPod Touch/iPhone, since it is tied to your iTunes account, I am quite sure you can have your bought apps on multiple devices you own (can't test though, iPod Touch was stolen).  However, now I have the Motorola Droid, and am waiting for a tablet, and am considering getting a Nook and rooting it to run my own apps.  Question is, if you buy an app on the marketplace, how is the security done:   Is it tied to your Gmail account so you can share it between devices you own? Is it tied to the device? (Don't break/replace your phone!) As long as it's installed, you're OK? (If you uninstall, or wipe your device, it's gone).   I assume 3 is highly unlikely, though a possibility, so leaving it here as a potential answer to my question.


I'm quite new to electronics and am doing it as a hobby. I recently bought a 16x2 LCD display online to use it with an Arduino. When I received it, it noticed that there were a few components missing on the back. Is the display still functional or do i need to buy new components? If i do, which components do I need?  The back of the display looks like the display on the top in this photo.

I've seen some PCBs were some components have been sketched, but they don't seem to be mounted on the board. See, this image (of a PlayStation 2) where the transformer has been drawn:    Why is this done on some circuits?


In these two different equations for the same (?) thing, not only is one directly proportional to height and one is inversely proportional to height, but they contain completely different variables, and this is my confusion. Additionally, in the second equation, we can see that the $U$ will decrease to 0 as the distance between the objects increases to infinity. This also confuses me, because my thinking would be that if you took two objects and separated them very far in empty space, they would come together because of gravity and they would both be moving pretty fast at the end of their journeys, but for this to happen we would need a high starting $U$.

Newton's Law of Universal Gravitation tells us that the potential energy of object in a gravitational field is $$U ~=~ -\frac{GMm}{r}.\tag{1}$$  The experimentally verified near-Earth gravitational potential is  $$U ~=~ mgh.\tag{2}$$  The near-Earth potential should be an approximation for the general potential energy when $r\approx r_{\text{Earth}}$, but the problem I'm having is that they scale differently with distance.  $(1)$ scales as $\frac 1r$.  So the greater the distance from the Earth, the less potential energy an object should have.  But $(2)$ scales proportionally to distance.  So the greater the distance from the Earth, the more potential energy an object should have.  How is this reconcilable?


What kind of the grammar is shown by the group of two words "let us"? Is it a phrase or a predicate or a clause ... or something else?

Let us go   is a correct construction in the English language and definitely not:     Let we go   However, the question is: since us is an object-case pronoun, what is the subject of this sentence?


I just noticed that I could not buy stocks of an IPO during the beginning to the trade at 9:30am. I tried NYSE:AMWL this morning. I can only buy the stock of an IPO several hours later. Does anyone know why? Why does this happen? Is this the same for every IPO?

So, I understand that today's Spotify IPO isn't a traditional IPO. But I think my question extends beyond this. At about 12:45pm today, shares of Spotify finally started trading on NYSE. Opening bell was 9:30am though, and I thought that was the "real" open. What was happening before the first trade, in terms of stock exchange mechanics? Alibaba in 2014 did a regular IPO and also didn't trade until almost 12:00pm on its opening day.  Update: Following some WSJ live updates, it seems like they were waiting for the spread to narrow before trading would begin:  The price range of Spotify’s first trade has just narrowed to $167 to $170, a sign that the opening could be drawing closer. The range has moved up a few times, illustrating investor demand. ― Alexander Osipovich  What I don't understand is whether the exchange has put a barrier in place (e.g. like a pre-open or delayed-open state where only passive, liquidity-providing orders are allowed), or traders are choosing not to trade for whatever market reasons. I thought it had to be the former, but then this update makes it sound like the first trade was not a scheduled event:  Shouts and applause broke out on the floor of the New York Stock Exchange as Spotify shares started trading at $165.90. A total of 5.6 million shares changed hands in the first trade. ― Alexander Osipovich


I am looking for an elementary statistics book, that contains topics such as descriptive statistics, sampling distributions of the mean and variance, etc. However, despite my interest in basic topics, I am looking for a book that teaches it in a high level, for example: when discussing the why the variance includes a squared difference from the mean and not absolute value, I am looking for a mathematical explanation (the problem with the derivative), or, a loss function explanation. In other words, I am looking for an elementary statistics book for mathematicians or statisticians, and not just a textbook. Can you please recommend me of such books, if exist? Thank you.

