Having  that in Old English the word for was written as fore, why is therefore still written as it is currently, and not as therefor?   Being a non-native English speaker, many times I automatically write therefor, as my brain probably is thinking on for. Alternatively, many times I also write fore, as my brain is probably thinking on therefore.   Edit: the  is about the difference between the two expressions, and it would only be relevant if the actual reason why it is therefore instead of therefor is to distinguish them. But since that is not the reason, I believe that question is not a duplicate of this.

I'm a non-native English speaker, and my automatic spellchecker seems to accept both therefore and therefor. Is one orthography preferred ? Is that a British vs. American difference ? Or an old vs. more recent orthography ? Or something else ?


Background:  One way to "prove" that $1+2+3+\dots=-\frac{1}{12}$ is to define the function $f(z)=\sum_{n=0}^\infty \frac{1}{n^z}$ for $z\in\mathbb C, \operatorname{Re}(z)>1,$ then define $\zeta(z)$ as the analytic continuation of $f$ to all of $\mathbb C$, and then show that $\zeta(-1)=-\frac{1}{12}$. Naively replacing the terms in the sum defining $f$ with $z=-1$ suggests that $1+2+3+\dots=-\frac{1}{12}$.  I am curious whether this general idea could be used to rigorously define sums of divergent series. Given a formal series such as $1+2+3+\dots$, could one define the sum to be the analytic continuation of any function definable somewhere in $\mathbb C$ using a summation formula that reproduces this sum somewhere else? Would such a definition lead to a unique answer?  Question:  Let $\{a_n\}_{n\in\mathbb N_0}$ be a family of functions $a_n:\mathbb C\to\mathbb C,z\mapsto a_n(z)$ such that:   $a_n(z_0)=n$ for all $n\in\mathbb N_0$ and for some $z_0\in\mathbb C$, $f(z):=\sum_{n=0}^\infty a_n(z)$ is well defined on some open subset $A\subset\mathbb C$.   Let $g$ be the analytic continuation of $f$ to the rest of $\mathbb C$. Must $g(z_0)=-\frac{1}{12}$?

A while ago, there was a great hype about the “identity” $$\sum_{n=1}^{\infty} n = -\frac{1}{12}.$$  Apart from some series manipulations where the validity seems to be at least questionable, the derivation of this always goes through the zeta function:  Where the series converges, the zeta function is defined by $$\zeta(s) = \sum_{n=1}^{\infty}\frac{1}{n^s}$$ and outside that range by analytic continuation. And it turns out that inserting $s=-1$ formally results in $$\zeta(-1) = -\frac{1}{12} = \sum_{n=1}^\infty n$$  However looking at the series in isolation, there is no indication that the zeta function should be chosen.  An obvious way to get an analytic function that at one point gives the sum of all natural numbers is $$f(x) = \sum_{n=1}^{\infty} nx^n$$ at $x=1$, however (not surprisingly) that function diverges at $1$.  Therefore my question:     Is it possible to get another finite value for the series by analytic continuation of another series?   Concretely, do there exist continuous functions $f_1, f_2, f_3, \ldots$ such that   On some non-empty open subset $S$ of $\mathbb C$, $f(x)=\sum_{n=1}^\infty f_n(x)$ converges to an analytic function. At some point $x_0$, $f_n(x_0) = n$ for all positive integers $n$. The analytic continuation of $f$ is well defined and finite at $x_0$. $f(x_0) \ne -1/12$   What if we demand the functions $f_n$ to be analytic rather than just continuous?


Can anyone please explain to me how to prove that Riemann zeta function is 0 for all negative even numbers. In many references , they have just given the statement without any proof. Any explanation or hint will be a great help. Thanks in advance.

The Riemann zeta function $ζ(s)$ is defined for all complex numbers $s ≠ 1$ with a simple pole at $s = 1$. It has zeros at the negative even integers, i.e., at $s = −2, −4, −6, ...$.   My question: How one can obtain these roots.


Are there men (who have not been exiled to the colonies) in Gilead who are not law enforcement or military (guardians/angels) and not part of the ruling elite (e.g. commanders)? If so are any of these named characters?

In the TV series The Handmaid's Tale we see a dystopian future where people live in classes.  I have heard of:   Ant - A worker Eye - Spy/Secret Police Aunt - Keeper of the Handmaidens Commander - Boss of some kind (I don't know if it is political or military) Martha - housekeeper Handmaid - Walking baby machines   Are there any other classifications and what do they mean?


i'm using Ubuntu on Dell Latitude E5420 (4G RAM, i5, HD 3000 ). Some times i feel lag when watching video on Youtube. Can i install HD graphics on newest ver of ubuntu?

Can someone help me out and explain or point me in the right direction on how to check video drivers and see if my video card running okay?  I had 10.04 installed on my Thinkpad r61 with Compiz Manager and life was great, until the machine took water damage. I bought an ASUS (X54H) since and am trying out 12.04, but the desktop just doesn't look right.  I always struggled with video driver installation. There are no proprietary drivers available in the hardware manager.  When I run lspci | grep VGA:  00:02.0 VGA compatible controller: Intel Corporation 2nd Generation Core Processor Family Integrated Graphics Controller (rev 09)   I will greatly appreciate your help. I want to use Linux more, but like I said video drivers appear to be my biggest concern. I have also tried 12.04 on my desktop PC, but again failed to configure video card, so switched back to Windows 7.


I applied for a US visa from a country other than my own(I am an Indian and I currently work in Japan). My application was put on administrative processing and its been 2 months. I still have no clue as to how long it will take them to process my application. But my Japanese visa will expire soon but I cannot travel to India since my passport is with the US embassy in Tokyo. Can I get my passport back and then submit it at a US embassy in India without affecting my application ?

I got a mail that my UK appointment is on August 16, and I was informed I have a training at work, so I updated the appointment to August 30 without cancelling the previous date. I didn't don't get any mail after the update. Which date is valid, 16th or 30th?


I am really confused between magnetic field (B)and magnetic field intensity(H) and magnetisation intensity(I) Please can someone explain them to me and these formula H=B/μ -I, I=M/V, I am a high school student so i may not be able to understand tensors and stuff which a lot of other articles i read used. I also don't yet know the analogies of these with there electrostatic counter parts.

As per :  "The term (Magnetic Field) is used for two distinct but closely related fields denoted by the symbols $B$ and $H$, where $H$ is measured in units of amperes per meter in the SI. $B$ is measured in teslas in the SI."  So, the two are closely related. Why do we need two, then? Could just one be used? As I remember from the university, for vacuum the Maxwell's equations are written usually in terms of $B$, while for media in terms of $H$ (and $B=\mu H$).


According to  (my emphasis),     In statistics, the standard deviation ... is a measure that is used to quantify the amount of variation or dispersion of a set of data values. A standard deviation close to 0 indicates that the data points tend to be very close to the mean (also called the expected value) of the set, while a high standard deviation indicates that the data points are spread out over a wider range of values.   The purpose of the standard deviation (SD), then, is to tell us how varied or uniform (SD → 0) the data is.  So, given a certain SD, how varied is the data? What does the size of the standard deviation mean?  Please explain the meaning of the SD by interpreting an SD = 1 (M = 0).  If you cannot interpret the size (quantity) of this SD, what other information would you need to be able to interpret it, and how would you interpret it, given that information? Please provide an example.  If, on the other hand, the quantity of the SD cannot be qualified in this manner, my argument is that it is essentially meaningless. If you disagree, please explain the meaning of the SD.       The following are earlier versions to give context to the answers. Unfortunately these didn't really convey what I wanted, and my attempt to ask it elsewhere was closed. (I don't need these versions answered now):  First revision:  What does the size of the standard deviation mean?  For example, if I want to study human body size and I find that adult human body size has a standard deviation of 2 cm, I would probably infer that adult human body size is very uniform, while a 2 cm standard deviation in the size of mice would mean that mice differ surprisingly much in body size.  Obviously the meaning of the standard deviation is its relation to the mean, and a standard deviation around a tenth of the mean is unremarkable (e.g. for IQ: SD = 0.15 * M).  But what is considered "small" and what is "large", when it comes to the relation between standard deviation and mean? Are there guidelines similar to the ones that Cohen gives for correlations (a correlation of 0.5 is large, 0.3 is moderate, and 0.1 is small)?    Original question:  We always calculate and report means and standard deviations. But what does the size of the variance actually mean?  For example, assume we are observing which seat people take in an empty room. If we observe that the majority of people sit close to the window with little variance, we can assume this to mean that people generally prefer siting near the window and getting a view or enough light is the main motivating factor in choosing a seat. If on the other hand we observe that while the largest proportion sit close to the window there is a large variance with other seats taken often also (e.g. many sit close to the door, others sit close to the water dispenser or the newspapers), we might assume that while many people prefer to sit close to the window, there seem to be more factors than light or view that influence choice of seating and differing preferences in different people.  At what values can we say that the behavior we have observed is very varied (different people like to sit in different places)? And when can we infer that behavior is mostly uniform (everyone likes to sit at the window) and the little variation our data shows is mostly a result of random effects or confounding variables (dirt on one chair, the sun having moved and more shade in the back, etc.)?  Are there guidelines for assessing the magnitude of variance in data, similar to Cohen's guidelines for interpreting effect size (a correlation of 0.5 is large, 0.3 is moderate, and 0.1 is small)?  For example, if 90% (or only 30%) of observations fall within one standard deviation from the mean, is that uncommon or completely unremarkable?

In the definition of standard deviation, why do we have to square the difference from the mean to get the mean (E) and take the square root back at the end? Can't we just simply take the absolute value of the difference instead and get the expected value (mean) of those, and wouldn't that also show the variation of the data? The number is going to be different from square method (the absolute-value method will be smaller), but it should still show the spread of data. Anybody know why we take this square approach as a standard?  The definition of standard deviation:  $\sigma = \sqrt{E\left[\left(X - \mu\right)^2\right]}.$   Can't we just take the absolute value instead and still be a good measurement?  $\sigma = E\left[|X - \mu|\right]$


I am trying to create a map of the UK based on a number of open data sources (Ordnance Survey Open Data, OSM, some CSV files etc).  My end goal is to create a map of the whole of the UK that I can view in OruxMaps or some other similar slippymap style offline client.  I am really struggling to work out the best way to do it though.  I have tried importing the data into QGIS, styling it and then using QGIS Server, but I can't figure out a good way of creating the slippy map from there.  I have tried TileMill, but it can't cope with the 2.5Gb contour .shp file.  I have looked around at various other things too, but just cannot work out the best way of doing this.  Any thoughts?

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?


How to accurately, unambiguously and concisely say something in the following cases:  Case 1. The predictor is significant, with 1.5615 times as much likely to get higher scores when it is true. Case 2. Subjects with A are 1.5615 times as much likely to get higher scores as those without A.  Maybe can I use "chance" instead of "likely" to form the sentence better?