What is a good introduction to statistics for a mathematician who is already well-versed in probability?  I have two distinct motivations for asking, which may well lead to different suggestions:   I'd like to better understand the statistics motivation behind many problems considered by probabilists. I'd like to know how to better interpret the results of Monte Carlo simulations which I sometimes do to form mathematical conjectures.   I'm open to the possibility that the best way to go is not to look for something like "Statistics for Probabilists" and just go to a more introductory source.


So I've been playing a DnD 5e campaign for the past couple of weeks, and I've come to the conclusion today that I'm not really having much fun with it.  I've come into the campaign midway-through and don't really have any good opportunities to insert my character into things, and I have trouble even getting into the character that I've made outside of using X spell to burn Y enemy, which just doesn't appeal to me.  I've given it a couple of weeks, but I find that I mostly am just stuck behind this screen (we use Maptools) for 3 hours each Sunday, watching text scroll by without much care for what any of it says.    So with all that in mind, I'd like to leave the campaign.  I don't have any problem with the system, or timing schedules, and while I might not be having as much fun with my character as I'd like, I feel like that's not going to change anytime soon - a lot of the current characters are already established, and I feel like mine doesn't fill any niche that hasn't already been filled. On top of which, the quirks my character does have don't seem to be that interesting to the other players, and I don't have much fun trying to play them out.  In short, I don't really like playing this campaign, but I have no excuse to leave the campaign except that I'm not having fun - and rather than keep my DM's hopes up that I'll be staying, I'd like to leave as gracefully as possible, without insulting his DMing skills.   He's not bad - the group is just kind of large already, and I feel like I don't get much out of it myself.  How can I let the DM know this, without insulting his DMing skills?

I have sometimes joined groups whose play style didn't work for me. At some point it became clear that as much as I wanted to enjoy the game I couldn't. And I was probably undermining the fun at the table for others too.  What is the best way to leave the group? Quietly or with a few explanations? Announce it in person or by email/phone/forum? Is it OK to recruit players from the group for another game?


I am using a external theme but I have little knowledge of JS / jQuery. It uses this function to show images on hover:  $(document).ready(function() {       ....     FirstLoad();     .... });  function FirstLoad() {     ....      $('.showcase-list li a').on('mouseenter', function() {         $('#showcase-gallery').addClass('visible');         $('.showcase-list li a').addClass('disable');         $(this).removeClass('disable');          var aux = $(this).data('aux'),         preview = $('.showcase-img[data-aux="' + aux + '"]');            $('#showcase-gallery').find('.showcase-img').removeClass('active');         preview.addClass('active');     }).on('mouseleave', function() {         $('.showcase-list li a').removeClass('disable');         $('#showcase-gallery').removeClass('visible');         $('.showcase-img').removeClass('active');        });      .... }// End First Load   But I trying to paginate this gallery with Inifite Scroll JS which is going well except that function does not work on the newly paginated content. I suspect its because it does not load.   I have this code:  var $showcasegallery = $('#showcase-gallery').infiniteScroll({     path: '.gallery_next',     append: '.ajax-case-images' ,     loadOnScroll: false,     status: '.page-load-status',   });  var $showcaselist = $('.wrapper-case-links').infiniteScroll({     path: '.gallery_next',     append: '.ajax-case-links' ,     loadOnScroll: false,     status: '.page-load-status',   });   // load next page  var $viewMoreButton = $('.view-more-button'); $viewMoreButton.on( 'click', function() {   $showcaselist.infiniteScroll('loadNextPage'); $showcasegallery.infiniteScroll('loadNextPage');  });   This is working fine, but how can I make sure that other function reloads too on button click so that I can use this zoom function from the theme?