Suppose John has 5 sweets. Is there any difference between the following two sentences?     Jack has 3 times as many sweets as John.      Jack has 3 times more sweets than John.   I prefer the first construction and would know unambiguously that Jack has 15 sweets in this case. However in the second construction I would be inclined to think that Jack has 20 sweets, since it seems to suggest 15 sweets in addition to the original 5.


This I approached the problem. I let $x = n + e$ where $n$ is an integer and $e$ is a decimal less than $1$ but not less than $0$. I substituted that into the equation to get $\left\lfloor \lfloor (n+e)/2\rfloor/2 \right\rfloor = \lfloor (n+e) / 4 \rfloor $  Then I will try for 4 cases.  case 1: $0 \le x < 1/4$  case 2: $1/4 \le x < 1/2$  case 3: $1/2 \le x < 3/4$  case 4: $3/4 \le x < 1$  Am I allowed to pull the n out of $\left\lfloor \lfloor (n+e)/2\rfloor \right\rfloor$?  If I can then i can simply plug in the cases into $e$, which will give me $0=0$ for all $4$ cases. Is that correct?

In class, we briefly covered what "floor" and "ceiling" mean.  Very simple concepts.  They were on one slide, and then we never heard about them again.  But now the following homework problem has popped up:  $$\lfloor\lfloor x/2 \rfloor / 2 \rfloor = \lfloor x/4 \rfloor$$  Usually when I post a problem (especially from homework), I like to demonstrate that I'm not just asking for the answer by showing what I've done, what I know so far, and so on... but in this case, I have absolutely no idea where to even begin.  I will say that my first approach was to create a chart and try various values for "x" in order to see if there's a pattern and to make sure there was no easy counter-example to prove it false.  That was all fine and well, but ultimately I couldn't figure out what to do with the results.  Googling for this is quite difficult, as everyone uses slightly different notation and therefore one search doesn't encompass all the actual results.  The only clue that I've seen so far that kind of sort of makes sense, was when some guy said that "x" should be replaced with "4n + k", since the right-hand side of the equation is divided by 4, so that k is any remainder 0 through 3.  How should one approach this problem?  What kind of manipulations can you do to floors?  What can you assume?  etc. etc. ...


While reviewing First Posts on Stack Overflow just now, I ran across an answer that gave a solution in code with an explanation in a language not English. Note that the question was in English. I flagged an answer as Very Low Quality only to subsequently realize that the code appears to be a pretty good solution. I realized it probably would have been better to simply edit the post with a translation, keeping the original because machine translations can suck sometimes.  I hate to waste the attention of our illustrious moderators, so I would like to recall or take-back the flag somehow. Is there a way I can do that?  The Help Center has this to say about removing flags:     Is there any way to remove flags?      There is often no need, as offensive and spam flags expire after 48   hours if the thresholds aren't reached.      Rolling back a post to a previous state will revert to the number of   offensive flags from that particular revision. This allows the OP (or   someone else with edit rights) to rollback a post that someone else   made offensive in a later revision. However as a general user, once   you mark a post as offensive, you cannot take it back.   This, however, only seems to speak to spam flags. Specifically, is there a way I can voluntarily remove one of my own flags?  If not, I would like to suggest adding this capability.

I'm wondering (since it just happened to me), is it possible to "cancel" ("undo", "delete", "retract", whatever) a flag I just raised if I misclicked it, so the mods won't waste time?  I looked everywhere, but I can't find such a feature.


I just read that the mass of a proton is one hundred times more than the sum of the masses of the quarks composing it. Now, I know that these numbers (the mass of the proton and the sum of the masses of the quarks) don't need to agree due to E=mc2, but why isn't the mass of the proton less than the sum of the quark masses? I mean, the quarks are obviously bound together to form a proton, and from QM I know that bound states require the total energies to be negative (assuming the potential energy at infinite separation is zero, but I guess that's fair if the strong force goes to 0 as the distance between two interacting particles, two quarks in this case, goes to infinity). In other words, the sum of the kinetic and potential energies of the quarks should be negative, causing the mass of a proton to be less than the masses of the quarks. This is similar to how the mass of an atomic nucleus is less than the sum of the masses of the protons and neutrons, or that the mass of an atom is less than the sum of the masses of the electrons, protons and neutrons. Why is this totally wrong, and how is it that a proton is as much as a hundred times heavier?

The mass of nucleons is bigger than the sum of the masses of its constituent quarks. I understand that it's because you have to take into account the binding energy of these quarks.   What I don't understand is this: In a nuclear physics course I was tought that the mass of the nucleai is less than the sum of the masses of its constituent nucleons because the binding energy between them is negative in order to make it stable.   So, if the binding energy of nucleons is negative because its suppose to be an atractive force that keeps nucleons stable, why does the binding energy of quarks add to the mass of nucleons instead of reducing it if it's also an atractive force keeping quarks stable?  I understand that in the quark regime we have to deal with quantum chromodynamics and the concept of force and energy are not that simple but I was expecting the binding energy of any atractive interaction to be negative anyway...


There's a syntax that Javascript adopted from C where you can perform a logical check, without checking anything:  if (foo) {  }   What is this equivalent to? Is it:  if (foo != null) { } if (foo !== null) { } if (typeof(foo) != 'undefined') { } if (typeof(foo) !== 'undefined') { } if (typeof(foo) != 'object') { } if (typeof(foo) !== 'Object') { }   My actual motivation for asking is wanting to ensure that a member "exists" (that is to say, if it is null or undefined then it doesn't exist):  if (window.devicePixelRatio !== null) if (window.devicePixelRatio != null) if (!(window.devicePixelRatio == null)) if (!(window.devicePixelRatio === null)) if (!(window.devicePixelRatio == undefined)) if (!(window.devicePixelRatio === undefined)) if ((window.devicePixelRatio !== undefined))   My concern is if the member is defined, but defined to be null, in which case (as far as i'm concerned) it's not assigned.   I know that the expressionless syntax returns true for a "truthy" value. I'm less interested in a "truthy" value, as an actual value.

What's the best way of checking if an object property in JavaScript is undefined?


Let $P_i$ be sequence of prime numbers i.e $P_1=2,P_2=3,P_3=5 ...$  Euler has proved that the sum $$\sum_{i=1}^{\infty}\dfrac{1}{P_i}$$ is divergent.   Set $a_i=P_{P_i}$ then $a_1=P_2=3$ , $a_2=P_{3}=5$ and $a_3=P_5=11$ ...  My question is that $$\sum_{i=1}^{\infty}\dfrac{1}{a_i}$$ is convergent or not. From a more general perspextive if set $$a_i=P_{P_{P_{._{._{P_i}}}}}$$ (n times sub) then can we conclude that   $$\sum_{i=1}^{\infty}\dfrac{1}{a_i}$$ is convergent ? if it is so, what is the minumum of such $n$ ?

What is the value of $\sum\limits_{i=1}^\infty\dfrac{1}{p_{p_i}}$ where $p_n$ is the nth prime (and so $p_{p_n}$ is the $k$th prime, where $k$ is the $n$th prime) ?  Thus $\frac{1}{3}+\frac{1}{5}+\frac{1}{11}+...=$ ??  How do I efficiently decide if $\sum_{i=1}^\infty\dfrac{1}{p_{p_i}}\gt1$ is true without using a computer ?  I assume this infinite sum is an irrational number. Has this already been proven ?


This is the get into -    And the finder view -    From a 2008 MacPro, running 10.5.8 Snow Leo. This wouldn't be an issue, except I was planning to update to an SSD. With only 60GB used, and much of it, I'm removing, a 120GB SSD for pretty cheap seemed a good way to boot this machine.   I'm used to the log files that need attention, or a reboot that clear caches that can get crazy. But, here we have 140GB that's missing.   To the question - how do I identify and remove the source of this phantom 140GB? Would a migration to a clean HD be a quick interim step? i.e. just find a blank 1TB drive, install clean OS, migrate? Or do I risk having that 140GB chunk migrate as well?   Edit - Disk Inventory X found this, instantly, a huge blue area - Now, how do I know what's safe to remove? Note - I'm not obsessing over ever last GB, it's just that a 3 to 1 filled/really used ratio seems pretty high.

I am using a Macbook air.  64GB.  My user directory has used 20.47GB  Disk Utility shows 'Other' is 41.33GB and I only have 2.9GB free.  What tools or command line commands can I use to find out what is taking up large amounts of this.  I can use finder with all files and sort by size but that is already about my directory and the space taken seems outside of my directory.


Quick basic question.  Is there a method to search questions on more than one criteria?   example, oldest, unanswered, with zero answers (as opposed to >0 answers, but no accepted answer)?  Where is, or how do we find the way to modify our search criteria  nb this is not about tags as such  I do not need a solution for the example

I was attempting to guide a new user into using the advanced search options today but realised that you can't do it from the Advanced Search Tips link on the search page itself (as it is collapsed by default).  I then tried the , however they are not explained here either.  I realise that you can just tell users to go to the search page and click advanced tips, however that seems clunky.  It also seems odd that the extended help page would just send you back to the old page after all the effort that has gone to to set it up.    I know there's a lot to be said for keeping the help pages concise for new users to easily navigate, however I would like to suggest that either advanced search options are added in full to the search help page or alternatively a new help entry for advanced search options is created.


I joined SE network sites. As I am new, I have low reputation. As a part of contribution, I cast votes.  But when I cast votes, I see the following message.    Today, I gained 15 reputation on money.stackexchange. Then I cast votes and those reflected immediately; the earlier message disappeared. That means my votes are being reflected now immediately.  Looking at the message above, I was assuming that my votes are being recorded. It's just that those are not visible publicly.  When I go to my Activity section of my profile, I see following:    That section shows I only cast two votes. I have cast those two votes after I got 15 reputation. I do not see the vote count for those I cast before that.

Users below 15 reputation can't effectively vote. It says:     Votes cast by those with less than 15 reputation are recorded, but do not change the publicly displayed post score   Does it mean that they will take effect after I reach 15 reputation or because they were cast before, they're recorded but ignored?


I have the following result of a logistic regression:                                    Estimate Std. Error z value Pr(>|z|)     (Intercept)                        3.34260    0.41116   8.130 4.30e-16 *** AgeGr18-22                        -0.61845    0.28974  -2.135 0.032799 *   AgeGr28-30                        -0.46384    0.27474  -1.688 0.091361 .   AgeGr31-35                         0.38351    0.28102   1.365 0.172352     AgeGr36-40                        -0.24538    0.25113  -0.977 0.328525     AgeGr41-50                         0.11316    0.23918   0.473 0.636140     AgeGr51-high                       0.49277    0.29597   1.665 0.095924 .   AutomobileGr1                      0.61832    0.17570   3.519 0.000433 *** AutomobileGr2-high                -0.07095    0.37665  -0.188 0.850590       The dummy "AutomobileGr2-high" (having 2 or more automobiles) have a P-value 0.85 and I would like to drop it from the model.  Would it make a difference if I just drop the dummy (i.e. create a regression formula without this group) or if I put it into the reference group (our reference group in the example above is AutomobileGr0 - ppl that do not have a car, hence the combined reference group will be AutombileGr0 & AutombileGr>=2 -> ppl either without a car or with at least 2).  From what I read so far () it should make a difference on the intercept hence on the whole resulting target log odds.  What approach is suggested as best practice (or what are the pros and cons of the two approaches)?