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


Over the last month or so I wrote a couple of posts about me worrying a lot about the way my mathematics PhD supervisor was dealing with things. Looking back on these my worries were unjustified and I have since done a lot of reflection upon what went wrong with my studies which made me feel that way. I decided to withdraw from my studies and move back home for a good while to re-evaluate my interests and think about where I want to be in life. I withdrew because:   the PhD was heavily analysis-based, whereas my background was much more towards the applied side (so the jump turned out to be too great for me in the end), and the choice of my PhD topic was based more on what I felt I "ought to know" rather than what I enjoyed and what I was already good at (out of the PhD offers I had at the time, the one I went for was probably the least suitable for me in terms of background, and this choice was exacerbated by the fact I was under pressure to choose a PhD programme during my final year of my undergraduate course) the above led to me finding it difficult to adapt to a routine and I was rapidly losing interest in the topic which had a very negative effect on my work ethic and research progress I was experiencing mental health difficulties and having trouble looking after myself the above were leading to my supervisors to worry a lot about my progress and so my main supervisor suggested that perhaps I withdraw from the studentship.   For now, my plan is to take a pause from academia and consider doing some teaching work in the meantime (or getting some other real-world experience), whilst being able to rectify any personal issues. So far I feel this has been a really positive move and I have been able to think much more clearly about my future and where my heart is. Furthermore, during my (limited) experience of being a research student, I learned a lot about what happens in a typical mathematics department, what research work usually involves, and what responsibilities a PhD student and his/her supervisor has.   I feel that there is a possibility that I would like to return to PhD studies in the future (I'm not ruling it out, at least), but with much more care and consideration towards the subject area and my suitability for research work.   However, I am aware that having dropped out of a PhD already might potentially hurt my chances if I consider reapplying later on - but I feel my justification is sound, and if I do consider applying for a PhD again in a year or two, then I can explain the situation to potential institution/supervisor and hopefully they would understand.   So my question is - would having withdrew from a PhD programme that wasn't a very good match for my mathematical background and strengths disadvantage me if I wanted to consider doing a PhD later on in something that was much more up my street? Furthermore, if I decide to take this route, would it be worth returning to my original institution where I know the faculty really well and have a good track record with them? (I obtained a 1st class Masters degree from there and was given numerous awards during my studies.)

In September I started a mathematics PhD at a UK university straight after my undergraduate MMath degree at a different university. On the whole, I am enjoying the experience. However, I've been having recurring thoughts that perhaps I am not cut out for doctorate level work and it might be a good idea to revisit mathematical studies at a later stage.   Basically, since coming here I've been feeling consistently like my heart isn't in it (and this has had a negative effect on my work ethic). This is not necessarily because I’m not capable of doing it, but rather because I never had a proper break from academia and I feel like I've been running out of steam. I know PhD students very frequently go through spells of feeling dispirited, but I feel that if my heart is really in mathematics that this shouldn't be happening. I would rather go into doctoral studies with a running start knowing that I am adequately trained in the area I am in, rather than adjusting to a learning curve (and an inexperienced supervisor).   Here are some options I have considered:   Having a complete break from academia (6 months to a year), followed by a period where I slowly ease myself back in at my own pace by reading. Taking CDT (Centre for Doctoral Training) courses. I had previously applied to this and been rejected, but now I think I would be more competitive. I think this rigorous training would be helpful for me.  Doing something altogether different -- learning another programming language and doing a programming job, or working in simulation/modeling at the Met Office, or another company that relies heavily on fluid dynamics. Or maybe even the EPSRC (which is where a lot of the funding for PhD mathematics students comes from) Getting a normal job to demonstrate people skills, and saving up money to do another Masters programme, which will put me in a very good position for my PhD.   After doing the above, I could return to a PhD programme much    later, when I am a much more mature person with a    better mindset towards my work.  Thankfully, my parents are willing to support me emotionally and financially while I pursue any of these.  My question is whether this is a good plan. In particular:   Is it a good idea to take a break from studies if wanting to continue them at a later date, especially for mathematics? Would it hurt any opportunities later on down the line to take up a PhD a year or so from now? Would my department or supervisor think badly of me for wanting to terminate my studies - and (generally speaking) would I not have to pay back the studentship instalments that I've been paid so far? (I've been funded solely by the University, not by a funding body such as the EPSRC). What would be some worthwhile things to consider doing during a break from academia?     Update: it sounds like this would not be a great idea, and I should only make the move if I am really, really convinced about it. Nonetheless, I'm leaning further and further towards it because I think it's better to take a break from my studies now rather than 3 years down the line. I don't seem to have the motivation required to be a good doctoral student at the moment. This is something I might speak to my advisor about.


Let $\Omega$ be an open domain, and let $\Sigma$ be a smooth and nonempty portion of the boundary. Let $u$ be a harmonic function in $\Omega$ and $u=D_\nu u=0$ on $\Sigma$. ($D_\nu$ is the derivative along the outward vector). How to prove $u=0$ in $\Omega$?  Can I use Green's formula to this "portion" of boundary?

Prove that if $\Delta u=0$ in $\Omega\subset \mathbb{R}^n$ and $u=\partial u/\partial\nu=0$ on an open smooth portion of $\partial \Omega$, then $u$ is identically zero.  I found a proof , but I'm not sure if it's the correct proof. Does anyone have any idea? Any hint would be appreciated.


This is driving me nuts. Since I upgraded to Catalina (10.15.7), the accountsd process goes up to 680% of CPU usage:  The only thing that 'fixes' this, is logging out of iCloud, but then I loose access to my notes and contacts.

Why are the accountsd and securityd processes using so much CPU on OS X 10.10.3? I am on a Early 2011 Macbook Pro.  What are these processes for? Is it safe to kill them? The machine has only been up 4 hours so has been rebooted recently.


If one instance of Datasnap server is running, trying to open another one crashes this second instance. How can you prevent users from opening more than one instance of datasnap server?  On create of the server application :  Application.Initialize;   Application.MainFormOnTaskbar := True;   Application.CreateForm(TForm1, Form1);   Application.CreateForm(TServerContainer1, ServerContainer1);   Application.Run;   I tried putting LMDOneInstance on the Form1 but the server still keeps opening another instance (visible in the windows task manager). It does not crash the newly created instance but it just creates another process.

How do i tell if one instance of my program is running? I thought I  could do this with a data file but it would just be messy :(  I want to do this as I only want 1 instance to ever be open at one point.


Problem :  Determine all functions $f : \mathbb{R} \rightarrow \mathbb{R}$ such that, for all real numbers $x$ and $y$, $$f \Big(f(x)f(y)\Big) + f(x + y) = f(xy)$$.

Find all functions $f\colon \mathbb R\rightarrow \mathbb R$ such that for all reals $x$ and $y$:   $$f(f(x)f(y))+f(x+y)=f(xy).$$   It was six hours ago in IMO 2017 (problem 2).  I tried  the standard way: $x=0$, $x=y$, $x=1$,etc. but without any success.   Let $f(0)=a$. Hence, for all $x\in\mathbb R$ we have $f(a(f(x))+f(x)=a$. What is the rest?   Also we have $(x-1)(y-1)-1+x+y-1=xy-1$ and  $1-(1-x)(1-y)+1-x-y=1-xy$.


Under Beamer, how to draw a sipmle arrow between words in itemize?  I do not need to configure the size, location or any other detail settings. What I need is simply a default arrow.  I tried \rightarrow and \implies but without luck.

This is what I'm after: I'd like to have the sentence 'John loves his mother.' displayed with an arrow running from 'his' to 'John'. I looked at gb4e, but I found the documentation confusing and I haven't been able to make it work.


I need to give a answer line along the question. what should I do?  That is if I have a question like this..  The value of $\sin^2\theta+\cos^2\theta=______________$   What should I do to put dash along the question itself.

In LaTeX, how would I make a long underscore?  For example,  Name _______  Signature _______


My tree requires a phase boundary across the vP. However, getting a curved line to mark a phase boundary has become a cumbersome job. If I can get a code that helps me do that it would be really useful.