After seeking clarification about linear model coefficients  I have a follow up question concerning non-signficant (high p value) for coefficients of factor levels.  Example: If my linear model includes a factor with 10 levels, and only 3 of those levels have significant p values associated with them, when using the model to predict Y can I choose to not include the coefficient term if the subject falls in one of the non-signficant level?  More drastically, would it be wrong to lump the 7 non-significant levels into one level and re-analyze?


I want to store some download counts with the name of the downloadfile in a database.  This is working fine:  $filename = $_GET['file']; // in combination with mysqli_query($link, "INSERT INTO download_manager (filename,downloads)                           VALUES ('$filename',1) ON DUPLICATE KEY UPDATE downloads = downloads+ 1;");   Now i want to escape the $_GET with mysqli_real_escape_string  When i do it like this, the script is not working anymore:  $filename = mysqli_real_escape_string($_GET['file']); // in combination with mysqli_query($link, "INSERT INTO download_manager (filename,downloads)                           VALUES ('$filename',1) ON DUPLICATE KEY UPDATE downloads = downloads+ 1;");   How can i use the mysqli_real_escape_string in this example on the right way?

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


We have an object of mass $m$ which can go through matter like a ghost. It's only affected by gravity, not by any other force, so it's in free fall.  At the instant $t=0$ it is at the surface of the Earth which is assumed to be a perfect sphere of radius $R=6.371 \times 10^6$ m, of mass $M=5.972 \times 10^{24}$ kg and of uniform density $\rho=5.515 \times 10^3$ kg/m$^3$. $G=6.674 \times 10^{-11}$ m$^3$ kg$^{-1}$ s$^{-2}$.  The object has an initial velocity $v_0$ directed precisely at the center of the Earth. Unlike   the velocity need not be zero.  My question: depending on the variables $m$ and $v_0$, how much time will it take to reach the opposite side of the Earth?

...And you jumped in.  What would happen when you got to the middle of the Earth? Would you gradually slow down, until you got to the middle and once you were in middle would every direction feel like it was up?


Let $L_1$ and $L_2$ be two undecidable languages.  1) Is it possible that $L_1 - L_2$ is regular and $L_1 - L_2 \neq \emptyset$ ?  Well I know that if I let $L_1 = L_2$ then $L_1 - L_2 = \emptyset$ which is obviously regular. In the case of this question however, I cannot set $L_1 = L_2$ if the outcome is an empty set, which makes me wonder what would $L_1 - L_2$ actually look like if they were not equal to each other.  2)  Is it possible that $L_1 \cup L_2$ is decidable and $L_1 \neq \neg L_2$ ?  This one is also tricky, since the obvious solution here would be to let $L_1 = \neg L_2 $.  Does anyone here have an idea as to how to finish my solutions here? I need to prove my solutions in both cases.

Let $L_1$ and $L_2$ be two undecidable languages.  1) Is it possible that $L_1 - L_2$ is regular and $L_1 - L_2 \neq \emptyset$ ?  Well I know that if I let $L_1 = L_2$ then $L_1 - L_2 = \emptyset$ which is obviously regular. In the case of this question however, I cannot set $L_1 = L_2$ if the outcome is an empty set, which makes me wonder what would $L_1 - L_2$ actually look like if they were not equal to each other.  2)  Is it possible that $L_1 \cup L_2$ is decidable and $L_1 \neq \neg L_2$ ?  This one is also tricky, since the obvious solution here would be to let $L_1 = \neg L_2 $  Does anyone here have an idea as to how to finish my solutions here? I need to prove my solutions in both cases.


When I run which java command in my Ubuntu, it tells /usr/bin/java.  I initially installed java using sudo apt-get install ... command. Using this command where does it install all java components?  In my system in /usr/lib/jvm i see the following listings:  java-1.5.0-gcj-4.8-amd64  java-1.7.0-openjdk-amd64  java-7-openjdk-amd64   I want to completely remove Java, I tried Googling, but the instructions used in didn't work. Can anyone help me do this?

How can I completely remove all traces of Java on my system?   I already know  in case I need it again.


I am using Gmail application in Android 6.0. I have > 777 messages in my inbox. I would like to Select All and Delete them from the pop3 account.     How can you Select All Pop3 messages in Gmail Android Application?

I've previously used the default Email app on my CyanogenMod 7 EVO because I had an Exchange account at work. However, I switched jobs recently and my new place just uses GMail corporate accounts (which I enjoy). Since I don't have the Exchange account anymore, I'd like to move over to the GMail app because I prefer the UI and whatnot, but I can't for the life of me find any kind of "Select All" functionality in it.  The Email app allows me to do this from the options menu (Menu->Select All selects everything in the current folder). In GMail I noticed that if I select one or more items, then "Deselect All" becomes available in the options menu, but not "Select All". I've also tried various forms of long-pressing on messages, accounts, and folders to no avail.  Is there any way to do this in the GMail app, or am I just stuck without it? I searched the issue tracker and didn't find anything relevant, which surprised me a bit, to be honest. Obviously I can do this from a computer if I need to empty a folder/label, but I'd kind of like to retain the functionality on my phone, too. Am I missing some non-obvious (or perhaps even obvious) menu item somewhere?


I have been trying to create sublists within lists so that I can call on the sum function to have all the value (each sublists must have the same length). I tried using the range function with having the start and end as variable, and after each variable, add up to the start and end.   temp1 = list() distance = list() start = 0 end = 3 distance_list = [1.4.5,5,3,5,4,5,8] for a in range(3):     for b in range(start,end):         temp1.append(distance_list[b]         distance.append(temp1)         start += 3         end += 3   Here, the expected result is to simply be able to create a list that is like  distance = [[1,4,5],[5,3,5],[4,5,8]]   However, the result that I got is the fact that the number b got extremely large.  What are some suggestion to tackle this problem?

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


I reinstalled UBUNTU 16.04 via the official iso burned to DVD on my Lenovo laptop (I am not simple boot) The installation ends as planned, I launch ubuntu, until then by problem, I make 5 updates via Ubuntu softawre. I restart the computer, I enter password to access my Ubuntu session and there: bulk pixels, then BLUE screen! My mouse disappears, appears, in short, I can not acceder my session and the terminal does not work.  I run the trial version of Ubuntu in live cd to have access to BOOT REPAIR as indicated in this forum:   I install it as expected, I restart the computer and I see that the Grub is displayed, so far no. But at the level of the blue screen it is the same ... I can not access my Ubuntu session.  Also, I tried to reinstalled 16.04 a second time. during the installation I got this message:  The microcode of this system has started the installer in UEFI mode but there seem to be other operating systems that use the BIOS compatibility mode. If you continue the installation in UEFI mode, it may be difficult to restart these operating systems at a later time. If you want to retain the ability to restart other installed systems; you should NOT (in uppercase in the text) force the installation into UEFI mode.   Anyone know more?  LAM

I am using Ubuntu 16.04 and I am stuck into blue screen with no message.  Its just showing a cursor nothing else.    Any help is appreciated.


I have a list like this:   grid_1 = ('  ##   ',           ' ####  ',           '####   ',           '#######',           ' ###   ',           ' ##    ')   Where each element is the same length and consists of a space ' ' or a hash '#'  I would like to generate a new list where each element above is in its own sub-list, and each character is separated by a comma.   This is what I have so far:   workable_grid = [[None]*len(grid_1[0])] * len(grid_1) for i in range(len(grid_1)):     for j in range(len(grid_1[0])):         workable_grid[i][j] = grid_1[i][j]   However the result I get is wrong:  wrong_list = [[' ', '#', '#', ' ', ' ', ' ', ' '],               [' ', '#', '#', ' ', ' ', ' ', ' '],               [' ', '#', '#', ' ', ' ', ' ', ' '],               [' ', '#', '#', ' ', ' ', ' ', ' '],               [' ', '#', '#', ' ', ' ', ' ', ' '],               [' ', '#', '#', ' ', ' ', ' ', ' ']]   Any advice is appreciated. Thanks!

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


;) My file cargo.tml contains  ... [dependencies] winapi = "0.2.7" user32-sys = "0.2"   And my main.rs  extern crate winapi; extern crate user32;   But, when i use cargo build. I have this error:  error: aborting due to previous error  error: Could not compile `user32-sys`. warning: build failed, waiting for other jobs to finish... error: build failed

Our build process uses Visual Studios 2003 link.exe for linking.  On one machine we're seeing the following error:  _X86_Win32/Debug/Intermediate/OurApp.exe LINK: extra operand `/subsystem:windows' Try `LINK --help' for more information   It appears to be using the same version of visual studios as the other machines.  Has anyone encountered this problem before?


I have sold my old android mobile to a person and made sure that the mobile was completely formatted.  But, when I try to view the list of devices in Play Store it is listing both my new and old mobile phones.  Is it possible to remove this old phone from the list so that the other person doesn't use my account?

Yesterday I bought a new Android smartphone & performed a factory reset on my previous HTC handset. Naturally (I think) I set up my new phone under the same Google account as was registered for my HTC.  If I login to the Google Play Store, I was expecting, and maybe naively assumed to find, a way to delete the HTC handset, but I cannot seem to find a way to achieve this!  As this is only my second Android device, I have not encountered this situation before. (Perhaps there were steps I should have taken on my HTC, prior to performing the factory reset.)  I am however surprised that Google does not allow you to carry out such a basic task.  Did I miss something?  Does Google wish you to create a new account every time you change phones/tablets?


When I imported this model into Unity a few parts of the model seem to be inside out. (the wings and the left engine)    I opened the model in blender, selected the relevant components, and recalculated normals. Now nothing is inside out.    However you can see that those parts are now really dark. And I can't fix this.    The problem itself can be seen in blender as dark faces. Similar to the problem seen when faces are inverted.  I have already tried:   recalculating normals on all components (the rest are unchanged) checking that the normals actually ARE facing outwards by showing the weights of the normal checking that both parts share the same material   why are these faces darker? how can I fix it?

While rendering a mesh with smooth shading on, I get a dark region/shadow on certain faces. The effect is more evident when smooth shading is applied to a mesh containing ngons, with the ngons turning black when rendered.   The blackening effect is visible in the viewport too.  How can I solve this problem?