's a picture example of what I want:     I'm able to make the type of arc that I want with this command:  \draw (-2,-2) [black,thick,dashed,domain=45:180] plot ({cos(\x)}, {sin(\x)}) ;   But it always creates the arc at the very top of the tree, even when I put the command inside the tree in the node where I want the arc. Here's the code I'm using:  begin{forest} [TP [T\textsuperscript{0}] [vP [DP\textsubscript{???},circle,draw] [v' [v\textsuperscript{0}] [VP,tikz={\draw[black,thick,dashed,domain=45:180] (2,2) plot ({cos(\x)}, {sin(\x)}) ;} [V\textsuperscript{0}] [DP\textsubscript{???},circle,draw] ]]]] \end{forest}


I posted many questions but most of the questions are put on hold as off-topic or duplicate or closed i dont know reason may be my english how to explain my issues or otherwise some senior stackusers dominate me?    [on hold]   [on hold]  [duplicate]

Questions can be closed or marked as duplicates.  What does it mean for a question to be "closed"? What does it mean for a question to be marked as a "duplicate"? Who can close a question? What are the reasons for closing a question ? Is closure the end of the road for a question? When are closed questions eligible for deletion?   Related        For more information, see "" in the .


I am curious why a signed integer value was used to hold Unix time. It clearly would have made significantly more sense to use an unsigned integer as time can't go backwards, so having a negative value for time is, well, impossible. However, on January 19, 2038 Unix time will overflow and it will be the end of time as many of us know it. We will go from 2,147,483,647 to -2,147,483,648... Not good.  So, why was a signed integer used and how hard would it be to implement a fix for this when the end of time does come near?

Why is a signed integer used to represent timestamps? There is a clearly defined start at 1970 that's represented as 0, so why would we need numbers before that? Are negative timestamps used anywhere?


In Lagrangian mechanics, the function $L=T-V$, called Lagrangian, is introduced, where $T$ is the kinetic energy and $V$ the potential one. I was wondering: is there any reason for this quantity to be introduced? Does it have any physical meaning?  A professor of mine once said its differential $\delta L=dT-dV$ is "the quantity of energy you must pump into the system to move it from a point $(q,\dot q)$ in the phase space to a point $(q+dq,\dot q+d\dot q)$". Is this interpretation correct? I'm not too convinced…

The action  $$S=\int L \;\mathrm{d}t$$  is an important physical quantity. But can it be understood more intuitively? The Hamiltonian corresponds to the energy, whereas the action has dimension of energy × time, the same as angular momentum.  I've heard the action being described as a measure of change, although I don't know how this description can be justified.


I have an algorithm which ,at first, sorts the vector and then iterate through its elements and XOR them. Should I sum the complexities of sort and for loop to calculate the overall algorithm complexity? So, I have next code:  std::sort(array.begin(), array.end()); for (int i =1; i < array.size(); ++i) {   result = array[i-1]^array[i]; }   We have a for loop which has O(N) complexity and std::sort which has O(N log N) comparisons on the average. So the complexity of the next code will be O(N + N log N)? Or in this case we just have to choose the highest time complexity class which is linearithmic time O(N log N) and don't sum them?

Most people with a degree in CS will certainly know what . It helps us to measure how well an algorithm scales.   But I'm curious, how do you calculate or approximate the complexity of your algorithms?


I have tried the same using java but the resulting byte array is not correct:  public void  publicKeyConvert{     final String PUBLIC_KEY_STRING="MIIBIjANBgkqhkiG9w0BAQEFAAOCAQ8AMIIBCgKCAQEAxl4aRnRMBB9GZk"; try{     System.out.println("Public Key in byte[] :"+ Arrays.toString(Base64.decode(PUBLIC_KEY_STRING, Base64.DEFAULT))); } catch (Exception ex) {     Log.e("Error converting key", ex.getMessage()); }   Rather than converting the string as I tried in my example I am looking for a solution where I can input the public key file (.pem format) and receive the byte array as output preferably using OpenSSL.

I have an image that is Base64 encoded. What is the best way to decode that in Java? Hopefully using only the libraries included with Sun Java 6.


I have 3 classes: Employee, Manager, Clerk.   Manager and Clerk are derived classes from the base class Employee.  There is one question being asked in my school work that I can't find a way to work it out:     Write a program that creates an array of 3 Employee objects named empArray.      Create objects for each of the array elements as follows:         For empArray[0], create an Employee object.   For empArray[1], create a Manager object.   For empArray[2], create a Clerk object.      Code I've tried:  Employee empArray[3];  empArray[0] = Employee{ "Employee A", 1000.01}; empArray[1] = Manager{ "Manager A", 1200.02, 300.30 }; empArray[2] = Clerk{ "Clerk A", 1200.22, 3 };   But by doing this, I can't have access to each derived class's methods afterwards.  The sample code of the classes:  class Employee { private:     string name;     double basicSalary;  public:     Employee(string aName, double aSalary)         :name(aName),basicSalary(aSalary){}  };  class Manager : public Employee { private:     double travelClaims;  public:     Manager(string aName, double aSalary, double aClaims)         :Employee(aName, aSalary),travelClaims(aClaims){}     //+some manager methods };  class Clerk : public Employee { private:     int overtimeHours;  public:     Clerk(string aName, double aSalary, int aHour)         :Employee(aName, aSalary),overtimeHours(aHour){}     //+some clerk methods };   I'm expecting by declaring only the instances of base class, and still able to access to the methods of the derived classes in my main program.

Someone mentioned it in the IRC as the slicing problem.


I used the following code:  \listoffigures \listoftables   However, for some reason it automatically starts a new page in between. I'm using \documentclass{report}. Before, I used document class article and it didn't happen, but I need to use report. Does anybody know how to get the list of figures and tables on the same page?  Thanks in advance!

Is it possible to put the list of figures and tables onto one page? I only have two tables in my thesis, so having it on an extra page looks quite bad.  I've read about the tocloft package and tried to use it. It moved both lists onto one page, but they're no longer shown in the table of contents.  So is there a way to get \listoffigures and \listoftables on the same page while preserving the ToC entry for them?


The following code is the BibTeX source:  @INPROCEEDINGS{El-Hakim2003b,   author = {El-Hakim, S.F. and Beraldin, J.-A. and Blais, F.},   title = {Critical Factors and Configurations for Practical Image-Based 3D     Modeling},   booktitle = {6th Conference on 3D Measurement Techniques},   year = {2003},   volume = {II},   pages = {159-167.},   address = {Zurich,Switzerland},   month = {Sept. 22-25},   owner = {Sayyad},   timestamp = {2014.08.04}   The output looks like:     El-Hakim, S., Beraldin, J.-A., and Blais, F. (2003b). Critical factors and congurations   for practical image-based 3d modeling. In 6th Conference on 3D Measurement Techniques,   volume II, pages 159{167., Zurich,Switzerland. 3   How can I have 3D? I don't want to have only 3.

When creating my bibliography it adds a number behind the book which links to the number of the footnote like:     Finkenzeller 2012      Finkenzeller, Klaus: RFID-Handbuch. Hanser, Carl GmbH + Co., 2012 5   As you can see its the number 5. How can I remove this number?  At the moment im just using this for bib:  \bibliography{Bibliographie}  \bibliographystyle{natdin}


So for example I'm trying to not match 'test'. I've tried [^t][^e][^s][^t]. It won't match it, but it also won't match if at least one of the characters match the notes in the same position.   Any idea how to get around this?  Just a note, this is POSIX version of regex, there are no look-aheads or look-behinds.  Also, to clarify, the word I want is between certain characters, i.e. for the string "sdkfjdlskj <dsfdjslj@example.com>" I am looking for everything between '<>'. The email part is easy, but not matching a certain word is quite boggling.