After installing ubuntu 18.08 LTS along side with windows 10 , i encountered some problems using ubuntu the first is the touchpad but thanks to askubuntu i corrected the problem. Now i'm searching solutions to another problem that is with my wifi wireless connection it doesn't work and more over when entering to wifi settings i see an No Wifi Adapter Found' i already tried some stuff but unluckily not working. when typingsudo lshw -C network` i get this :     *-network                         description: Ethernet interface        product: RTL8101/2/6E PCI Express Fast/Gigabit Ethernet controller        vendor: Realtek Semiconductor Co., Ltd.        physical id: 0        bus info: pci@0000:01:00.0        logical name: enp1s0        version: 07        serial: 98:29:a6:67:23:2b        capacity: 100Mbit/s        width: 64 bits        clock: 33MHz        capabilities: pm msi pciexpress msix vpd bus_master cap_list ethernet physical tp aui bnc mii fibre 10bt 10bt-fd 100bt 100bt-fd autonegotiation        configuration: autonegotiation=on broadcast=yes driver=r8169 firmware=rtl8106e-1_0.0.1 06/29/12 latency=0 link=no multicast=yes port=MII        resources: irq:16 ioport:4000(size=256) memory:b1200000-b1200fff memory:b1000000-b1003fff   *-network UNCLAIMED        description: Network controller        product: Realtek Semiconductor Co., Ltd.        vendor: Realtek Semiconductor Co., Ltd.        physical id: 0        bus info: pci@0000:02:00.0        version: 00        width: 64 bits        clock: 33MHz        capabilities: pm msi pciexpress bus_master cap_list        configuration: latency=0        resources: ioport:3000(size=256) memory:b1100000-b110ffff   *-network        description: Ethernet interface        physical id: 3        logical name: enp0s20f0u2        serial: 22:2e:f7:46:24:ff        capabilities: ethernet physical        configuration: broadcast=yes driver=rndis_host driverversion=22-Aug-2005 firmware=RNDIS device ip=192.168.42.91 link=yes multicast=yes   When typing `lspci -knn | grep Net -A02:00.0  i get :  02:00.0 Network controller [0280]: Realtek Semiconductor Co., Ltd. RTL8821CE 802.11ac PCIe Wireless Network Adapter [10ec:c821]     Subsystem: Lenovo RTL8821CE 802.11ac PCIe Wireless Network Adapter [17aa:c024]     Kernel modules: wl   When trying rfkill list i get :   0: ideapad_wlan: Wireless LAN     Soft blocked: no     Hard blocked: no 1: ideapad_bluetooth: Bluetooth     Soft blocked: no     Hard blocked: no 3: hci0: Bluetooth     Soft blocked: no     Hard blocked: no   Help please i want back my wireless connection

We just bought a Lenovo  (which is supposed to have the Intel 8265 for wireless). This laptop was bought in part because it is certified to run Ubuntu and as such to me at least it would make sense for things to work out of the box... but no such luck.  First, I installed Ubuntu 17.10 and after installation realised Wi-Fi was not working. I also tried Ubuntu 16.04 from a USB drive since that is the version of Ubuntu it is certified for, but no luck there either.  The wireless chip is not detected by lshw (or even lspci by the looks of it), ip link does not show a wireless interface, and the iwlwifi kernel module is not loaded at boot (I can load this myself using modprobe iwlwifi but this does not make Wi-Fi work). I think it is a combined Wi-Fi/Bluetooth chip, and Bluetooth does appear to work (or at least Bluetooth shows up in Gnome and rfkill list).  modinfo iwlwifi | grep 8265 shows me a file ending in -34 is supposedly loaded but only a file ending in -33 (and some other lower numbers) is present in /lib/firmware, if that helps).  I have also installed the Linux 4.14.9 kernel in an attempt to get things to work, but this did not resolve the issue either.  Further information  root@ThinkPad-E570:~# modinfo iwlwifi | grep 8265 firmware:       iwlwifi-8265-34.ucode root@ThinkPad-E570:~# rfkill list all 0: tpacpi_bluetooth_sw: Bluetooth     Soft blocked: no     Hard blocked: no 1: hci0: Bluetooth     Soft blocked: no     Hard blocked: no root@ThinkPad-E570:~# dmesg | grep iwl root@ThinkPad-E570:~# lspci -nnk | grep 0280 -A3 05:00.0 Network controller [0280]: Realtek Semiconductor Co., Ltd. Device [10ec:c821]     Subsystem: Lenovo Device [17aa:c024]   Update  I just noticed that the laptop does not have an Intel wireless chip at all, but in fact has a Realtek one... which means that the  of the shop I bought this laptop at were not accurate... Sigh. Same problem stands, however, just with a crappier wireless chip.


The general rule I was given as a youngster was that if the initial sound of the noun is that of a vowel, the correct indefinite article is “an”, while if it started with a consonantal sound or ‘y’, I should use ‘a’. However, I’m writing an article for a magazine (I’m the editor, too, so telling me to check the ‘house style guide’ is not going to work...), and I find that the rule described and Microsoft Word seem to disagree with respect to the borrowed term hors d’oeuvres. I learned to pronounce it (pardon the lack of IPA) roughly as “OR DERVZ”, which would imply the use of “an”; Word seems to want me to use “a”. Should I accede to Word’s correction, or did Microsoft goof on this one?  The problem with the proposed duplicate and the other relevant questions linked to it is that none of them seem to give an authoritative answer; the general weight of opinion confirms my early education, but while I will not hesitate to disagree with Microsoft’s algorithm and stick to my own inclinations in most cases, this particular case - a borrowing from French that has not been fully Anglicized - plus my lack of exposure to French to understand where a partial Anglicization may have altered the pronunciation (so that I may be pronouncing it “wrong” even for what American standard may exist) leaves me with little enough confidence that I’m not comfortable with accepting either alternative unsupported by some sort of authoritative citation.

In the following example, is it appropriate to use a or an as the indefinite article, and why?     He ate __ green apple.   I know that in the case of just "apple", it would be "an apple," but I've heard conflicting answers for "green apple," where the noun is separated from the article by an adjective.  Also, which is more appropriate in this case:     He ate  __ enormous Pop-Tart.


I was reading Zee book about gravity, it was asked by him to the reader how to know if this two space below are flat or curved: $$ds^2 = d \rho^2 + sin^2(\rho)d \phi^2$$ $$ds^2 = cos^2(\rho) d\rho^2 + sin^2(\rho)d \phi^2$$ I know nothing about Gauss study and Riemann study in the space curvy subject, so i tried to know if it is flat or curvy by myself for while. $$A = |d \rho^2 [vector product] sin^2(\rho)d \phi^2| = |sin^2(\rho)| $$$$ A = |cos^2(\rho) d\rho^2 [vector product] sin^2(\rho)d \phi^2| = |sin^2(\rho) cos^2(\rho)|$$ now the first area with respect to the first space is equal the area in a flat space iff $$(\rho) = \phi/2$$ While the area on the second space will never be equal the area in a flat space, so the first space is flat only in a special case, while the other space is not flat Is this a reasonable way to check if a space if flat or not?

I was reading up on the  (from Sean Carroll's book) and something that he said confused me.   To start with, the Kerr metric is pretty messy, but importantly, it contains two constants - $M$ and $a$. $M$ is identified as some mass, and $a$ is identified as angular momentum per unit mass. He says that this metric reduces to flat space in the limit $M \rightarrow 0$, and is given by $$ds^2 = -dt^2 + \frac{r^2 + a^2 \cos^2\theta}{r^2 + a^2}dr^2 + \left(r^2 + a^2 \cos^2\theta \right)d\theta^2 + \left(r^2 + a^2 \right)\sin^2\theta d\phi^2 $$  and $r$, $\theta$ and $\phi$ are regular spherical polar co-ordinates.   But I don't understand why this space is obviously flat. The Schwarzschild metric also contains terms involving $dt^2$, $dr^2$, $d\theta^2$ and $d\phi^2$ but is curved. I always thought that a metric with off diagonal elements implied a curved space, but clearly I was very wrong.  Question: How do you tell if a metric is curved or not, from it's components?


After some awesome help yesterday on this site, I am back with another question. I have my input/output equation the way I want it but need help rounding the decimal off to the hundredths position. The way it is set up now the output of pounds seems to just repeat the answer. I have been inputting 10.2 as the weight in kilograms and the answer I keep receiving in pounds is 22.4422.44. I know it is something with the String.format I am using but after messing with it for quite a while I can't seem to figure it out. I know it is something silly but I have been working on this for a while now and I think my brain may be mush. Below is my program.  //This program converts kilograms to pounds using input/output dialog boxes.  import javax.swing.*;  public class SNHU2_3 {      public static void main (String[] args){          String inputStr;         String outputStr;           double pounds;         double kilograms;           inputStr = JOptionPane.showInputDialog("Enter weight in kilograms");         kilograms = Double.parseDouble(inputStr);          outputStr = ("Kilograms = " + kilograms) + "\n" + ("Pounds = " +  (kilograms * 2.2)) + String.format("%.2f", (kilograms * 2.2));          JOptionPane.showMessageDialog(null, outputStr, "Weight Conversion", JOptionPane.INFORMATION_MESSAGE);         System.exit(0);       } }

What I would like is a method to convert a double to a string which rounds using the half-up method - i.e. if the decimal to be rounded is 5, it always rounds up to the next number. This is the standard method of rounding most people expect in most situations.  I also would like only significant digits to be displayed - i.e. there should not be any trailing zeroes.  I know one method of doing this is to use the String.format method:  String.format("%.5g%n", 0.912385);   returns:  0.91239   which is great, however it always displays numbers with 5 decimal places even if they are not significant:   String.format("%.5g%n", 0.912300);   returns:  0.91230   Another method is to use the DecimalFormatter:  DecimalFormat df = new DecimalFormat("#.#####"); df.format(0.912385);   returns:  0.91238   However as you can see this uses half-even rounding. That is it will round down if the previous digit is even. What I'd like is this:  0.912385 -> 0.91239 0.912300 -> 0.9123   What is the best way to achieve this in Java?


Would be glad if someone helps me do this. I'm trying to convert a raster .tif file to a .shp file for some analysis. I'm using a 1.5GB data file and have installed GDAL using Conda. But if I run the code it says the following error:      RuntimeError: This is a BigTIFF file.  BigTIFF is not supported by   this version of GDAL and libtiff.   What should I do to solve this error? Please explain as I'm totally new to Python environment!  import os from osgeo import gdal, ogr import sys # this allows GDAL to throw Python Exceptions gdal.UseExceptions()  #  get raster datasource  src_ds = gdal.Open("IND_ppp_2015_v2.tif") print (src_ds)

I have some BigTiff files that I need to read into Python using gdal to do some analyses. According to GDAL's documentation:     When built with internal libtiff or with libtiff >= 4.0, GDAL also supports reading and writing BigTIFF files (evolution of the TIFF format to support files larger than 4 GB).   My version of libtiff is 4.0.9, so there should be no problem. However, if I try  bt = gdal.Open('path_to_bigtiff.tif'),    bt is a NoneType. I tested to ensure that non-BigTIFF files are readable with gdal.Open(), which they are.  Furthermore, if I check the list of gdal's supported drivers' metadata like this:  md = gdal.GetDriverByName('GTiff').GetMetadata() if md['DMD_CREATIONOPTIONLIST'].find('BigTIFF') == -1:     return 'BigTIFF is not supported'   BigTIFFs are not supported. My version of gdal is 2.2.2.   Using Anaconda, I created a new environment with  conda create --name test1 gdal   but I get the same result--gdal 2.2.2 is installed along with libtiff 4.0.9 and BigTiff files still cannot be read.  Using Anaconda again, I created a new environment with   conda create --name test2 gdal=2.3.1 -c conda-forge   but when I run import gdal in the test2 environment, I get the error message      ImportError: DLL load failed: The specified module could not be found.   How can I install a version of gdal that will permit me to load BigTiffs? I would also like it to be compatible with rasterio and fiona if possible.  Here is the output from conda info for the environment containing 2.2.2: (geoenv) C:\Users\Jon>conda info       active environment : geoenv     active env location : C:\Users\Jon\Anaconda3\envs\geoenv             shell level : 2        user config file : C:\Users\Jon\.condarc  populated config files : C:\Users\Jon\.condarc           conda version : 4.5.9     conda-build version : 3.0.27          python version : 3.6.3.final.0        base environment : C:\Users\Jon\Anaconda3  (writable)            channel URLs : https://repo.anaconda.com/pkgs/main/win-64                           https://repo.anaconda.com/pkgs/main/noarch                           https://repo.anaconda.com/pkgs/free/win-64                           https://repo.anaconda.com/pkgs/free/noarch                           https://repo.anaconda.com/pkgs/r/win-64                           https://repo.anaconda.com/pkgs/r/noarch                           https://repo.anaconda.com/pkgs/pro/win-64                           https://repo.anaconda.com/pkgs/pro/noarch                           https://repo.anaconda.com/pkgs/msys2/win-64                           https://repo.anaconda.com/pkgs/msys2/noarch           package cache : C:\Users\Jon\Anaconda3\pkgs                           C:\Users\Jon\AppData\Local\conda\conda\pkgs        envs directories : C:\Users\Jon\Anaconda3\envs                           C:\Users\Jon\AppData\Local\conda\conda\envs                           C:\Users\Jon\.conda\envs                platform : win-64              user-agent : conda/4.5.9 requests/2.18.4 CPython/3.6.3 Windows/10 Windows/10.0.15063           administrator : False              netrc file : None            offline mode : False


In  a number of 'magic links' were added.  These translate things such as [help/on-topic] into  in the comments (rendered as "help center").  With the loss of the privileges link from the header it can be (slightly) harder to instruct people where to find this information.  Could [help/privileges] be made to link to  (as appropriate for the site) when used in comments?

I have been viewing a lot of first posts from new users. I often see answers such as "thanks", or "me too", or they are asking a different question altogether. I like to point out the fact that they will eventually be able to comment their opinions and upvote answers that they like. So I would like to have a comment such as     Hello user, and welcome to [main]. It is great that the answer helped you, however, that is not the purpose of adding an answer. Soon enough, with just a little bit of work, you will gain [help/privileges/comment] and be able to comment and upvote answers that help you.   [privileges] would link to the site's privilege page, and /comment would link to the page in privileges that talks about commenting. Hash tags could be used to indicate any section of the privileges page. , because each privilege is a different page, the magic links would have to be slashes. For example    - Comment page  - Established user  - Protect Questions   This would work similar to the FAQ magic link comments


Imagine I have a template class, where I've defined typdedef of function pointer to BaseClass function, that returns T and has no arguments:  template <typename T, typename BaseClass> class TConnectionPoint {     typedef   T (BaseClass::* PConnectionFunction)();     private:        PConnectionFunction _func;     public:        T Call(); }   This template has method Call():  template <typename T, typename BaseClass> T TConnectionPoint<T,BaseClass>::Call() {     return _func(); }   The problem appears when I try to execute Call() function - VS2013 send me this error, which is a little confusing me:     term does not evaluate to a function taking 0 arguments   What I'm doing wrong?

I am trying to pass a member function within a class to a function that takes a member function class pointer.  The problem I am having is that I am not sure how to properly do this within the class using the this pointer.  Does anyone have suggestions?  Here is a copy of the class that is passing the member function:  class testMenu : public MenuScreen{ public:  bool draw;  MenuButton<testMenu> x;  testMenu():MenuScreen("testMenu"){     x.SetButton(100,100,TEXT("buttonNormal.png"),TEXT("buttonHover.png"),TEXT("buttonPressed.png"),100,40,&this->test2);      draw = false; }  void test2(){     draw = true; } };   The function x.SetButton(...) is contained in another class, where "object" is a template.  void SetButton(int xPos, int yPos, LPCWSTR normalFilePath, LPCWSTR hoverFilePath, LPCWSTR pressedFilePath, int Width, int Height, void (object::*ButtonFunc)()) {      BUTTON::SetButton(xPos, yPos, normalFilePath, hoverFilePath, pressedFilePath, Width, Height);      this->ButtonFunc = &ButtonFunc; }   If anyone has any advice on how I can properly send this function so that I can use it later.


I'm trying to paste some R code into my latex file but when I use the listing package it fails to display the - next to the <. My latex file is as follows:  \documentclass[12pt]{article} \usepackage{listing}  \begin{document}     \begin{lstlisting}[language=R] ftn_deriv_1 <- function(x) { # Input: n-dimensional vector x0 # Output: n-dimensional vector x with first derivative  #of scalar function ftn(x) x1 <- 1/(x[1]*(1+x[2]))-log(x[2])/(1+x[1])^2; x2 <- -log(x[1])/(1+x[2])^2 + 1/(x[2]*(1+x[1])); y <- c(x1,x2); return(y); }  ftn_deriv_2 <- function(x) { # Input: n-dimensional vector x0 # Output: n by n matrix with second derivative of scalar function ftn(x) x11 <- -1/((1+x[2])*x[1]^2)+2*log(x[2])/(1+x[1])^3; x21 <- -1/(x[1]*(1+x[2])^2) -1/(x[2]*(1+x[1])^2); x12 <- -1/(x[1]*(1+x[2])^2) -1/(x[2]*(1+x[1])^2); x22 <- 2*log(x[1])/(1+x[2])^3 -1/((1+x[1])*x[2]^2); y <- matrix(c(x11,x21,x12,x22),2,2); return(y); } \end{lstlisting} \end{document}   When I compile this I get the following output:   As you can see the - does not show after the <. I am using TeXstudio version 2.11.2 for macboook. Any remedy for this?  Thanks in advance!

I'm using lstlisting to include my R code in my LaTeX, however, the minus sign after < is not appearing in the compiled file.  \usepackage{listings} \begin{document}  \begin{lstlisting} [language=R]  n<- c(10, 15, 20, 35) w <- c(300, 500, 700,100) i <- c(1, 1, 2, 2)  j <- c(1, 2, 1, 2)  beta <- c(1, 1)  for (iter in 1:20) {  alpha <- sqrt(tapply(w*n^2/beta[j], i, sum)/                tapply(w*beta[j], i, sum))  beta <- sqrt(tapply(w*n^2/alpha[i], j, sum)/               tapply(w*alpha[i], j, sum))}  alpha        1        2  11.41714 24.63072    beta         1         2  0.8229245 1.3470172  \end{lstlisting} \end{document}


Is there an inner product on the vector space of continuous real functions $\mathcal{C}(\Bbb R,\Bbb R)$ ? If so what is it and if not why ?

With axiom of choice it is possible to construct an inner product on $C(\mathbb R)$. My question is, is it possible to explicitly construct an inner product on $C(\mathbb R)$? I.e. to give a closed formula to calculate the inner product? I know it is straight-forward to write down a scalar product using a Hamel basis. This is not the answer I am looking for. This question came to me, when a student asked me in the lecture today 'whether there are vector spaces without inner products'. So I tried to find scalar produces for function spaces. I think I managed to write one down for $L^1((0,1))$. But I failed to construct one for $C(\mathbb R)$.


I'm having a hard time with resizing a UITextView generated with code. I'm using swift, but examples in Obj-C are definitely welcomed. There seems to be two problems here, which are directly related to each-other:   A constraint is being ignored (Trailing) The height calculation is off, probably because the constraint is being ignored.   Here's the code I'm using the generate the UITextView:  if !loaded.biography.isEmpty {     biographyView = UITextView()     biographyView?.translatesAutoresizingMaskIntoConstraints = false     biographyView?.scrollEnabled = false     biographyView?.text = loaded.biography     biographyView?.textColor = UIColor.blackColor()     print("Set text to: " + loaded.biography)      biographyConstraints.append(         NSLayoutConstraint(item: biographyView!, attribute: .LeadingMargin, relatedBy: .Equal, toItem: interactionView, attribute: .LeadingMargin, multiplier: 1, constant: 0)     )      biographyConstraints.append(         NSLayoutConstraint(item: biographyView!, attribute: .TrailingMargin, relatedBy: .Equal, toItem: interactionView, attribute: .TrailingMargin, multiplier: 1, constant: 0)     )      biographyConstraints.append(         NSLayoutConstraint(item: biographyView!, attribute: .Bottom, relatedBy: .Equal, toItem: interactionView, attribute: .Bottom, multiplier: 1, constant: 0)     )      interactionView.addSubview(biographyView!) }  view.addSubview(interactionView) NSLayoutConstraint.activateConstraints(interactionConstraints) if !loaded.biography.isEmpty {     NSLayoutConstraint.activateConstraints(biographyConstraints)      let rect = biographyView?.sizeThatFits((biographyView?.bounds.size)!)      print("Width of bio view is: " + String(biographyView?.bounds.width))     NSLayoutConstraint.activateConstraints([         NSLayoutConstraint(item: biographyView!, attribute: .Height, relatedBy: .Equal, toItem: nil, attribute: .NotAnAttribute, multiplier: 1, constant: (rect?.height)!)     ])      print("Set height constraint to: " + String(rect?.height))      print("Added interaction & bio & set constraints")  }   The output of this when ran is the following:  Set text to: TESTING TESTING 123 THIS SOME FAKE BIOGRAPHY, I KNOW IT'S NOT MUCH BUT IT'S PLACEHOLDER TEXT, THIS SHOULD BE THE END, OH WAIT, BUT HEY RANDOM EMOJI: 😍 Width of bio view is: Optional(0.0) Set height constraint to: Optional(30.0) Added interaction & bio & set constraints   The field is positioned correctly, however the height adjustment is incorrect and the text spans off the screen on the right side. Even though it seems to end at the Trailing margin, the text-field continues to only be a single line of text. I want the text field to adapt to the height of the text.   Can anyone help me figure this out?

Is there a good way to adjust the size of a UITextView to conform to its content? Say for instance I have a UITextView that contains one line of text:  "Hello world"   I then add another line of text:  "Goodbye world"   Is there a good way in Cocoa Touch to get the rect that will hold all of the lines in the text view so that I can adjust the parent view accordingly?  As another example, look at the notes' field for events in the Calendar application - note how the cell (and the UITextView it contains) expands to hold all lines of text in the notes' string.