I know it's possible to match a word and then reverse the matches using other tools (e.g. grep -v). However, is it possible to match lines that do not contain a specific word, e.g. hede, using a regular expression?   Input:  hoho hihi haha hede   Code:  grep "<Regex for 'doesn't contain hede'>" input   Desired output:  hoho hihi haha


This is how it looks when I am in solid view. It is very annoying to edit like this - how can I make it look normal?

I changed my Blender Units to Metric System, but when I'm building things, my meshes are transparent, i.e. I can see through faces like in wireframe even though my wireframe is turned off. All faces have a light white in non-wireframe mode, but I can still see through them.   How do I reverse this?  Another issue I get is this    Looks like clipping is not working properly.


I'm not talking about logarithms like $\log_2 \sqrt{32}$, that's really easy for me. I want to calculate without tables logarithms like $\log 17$ or $\ln 912$. Can you tell me how I can do it, please?

As the title states, I need to be able to calculate logs (base $10$) on paper without a calculator. For example, how would I calculate $\log(25)$?


I'm trying to log-in to my tablet, which I haven't been on in about 2 months. I can't remember my PIN. It's not giving me a chance to log-in with my Google account, so I don't know what to do.

On my CM9 / ICS 4.0 phone, if I incorrectly enter the drawn pattern five times in a row, it locks itself for 30 seconds. I can't enter any more passwords, but I can click a "forgot my password" button and enter my Google Account password.  On my rooted 4.0.3 tablet running a custom ROM, my lock screen is set with a numeric PIN. If I input it incorrectly five times or more, it locks itself and I can't enter any more passwords.   I'm not offered the option to enter my google account password to bypass this, although I have configured a Google account on the device.  I want to activate the "I forgot" button in order to enter my Google Account credentials. Is it possible?


How can I get the exit code from command exec ?  This is the sample code. For the others commands it works but not for exec.  exec "somethings" if [ $? == 0 ]; then     echo -e "Done\n"     exit 0 else     echo -e "error\n"     exit 1 fi

When running a command with exec, the parent shell will exit upon the command finishes running. How can I tell if a command executed by exec runs successfully or not?


Given $\mathbb{R} \setminus \{-1\}$ with the operation $a*b=a+b+ab$, check whether is it or not a group.  My solution:   Associative  $$(a*b)*c=(a+b+ab)*c=a+b+ab+c+(a+b+ab)c=\\ =a+b+ab+c+ac+bc+abc;$$  $$a*(b*c)=a*(b+c+bc)=a+b+c+bc+a(b+c+bc)=\\ =a+b+ab+c+ac+bc+abc$$ Existence of identity el.   If $e$ is the identity, then, for each a in the set, $a*e=e*a=a \rightarrow a*e=a+e+ae=a$. Here, it seems that the identity is $0$, but if $a=1$, the equation has no solution. So there is no identity element and therefore the set is not a group.  Is that right?

So basically this proof centers around proving that (S,*) is a group, as it's quite easy to see that it's abelian as both addition and multiplication are commutative. My issue is finding an identity element, other than 0. Because if 0 is the identity element, then this group won't have inverses.  The set explicitly excludes -1, which I found to be its identity element, which makes going about proving that this is a group mighty difficult.


Background  The use of the word "" occurs frequently in Catholicism when referring to God's nature, 3 persons in 1 God.  What words would describe a being that is 2 persons, 4 persons, 5 persons, etc.?

In Christianity, there is the doctrine of the "trinity" of God. What would be the name of the corresponding doctrine if the number three were replaced with two, four or five?


What is the best way to be notified of an apps' update that is not installed on my phone? Is there a site place such as the Play store, Playboard, Aptoide or elsewhere that I can get an rss feed, email or another way of notification?  For example, I do not have Google Camera installed, but I may want to install it when a new feature I'm looking for has been added to it.  I am aware of the defunct app, "Changelog Droid" which is no longer maintained since January 2014. "The app is currently not maintained. There is an (unlikely to be fixed) issue with paid apps. Please don't contact me in this regard." So an alternative solution beyond that would be greatly appreciated.

Is there any way to receive an update/new version released notification from the Play Store for an app that is not installed in my phone? I'm using 4.3 on a Nexus 4.