I need to write a formal letter to a group of people consisting of two females and two males. One of the females is unmarried.   "Dear Sirs" must be out of the question. "Dear Madam / Miss / Sirs" also doesn't sound right; "dear all", "hello" or "hi" all sound to informal. As there are four of them I thought about "Dear Group", but I'm afraid some may take this the wrong way. Using their names as in "Dear Ms Black, Ms Brown, Mr Green and Mr White" could also be a possibility I guess, but it doesn't sound good to me either. Not being a native English speaker only makes finding a good solution more difficult.  Good ideas, anyone?

When is it appropriate to use the terms Dear Sir or Madam and To whom it may concern?  The rules I was taught state that Dear Sir or Madam should be used when you're writing a letter to a person about something that person has direct involvement in (e.g. returning a defective product to a customer service department).  By the same rules, To whom it may concern would be used for situations in which the recipient is a third party to the topic of the letter (e.g. regarding a letter of reference or recommendation).  Was I taught correctly?  Is the rule actually something else?  Or is this one of those situations where many people have an opinion but there is no real rule?


Prove that $[0,1] \approx  [0,a)$ where $a$ is a positive real number.  I know I need to fine a bijective function function between the two sets. The $a$ in the second set is throwing me off. Origninally I was thinking of doing $x=\frac{1}{a}$ that would get me $[0,x)$. But i am unsure if this is the correct route. Also how do I address the open interval on $a$ as oppose to a closed interval?

How to define a bijection between $(0,1)$ and $(0,1]$?   Or any other open and closed intervals?   If the intervals are both open like $(-1,2)\text{ and }(-5,4)$ I do a cheap trick (don't know if that's how you're supposed to do it): I make a function $f : (-1, 2)\rightarrow (-5, 4)$ of the form $f(x)=mx+b$ by \begin{align*} -5 = f(-1) &= m(-1)+b \\ 4 = f(2) &= m(2) + b \end{align*} Solving for $m$ and $b$ I find $m=3\text{ and }b=-2$ so then $f(x)=3x-2.$  Then I show that $f$ is a bijection by showing that it is injective and surjective.


This is a dual boot laptop HP 8570p with Ubuntu 18.04 and Win 10. I've installed exfat-fuse and exfat-utils (both are of version 1.2.8-1 and they are now located in directory: /dev/sda5/usr/share/doc in form of changelog.Debian.gz), Ubuntu is in this /dev/sda5 device.   I tried to mount exfat using terminal two commands:  1.) at first 'mount exfat usr/share/doc', but the reply was: 'mount: only root can do that';  2.) and secondly 'sudo mount -t exfat /dev/sda5/usr/share/doc  /media/exfat, but the reply was:  'FUSE exfat 1.2.8  ERROR: failed to open '/dev/sda5/usr/share/doc': Not a directory.'  How can I proceed with mounting correctly ?   After this I tried to format USB stick to exFat with GParted, but my GParted (vers 0.30.3) does not support exFat. Can I do something to make my GParted to support also exFat ?

In Ubuntu 13.04 there was an option to use the PPA by Relan in order to get ExFat functionality. Seeing that in Ubuntu this functionality is now available from the repositories without the PPA I tried this but failed to make it work.  So my question is how do I enable exfat support?


What kind of calculations are there are behind 'flat' colors? Where I can start to choose them effectively? What are the properties?  I found . It's great but I'd like to know more about this field.

When I am using Color Picker in Photoshop or Illustrator I am unable to get a Flat color. What are the things or basic points that I should keep in mind so that I am able to judge a color whether it is flat or not. Although flat color can be picked form websites such as       e.t.c.    Picking a flat color is not my problem. I want to learn the skill needed to judge and differentiate a flat color from other. Do all flat  colors values follow a pattern ?(like specific hue and saturation).


Brand new QGIS user here. I'm on version 2.12.3 on a Win7 machine.  I've downloaded a vector layer as part of an assignment. After adding an OpenStreetMap base layer, the project placed my vector feature somewhere in Nigeria, when it's supposed to be in Navarro, the US.  What is likely to be the problem here? Both layers are on the WGS 84 / Pseudo Mercator (EPSG:3857), and I have OTF projections turned on.  addendum:

So I'm pretty new to GIS, and I'm working on a mapping project using data for Vancouver, Canada. I want to combine OpenStreetMap data along with data provided by the City of Vancouver. But the City data don't line up with the OSM data when I map them in QGIS.  Following the advice of an answer to , I checked the two data sources against a third (a map of the world). The OSM data is right -- British Columbia is in the right spot -- but the City data puts Vancouver in the south of France.   My data sources are:   Bikeways and libraries . (Both are SHP files.) These are the data that don't align with the others. A map of British Columbia from Open Street Map. I put the data into a database using osm2pgsql. A world map that's part of the Open Street Style project.    Projections:   The City data are projected in UTM zone10, NAD83 (CSRS). I've selected this in QGIS's Layer Properties screen for those layers. Projection string: +proj=utm +zone=5 +ellps=GRS80 +datum=NAD83 +units=m +no_defs The OSM maps are in Mercator projection. QGIS has many Mercator choices, and I wasn't sure which one to use, so I guessed "Popular Visualization CRS / Mercator". +proj=merc +lon_0=0 +k=1 +x_0=0 +y_0=0 +a=6378137 +b=6378137 +towgs84=0,0,0,0,0,0,0 +units=m +no_defs For the world map, Quantum GIS loaded the projection from the .prj file. That's +proj=merc +a=6378137 +b=6378137 +lat_ts=0.0 +lon_0=0.0 +x_0=0.0 +y_0=0 +k=1.0 +units=m +nadgrids=@null +wktext +over +no_defs    talks about zone problems. That sounds like what I might be experienceing. So I tried changing the libraries from UTM zone 10N to other zones (15N and 60N) but nothing changed.  Does anyone have suggestions for what to try next?


All these three forms, high throughput, high-throughput or high through-put, are used in the scientific community by Google Scholar searching. Where is the hyphen should be? Is there a specific context for their using?  Thank you!

Some compound words are written without hyphens (nonaggression, nonbeliever), some with hyphens (well-intentioned), and others with spaces (post office).  Is there a rule or good guide as to which option should be used?


When I clicked the little down  arrow in order to discard the comment I was writing, I was a little surprised (and baffled for a moment), when it showed me the following dialog:        Shouldn't that cancel button which for some reason says "Nevermind", say, well, "Cancel" instead ?  In all the other dialogs, it does say "Cancel", just not in this one for some reason.

I was using the Android app earlier, and decided not to post a comment after beginning. When I cancelled, I was mildly confused by the choice I was offered:    "Nevermind," to me, could also mean "never mind, I don't want to write this comment after all."  Can this be replaced with a simpler and less confusing text? The simplest option would probably be "Do you want to discard your comment? [Yes/No]" (ht Shadow Wizard, Shub)


It is true that an irrational number to the power of an irrational number could be rational. I am curious about the following:  Are there conditions that imply irrational to the power of irrational will be rational ?

Can an irrational number raised to an irrational power be rational?  If it can be rational, how can one prove it?


Are both sentences are correct or only the second one is idiomatic, but the first one must be "They were eating."?     They were eating their dinner.       They were having their dinner.

I used to think that the verb have can only be used when we talk about meals, which   an occasion when people sit down to eat food, especially breakfast, lunch, or dinner. But I see native speakers say:     I eat breakfast.   I mean they use the verb eat for a meal like breakfast or dinner. So my questions are:   Is this common to say "I am eating breakfast, lunch or dinner"  for a meal time? Can we use the word have with the word eat interchangeably?   For example when somebody phoned us while we are eating something (at anytime) and asks      What are you doing?   Can we also say:     I having some pizza now. I'll call you back.


just an hour ago, I installed some package which was supposed to solve the problem with dead keys. After that I restarted my laptop and could not log in because of infinite loop with the login page. I can use the user account but what can I do from it?  I cannot access BIOS, booting from USB does not work. I tried to switch from GUI to the shell Str+Alt+F3 and login in using my superuser credentials but sudo is not recognized in the shell. This is the error message I got:  Command ´Sudo´ is available in /usr/bin/sudo this command cound not be located because /usr/bin is not included in the PATH environment variable. Sudo command not found.  Im begging for help.

My Ubuntu is stuck in a login loop when trying to enter my desktop. When I login, the screen gets black and soon after that the login screen comes back.   I've read that the problem might be caused by an error depending on the graphics, here's my graphics card: ATI Radeon 7670M


I need to execute following command:  scp -r ~/dataIn yatsuk@192.168.1.1:~/dataOut   In ubuntu (16.04) terminal this command work correctly.  yatsuk@192.168.1.1 is localhost.  So I try this code using jcabi:  Shell shell = new SSHByPassword("192.168.1.1", 22, "yatsuk", "passw"); String stdout = new Shell.Plain(shell).exec("scp -r ~/dataIn yatsuk@192.168.1.1:~/dataOut"); System.out.println(stdout);   And this code by JSch:  JSch jsch = new JSch(); JSch.setConfig("StrictHostKeyChecking", "no"); Session session = jsch.getSession("yatsuk", 192.168.1.1, 22); session.setPassword("passw"); session.connect();  Channel channel = session.openChannel("exec"); ((ChannelExec) channel).setCommand("scp -r ~/dataIn yatsuk@192.168.1.1:~/dataOut"); ((ChannelExec) channel).setErrStream(System.err); channel.setOutputStream(System.out); channel.setInputStream(System.in); channel.connect();  while (!channel.isClosed()) {     Thread.sleep(1000); } channel.disconnect(); session.disconnect();   Both return me:  Permission denied, please try again. Permission denied, please try again. Permission denied (publickey,password). lost connection   Simple commands like "echo 1 > 1.txt" works perfectly. Maybe something I do not understand?

I know it is not recommended, but is it at all possible to pass the user's password to scp?  I'd like to copy a file via scp as part of a batch job and the receiving server does, of course, need a password and, no, I cannot easily change that to key-based authentication.


Is there a way to find a man page given a Standard-C-type or POSIX-type? Such as man size_t or man uintptr_t. This kind of thing can get confusing because uintptr_t is defined in stdint.h, and size_t is defined in stddef.h. I have the docs for both stdint.h and stddef.h , and I can for example run man stddef.h if I know the header name?  This is specifically about types, I want to find the man pages for the type -- the header they're defined in.

Does anyone have any tricks and tips for finding information in man pages?


When a character kills an enemy, do only they get the experience, or does everyone in the whole group get the experience?  That is, does it matter who made the last hit that took the enemy down?

At this point, I am unclear as to how to handle encounter XP. Does each surviving party member receive a proportional share, or the full amount? That is, assume a 4-character party had completed an encounter worth 400 XP. Would each party member receive 100 XP, or 400 XP?


Prove that $$\frac{k^7}{7}+\frac{k^5}{5}+\frac{2k^3}{3}-\frac{k}{105}$$ is an integer using mathematical induction.  I tried using mathematical induction but using binomial formula also it becomes little bit complicated.  Please show me your proof.  Sorry if this question was already asked. Actually i did not found it. In that case only sharing the link will be enough.

This is what I got: If this must be possible i.e.if it must be an integer then $(\frac{15k^7}{7} + \frac{21k^3}{3}+ \frac{70k^2}{2}-k)$ must be divisible by 105. $k(\frac{15k^6}{7} + \frac{21k^2}{3} + \frac{70k}{2}-1)$ must be divisible by 105. For the purpose of using math induction I found out htks, but then I am stuck!! Therefore it works for 1 but how do I further prove it for $k+1$?


In SharePoint Online, how do I update my typescript version? I think I narrowed down my problem to typescript versioning. My helloworld web part works. The one thing that it has that many of my other web parts do not have is [tsc] typescript version: 3.3.4000 when I run gulp serve:    My many web parts that don't work, ALL have [tsc] typescript version: 3.2.4 and throw an error for no typescript rules.   Here is the [tsc] typescript version: 3.2.4 error message:     I think If I can get a working way to change the version of typescript when gulp serve runs may have a solution.  This is not a repeat of . While very helpful, I do not have a dependency for typescript, @microsoft/gulp-core-build-typescript": ">=2.2.5 <3.0.0 or anything like it.  I have rush compiler, which sets the typescript of 3.2: "dependencies": {     "@microsoft/rush-stack-compiler-3.2": "^0.5.12",  This is a good resource for people looking to change their typescript version:   Using SPFX 1.10.0, npm 6.13.4, node 10.16.0, gulp 3.9.1, CLI 2.2.0,    I ran npm list -g --depth=0 and have errors too:

I set up a new project using the yeoman template for SharePoint Framework web parts. Everything is working fine, I can run gulp serve and work in the local workbench. Good.  Now I need to change the TypeScript version. When running gulp serve the console is showing:  [09:12:38] [typescript] TypeScript version: 2.1.6   Where does this version come from? How can I bump this to 2.2.x?


I was trying to get a program to work, and installed a different version of wine that overwrote the version of wine I already had. (That version ended up not working) So I tried installing the default version of wine i already had, and it tells me to use sudo apt-get -f install because some wine packages are missing their dependencies, but when I run -f install it won't work because it tries to remove the package "sudo"  You might want to run 'apt-get -f install' to correct these: The following packages have unmet dependencies:  wine:i386 : Depends: wine1.6:i386 or                       wine1.8:i386 but it is not going to be installed  wine1.6-i386:i386 : Depends: wine1.6:any:i386 (= 1:1.6.2-0ubuntu4) E: Unmet dependencies. Try 'apt-get -f install' with no packages (or specify a solution). ryan@ryan-X551MA:~$   ryan@ryan-X551MA:~$ sudo apt-get -f install Reading package lists... Done Building dependency tree        Reading state information... Done Correcting dependencies... Done The following packages were automatically installed and are no longer required:   attr libacl1:i386 libaio1 libattr1:i386 libav-tools libavdevice53   libavfilter3 libavresample1 libboost-filesystem1.54.0 libboost-regex1.54.0   libbsd0:i386 libbz2-1.0:i386 libcap2:i386 libgksu2-0 libgtkglext1   libhdb9-heimdal libkdc2-heimdal libldb1:i386 libncursesw5:i386   libnss-winbind libntdb1:i386 libopencv-highgui2.4 libpam-winbind   libpopt0:i386 libpython-stdlib:i386 libpython2.7:i386   libpython2.7-minimal:i386 libpython2.7-stdlib:i386 libreadline6:i386   libtalloc2:i386 libtdb1:i386 libtevent0:i386 libwbclient0:i386 mkvtoolnix   ocl-icd-libopencl1 p7zip python-dnspython recordmydesktop samba   samba-dsdb-modules samba-vfs-modules simplescreenrecorder-lib tdb-tools   ttf-wqy-microhei winbind wine-gecko2.21 wine1.6-amd64 Use 'apt-get autoremove' to remove them. The following extra packages will be installed:   libaudit1:i386 libpam-modules:i386 libpam0g:i386 sudo:i386 unrar:i386   wine1.6:i386 wine1.6-amd64 winetricks:i386 Suggested packages:   libpam-doc:i386 dosbox:any:i386 Recommended packages:   winbind:i386 The following packages will be REMOVED:   sudo The following NEW packages will be installed:   libaudit1:i386 libpam-modules:i386 libpam0g:i386 sudo:i386 unrar:i386   wine1.6:i386 wine1.6-amd64 winetricks:i386 0 upgraded, 8 newly installed, 1 to remove and 36 not upgraded. Need to get 0 B/17.6 MB of archives. After this operation, 129 MB of additional disk space will be used. Do you want to continue? [Y/n] y   Preconfiguring packages ... (Reading database ... 201469 files and directories currently installed.) Removing sudo (1.8.9p5-1ubuntu1.2) ... You have asked that the sudo package be removed, but no root password has been set. Without sudo, you may not be able to gain administrative privileges.  If you would prefer to access the root account with su(1) or by logging in directly, you must set a root password with "sudo passwd".  If you have arranged other means to access the root account, and you are sure this is what you want, you may bypass this check by setting an environment variable  (export SUDO_FORCE_REMOVE=yes).  Refusing to remove sudo. dpkg: error processing package sudo (--remove):  subprocess installed pre-removal script returned error exit status 1 Errors were encountered while processing:  sudo E: Sub-process /usr/bin/dpkg returned an error code (1)

There are now errors when updating and I cannot install most software due to a corrupted  /etc/apt/sources.list   file. Is there a copy I can download to replace it?  The file would be for Ubuntu 12.04 (Final Beta) in the United States.


Basicly the title. I know it's easy but I can't figure it out. [Edit] Not a duplicate has a 2x instead of x.

As the title says, I want to show that the limit of  $$\lim_{x\to 0} \frac{\cos(x)}{x}$$  doesn't exist.  Now for that I'd like to show in a formally correct way that   $$\lim_{x\to 0^+} \frac{\cos(x)}{x} = +\infty$$  I'm sure this is right since $\displaystyle\lim_{x\to 0^+} \cos(x) = 1$ and $\displaystyle\lim_{x\to 0^+} x = 0$, but since $\displaystyle\lim_{x\to 0^+} x = 0$ I can't just say:  $$\lim_{x\to 0^+} \frac{\cos(x)}{x} = \frac{1}{\displaystyle\lim_{x\to 0^+} x}$$   Things I tried: expand the fraction and use L'Hospital's rule (This didn't seem to yield results even though I tried quite a few things, should it? If it does, should it always work? It worked for similar problems) and going by the definition of the limit which didn't work for me either.  I'm grateful for any hints for doing this problem and similar problems especially.


I have a scenario where i need to call two remote action methods.  Second method needs an input parameter which is the output of first method.  Can i nest the second remote call into first one. Is there anything wrong in doing this ? Is there any better approach ?

I am using javascript remoting.  I have a situation where I need remote actions to execute in order.  The problem I am running into is the second remote action executes prior to the first one finishing.  Since remote actions are asynchronous, is it possible to execute them in order?  What is the best way to do so?  Visualforce.remoting.Manager.invokeAction(   '{!$RemoteAction.ChoptankRates.method1}',   document.getElementById('var1').value,    function(result, event) {     document.getElementById('var1').value = result[0].somevalue;      //SECOND REMOTE ACTION SHOULD EXECUTE NOW.   } ); Visualforce.remoting.Manager.invokeAction(   '{!$RemoteAction.ChoptankRates.method2}',   document.getElementById('var1').value,    function(result, event) {     //do something here   } );


I was watching a PHP tutorial and noticed that the teacher was adding varibles to his echo statements in a different way to me. This got me thinking, which way should I be using? Is one more correct than the other?  Here's what the teacher was doing  echo "Example " . $example;   Here's what I do  echo "Example $example";   My method works, but I don't want to get into any bad habits. Could someone please tell me which way I should be using (preferably with some evidence)?

In languages like Java and C#, strings are immutable and it can be computationally expensive to build a string one character at a time.  In said languages, there are library classes to reduce this cost such as C# System.Text.StringBuilder and Java java.lang.StringBuilder.  Does php (4 or 5; I'm interested in both) share this limitation?  If so, are there similar solutions to the problem available?


I was wondering if there is any good references where I could read to understand the construction of Unitary Operators such as the Diffuse Operator in Grover's Algorithm. I am looking to build my own set of unitary operators with the objective of boosting the amplitude of specific quantum states for which there is no access to oracles to perform the phase flip prior to the inversion about the mean.

I know how Grover's diffusion operator works ($U_s = 2|s\rangle\langle s|-I$) with the inversion around the mean. However, I want to implement it in simpler gates, to use the algorithm. How can I do this ?


Im using Blender 2.78c and where I have seen in many tutorials people can select their graphics card in the User Preferences>System by clicking CUDA. I only have the option to click OpenCL and when I do it says only Hanain under it.

I have an AMD Radeon R7 M265, and when I force OPENCL with the batch file it only shows Iceland, Intel HD and the CPU.  I followed this instructions:   R, type CMD, press ⏎ Enter, go to your blender folder. ex:  cd C:\Program Files\Blender Foundation\Blender  Press ⏎ Enter and then type: set CYCLES_OPENCL_TEST=all Start Blender with blender.exe Inside blender go to File -> User preferences -> System Under compute device select OpenCL and then your card Close the preferences and go to the render panel and select device: GPU Compute.  I have the latest beta driver from AMD, but when I try to change the compute device it only shows this list:     Am I doing something wrong? Is my GPU is not supported? Or is it because it's in development and not every card is supported yet?  I've tried blender v2.74.5, v2.62, and v2.63. Every one gives the same list.


Is there any idiom for someone trying to hide or to gloss over or to understate the defects in their work as opposed to covering up to make themselves not look bad?  By "covering up" I mean do something superficial or nominal to pacify the person who pointed out the error but do not actually address the problem (admittedly not precise). By "hide" I mean not acknowledge the problem at all or just disregard the problem or pretend as if there is no problem.

What word/phrase can I use to describe the activity of hiding a stupid mistake/incident, such as quickly cleaning up tea spilled by accident before anyone could notice?


Is it possible to have a norm in an inner product space, such that $\lVert v\rVert\neq\sqrt{\langle v,v\rangle}$?  In my linear algebra class, we've defined $\lVert v\rVert$ to be equal to $\sqrt{\langle v,v\rangle}$, for each $v\in V$, where we were dealing with an inner product space $(V,\langle.,.\rangle)$.  However, now in a more advanced class in Analysis where we're going to work in multiple dimensions, the norm is defined on a vector space, such that certain properties hold. Does this mean that the definition in my Linear Algebra book was too specific, in the sense that it's also possible to have a norm in an inner product space where the above equality doesn't hold? Or is it true that for each inner product space, the norm equals $\sqrt{\langle v,v\rangle}$?

Do these three kinds of vector spaces, those with an inner-product, those with a norm and those with a metric, are the same sets of vector spaces? At least for finite dimensional vector spaces all of these coincide?   It would be great to know finite dimensional counter-examples if they exist any and if anyone can link to some lecture notes explaining this point.     Like are there examples of inner product spaces which cannot have a metric or metric spaces which cannot have a norm or various other such possible conflicts between these 3 properties.


I know that this question has been asked couple of time already. But the situation is a bit different.  Indeed we already have icon for feedback on our website (that I can easily move where I want), and we'd like to add a Live Chat function.  In that particular case, what would be the best places for each features?  Thanks

Where is the best place for a live chat window on a webpage, so it doesn’t hinder the user’s navigation?


In the past, I learned that the amount of data that can be sent through the HTTP GET method is limited and this is due to the limitation of the number of the characters in the URL, because an URL can not contain more than 255 characters.  But recently I noticed an URL that contains 294 characters where the query part (the string after the ?) contains 269 characters.  So, is there really a limit in the data sent through GET ? or am I outdated ?

What is the maximum length of a URL in different browsers? Does it differ among browsers? Is a maximum URL length part of the HTTP specification?


which batsman take strike if batsman hit the ball and catch and during that time both the batsman complete the first runs and also cross for second run? Now the new batsman take strike or the non striker which is already on the crease take strike?

Today while we were playing, we had a following situation,   Striker hits the ball and gets caught in the boundary Non-Striker crossed the center of the pitch  and the Striker too. Striker is out of his crease but has not crossed the center of the pitch.   We had these arguments about who will take strike:   Two strikers must cross the center of the pitch for the non-striker to take  strike. Both batsmen must cross each other for the non-striker to take strike. Just non-striker need to cross the center for being striker before the catch.   Even after reading , I am not clear on this situation. So, someone please clarify this issue.


On my laptop I want to install Ubuntu 14.04 but both my USB and CD drives are broken. I want to know how to install without needing the USB or CD. If you can help that is welcome.

So basically as it stands I have a laptop which has no cd/dvd drive, and I don't have a usb drive.  The laptop has windows 7 installed with ubuntu 11.04 installed through wubi.  What I want to do is remove windows completely, and make ubuntu the only OS installed on the system.  Is there a way to do this without re-installing ubuntu? (i.e. can I take my wubi install away from windows?)  or is there a way to from inside ubuntu have it run the ubuntu iso somehow so I can just wipe the system and install it fresh? (even if it means I need to have an e.g. 2gb partition just for the image to reside in).


How can I execute four ping requests for each URL from a text file that includes URLs, calculate the average respond time and store the results in another text file?

I have a .txt file with 5 urls in it. I want to read it line by line, and perform 4 ping requests for each site, and extract the time. The code I wrote is below, but it isn't working.   Can anyone give me a hint?   #!/bin/bash  cat /home/akis/Desktop/sites.txt declare -i var=1 while read -r line do     while $var <= 5      do         var2=$((var2+1))          name="$line" | ping -c 4 $name > $var.txt | awk '{ print $8 }' < $var.txt | awk '/time/' > $var2.txt | tr '=' '\t' < $var2.txt | awk '{ print $2 }' > $var2.txt     done      var=$((var+1))   done


I just found a link to .  Running the query (which takes some time) and viewing the graph produces some...odd...results    So what is it the query does, and is the results it produces "expected?"

I wanted to run a  query to return a large amount of data so I could export the lot to CSV. Problem is, the page is crashing my machine - the query triggers graphing, and the graphing code can't handle the data!  This screenshot of the insane graph was just barely obtained by another user:   I'm currently unable to modify the SQL as it kills the browser (latest Chrome on a Mac). EDIT Initially I thought it was simply due to the amount of data and perhaps that pagination would help, however the comments (thanks guys!) have uncovered that it was the graphs being drawn.


I'd like to form a 500 meter buffer around a coordinate. That coordinate is in WGS 84.  I've been playing with this for a little and seem to have a solution, but is seems way too complicated:  SELECT ST_AsText(ST_Transform(ST_Buffer((ST_Transform(ST_GeomFromText('POINT(-71.104 42.315)', 4326), 3857)), 500), 4326))   In this solution I first transform the point to a metric coordinates system (EPSG:3857) so the buffer distance is metric. Then I generate the buffer and then I transform the buffer back into WGS, as I need the result in WGS.  Isn't there a simpler solution?

I have a specific location: lat, lng and accuracy(meters) I want to return a geography object that will represent a polygon that surrounds this point with a given radius that will be equivalent to accuracy (I don't want to use a circle)  postgis code:  SELECT ST_AsText(CAST(ST_Buffer(ST_SetSRID(ST_Point(-74.005847, 40.716862),4326),10) As geography));   returns an object with points such as: (-64.005847 40.71.6862) That are on a huge radius and not 10 meters as requested.  What am I doing wrong here?


I want to move all my villagers back to the middle of my town. I'm trying to work with the /tp command, but almost every time it says Entity not found. /tp @e[type=minecraft:villager,dx=300,dy=300,dz=300] @p  /tp @e[type=minecraft:villager,distance=200] @p  The only time it worked was when I did this: /tp @e[type=minecraft:sheep] @p  and it teleported like a hundred sheep into me. Is there a reason the above ones wouldn't work? 1.14.4, using LAN mode with one other person

I can't seem to figure this out. I am trying to testfor if a player is near certain coordiantes, namely {-9, 100, 16}, and then to teleport them somewhere else.  In earlier versions it would be /testfor @a[x=-9,y=100,z=16,r=2] in a repeating command block going into a chain conditional command block that says /tp @p ~8 ~ ~, although it seems in 1.13 they have removed /testfor. I've seen that apparently I'm supposed to use /execute now in some way but I'm not sure how.


I have read the  and  and I understand when each action should be taken. Yet those do not address moderator only actions that can be taken from within the review queue.  There are lots of cases when reviewing the low quality queue I convert the answer to a comment (that is a mod only action). That unfortunately does not count towards my review history, all it does is remove it from the review queue.  Is it possible to also make any moderator action count as reviewing that specific post?

When I'm checking the review queues as a moderator - particularly the Low Quality Posts queue - I'm presented with an extra link beside the question mod. This gives me access to the moderator tools which include the "convert to comment option".  A valid option for some low quality answers is the option to convert them to a comment on the question. However, selecting the mod tools and that option    Doesn't count towards my review total.   Now I know it's not much in the scheme of things, but I have reviewed that question. The only workaround I have is to   Open the page in a new tab Use the delete button to increment the review count. Switch to the other tab Undelete the answer Use the mod tools to convert it to a comment.   Needless to say I'm not doing this as life's just too short, but it does annoy me that I'm not getting any closer to the Reviewer or Steward badge in that queue.


Hopefully, someone can help me with my problem.  I have tried to implement the following code from an old post in my cv project:   Unfortunately, I failed :(  My code:   The design and colours should remain as they are, I just want the possibility to fill these circle half.  Looking forward to getting help form you :)  Best, Andreas

Here is a old post:   I tried to adjust the code to have semi-filled circle steps, but failed...  My .cls-file code:  \newcommand{\cvskill}[2]{% \textcolor{emphasis}{\textbf{#1}}\hfill \foreach \x in {1,...,5}{%   \space{\ifnumgreater{\x}{#2}{\color{body!30}}{\color{accent}}\ratingmarker}}\par% }   My .tex-file code:  \cvskill{German}{5} \divider  \cvskill{English}{4} \divider  \cvskill{French}{3} \divider  \cvskill{Spanish}{1}   Full code:   How it looks at the moment:   Can someone please help me out?  Thanks, Andreas


Clue #2: He’s making 10 sales a month. Even if I wrote pants-droppingly good copy for him and increased his sales by 200% — a % lift any CRO expert would blog & tweet about — this would only generate an extra $200 per month for his business:   what does "pants-droppingly" mean?

What does pants-dropping mean?  Examples:     A pants-droppingly good film.         About the orphan kid who goes on to become pantsdroppingly wealthy.


I know the classic way of using  tag  <picture>             </picture>   But I found a website using instead just divs and using all the time background-image to display the image.  Is there any advantage or reasons they's do that ? It is because it's easier to put the two images that appear dynamically on hover 'bid now' and 'watch list'

               &nbsp;
               Bid Now           + Watchlist
   To check: it is taken from  ?  thanks

In what situations is it more appropriate to use an HTML IMG tag to display an image, as opposed to a CSS background-image, and vice-versa?  Factors may include accessibility, browser support, dynamic content, or any kind of technical limits or usability principles.


I read this story back in the 1980s.  It was from an anthology on fantasy from a used book store so it was likely written the 1960s.  The main character had a psychic ability, basically an invisible hand and he could manipulate things about an arms length away.  In the end, he kills his enemy by squeezing his heart with his psychic hand.  I recall the detective lost his hand hunting asteroids and had to change his career.

I don't remember when I read this. At least 20 years ago but maybe more. Nor the length. Probably not a very short short story but whether a novelette or a full length novel I have no idea.  It was at the same time SF and fantasy, because the only thing I remember is that one of the characters, while in a spacesuit in the vacuum (SF!) was able use his "phantom-hand" (Fantasy!).  I think that at some point he had lost an arm and developed this strange telekinetic power which he interpreted as a "ghost arm". Later he was grafted an artificial arm, but retained his telekinetic power as a "third" arm that could penetrate matter and for instance wipe his sweat from his brow while in his space suit. I don't remember anything more, alas.


In QGIS I'm trying to create a 1/4 mile radius (1,320 ft) around a point. I could obviously use buffer, which shows 'as the crow flies' - but I would like this along with the road network (in green). See below: buffer gives me the circle in blue, I want the irregular shape in green.    I've tried using Network Analysis (Service Area - from the point), but the results seem way off: the shape seems like a regular diamond, and the length is way more than I'd input. The radius is a 1/4 mile buffer, while the blue lines are the result from running Service Area from the point, even though I'd inputted 1,320 feet.    Any idea what I'm doing wrong?   Not sure if it makes a difference, but I've been putting in XY coordinates for the starting point.  [    I've figured it out.  Step 1: processing toolbox > network analysis > service area from point. Easy enough. For some reason the 'distance' is in meters even though all layers are in NAD83 (feet)...? Step 2: processing toolbox > vector geometry > Concave Hull (k-nearest neighbor).

There is a set of isolines produced with . It shows distances in meters [400, 800, 1200, and everything further] from a certain point.  My desired output is an . However, I do not know yet how to merge/aggregate isolines into polygons, where each isoline located exactly in a proper polygon with no overlaps etc. Better to say I want to draw an outline from the farthest points of each isoline class. What is the best approach? I have tried:  extracting nodes from lines Vector > Geometry Tools > Extract nodes, filtering with a certain isoline class, and then Vector > Geometry Tools > Concave Hull. deploying the QGIS plugin, namely .  Both outputs are represented on the image below, numbered appropriately. But there is a problem, nodes from the higher-class isoline group overlap the lower-class isoline group. How can I handle this issue?  I have seen these articles but nothing spectacular: