I am not a native speaker. So please excuse my "silly" question.   I have learned in my school that one can only use the word "where" in contexts describing locations, positions [or directions]. But I have come across two sentences used by a native speaker and I wonder if they are correct.     1) It can fill in details where experimental methods cannot.       2) Computer simulations are accurate on predicting molecular motions   but work poorly where quantum effects are important.   Can someone explain to me why he can use the word "where"? Many thanks!

In my mother tongue I can use the word where not only to describe something connected to a location, but also to substitute in which.   My question is: Is it correct to use where in a sentence like this?       Describe a situation where you had to show leadership.   Or it would be better to use in which instead?


Please someone who specializes as a grammarian answer this: The family is/are pursuing their individual interests.  Could you also give me the authoritative source for the answer!!!

Possible Duplicate:             I've done a bit of research and I understand that "family" should be preceded by  singular or plural verb depending on how you want it to be treated. For example,      His family is one of the oldest in the county.   and     His family are all doctors.   These are apparently both correct.   But in the following instance, could a grammar expert tell me which should be be?     When his family are abducted   or      When his family is abducted   ?  Thanks.


I am relatively new in statistics and it is also not my major. I am just using it due to the need. I have used the SPSS tool to establish the statistical significance of two or more scales between three groups using Kruskal Wallis H Statistics. It generates the output as follow:  However, despite a lot of Googling, I am still unclear why SPSS says retain the hypothesis with 0.05 confidence while asymptotic significance is not more than 0.95? Please pardon me if my understanding is totally wrong here but I am totally lost at this stage especially on how to interpret that output.

After taking a statistics course and then trying to help fellow students, I noticed one subject that inspires much head-desk banging is interpreting the results of statistical hypothesis tests.  It seems that students easily learn how to perform the calculations required by a given test but get hung up on interpreting the results.  Many computerized tools report test results in terms of "p values" or "t values".  How would you explain the following points to college students taking their first course in statistics:   What does a "p-value" mean in relation to the hypothesis being tested?  Are there cases when one should be looking for a high p-value or a low p-value? What is the relationship between a p-value and a t-value?


I know in groups we often demand one unique inverse and it brings some particular properties. But what would we call something algebraic where each element has two different inverses?  Does this happen in any algebra? If so, what does it lead to?    Imagine in New York starting at some crossing we go s7a4 : seven streets up and 4 avenues up.   Then inverse (in the sense of taking us back to our original position) could be either s-7a-4 or a-4s-7 depending on if we want to go downwards streets or avenues first. It is completely reasonable to consider these different things as we encounter different stuff on the way. Different amount of traffic, different shops, different bars, and so on.

Let $S$ be a set with a binary operation $xy$ defined on it, with a neutral element, but not satisfying associativity. I want to prove that the inverse isn't necessarily unique.  My attempt to answer this is in the answer below.


What is a word or phrase that means a person or thing which is quite small yet capable of having big influence and impact on society?

What can I call a person or a thing that is very small yet capable of defeating big giants?  I need different words that can be connected closely to this meaning.  It can be related to success,war, or anything else.


What does this  image mean?   I see this image on posts that I've flagged.     And what about this flagged post? It's marked as helpful but not marked as duplicate.

My flagging summary page displays "active" for a particular flag that seems to be not actioned yet. What does that mean?


I have just downloaded the latest image ISO file of Kubuntu 16.10.   I would like to learn if there is a way to upgrade my current operating system from Kubuntu 16.04 LTS to Kubuntu 16.10 using the new ISO image file that I have just downloaded.   Note: I know that I can get the latest upgrade using the following command:  sudo do-release-upgrade   The above upgrade command though will re-download the same files that I have already downloaded.

When I attempted to upgrade from 12.04 to 12.10, there was no autorun feature for the upgrade.  So I went into Update Manager, Settings, and clicked "Add Volume" and it added the DVD I had downloaded and burned.  However, during the upgrade it says "1,164M to download".   How can this be true?  I have almost all the packages on the DVD.  Is there something additionally I should do to avoid downloading?


I want one minipage with text, to be next to another minipage with two tikzpictures.  I have this code:  \subsection*{7. Bereken exact de lengte van lijnstuk $TP$.} \begin{minipage}[l]{0.6\textwidth} $BD = \sqrt{1^2+1^2}= \sqrt{2}$ \\ \\ In $\triangle BDT$ is $TD=\sqrt{2}$ en $BD = \sqrt{2}$. \\ Dus $BT=\sqrt{(\sqrt{2})^2+(\sqrt{2})^2}=\sqrt{2+2}=2$. \\ \\ In $\triangle ADT$ is $AT=\sqrt{1^2+(\sqrt{2})^2}=\sqrt{3}$. \\ \\ \\ \\ \\ \\ \\ \\  De oppervlakte van $\triangle ABT$ hiernaast is $\dfrac{1}{2} \cdot 1 \cdot \sqrt{3}=\dfrac{1}{2}\sqrt{3}$ \\ De oppervlakte kun je ook berekenen door: \\ $\dfrac{1}{2} \cdot BT \cdot AP = \dfrac{1}{2}\sqrt{3}$ \\ \\ $\dfrac{1}{2} \cdot 2 \cdot AP = \dfrac{1}{2}\sqrt{3}$ \\ \\ $AP = \dfrac{1}{2}\sqrt{3}$ \\ \\ In $\triangle APT$ is $TP=\sqrt{(\sqrt{3})^2-(\frac{1}{2}\sqrt{3})^2}=1\frac{1}{2}$. \end{minipage}  \begin{minipage}[r t]{0.4\textwidth} \begin{tikzpicture}[scale=0.75] \coordinate [label=above left:A] (A) at (0,0,4); \coordinate [label=below right:B] (B) at (4,0,4); \coordinate [label=above right:C] (C) at (4,0,0); \coordinate [label=above left:D] (D) at (0,0,0); \coordinate [label=above:T] (T) at (0,5,0); \coordinate [label=above right:P] (P) at (3,2,3.5);  \draw[color=gray, style=dashed] (0,0) -- (4,0,0); \draw[color=gray, style=dashed] (0,0) -- (0,5,0); \draw[color=gray, style=dashed] (0,0) -- (0,0,4); \draw (0,5,0) -- (0,0,4) -- (4,0,4) -- (0,5,0) -- (4,0,0) -- (4,0,4); \draw (0,0,4) -- (3,2,3.5) -- (4,0,0); \end{tikzpicture} \begin{tikzpicture}[scale=0.75] \coordinate [label=below left:A] (A) at (0,0); \coordinate [label=left:$\sqrt{3}$] (X) at (0,2.5); \coordinate [label=below:$1$] (X) at (1.5,0); \coordinate [label=below right:B] (B) at (3,0); \coordinate [label=below left:T] (T) at (0,5); \coordinate [label=above left:$2$] (X) at (2.75,2.5); \coordinate [label=above right:P] (P) at (2.16,1.43);  \draw (0,0) -- (0,5) -- (3,0) -- (0,0); \draw (0,0) -- (2.16,1.43); \draw (2.22,1.3) -- (2.13,1.24) -- (2.06,1.35); \end{tikzpicture} \end{minipage}   They somehow appear underneath each other.

I have the following code to layout two tables side by side:  \begin{minipage}{0.3\textwidth} \begin{tabular}{c | c | c | c | c | c | c} F & D & E & G & P & A & L\\ \hline C & H & I & I & U & G & F\\ \hline G & Z & G & A & F & Z & U\\ \hline F & R & \textbf{H} & \textbf{A} & \textbf{U} & \textbf{S} & Z\\ \hline R & P & L & I & N & F & H\\ \hline L & U & G & I & A & C & T\\ \hline A & B & D & N & E & R & Z\\ \end{tabular}  \end{minipage}  \begin{minipage}{0.3\textwidth} \begin{tabular}{c | c | c | c | c | c | c} F & D & E & G & P & A & L\\ \hline C & H & I & I & U & G & F\\ \hline G & Z & G & A & F & Z & U\\ \hline F & R & \textbf{H} & \textbf{A} & \textbf{U} & \textbf{S} & Z\\ \hline R & P & L & I & N & F & H\\ \hline L & U & G & I & A & C & T\\ \hline A & B & D & N & E & R & Z\\ \end{tabular}  \end{minipage}   But it doesn't work. The tables are one below the other. What am I doing wrong?


I have a set of 6 statistics which I have measured on many simulations, and I have combined them using PCA to use just the two first principle components. But looking at the relative importance of each of the statistics in my PCs, some of them seem to have surprisingly low weights given that I know they separate my simulations very well.  To give an example, statistic A varies very nicely across my simulated parameter space with small standard deviations, but has weights of less than 0.1 in most of the principle components!   I have noticed that statistic A has a small dynamic range (varies between 0.01 and 0.2) while others have much bigger ranges (varying form 2 to 8, for example). Would this cause it to have a lower weighing in my analysis?

What are the main differences between performing principal component analysis (PCA) on the correlation matrix and on the covariance matrix? Do they give the same results?


Let me explain a little better with some code. class Opcode (Enum):     WEEK=    1     EMAIL=   2     NAME=    3     DOB=     4  I then have a parameters class which processes data received by the server, and stores it in the appropriate variable : class parameters:     week = None     email = None     name = None     dob = None          def __init__(self, conn):         #some initialization stuff, irrelevant              def process_input(self, opcode, data):         if opcode == Opcode.WEEK.value:             self.week = data                      elif opcode == Opcode.EMAIL.value:             self.email= data                   elif opcode == Opcode.NAME.value:             self.name= data          elif opcode == Opcode.DOB.value:             self.dob= data          .          .          .           else :             print("unknown opcode provided. disconnecting ... ")             #disconnect from client ...  This doesn't seem too bad with only 4 opcodes, but in reality my  program has 12 opcodes and so this long if...elif...elif...else branch seems like a bad way of processing inputs. I'm use to working with C++, in which case I'd have used a switch-case, but they don't appear to be a thing in python, so perhaps there is a better solution I just don't know about. Any advice?

I want to write a function in Python that returns different fixed values based on the value of an input index.    In other languages I would use a switch or case statement, but Python does not appear to have a switch statement.  What are the recommended Python solutions in this scenario?


Let $R$ be a ring and let $I$ be an ideal in $R$. Prove that the following statements are equivalent.  (1) $I = R$  (2) There exists $u \in R$ such that $u$ is a unit and $u$ belongs to $I$  (3) $1$ belongs to $I$  I only can get that From (1) I know the ring is closed under subtraction and left-right multiplication. And I know I need to prove that equivalent shows that (1) implies (2). Then show (2) implies (3). Could someone help me to finish it? I'd appreciate it.

Show that an ideal $I$ of $R$ is proper if and only if it does not contain $1$ iff and only if it does not contain any units. ($1$ is the identity element) I'll need to show 3 parts: (1) $\implies$ (2): Let $I$ be a proper ideal and assume $1 \in I$. I want to show that $1 \notin I$. (2) $\implies$ (3): Let $I$ be a proper ideal that doesn't contain $1$ and assume there are units in $R$. By the definition, units of $R$ are elements with multiplicative inverses. So I need to show that there aren't multiplicative inverses. (3) $\implies$ (1): Assume there are no units in $R$ and then show that $I$ is a proper ideal. For this part I was thinking of doing something like this- Let $u \in I$ such that $u$ has a multiplicative inverse. Let $x \in R$. Then \begin{align}u^{-1}x \in R;\\ x=u(u^{-1}x) \in I,\end{align} so $R \subseteq I$ which implies that $I = R$. But this is a contradition so therefore $I$ must be a proper ideal. I just need help completing the proof.


I am a new StackExchange user and was frustrated to find that the only way to gain reputation at first was to ask a question or answer one quickly. I feel this incentivises new users to post poor-quality answers.  I feel that I have plenty to contribute to scicomp.stackexchange, I just don't have a massive list of new questions to ask.  Can anyone suggest any modifications to the reputation system to aid new users? Perhaps a short-term loan of reputation to perform a few actions - if used sensibly, they get to keep the reputation?  P.S. tried to tag this discussion with 'scicomp.stackexchange' but I need 500 reputation?! Surely this reduces the usefulness of the tags because everyone spams #discussion etc? I redirect you to the question above!

As a new user, I find it impossible to contribute to the community or to even begin contributing. I know why the reputation system is in place and I respect it, but at the same time it is too hard on new users.  It started with me wanting to upvote a question...     "Vote Up requires 15 reputation"   Just to appreciate a good question that helped me I need 15 rep? OK..., so I find out how I can get reputation points. More or less, I need to ask a question for +5 and add an answer for +10. I don't have any questions at the moment and I don't want to spam a random question, but I did happen to have a slightly different answer to the earlier question that I wanted to upvote. So I try to answer...     This question is protected to prevent "thanks!", "me too!", or spam answers by new users. To answer it, you must have earned at least 10 reputation on this site.   Now... I know this doesn't apply to every question, but at the same time, this means I'm forced to answer yet another question, and I don't want to go around looking for random questions and spam irrelevant answers...  Now I'm stuck. So I try to talk to some other users in the chat rooms about how to go about getting reputation points and how they first started. I entered into a "casual chat room".     You must have 20 reputation on Meta Stack Overflow to talk here.   Yes... I can understand why this is enforced, because we don't want new users to spam chat rooms, but all I wanted to do was ask for help. So I can't even talk to anyone about my newbie problems. So okay, I'll just settle for upvoting comments in the question that helped me. I don't see an upvote hover-over button so I can't even do that.    So now I'm stuck at 1 reputation point, unable to cross that 15 rep barrier, and even after posting this question I'll only have 6 rep points and still unable to do anything, and I'll be forced to look for questions to answer. Yes, I should be contributing to the community, but I shouldn't need to begin answering or making questions to upvote questions and answers. This only spurs more spam/irrelevant answers if anything.   Very, very, very new-user unfriendly.


I want to write an application which starts a .NET application depending on the computer supported .NET version. I think, I need to check the already installed .NET version and start the matching application.  Example:  I start a native C++ application which starts the correct VB.NET application for the currently supported .NET version.  My target: Get latest supported .NET version.

A similar question was asked , but it was specific to .NET 3.5. Specifically, I'm looking for the following:   What is the correct way to determine which .NET Framework versions and service packs are installed? Is there a list of registry keys that can be used? Are there any dependencies between Framework versions?


Consider the first law of thermodynamics, $$ dU = dq +dw$$ simplfying, $$ dU + P_{\text{ext}} dV = dq$$ Now we can say that $ q $ is a function of $ U$ and $V$ $ dq(U,V) = dU + P_{\text{ext}} dV$  For a differential $dF(x,y) = A\, dx + B\, dy $ to be exact, $$ \frac{\partial A}{\partial y} = \frac{\partial B}{\partial x}$$ is a necessary  condition.  Clearly the  function $q(U,V)$ doesn't obey this definition, and hence, let us multiply both sides by an integrating factor $ \phi(U,V)$ such that the condition of exact differential is satisfied. $$  \phi(U,V) \, dq = \phi(U,V) \, dU + \phi(U,V) P_{\text{ext}} \, dV$$ For this to be exact, $$ \frac{ \partial \phi(U,V) P_{\text{ext}} }{\partial U} = \frac{\partial \phi(U,V) }{\partial V}$$ Which leads to: $$ \left( \frac{\partial P_{\text{ext}} }{ \partial U} \right)_V \phi + P_{\text{ext}}(\frac{\partial \phi}{\partial U})_V =(\frac{\partial  \phi}{\partial V})_U $$ Now, I'm not sure how to get a general solution for the above partial differential equation...  My real goal is to derive the expression for entropy at end and prove that $ \frac{1}{T}$ is the integrating factor but I'm a bit stuck. I've seen the proof that $ \frac{1}{T}$ is the integrating factor by people pointing to carnots theorem that the circulation of the differentials over a loop is zero but I wanted to derive it using differential equations. Now, I'm thinking of how I can include the assumption that the process is reversible because the entropy definition is written used $ dq_{\text{rev}}$; also maybe derive the entropy generation term. Any hints?

How would you prove that $1/T$ is the most suitable integrating factor to transform $\delta Q$ to an exact differential in the second law of thermodynamics: $$dS = \frac{\delta Q}{T}$$  Where $dS$ is the change in entropy, $\delta Q$ is the change in heat energy, and $T$ is the equilibrium temperature.


Exercise requires to simplify this sum: $$\sum_{k=0}^{20} \binom{50}{k}\binom{50}{20-k}$$  Tried to figure this out with no success. I have only final answer, which is $\binom{100}{20}$.  Please help me figure out the logic behind this simplification. Thanks!

Can you please show me how to get from the left side to the right side?  $$\sum\limits_{k=0}^{20}\binom{50}{k}\binom{50}{20-k} = \binom{100}{20}$$


We all know that speed of light can not be exceeded. So the question is if electric field accelerates electron in a vacuum tube with enormous length won't the electron accelerate till a point where it overcomes the speed of light? The same question applies for electrons flowing in materials in superconductive state isn't the resistance zero which means there is nothing that can deccelerate them? I know that many of you will find this question stupid but I'm very curious because this is not the kind of questions that bring professors up in classes.

I'm in a freshmen level physics class now, so I don't know much, but something I heard today intrigued me. My TA was talking about how at the research facility he worked at, they were able to accelerate some certain particle to "99.99% the speed of light". I said why not 100%, and I didn't quite understand his explanation, but he said it wasn't possible. This confused me. Since the speed of light is a finite number, why can we go so close to its speed but not quite?  Edit: I read all the answers, and I think I'm sort of understanding it. Another silly question though: If we are getting this particle to 99.99% the speed of light by giving it some sort of finite acceleration, and increasing it more and more, why cant we increase it just a little more? Sorry I know this is a silly question. I totally accept the fact we cant reach 100%, but I'm just trying to break it down. If we've gotten so close by giving it larger and larger acceleration every time, why cant we just supply it with more acceleration? And how much of a difference is there between 99.99% the speed of light, and the speed of light? (I'm not really sure if "difference" is a good word to use, but hopefully you get what I'm asking).


I have accidentally changed the permission of a file now I want that file to back to the last permission state but how to do this? Is there any procedure or tool or any command line script which keep tracks of all permission list of a specific folder OR We can see the numeric permission on context menu and also to set back to it's last permission? Please suggest how to do it. update I know the alternative and basic approach: check the permission first and then set back.

I was wondering if it was possible to reset all the folders' rights. I was having trouble when trying to install LAMP on my Ubuntu 11.04 installation, and I modified many permissions like /var /etc and I want to cancel everything I did and have permissions set to how they would be after a new install.


I am looking for a  option — like the one at Wikipedia — which would allow me to keep track of the changes made to a set of questions over several days.  I think there are duplicate requests for this, but I could not find them.  Update: Oh yeah, I know you can ask me to use RSS, but that's not similar to Wikipedia's watchlist.  Update: Noticed a change, now you get a banner with a summary of changes to your Favourites. They have implemented it, I guess. More details .

For questions I'd like to keep an eye on (e.g. to see if anyone else posts an answer) is there a way to maintain a list of such questions other than adding them as favourites or using the RSS feeds?


I am getting this stack trace while clicking on import button on web-page, It is working fine on live server but not on localhost in Java, Is it any configuration issue in localhost?   Dec 21, 2015 12:46:32 PM org.apache.catalina.core.StandardWrapperValve  invoke SEVERE: Servlet.service() for servlet [action] in context with  path [/tools/wse/wmi] threw exception java.lang.NullPointerException     at  org.apache.struts.action.RequestProcessor.processForwardConfig(RequestProcessor.java:441)     at  org.apache.struts.tiles.TilesRequestProcessor.processForwardConfig(TilesRequestProcessor.java:320)     at  org.apache.struts.action.RequestProcessor.process(RequestProcessor.java:279)     at  org.apache.struts.action.ActionServlet.process(ActionServlet.java:1482)     at  org.apache.struts.action.ActionServlet.doPost(ActionServlet.java:525)     at javax.servlet.http.HttpServlet.service(HttpServlet.java:647)     at  javax.servlet.http.HttpServlet.service(HttpServlet.java:728)   at  org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:305)     at  org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210)     at  org.apache.tapestry5.TapestryFilter.doFilter(TapestryFilter.java:151)     at  org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:243)     at  org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210)     at  tools.wse.model.conf.AuthenticationFilter.doFilter(AuthenticationFilter.java:192)   Here is code:  public void doFilter(     ServletRequest req,     ServletResponse resp,     FilterChain chain)     throws ServletException, IOException {      HttpServletRequest request = (HttpServletRequest) req;     HttpServletResponse response = (HttpServletResponse) resp;     request.setAttribute(TapestryFilter.REGISTRY_CONTEXT_NAME, servletContext.getAttribute(TapestryFilter.REGISTRY_CONTEXT_NAME));     //for multi-charset support     request.setCharacterEncoding("utf-8");      UserToken userToken = (UserToken) request.getSession().getAttribute(WebKeys.USER_TOKEN);     //check user authorization     if (userToken == null || request.getParameter(LOGIN_TEST_BUTTON)!=null) {      //not coming inside if block      //code of if block     }     else {         chain.doFilter(req, resp);//Error in this line 192     ConnectionTracker.logUnclosedConnectionErrors(request.getPathInfo());     } }

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


Back in December I downloaded and burned an Ubuntu install CD that had kernel 4.13.0-19-generic.  I built two minimal servers and they worked fine with nVidia CUDA.RUN package.  I recently tried building a 3rd system openssh server using the same CD.  I see kernel ...19 go in but after the download from the US repository I end up with kernel ...32 which has a bug documented on the nvidia developer forum that does not allow the kernel to be built.  I assume they will have a fix for this eventually but in the meantime I would like to install ...19 or any version that still works with the nVidia cuda run package.  I retried the install from my old CD but there was no option to select the version of the package to download.  I see 19 come off the CD but end up with 32.    How do I restrict the install to 19?  Maybe I can revert back to 19 after getting 32 running?  Alternately, I could clone the flash drive from one of the other systems.  I did try that with acronis clone tool under windows 10, but it didnt boot. Maybe there is a better cloning tool?  Thank you for looking at this.  [SOLVED WITH HELP FROM MIKEWHATEVER thanks mike!]  sudo apt-get install linux-image-4.13.0-19-generic   (reboot and select 19)  sudo apt-get purge linux-image-4.13.0-32-generic sudo apt-get purge linux-headers-4.13.0.32 sudo apt-get install linux-headers-$(uname -r) sudo apt-get install libxi-dev libxmu-dev freeglut3-dev build-essential binutils-gold sudo sh ./cuda384.run --override   results as follows:  27-Jan-2018 12:24:55 [---] CUDA: NVIDIA GPU 0: GeForce GTX 670 (driver version 384.81, CUDA version 9.0, compute capability 3.0, 1994MB, 1874MB available, 2704 GFLOPS peak) 27-Jan-2018 12:24:55 [---] OpenCL: NVIDIA GPU 0: GeForce GTX 670 (driver version 384.81, device version OpenCL 1.2 CUDA, 1994MB, 1874MB available, 2704 GFLOPS peak)   I thought I had to use update-initramfs -u after the CUDA install.  That put 32 into the boot which caused a problem.  It was not necessary and forced a re-install to recover.  I went back to 19 because it worked with the nVidia CUDA kit and nVidia has not released a fix yet for having their source headers out of order when being built into the 32 kernel.  [EDIT]  Strange - I see where 5 gurus here report this question is "an exact duplicate of an  question".  I went there and looked and that question was how to prevent an upgrade which is nice if you know the upgrade will cause a problem.  This question was how to recover from an upgrade.  I actually spent some time googling for how to restore a previous version.  I found nothing informative until I came here and was told to use "apt-get install linux_image...".  Want to ask the gurus here, what good is it to install 32 and get protection from meltdown and specter when there are no known exploits of those defects and the application you are required to run requires a package that does not work under 32?

Because of  I'd like to prevent apt-get upgrade and Update Manager from updating the "libgtk2.0-0" package.   How can this be achieved?


Let $G$ be a finite group, $p$ be  the smallest prime divisor of $|G|$ and x $\in$  G an element   of order $p$. Suppose $ h \in  G  $ is such that $h^{-1}xh = x^{10}$. Show that $p = 3$.   I cant solve this problem i think it should be solved without using any special theorem please firstly give me a hint .

Question. Let $G$ be a finite group and $p$ be the smallest prime dividing $|G|$.  Let $x$ be n element of order $p$ in $G$. Assume that there exists an element $h\in G$ such that $hxh^{-1}=x^{10}$.  Show that $p=3$.    What I have done so far is use the fact that $o(hxh^{-1})=o(x)=p$ and $o(x^{10})=p/\gcd(p,10)$.  By hypothesis we have $p=p/\gcd(p,10)$, giving $\gcd(p,10)=1$.  Here I am stuck.  I have not been able to make use of the fact that $p$ is the smallest prime divisor of $|G|$.  Can somebody help?


I have two existing dictionaries, and I wish to 'append' one of them to the other. By that I mean that the key,values of the other dictionary should be made into the first dictionary. For example:  orig = {    'A': 1,    'B': 2,    'C': 3, }  extra = {    'D': 4,    'E': 5, }  dest = # Something here involving orig and extra  print dest {    'A': 1,    'B': 2,    'C': 3,    'D': 4,    'E': 5 }   I think this all can be achieved through a for loop (maybe?), but is there some method of dictionaries or any other module that saves this job for me? The actual dictionaries I'm using are really big...

What is the best way to extend a dictionary with another one while avoiding the use of a for loop? For instance: >>> a = { "a" : 1, "b" : 2 } >>> b = { "c" : 3, "d" : 4 } >>> a {'a': 1, 'b': 2} >>> b {'c': 3, 'd': 4}  Result: { "a" : 1, "b" : 2, "c" : 3, "d" : 4 }  Something like: a.extend(b)  # This does not work


I have three related questions about what theories or equations can calculate and what is an input parameter/constant to the theories. This question is not about parameter units (as another similar question) but calculations.   Can the value of $c$ be calculated from the theory of Relativity (or Maxwell’s equations)?  Can the value of $h$ be calculated from Quantum Mechanics?   Can the value of $G$ be calculated from Newtonian Mechanics?

Is there a fundamental way to look at the universal constants ? can their orders of magnitude be explained from a general points of view like stability, causality, information theory, uncertainty?   for example, what sets the relative magnitudes of Planck's constant compared to say charge of electron or is it just a matter of choice of units.   Does the physics become more or less cumbersome, insightful if we set all fundamental constants to 1 in appropriate units.


Unit impulse function is one of the special functions which is widely used in the field of signal processing. It has nice properties that helps in some situations specially its sifting property. But This depends on the fact of its integral is equal to one. As you know the continuous impulse function  S(t) is equal to inf at zero and equal to zero elsewhere. So the boundaries of the integral of it is reduced to the period [0,0]. I need a proof of how did we calculate its integral to get 1.

Is Dirac delta a function? What is its contribution to analysis?   What I know about it: It is infinite at 0 and 0 everywhere else. Its integration is 1 and I know how does it come.


My program is written in C++. compiled with gcc, using -g3 -O0 -ggdb flags. When it crashes, I want to open its core dump. Does it create core dump file, or I need to do something to enable core dump creation, in the program itself, or on computer where it is executed? Where this file is created, and what is its name?

I have a process in Linux that's getting a segmentation fault.  How can I tell it to generate a core dump when it fails?


<?php function CreateDatabase($username, $database) { global $con; if($con) {     $createdatabase = $con -> prepare("                                               CREATE DATABASE ?");     $createdatabase -> execute(array($database));     $createdatabase = $con -> prepare("                                         GRANT ALL                                          ON                                              ?.*                                          TO                                               ?@'localhost'");     $createdatabase -> execute(array($database, $username));     $createdatabase = $con -> prepare("                                         FLUSH PRIVILEGES");          $createdatabase -> execute();     return true; } return false;   }   For some reason this code won't run the way it should. I quadrupled checked that the strings $username and $database are correctly passed on.  Can you see any errors here? Any hints, tips on how to resolve this? Just started learning PDO today, so if I'm doing it wrong or do it in a bad practice, please tell me.  I'm creating a database management system for my clients, where they can create a user if it doesn't already exist, then create a database and look over the info. If anyone is interested in helping out finishing it, I would be most grateful!

Why can't I pass the table name to a prepared PDO statement?  $stmt = $dbh->prepare('SELECT * FROM :table WHERE 1'); if ($stmt->execute(array(':table' => 'users'))) {     var_dump($stmt->fetchAll()); }   Is there another safe way to insert a table name into a SQL query? With safe, I mean that I don't want to do  $sql = "SELECT * FROM $table WHERE 1"


I'd like to know if is it possible to get the URL of an external system from which a user has modified a record. For example, if a user gets connected to  (or SalesLoft, or another one) and updates a given record, how can I get "workbench.developerforce.com" (to be stored in a field)?

We have various ways of invoking apex. Triggers, Inbound Webservices, @InvocableMethod,@RemoteAction and what not. Often we call some or other utility methods from these execution contexts. I have some generic utility method,that should behave differently from the context it is called?  I know about Trigger.isExecuting but it only tells if its running in trigger context or not.  I have a utility method that creates lead from Webservices, VF button click and via Lightning . Whenever we create a lead I want some special operations to be done via the source it was originated.(Its not just updating a simple field leadSource, I have some methods that creates some childs and update other records of other type) . I can achieve this by passing an extra parameter to utility method to tell about source, but i have then to edit hundred of other class that uses this utility method. If i could dynamically find out via which context this piece of code is running,then i would have to change only one class to satisfy my requirement.    Is there something in APEX that tells in what context the apex method was called?


We are taught that the centripetal force provided to the satellite by the earth's gravitational force gets equalized to the centrifugal force produced due to the inertia of direction  of the orbiting satellite. If the force which keeps the satellite   in a constant motion is equaled by an opposing force, how does the satellite still keep rotating creating a resemblance to free fall. Just wanted to know it quite deep.

The following is written in my textbook as the reason for weightlessness felt in satellites:     The gravitational pull is counterbalanced by the centripetal force.   This introduces two problems:   For satellites orbiting around Earth, gravity is, in fact, the centripetal force. If the gravitational pull and centripetal force on a satellite are both in the same direction, then how do they cancel each other out?


What is the standard rule, if there is one, for pronouncing words beginning with the prefixes com-, col-, cor-, con-?   Very often these words have an /ɒ/ vowel, like in the word hot - in Gen American, I think it's the vowel /ɑː/. Other times they may have a schwa, /ə/, like the first vowel in amazing. Sometimes they seem to have a syllabic consonant, /m, l, r, n/.   Sometimes there even seem to be two words which are spelled the same but have a different pronunciation. For example content meaning "happy" and content as in "the content of the lecture", for which Cambridge Dictionaries gives the transcriptions  /kənˈtent/ and /ˈkɒntent/ [US:/ˈkɑːntent/] respectively.  Here are some examples with transcriptions from Cambridge Dictionaries Online:   common /ˈkɒm.ən/  commercial  /kəˈmɜː.ʃəl/   colleague /ˈkɒl.iːɡ/  collection /kəˈlek.ʃən/ correlate /ˈkɒr.ə.leɪt/   correct /kəˈrekt/   So my question is:   Is there any rule for whether a schwa or full /ɒ/ or /ɑː/ is used? Are there generalisations that can be made which will help me have a good guess at which to use. Are there any rules that will enable me to tell in certain restricted situations. If I'm unsure about a particular example, would I be better to go with a schwa or a full vowel. Why?

I know there is no strict rule on pronunciation of words in English but here my question is about the words which begin with 'con' and 'com', more than asking general rule. When I look at the words begin with 'con' and 'com', I see mostly two patterns : One of them is schwa /ə/ sound and the other one is /o/ or /ɒ/ sound.But the second  pronunciation can be pronounced slightly differently depending on dialect. An example word for the first pronunciation is the word computer whose pronunciation is represented    in Cambridge Online Dictionaries. An example for the second type of pronunciation for "co" could be the word contrast whose pronunciation is represented     in Cambridge Online Dictionaries. So my question is there any rule/pattern which can help us guess how to pronounce these words correctly? I am not asking about the words like cool, come or coke. My question is about words like contract, combination, continue, combat.


My system: Dell XPS15 9550  Processor: i7 6700HQ  RAM:   16GB DDR4  Disk:    Samsung pm951 (512GB NVMe SSD)  GPU:   960M  I'm new to Linux so I will dual boot Windows 10 + Ubuntu 16.04. I'm a network administrator, learning Linux Ubuntu until I'm very comfortable with Linux then I will be using Kali to practice pen testing.  How much Swap do I need, other advice?

I read many places that the rule of thumb for swap space is to double the amount of physical RAM. However, 32 GB does seem a LOT. Do I need that much? Do I need it at all with this high amount of physical RAM?


I have the following code to write a string on a file (relative path loaded):  void writeFile(String string){         try {             //ClassLoader classLoader = Thread.currentThread().getContextClassLoader();             ClassLoader classLoader = getClass().getClassLoader();             File newFile = new File(classLoader.getResource("conf/passwords.txt").getFile());              //Path of "passwords.txt" where it writes the info             System.out.println("ABSOLUTE PATH: " +newFile.getAbsolutePath());              FileWriter flux = new FileWriter(newFile);             BufferedWriter writer = new BufferedWriter (flux);             writer.write(string);              writer.close();         } catch (IOException e) {             System.out.println("ERROR on file writing.\n" +e.getMessage());             e.printStackTrace();         }     }   It works, but the string is not written on my original file that is located on the project path, as it follows: src/conf/passwords.txt  Instead of this, the string is saved on the following path: C:\Users\becario01\workspace.metadata.plugins\org.eclipse.wst.server.core\tmp0\wtpwebapps\searchLef\WEB-INF\classes\conf\passwords.txt  I want to write the string on my original file, to show easily while I´m working on my workspace.   I would thank a lot any helpful reply.  Regards.

So my 2009 new years resolution is to learn Java.  I recently acquired "Java for Dummies" and have been following along with the demo code in the book by re-writing it using Eclipse.  Anyway, every example in the book that uses a relative path does not seem to read the .txt file it's supposed to read from.  Here is the sample code:  import java.util.Scanner; import java.io.File; import java.io.IOException; import javax.swing.JFrame; import javax.swing.JLabel; import java.awt.GridLayout;  class TeamFrame extends JFrame {      public TeamFrame() throws IOException {         PlayerPlus player;         Scanner myScanner = new Scanner(new File("Hankees.txt"));          for (int num = 1; num <= 9; num++) {             player = new PlayerPlus(myScanner.nextLine(), myScanner.nextDouble());             myScanner.nextLine();             addPlayerInfo(player);         }                add(new JLabel());         add(new JLabel("   ------"));         add(new JLabel("Team Batting Aberage:"));         add(new JLabel(PlayerPlus.findTeamAverageString()));         setTitle("The Hankees");         setLayout(new GridLayout(11,2));         setDefaultCloseOperation(EXIT_ON_CLOSE);         pack();         setVisible(true);     }      void addPlayerInfo(PlayerPlus player) {         add(new JLabel(player.getName()));         add(new JLabel(player.getAverageString()));     } }   And you can see in the below screen shot I have included this file.  image no longer available  Also, I have verified that when I build the application that a copy of Hankees.txt is placed in the bin folder with the compiled .class files.  Lastly, if I change line 12 to the following and place Hankees.txt in the root of my C:\ drive the program compiles and runs fine.  Scanner myScanner = new Scanner(new File("C:\\Hankees.txt"));   So basically, my question is what am I doing wrong?  Or is Eclipse responsible for this in some way?  Thanks for any and all help!


I have been trying to set up a SFTP server with multiple users chrooting into their home directories. I followed the advice on  () and then executed the following commands on the user's directories  chown root:root /home/user/ chmod 755 /home/user/   There is an additional folder in every user's home directory called public, which is owned by its user so as to allow them to create directories and upload and remove files as needed. (This was advised in the guide I mentioned earlier)  Now when I execute sftp -P 435 user@localhost, I get this error:     Write failed: Broken pipe   Couldn't read packet: Connection reset by peer   How do I proceed from here? The ultimate idea is to have each user on some other machine use FileZilla to log into their chrooted home directories and then be able to upload directories and files. All this in SFTP (because it's more secure)

I want to give a client access to my server, but I want to limit those users to their home directories. I will bind-mount in any files I want them to be able to see.  I've created a user called bob and added him to a new group called sftponly. They have a home directory at /home/bob. I've changed their shell to /bin/false to stop SSH logins. Here is their /etc/passwd line:  bob:x:1001:1002::/home/bob:/bin/false   I've also changed the /etc/ssh/sshd_config to include the following:  Match Group sftponly         ChrootDirectory /home/%u         ForceCommand internal-sftp         AllowTcpForwarding no   When I try to log in as them, here's what I see   $ sftp bob@server bob@server's password:  Write failed: Broken pipe Couldn't read packet: Connection reset by peer   If I comment out the ChrootDirectory line I can SFTP in but then they have free rein over the server. I have found that ChrootDirectory /home works, but it still gives them access to any home directory. I have explicitly tried ChrootDirectory /home/bob but that doesn't work either.  What am I doing wrong? How can I limit bob to /home/bob/?  ----EDIT-----  Okay so I just had a look at /var/log/auth.log and saw this:  May  9 14:45:48 nj sshd[5074]: pam_unix(sshd:session): session opened for user bob by (uid=0) May  9 14:45:48 nj sshd[5091]: fatal: bad ownership or modes for chroot directory component "/home/bob/" May  9 14:45:48 nj sshd[5074]: pam_unix(sshd:session): session closed for user bob   I'm not entirely sure what's going on there,  but it suggests something is wrong with the user directory. Here is the ls -h /home output:  drwxr-xr-x 26 oli      oli      4096 2012-01-19 17:19 oli drwxr-xr-x  3 bob      bob      4096 2012-05-09 14:11 bob


If $p$ is prime number, prove that $$\mathbb{Z}_{(p)}=\left\{\frac{a}{b}\in\mathbb{Q}: \text{$p$ doesn't divide $b$}\right\}$$ is a PID.  So, first step is to show that $\mathbb{Z}_{(p)}$ is an Ideal Domain and then show that every ideal in it is principal.  I know that $\mathbb{Z}_{(p)}$ is the subring of $\mathbb{Q}$ then it follows that $\mathbb{Z}_{(p)}$ is commutative. Then I'm lost what to do. Any help is appreciated :)

Let $R$ be a UFD and $r\in R$ irreducible. If $S=R-(r)$, why is $S^{-1}R$ a PID?   I've finished proving the integral domain part, which was pretty easy.  How to prove it's principal? consider $R \subset S^{-1}R \subset F$, where $F$ is the field of fractions of $R$?  thank you! :p


A point P in the interior of a convex polyhedron in Euclidean space is called a pivot point of the polyhedron if every line through P contains exactly 0 or 2 vertices of the polyhedron. Determine, with proof, the maximum number of pivot points that a polyhedron can contain.

In geometry there is a term called a pivot point. There exists a pivot point 'P' in the interior of a convex polyhedron in a euclidean space if and only if every single line through 'P' contains exactly zero or two vertices of the polyhedron.  I asked one of my professors, but he gave me a very narrow example of a cube, but I want to know the maximum number of pivot points that exist in a polyhedron. Can someone please help me prove how many exist?


Every once in a while when I try to remove a file I have been working with, Windows tells me I cannot remove it, because some application is still using it.  Sometimes it's just my own stupidity, and closing the app I was working with releases the file, but sometimes I cannot for the life of me imagine any of the remaining applications holding the file.  Sometimes when I close everything I have started, it is still reported as locked and not deletable.  Is there any low-level tool that I can point at a file that can tell me which applications are holding a reference to it, to diagnose how to resolve this without resorting to a reboot and delete cycle?

I'm trying to delete some folder but this error is preventing from doing it:     Cannot delete [FileName]: It is being used by another person or program.      Close any programs that might be using the file and try again.   How can I identify what application is using the file?   I want to end the application using a Task Manager, but I didn't know what application is using it.  The folder is not shared and my user account is an administrator.


[This is pretty much a copy and paste job from Technetium question but I wanted to add this one in case there was some other explanation] So, I understand that PM doesn't exist in nature [though, I don't know why every reference I see regarding PM says that and then goes on to state that it is found in some stars...] but, if that's the case, then why is it found in some stars? This element doesn't fuse in stars (I think, I found a graph saying that it does) so it has to be left over from supernovae. Lastly, how many stars have been discovered that contain promethium? Thanks much.

So, I understand that TC doesn't exist in nature [though, I don't know why every reference I see regarding TC says that and then goes on to state that it is found in some stars...] but, if that's the case, then why is it found in some stars? Furthermore, why is this element skipped during the regular process of nucleosynthesis? And, why do some stars magically fuse technetium while others don't? Lastly, how many technetium stars have been discovered? Thanks much.    ***Just a note, I was just looking at this all again and started thinking about how Technetium is way heavier than iron, so it's not formed in regular nucleosynthesis, right? Which means the TC is left over from supernovae explosions, right? So, if that's the case, why is it not produced naturally? What is natures aversion to this element?


Very vague on the details. I would have read these books in the late 80s, possibly around '87-'88. They were in my school library, which had students from age 6 to 10, so would have been age appropriate.  You could also say the ship was shaped like a nautilus, I guess. I'm pretty sure there were diagrams of the ships layout in the cover.  There may have been a robot sidekick. I have an inkling of a mining/industrial element or aesthetic.

I'm looking for a sf story that was broadcast on BBC children's TV in the early 1980's, probably as part of the long running Jackanory series. Based on what i recall of other events at the time of watching I think this was 1982. The story is of a group of children who are either orphans or in a boarding school and who build a spaceship from the scrap of other ships and (I think) an asteroid. They launch it into space and have subsequent adventures. One scene that particularly sticks in my mind was the oxygen failing on the ship and the children all falling asleep except for a girl who is bullied by a robot into fixing the problem. I'm reasonably sure that the author of the stories would be British as it was an adaptation for the BBC. I also have a feeling that this was adapted from a series of children's books with each volume being compressed into one episode. It ran Monday to Friday for one week. I vaguely recall a female narrator. The story was interspersed with still drawings and acted scenes with children. I'm looking for the title of the story (stories) in either TV or book form and the author. Note, the description of acted scenes and drawn illustrations makes this sound like Captain Zep: Space Detective, another BBC show. It was not this one although they would have been made at similar times. Hope there is enough detail here for a answer. Thank you!


I cannot install Wine on Ubuntu 14.04.  When I try to install it on the Ubuntu Software Center I always get a message that says I have unmet dependencies. I tried installing Wine through the terminal and I get this:  Reading package lists... Done Building dependency tree        Reading state information... Done Some packages could not be installed. This may mean that you have requested an impossible situation or if you are using the unstable distribution that some required packages have not yet been created or been moved out of Incoming. The following information may help to resolve the situation:  The following packages have unmet dependencies:  wine : Depends: wine1.6 but it is not going to be installed E: Unable to correct problems, you have held broken packages.

I am looking for a step by step instruction to guide me in the ways of installing, configuring and debugging many of the issues new users have when dealing with Wine in Ubuntu.  What is the recommended way of installing Wine, some of the key issues that it has and how to solve them?  If I have a specific problem with an App in Wine, how do I go about solving it? What are the recommended steps to ensure that I can fix a problem related to an app I wish to use?


I have a list with IP address, role and group. I want to firstly sort the the entire list with its group number. And based on the new list, for each group, I want to sort again by the role. Finally, based on the former sort, sort again by the IP address. I can't find a way to achieve my goal and struggle in it for a couple hours, please help, thank you in advance.  for example, the list is like:   { <192.168.1.1, 1, "group 2">, <192.168.1.3, 1, "group 1">,     <192.168.1.7, 2, "group 1">, <192.168.1.25, 2, "group 1">, <192.168.1.1, 2, "group 2"> }   Ideally, after three sorts, the output should be something like:  { <192.168.1.3, 1, "group 1">, <192.168.1.7, 2, "group 1">, <192.168.1.25, 2, "group 1">,  <192.168.1.1, 1, "group 2">, <192.168.1.1, 2, "group 2"> }

Assume you have some objects which have several fields they can be compared by:  public class Person {      private String firstName;     private String lastName;     private String age;      /* Constructors */      /* Methods */  }   So in this example, when you ask if:  a.compareTo(b) > 0   you might be asking if a's last name comes before b's, or if a is older than b, etc...  What is the cleanest way to enable multiple comparison between these kinds of objects without adding unnecessary clutter or overhead?   java.lang.Comparable interface allows comparison by one field only Adding numerous compare methods (i.e. compareByFirstName(), compareByAge(), etc...) is cluttered in my opinion.   So what is the best way to go about this?


I was downloading iOS 7 to my iPhone 4 and the update was going for almost 1 day. I left it overnight and when I was about to use my phone it is stuck on the 'Connect to iTunes' screen (iTunes logo with a USB cord). My phone is still stuck on that and when I try to fix it with iTunes with my PC (Windows 7) the message always pops up saying that my phone needs to restore. Can you help me with this?

I'm not really sure how, but after I woke up today, my phone was just displaying the loading spinner and doesn't start up anymore. It's weird because my phone turned off last night and suspecting that it was probably out of charge, I thought charging it overnight would fix the problem.   So, my iPhone is currently stuck on the iTunes/Apple Logo loop. When I put it into DFU/Recovery Mode and connect it to iTunes, it isn't able to restore it. It keeps throwing "Network Connection Problems" -- it downloads iOS 10 for a bit and suddenly stops downloading, throwing the error. I've also tried downloading a custom .ipsw from  but it seems that the file is corrupted whenever iTunes tries to unpack it.   Any thoughts on how I could go about fixing this?   Note - I don't have a jailbroken iPhone.


I want to add  on my blog hosted on Blogger. The only solution I found is , but it requires a hosting server. Any other option?

To set up MathJax, one recommendation is to post this code into Blogger design:  <script src='http://cdn.mathjax.org/mathjax/latest/MathJax.js' type='text/javascript'>         MathJax.Hub.Config({         HTML: ["input/TeX","output/HTML-CSS"],         TeX: { extensions: ["AMSmath.js","AMSsymbols.js"],                 equationNumbers: { autoNumber: "AMS" } },         extensions: ["tex2jax.js"],         jax: ["input/TeX","output/HTML-CSS"],         tex2jax: { inlineMath: [ ['$','$'], ["\\(","\\)"] ],                    displayMath: [ ['$$','$$'], ["\\[","\\]"] ],                    processEscapes: true },         "HTML-CSS": { availableFonts: ["TeX"],                       linebreaks: { automatic: true } }     }); </script>   But I failed to find header and design in my Blogger.  Can someone show me the process how to paste this code?


In android coding i have two different arraylist. i have matched both arraylist elements. But my problem is that when my matched data found  in loop, if statement not running. this is my code  for (int i = 0; i < mname.size(); i++)  {     if(i<jsonArray.length())     {      JSONObject jo = jsonArray.getJSONObject(i);      String paid = jo.getString("name");      instname.add(paid);      }      else      {      instname.add("0");      }      System.out.println(instname.get(i)+ "  " + i );      for(int j=0;j<mname.size();j++)      {          System.out.println("instname "+i + "  " + "mname  "+j);          if(instname.get(i) == mname.get(j))          {              System.out.println("instnam=" + instname.get(i));              System.out.println("mem="+ mname.get(j));              pay = instname.get(i);              break;          }      } }   Here in code mname and instname is arraylist. mname has 2 names, 'name1' and 'name2' and instname hase 1 name, 'name2'. In my logcat result like      name2  0     instname 0  mname  0     instname 0  mname  1     0  1     instname 1  mname  0     instname 1  mname  1   instname 0 and mname 1is true matched data contains both name2, but my if condition not run. it results pay = null

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


Let $\{x_n\}$ be a convergent sequence in $\mathbb{R}$ such that it converges to $x$. Then $\frac{x_1+2x_2+...+nx_n}{n^2}\rightarrow \frac{x}{2}$ as $n\rightarrow \infty$. Any help is appreciated. It would be great if an $\epsilon-\delta$ argument is provided. EDIT: I had written the limit incorrectly. I guessed that it should have been the limit, but now I think it is $\frac{x}{2}$.

Let $\{x_n\}_{n=1}^{\infty}$ be a convergent sequence in a  $(S, ||\cdot ||)$. Find the limit of the sequence \begin{align} \left\{\frac{x_1 + 2x_2 + \cdots + nx_n}{n^2}\right\}_{n=1}^{\infty} . \end{align}  Could you please give me some hints where to start?


I am using \question environment to make a Objective type question paper. I am using the following code:  \question Which compound would give 5-keto-2-methyl hexanal upon ozonolysis ?  \begin{oneparchoices}     \choice \begin{minipage}[c]{8em} \vspace{0pt} \chemfig{[:18]*5(--(-[:30]CH_3)=(-[:90]CH_3)--)} \end{minipage}     \choice \begin{minipage}[c]{8em} \vspace{0pt} \chemfig{[:18]*5(-(-[:-30]CH_3)-=(-[:90]CH_3)--)} \end{minipage}     \choice \begin{minipage}[c]{8em} \vspace{0pt} \chemfig{[:18]*5((-[:210]CH_3)--=(-[:90]CH_3)--)} \end{minipage}     \choice \begin{minipage}[c]{8em} \vspace{0pt} \chemfig{[:18]*5(--=(-[:90]CH_3)-(-[:150,0.9])-)} \end{minipage} \end{oneparchoices}   Issue is how do i make the options aligned into two sections like option A and B in one line and option C and D in another line(exactly below the option A & B)  Should I use oneparchoices or should i use something else to rectify the problem?  I want options to be like :     Que...   A.)                          B.)   C.)                          D.)

\documentclass[12pt,a4paper]{exam} \renewcommand{\baselinestretch}{1.2} \oddsidemargin 0in \evensidemargin 0in \topmargin 0in \textheight 9.2in \textwidth 6.5in %\hoffset -1in %\voffset -1in %\evensidemargin 14pt \usepackage{amsmath,amsthm,amsfonts,amssymb,dsfont} \pagestyle{headandfoot} \extraheadheight{.5in} \lhead[]{} \chead[ \vskip .1in  MATHEMATICS\\ STANDARD X(CBSE)\\       %\hrule     \textbf{PAIR OF LINEAR EQUATIONS IN TWO VARIABLES} \linebreak        \textbf{Time: 1 Hour}   \hskip 1.3in  \textsf{ }        \hfill{\textbf{Max. Marks:30}}\vskip.05in \vskip -.5in]{} \rhead[]{} \lfoot{David 7502878908} \cfoot{HOME TUITIONS} \rfoot{\iflastpage{$\maltese\maltese\maltese \maltese \maltese$}{Continued...\ldots}} \pointsinrightmargin \newcommand{\ntt}{\normalfont\ttfamily} %    command name \newcommand{\cn}[1]{{\protect\ntt\bslash#1}} \hfuzz1pc % Don't bother to report overfull boxes if overage is < 1pc  \newcommand{\thmref}[1]{Theorem~\ref{#1}} \newcommand{\secref}[1]{\S\ref{#1}} \newcommand{\lemref}[1]{Lemma~\ref{#1}} %\newcommand{\bysame}{\mbox{\rule{3em}{.4pt}}\,} \newcommand{\sqt}[1]{\sqrt{\smash[b] {#1}}}  %    \interval is used to provide better spacing after a [ that %    is used as a closing delimiter. \newcommand{\interval}[1]{\mathinner{#1}}  %    Notation for an expression evaluated at a particular condition. The %    optional argument can be used to override automatic sizing of the %    right vert bar, e.g. \eval[\biggr]{...}_{...} \newcommand{\eval}[2][\right]{\relax   \ifx#1\right\relax \left.\fi#2#1\rvert}  %    Enclose the argument in vert-bar delimiters: \newcommand{\envert}[1]{\left\lvert#1\right\rvert} \let\abs=\envert  %    Enclose the argument in double-vert-bar delimiters: \newcommand{\enVert}[1]{\left\lVert#1\right\rVert} \let\norm=\enVert \newcommand{\pad}[2]{\frac{\der #1}{\der #2}} \newcommand{\IC}{{\mathbb C}} \newcommand{\IN}{{\mathbb N}} \newcommand{\IR}{{\mathbb R}} \newcommand{\gol}{\mbox{$\,${\rm Log}$\,$}} \newcommand{\Log}{\ln} \newcommand{\ov}[1]{\overline{\smash[b] {#1}}} \newcommand{\Ndash}{\nobreakdash--} \newcommand{\IE}{{\mathds{R}^n}} \newcommand{\IF}{{\mathds{R}^m}} \begin{document}  \hrule   \vskip .1cm {\hskip 2.5in \textbf{Part A} \hfill{}}   \underline{Answer all the questions:}   \begin{questions}  \question Which subject you like very much?  \choice mathematics \choice physics \cchoice chemisty %cchoice means that correct choice \choic biology   \end{questions} \cfoot{$\maltese\maltese\maltese \maltese \maltese$} \rfoot{} \end{document}   I need these commands in my questions with the following alignments..that is the output should be like this.  1.Which subject you like very much?  (a) mathematics                      (b) physics (c) chemistry                        (d) biology   What should i do for this.. and if the choices are lengthy it has to be aligned automatically...kindly help me...


After some research for a laptop that may works with dual boot I found VivoBook S S510UA. I must use Windows for work and want Ubuntu for me. I have some small idea how Ubuntu functions however I could not find clear instructions about the installing process. My biggest concern is buying the wrong computer (not able to handle a partition) and the installing process.   These are my specs:   Processor Intel® Core™ i7-8550U processor 1.8 GHz 8M Cache, up to 4.0 GHz Ram 8GB DDR4 Graphics Controller Intel UHD Graphics 620 Hard Drive 1TB 5400 RPM HDD   128GB SATA3 M.2 SSD   Is this the right laptop? And where can I find the instructions to do the partitioning?   Thank you for your help!

For a given hardware configuration, how do I find out if Ubuntu will run on it? What considerations should I take into account when choosing an Ubuntu version and  such as:    with a lighter desktop than the usual Gnome and Unity  with the even lighter LXDE desktop   Obviously Ubuntu does not run on some processor architectures. So how do I go about choosing the right version and derivate. How can I find out the minmal system requirements?


I have only one variable in bash script ${PHP_V} and trying to pass in nginx config file like:  cat <<'EOF' > /etc/nginx/sites-available/default server {     listen 80 default_server;      listen [::]:80 default_server;       listen 443 ssl default_server;      listen [::]:443 ssl default_server;       root /vagrant/webroot;       index index.php;       server_name _;       ssl_certificate /etc/nginx/certs/vagrantbox.crt;      ssl_certificate_key /etc/nginx/certs/vagrantbox.key;        location / {          try_files $uri $uri/ /index.php?$args;      }       location ~ \.php$ {          try_files $uri =404;          include fastcgi_params;          fastcgi_pass unix:/run/php/php${PHP_V}-fpm.sock;          fastcgi_index index.php;          fastcgi_intercept_errors on;          fastcgi_param SCRIPT_FILENAME          $document_root$fastcgi_script_name;      } } EOF   but without success. How to do?

I have a script that has to do many different things on many different remote machines.  I thought that a heredoc would work for this, but I am not able to use a variable defined elsewhere in the script and one defined in the heredoc. Here is some code: #!/bin/sh  FOO="foo" ssh some.remote.host << EOF   BAR="bar"   echo "FOO=$FOO"   echo "BAR=$BAR" EOF  This only prints the following:  FOO= BAR=bar  If, however, I quote the EOF line like this: ssh some.remote.host << "EOF" then it only prints the following:  FOO=foo BAR=  Any hints on how I can use both variables inside the heredoc? Thanks.


Let $(X_n)$ be a supermartingale such that $EX_n$ is constant. show that $X_n$ is a martingale. My problem here in this question is how can I use the constant expectation concept given to prove the statement.

In my lecture notes they use the fact, that every supermartingale $(M_t)$ for which the map $t\mapsto E[M_t]$ is constant is already a martingale. Unfortunately I can't prove it. Some help would be appreciated.   By definition of a supermartingale we have: $E[M_0]\ge E[M_s]\ge E[M_t]$ for $t\ge s\ge 0$. I also know that $M_s\ge E[M_t|\mathcal{F}_s]$. If I would take expectation I  would get an equality by assumption. However I do not see how this helps here to prove $M_s= E[M_t|\mathcal{F}_s]$


After reading several "tutorials" on SVD I am left still wondering how to use it for dimensionality reduction.  Here is my confusion in an applied setting. If I limit svd to only considering the first two singular values / vectors and "recreate" the matrix, the dimensionality is still the same (4 columns). What should be done here to instead only use 2 columns?  data(iris) s<-svd(iris[,-5])  u<-as.matrix(s$u[,1:2])     v<-as.matrix(s$v[,1:2]) d<-as.matrix(diag(sing$d)[1:2, 1:2])  s2<-u%*%d%*%t(v)

Principal component analysis (PCA) is usually explained via an eigen-decomposition of the covariance matrix. However, it can also be performed via singular value decomposition (SVD) of the data matrix $\mathbf X$. How does it work? What is the connection between these two approaches? What is the relationship between SVD and PCA?  Or in other words, how to use SVD of the data matrix to perform dimensionality reduction?


How i can execute commands of cmd and return the values of this. For example, i execute the command Ipconfig and return a list of interface available Thanks.

How do I execute a command-line program from C# and get back the STD OUT results? Specifically, I want to execute DIFF on two files that are programmatically selected and write the results to a text box.


I was playing Minecraft and I had every achievement except for "The Beginning". Because I had just spawned The Wither. I tried going at it but every time I hit it, it just regenerated health. How do I kill it?

Ever since I've defeated the Ender Dragon I've been preparing to go against the Wither Boss. What is the easiest way to defeat him?


I am trying to setup a computer with a browser page. The webpage allows people to enter their email address and submit a form.   However, it is intended to be a kiosk. I don't want people to be able to minimize or move or drag around or visit any other URL.   How can I lock things down? Can I configure local security policy somehow? I am planning on using a Windows XP, or Windows 7.  Thank you,

I have been tasked with building several PCs to act as secure kiosks that allow users to view and use an intranet site at my company.  Our LP staff will cover physical security, so that is not a concern. To prevent booting from a USB drive or walking with the HDD, I will be encrypting with BitLocker.  What I am having trouble with is deciding on a method to lock down Windows 7 in such a way that the only thing a user has access to is a browser (in this case, IE9) and limit the browser to specific URLs (or domains). I have considered doing this through Group Policy, but it seems there would be a substantial amount of research, development, and testing involved to get it right. With that said, does anyone know of a free or inexpensive piece of software that can accomplish this? Any recommendations would be appreciated.


When I have a Fluke True-RMS multimeter. Does the meter measure DC-RMS voltage or the average voltage?

I've a full bridge rectifier and I put the following function into it:  $$5\sin(100\pi t)\tag1$$  So, at the output I get:  $$\left|(5-2V_d)\sin(100\pi t)\right|\tag2$$  Where \$V_d\$ is the voltage over one diode.  Now, why do I measure (with a Fluke multimeter) a DC-voltage of \$1.4\$ volts and an AC-voltage of \$0.5\$ volts. Why do I measure an AC-voltage, is it not completely DC?


my goal is the evaluate the following using .net core and c#.  "XYZ = XYZ"   My goal is the use the following string to evaluate if the string will return true or false. In this example the result should be true whilst in this example:  "XYdddZ = XYZ"   `Which should return false instead.  essentially it would look similar to:  if ("XYZ = XYZ"){  }   EDIT:  the string may be dynamic and contain something like "XYZ = XYZ and XYZ != XYaZ" Therefor splitting may be hard

I can do an eval("something()"); to execute the code dynamically in JavaScript. Is there a way for me to do the same thing in C#?  An example of what I am trying to do is: I have an integer variable (say i) and I have multiple properties by the names: "Property1", "Property2", "Property3", etc. Now, I want to perform some operations on the " Propertyi " property depending on the value of i.   This is really simple with Javascript. Is there any way to do this with C#?


main(int argc,char *argv[]) { ......; ......; }   Here argc is an interger variable and indicates the number of parameters passed. argv is an array of pointers to characters My doubt is I seen an program using   main(int argc, int*argv[]) { ......; ......; }   is it valid can we use argv as an array of pointers to integers?

What is the correct (most efficient) way to define the main() function in C and C++ — int main() or void main() — and why? And how about the arguments? If int main() then return 1 or return 0?  There are numerous duplicates of this question, including:       — For C++, with a very good answer indeed.     Related:


I remember a quote about "it's eye was bigger than alaska". It's about a monster dragon that was huge and constantly demanded to be fed

I'm hoping someone recognizes this short story I read as a boy. The story was about a robotic eyeball that rolled around on a beach until it found a hand. The two parts joined up and wiggled around until they found a leg. They joined the leg and hopped around. That is all I can remember. I would like to know the ending. Does anyone remember this short story or know where it came from?


I tried to init char[][] static public field in class but in another function this field is undefined. How I use consexpr  or exists another method to init static (dictionary) array?  class A {     public:         constexpr static char dict[][3] = {             "a",             "bb"         };          void print() {             printf(A::dict[1]);         } };  int main() {     A a;     a.print();     return 0; }   10  undefined reference to `A::dict'

Can anyone explain why following code won't compile? At least on g++ 4.2.4.  And more interesting, why it will compile when I cast MEMBER to int?  #include <vector>  class Foo {   public:       static const int MEMBER = 1;   };  int main(){       vector<int> v;       v.push_back( Foo::MEMBER );       // undefined reference to `Foo::MEMBER'     v.push_back( (int) Foo::MEMBER ); // OK       return 0; }


May I please have assistance with installing WineHQ on Ubuntu 18.04 I have spent the last few hours going over the WineHQ official site's guide for install, and multiple other 3rd party linux based websites. I continue to get  E: Unable to correct problems, you have held broken packages   However, every fix I have come across (even on this site) results in  The following packages have been kept back.   Any suggestions?  As some background, I have had everything installed once I got this machine. Wine, Play On Linux, Steam, and some other things. Everything was working fine until a recent update caused my screen to not wake up from suspend/sleep. Then I continued to get OS error messages that I would "report" but then when checking my activity log, nothing was showing as an issue. So I reinstalled Ubuntu.

After upgrading from 10.04 to 12.04 I am trying to install different packages.  For instance ia32-libs and skype (4.0).  When trying to install these, I am getting the 'Unable to correct problems, you have held broken packages' error message.   Output of commands:  sudo apt-get install -f Reading package lists... Done Building dependency tree        Reading state information... Done 0 upgraded, 0 newly installed, 0 to remove and 0 not upgraded.   After running this:  sudo dpkg --configure -a foo@foo:~$ sudo apt-get install -f Reading package lists... Done Building dependency tree        Reading state information... Done 0 upgraded, 0 newly installed, 0 to remove and 0 not upgraded.


I need your help, I have an error with the following function:  blur = cv2.GaussianBlur(res, (15,15),0)                                           ^ IndentationError: unindent does not match any outer indentation level  Can anybody help me? I have the opencv 3.0.0  my code is :  import cv2 import numpy as np   cap = cv2.VideoCapture(0)  while True :      _,  frame = cap.read()     hsv = cv2.cvtColor(frame, cv2.COLOR_BGR2HSV)       # hsv hue sat value     lower_red = np.array ([50,0,0])     upper_red= np.array([100,255,255])      mask = cv2.inRange(hsv, lower_red, upper_red)     res= cv2.bitwise_and(frame, frame, mask= mask)      kernel = np.ones((15,15), np.float32)/ 225     smoothed = cv2.filter2D(res, -1, kernel)      blur = cv2.GaussianBlur(res, (15,15),0)       cv2.imshow('frame',frame )     #cv2.imshow('mask', mask)     cv2.imshow('res', res)     cv2.imshow('smoothed', smoothed)     cv2.imshow('gaussian', blur)      k = cv2.waitKey(5) & 0xFF     if k==27:         break        cap.release()     cv2.destroyAllWindows()

When I compile the Python code below, I get      IndentationError: unindent does not match any outer indentation level     import sys  def Factorial(n): # Return factorial     result = 1     for i in range (1,n):         result = result * i     print "factorial is ",result     return result   Why?


I'm trying to query the ErrorLog files, but it sometimes fails on some of my servers. For some reason a file go missing from time to time. I do not know why. I do not think that I deleted the file :-). Worse, SQL Server "crash" with this error  Msg 0, Level 11, State 0, Line 60 A severe error occurred on the current command.  The results, if any, should be discarded.   If I run   EXEC master..xp_readerrorlog 999   I do get a proper error:  Msg 22004, Level 16, State 1, Line 63 xp_readerrorlog() returned error 2, 'The system cannot find the file specified.'   I have tried many things; TRY-Catch block, a separate sproc to do the insert and dynamic SQL. They all eat my error message.  Here is my code:   SET NOCOUNT ON   DROP TABLE if EXISTS #ReportSQLErrorLogs  CREATE TABLE #ReportSQLErrorLogs (     row_id BIGINT NOT NULL IDENTITY(1,1),      log_date datetime NULL,     processinfo nvarchar(16) NULL,     ProcessText NVARCHAR(2048) NULL,     CurrentLogNum TINYINT NULL )  DECLARE @NumErrorLogs INT, @CurrentLogNum INT SET @CurrentLogNum = 0  -- Get total number of log files from registry EXEC master.dbo.xp_instance_regread N'HKEY_LOCAL_MACHINE', N'Software\Microsoft\MSSQLServer\MSSQLServer', N'NumErrorLogs', @NumErrorLogs OUTPUT SELECT @NumErrorLogs = ISNULL(@NumErrorLogs, 6) -- NULL in registry entry for Error Log files mean default of 6 value  WHILE @CurrentLogNum < @NumErrorLogs BEGIN     INSERT INTO #ReportSQLErrorLogs ( log_date, processinfo, ProcessText )     EXEC master..xp_readerrorlog @CurrentLogNum     --PRINT @CurrentLogNum     RAISERROR ('at %i', 10, 1, @CurrentLogNum) WITH NOWAIT      UPDATE #ReportSQLErrorLogs SET CurrentLogNum=@CurrentLogNum WHERE CurrentLogNum IS NULL     SELECT @CurrentLogNum = @CurrentLogNum + 1 END   And bonus points if you happen to know why errorlog files can go missing.

I have some code to help automate checking the error logs daily on our SQL Server.  This code calls xp_readerrorlog 0 to check the error log, and xp_readerrorlog 0,1 to check the SQL Server log.  Sometimes, however, there is more than one error log I need to scan.    I would like to be able to see, by T-SQL, the date of the log or, barring that, find the number of logs that exist.  I read that we can have up to 99 archive logs, but the server throws the following error message when trying to display an error log that doesn't exist.  "xp_readerrorlog() returned error 2, 'The system cannot find the file specified."  I know the date information and number exists since SSMS displays it( see the image below.)


Umm, I need help about my Iphone 4... I recently bought it and was able to connect to our home wifi perfectly.. But one day, we don't know why, but me and my brother's iphone 4 was unable to connect to the home wifi. Although, we could connect to our school and other places's wifi network except our home wifi!!! :( Help please??? Thank you!

I recently got an iPhone 4. At home, it connected to our wifi and worked perfectly. Now I am at school. My iPhone is now connected to the wifi here, it says that it is connected and has strong wifi signal. However apps that require internet like email, Facebook app, and online games (like words with friends, etc) load and stall showing "updating". All apps are unable to actually update. It shows it is loading for forever.   What can I do to fix this?


I have some weird filter results with Inkscape. I am using Windows 10 and Inkscape Version 0.92. When I apply Filter > Bevel > Combined Lightening filter the following result is being rendered:    First I thought it is just a preview to save render performance but as I exported the graphic as .png it still looked the same. What is happing here? In all the "Bevel" tutorial videos it looks all great.

I'm running Inkscape 0.92.4 on Ubuntu Linux 19.10. My graphics driver is from NVidia. I'm given to believe that Inkscape's filters should work and render fairly similarly to how filters work in GIMP. My expectations are based on this image which shows various filter effects which ship with Inkscape:    However, when I apply filters to even very simple shapes, I get horrible pixelated garbage like this:      Can anyone help me understand what is wrong and how to correct it? Thanks!


I've been trying to model a realistic rocket engine and if you've never seen a rocket engine before, they have some really complicated plumbing structure.     I've tried getting some crazy shapes using either the Array or Curve modifier but they don't work that well with complicated curves and always produce some weird results. Is there a better way to make a weirdly bent pipe or wire?

I'm wondering how to approach duct work, piping, and wiring? In the past, I have used the spin tool to make corners, but I find it very cumbersome. How do you do duct work and piping? I have seen people use curves, but I find it's hard to get straight 90 degree angles or just uniform angling across the whole model. It's also hard connecting piping together if they started from different locations. Here's some reference:


Is there a way to revert to a previous version of a file that has been changed by a program different from a text editor?  In my case I was using KeePassX and after adding a new password and saving the database, its size was '0 bytes' and couldn't be opened anymore. So all my passwords are now inaccessible.   Is there a way to access the previous, non-destroyed version of the database? Unfortunately, I never made any backups of it.  I am using Ubuntu 14.04 with KeePassX 0.4.3.  I am aware of this question  but its focus is on command line actions such as copy or move.

I am not talking about  , but overwritten files. Namely by the following methods:  # move mv new_file old_file  # copy cp new_file old_file  # edit vi existing_file > D > i new_content > :x   Is it possible to retrieve anything if any of the above three actions is performed assuming no special programs are installed on the linux machine?


Consider the hypothetical: I'm splitting a dataset into a training set, a validation set, and a test set. I've found the hyperparameters that maximize the fit of a model relative to the validation set and report the fit of that model with those hyperparameters on the test set.   After that, can I train a model on the whole dataset (no splitting) with the hyperparameters I found earlier? Or are these hyperparameters only useful when we use the original training set outlined in the previous paragraph?

TL:DR: Is it ever a good idea to train an ML model on all the data available before shipping it to production? Put another way, is it ever ok to train on all data available and not check if the model overfits, or get a final read of the expected performance of the model?    Say I have a family of models parametrized by $\alpha$. I can do a search (e.g. a grid search) on $\alpha$ by, for example, running k-fold cross-validation for each candidate.   The point of using cross-validation for choosing $\alpha$ is that I can check if a learned model $\beta_i$ for that particular $\alpha_i$ had e.g. overfit, by testing it on the "unseen data" in each CV iteration (a validation set). After iterating through all $\alpha_i$'s, I could then choose a model $\beta_{\alpha^*}$ learned for the parameters $\alpha^*$ that seemed to do best on the grid search, e.g. on average across all folds.  Now, say that after model selection I would like to use all the the data that I have available in an attempt to ship the best possible model in production.  For this, I could use the parameters $\alpha^*$ that I chose via grid search with cross-validation, and then, after training the model on the full ($F$) dataset, I would a get a single new learned model $\beta^{F}_{\alpha^*}$   The problem is that, if I use my entire dataset for training,  I can't reliably check if this new learned model $\beta^{F}_{\alpha^*}$ overfits or how it may perform on unseen data. So is this at all good practice? What is a good way to think about this problem?


I have used the code below to deserialize the json but throwing an error.   Map<String,Object> root =(Map<String,Object>)JSON.deserializeUntyped(res.getBody()));      "Callout error Invalid conversion from runtime type List<ANY> to Map<String,ANY>"    I want to deserialize the JSON using an apex class to get the list of values?  {    "controllerValues": {},    "defaultValue": null,    "eTag" : "",    "url" : "",    "values" : [     {             "attributes": null,             "label": "PicklistValue1",             "validFor": [],             "value": "PicklistValue1"     },     {             "attributes": null,             "label": "PicklistValue2",             "validFor": [],             "value": "PicklistValue2"     }    ] }

How can I deserialize this json object:      {     "response": {         "count": 1,         "benchmark": 0.22567009925842,         "requests": [             {                 "request": {                     "id": 537481,                     "image_thumbnail": "",                     "title": "Request for new bin(s) - residential",                     "description": "Propmain ref  3234-1114",                     "status": "submitted",                     "address": "36 Pine Tree Close",                     "location": "Peterborough, England",                     "zipcode": "PE1 1EJ",                     "user": "",                     "date_created": 1417173208,                     "count_comments": 0,                     "count_followers": 0,                     "count_supporters": 0,                     "lat": 52.599967,                     "lon": -0.233482,                     "user_follows": 0,                     "user_comments": 0,                     "user_request": 1,                     "rank": "0"                 }             }         ],         "status": {             "type": "success",             "message": "Success",             "code": 200,             "code_message": "Ok"         }     } }   What i've tried:   Map<String,Object> rawObj = (Map<String,Object>) JSON.deserializeUntyped(jsonString);     Map<String,Object> responseObj = (Map<String,Object>)rawObj.get('response');     List<Object> reqs = (List<Object>) responseObj.get('requests');     System.debug('Map Size = ' + reqs.size());     Map<String, Object> i = new Map<String, Object> ();     for (Object x : reqs) {          i = (Map<String, Object>)x; }     Map<String,Object> requests = (Map<String,Object>)i.get('request');     System.debug('Map Size = ' + i.size());     for (String field : i.keySet()){          Object id = i.get(field);         Object title = i.get('title');         System.debug('Id : ' + id);         System.debug('title : ' + title);          //System.debug('Title : ' + title);       }


I was looking at my Impact rating on Arqade earlier, and I noticed that it had reached 945K.  Excited, I waited a few hours to see if it was climbing at a steady rate, only to find it had gone back down to 944K.   I don't have a screenshot to prove this, but I'm almost certain that it was 945K earlier.  I know this is a new metric for SE, but is it possible for it to go down over time?  It says it's based on upvotes and question views, but neither of those went down between the time I saw the 945K and the time it went back to 944k.

I posted this  a few weeks ago. The photo I posted shows that I had impacted 25k people. Now it says this:   I only impacted 1k people, 24k less than what my impact was a few weeks ago! I am sure that 24k people didn't delete their accounts within a few weeks and this is probably a bug. What happened to my impact score?


I'm needing to free up space on my Mac and I have a migrated iPhoto library of 178 GB that I would like to move to an external drive as I'm too scared to delete it. However, it won't let me move it across to the hard drive - it just pings back to it's location.  Looking for advice please on what to do with this iPhoto library.

Wife has been using iPhoto/Photos and iMovie for storing family photos and videos for roughly 5 years. Have about a 300 GB iMovie library and 100 GB iPhoto library.  MacBook Pro is getting full (less than 10 GB free) which is obviously beginning to effect performance. Have always used a NAS for Time Machine to back-up but not doing anything offsite.   Not sure what to do to move these libraries or archive them to a) an external HD or b) an offsite storage. Is it possible to just "close" the library and move it to an external HD for archiving. From what I understand in iPhoto/iMovie, if you wanted to access that library later you could simply load that library.   Is there any how-to on this or a better method? Also moving forward should I be keeping the libraries on an external an just accessing them with Photos/iMovie?


I tried to calculate this dominant convergence theorem to solve this limit. Evaluate the following limit for $x=0$ and for $x>0$: $$\lim_{n \to \infty} \int_{0}^{1} n(2^x-1)^n dx$$ and I got the limit value : $\frac{1}{2\ln{2}}$ did I do the right thing?

Suppose $f:[0,1]\to \mathbb{R}$ is continuous. Show that   $$\lim_{n\to\infty} n\int_0^1 f(x)x^n\,dx = f(1).$$  My answer so far: First I want to assume that $f\in C^1$. Then   $$n\int_0^1f(x)x^n\,dx = \left[\frac{n}{n+1}x^{n+1}f(x)\right]_0^1 - \frac{n}{n+1}\int_0^1 x^{n+1}f'(x)\, dx\\ \frac{n}{n+1}f(1) - \frac{n}{n+1}\int_0^1 x^{n+1}f'(x)\, dx,$$  which goes to $f(1)$ because the last integral goes to zero.  But approximating $f$ by $\phi\in C^1$ won't necessarily work, because $\phi(1)$ may not equal $f(1)$... how can we finish the argument?


After I have asked the OS to safely remove device (USB) and can no longer access it. Without plugging out and in the USB how can I make the OS gain access to the USB device again?  Basically triggering the same event which is fired when the OS detects a device was plugged in, or something else.

It is possible for a USB storage device to become logically disconnected: the device is still plugged in, but is invisible from the operating system (e.g. it's not listed under /proc/bus/usb). Maybe this can happen to other kinds of USB or other removable devices as well. This can happen for example:   ; after VirtualBox has claimed a USB storage device (the device disappears from the Linux host when it is attached in the guest, and does not automatically reappear if it is detached from the guest).   What is going on in the driver or in the hardware, and most importantly, (how) can the device be logically reconnected (without physically plugging it out and back in)?  Note that this question is not about mounting. In the “logically disconnected” state, the kernel believes there is nothing on the USB bus (and so of course there is no entry under /dev).


Im setting up ubuntu for the first time. I downloaded the version 12.  My wifi card is BCM4313 I read the manual on how to get the wifi up and running:   I downloaded the bcmwl-kernel-source and followed the instructions.  Here is the problem I cant activate the driver. I get an error: sorry installation of this driver failed check /var/log/jockey.log  and when I check it, terminal says no directory or file found.  I need some help, because I cant get internet on the wifi. I tried google already but it didnt give me any usefull answers.   many thanks in advance!

After installing Ubuntu 12.04 LTS on my HP Folio 13 I cannot get wireless to work. My kernel is 3.8.0-29-generic and my wireless module is a Broadcom BCM4313.  After running rfkill list all:  0: hp-wifi: Wireless LAN Soft blocked: no Hard blocked: no 1: hp-bluetooth: Bluetooth Soft blocked: no Hard blocked: no 2: hci0: Bluetooth Soft blocked: no Hard blocked: no   The wired connection works fine. The driver activation for Broadcom STA wireless driver fails every time. in the log it says  FATAL: Module wl not found. FATAL: Error running install command for wl   After running lspci -nnk | grep -iEA3 "(wireless|network|wlan)":  02:00.0 Network controller [0280]: Broadcom Corporation BCM4313 802.11bgn Wireless Network Adapter [14e4:4727] (rev 01) Subsystem: Hewlett-Packard Company Device [103c:1795] Kernel modules: bcma 03:00.0 Unassigned class [ff00]: Realtek Semiconductor Co., Ltd. RTS5209 PCI Express Card Reader [10ec:5209] (rev 01)   I have also tried this method and it did not work: .


Thomae's function  gives the existance of a function continuous at every irrational number and discontinuous at every rational number. Is there existance of a function that is  continuous at every rational and discontinuous at every irrational

Possible Duplicate:          Motivated by the examples of the Dirichlet's no-where continuous function and , we know that a function can have discontinuities at the reals, or at the rationals. My question is whether the set of discontinuities can actually be at the irrationals only.  tells us that such a function cannot be monotone, so that cuts down on the search. Are there other obstructions? Can we exhibit such a function?


I want to install Tkinter in python 2.7.9 I tried sudo apt-get update sudo apt-get install python-tk i even tried to upgrade python so as to install Tkinter but that didn't work either. Everytime i try to install this is what comes  sudo apt-get install python-tk  Reading package lists... Done  Building dependency tree    Reading state information... Done  Package python-tk is not available, but is referred to by another package.  This may mean that the package is missing, has been obsoleted, or is only available from another source  E: Package 'python-tk' has no installation candidate

Recently I have installed an older version of Ubuntu on my old machine. Whenever I try to install any software, I get an error saying it couldn't be found:  $ sudo apt-get install vlc Reading package lists... Done                Building dependency tree        Reading state information... Done     E: Couldn't find package vlc


I have an array that has a startTime. I want to get items where startTime in between 2020-12-10 09:30:00 and 2020-12-10 13:20:00. I am using the filter method to get the items from the array. startTime>'2020-12-10 09:30:00' // is working, returns array with 6 items but when i add startTime>'2020-12-10 09:30:00' &&  startTime<'2020-12-10 13:20:00' // returns null not able to understand why it not filtering the result when I use less than here is my code var empStart = empShift.filter(item => {     return item.startTime>'2020-12-10 09:30:00' && item.startTime<'2020-12-10      13:20:00'     })

Can someone suggest a way to compare the values of two dates greater than, less than, and not in the past using JavaScript? The values will be coming from text boxes.


Show that the polynomial $f(X) = 7X^5 + 71X^3 - 9$ is irreducible in $\mathbb{Z}[X]$  My solution:  Using the irreducibility test: "Reduction Mod p Test"  $f(X)$ is clearly primitive and that the prime number 2 does not divide the leading coefficient.  It is therefore enough to prove the polynomial $\bar{\pi}_2(f(X)) = X^5+X^3-\bar{1} \in (\mathbb{Z}/2\mathbb{Z})[X]$ is irreducible.  $\bar{\pi}_2(f(X))$ has no roots in $(\mathbb{Z}/2\mathbb{Z})[X]$ (to verify this evaluate the polynomial at the two elements $\bar{0}$ and $\bar{1}$ of $(\mathbb{Z}/2\mathbb{Z})[X]$  Thus, if it were reducible then it would have to be of the form $g(X) \cdot h(X)$, where $g(X), h(X) \in (\mathbb{Z}/2\mathbb{Z})[X]$ are both irreducible of degree $2$. Which is not possible.  Concluding that $\bar{\pi}_2(f(X))$ is irreducible in $(\mathbb{Z}/2\mathbb{Z})[X]$, whereby $f(X)$ is irreducible in $\mathbb{Z}[X]$.

Show that the polynomial $X^5 + X^3 + \bar{1}$ in $(\mathbb{Z}/2\mathbb{Z})[X]$ is irreducible. (Hint: if it were reducible, it would either have a root or be of the form $g(X) \cdot h(x)$, where deg$g(X) = 2$ and deg$h(X) = 3$) Recall that $\bar{a}$ is shorthand for the coset $a + 2\mathbb{Z} \space $in$ \space (\mathbb{Z}/2\mathbb{Z})[X]$ (for any $a \in \mathbb{Z}$)  This question is worth $7$ marks out of a possible $75$, this is my solution..  $f(X) = X^5 + X^3 + \bar{1}$ is irreducible in $\mathbb{Z}/2\mathbb{Z}[X]$ iff it has no roots in $\mathbb{Z}/2\mathbb{Z}$. Since $f(\bar{0}) = \bar{1}$ and $f(\bar{1}) = \bar{1}$, it follows that $f(x)$ is irreducible in $\mathbb{Z}/2\mathbb{Z}[X]$.  Would this be a sufficient answer? am I missing something?


In this article:  The author uses a popular Katy Perry lyric "baby you're a firework" as an example of a metaphor. Katy Perry could just have easily said "baby you're like a firework" but it wouldn't have sounded as good. So isn't this kind of like a "fake metaphor"? It is a very simile-like comparison but people call it a metaphor just because it doesn't use the words "like" or "as". To provide a different example, if I were to say that I longed for connection to my spouse but due to past trauma I found myself hiding behind a wall, that seems a much stronger example of a metaphor. In order to express the same sentiment as a simile, I would have to say something like: I longed for connection to my spouse, but due to past trauma I had distanced myself by creating a set of behaviours that were like a wall. So you could still say the same thing as a simile but it would be totally stupid. Therefore shouldn't we be teaching people that if you can insert the word like or as into the metaphor without making any substantial changes to the syntax, then it's not really a metaphor?

I've always been taught that metaphors and similes both draw a parallel between two disparate ideas/thoughts/objects, but that a simile is a more explicit comparison using the word "like" or "is", whereas a metaphor's connection is more implicit. For example, "His injured ankle burned like a hot stove" is a simile, where as, "His injured ankle was a hot stove of pain" is a metaphor.  However, I recently heard a colleague note that similes are nothing more than a special kind of metaphor. In other words, all similes are metaphors. This seems to contradict what I was always taught (and , for what that's worth). Can anyone straighten me (or my colleague) out?


Why do some mobile phone batteries have 4 terminals? I want to use a mobile phone battery for my project.

Lots of new batteries (for mobile devices, MP3 players, etc) have connectors with 3 pins. I would like to know what is the purpose of this and how should I use these three pins?    They are usually marked as (+) plus, (-) minus, and T.


What is the difference between Math.Floor() and Math.Truncate() in .NET?  For example, Math.Floor(4.4) = 4 Math.Truncate(4.4) = 4.

What is the difference between  and  in .NET?


I am new to salesforce and just discovered that there are two options to deploy metadata to production:   using ChangeSets  using Force.com Migration tool   Could somebody please clarify me on which one to use under what conditions?

Can any one help me out with the advantages,disadvantages of Changesets ,Force.com IDE(Eclipse),Migration tool.  Which tool is preferred.  Correct me if im wrong  Changes Sets :Track the history,profiles can be moved.  Eclipse :profiles,premission sets cannot be moved,Any changes done in sandox is updated in production whereas in changeset we need to select nd move in to production.  Any help very much appreciated.


For example, I'd like a Terminal icon on the desktop.

In older versions it was easy to create a launcher on my desktop. All I had to do is right click on my desktop and select the "create launcher" option.  How can I create such launchers now?


I cannot differentiate when I should use a noun like "distribution" as an adjective to another noun, or when should I use an "-ing" participle as an adjective. Could you please clarify the differences in the meaning?

I cannot differentiate the meanings of the two words. Could you please clarify?   In general, when should I use a noun (distribution) or an adjective (distributed) for verbs similar to distribute, like organize, create?


When I vote to close a question and I open back up the dialogue window it will say      You voted to close this question {time} ago   which is fair enough.    However, if I flag a post I will get told      You have already flagged this post for moderator attention    only after I try and submit a second flag. I think it would be helpful to display      You flagged this post as {reason}, {time} ago   if I open the dialogue box again.

I flagged a post today, typed out a fairly thorough explanation, clicked the button... and got told that I'd already flagged this post (for something else, which I'd forgotten about) so this flag wasn't allowed.  (This happens if the first flag is still active.)  The dialogue with my explanation was gone at this point, so if I wanted to communicate with the moderators about that, I was going to have to start over.  (In case you're wondering how this could happen, one flag was related to the post itself and one was related to the user -- there being no way to flag a user directly, you have to hang it off of a post.  But I've also seen this with cases where the first flag hangs around unhandled for a week or two and I've forgotten about it.)  Since the system is going to detect that I've already flagged a post and reject a second flag, can it do that after I click the "flag" link instead of waiting until the end of the process?  (Or gray out the link so I can't click it in the first place?)  2015-12-18: someone suggested to me in chat today that this had been implemented, so I tested again.  The behavior has not changed: I flagged a post using "other", then flagged it again (also "other") before the first flag was handled, and the flag was rejected only after I'd typed the message.  (I did this on a site where I'm a moderator so I could then clean up after myself.)


Is this proof rigorous enough? (monomorphism: injective homomorphism) Since f is a homomorphism, recall that for any a,b ∈ f(ab), f(ab)=f(a)f(b). Forward direction (injective homomorphism implies kernel is trivial): let a ∈ ker(f). Then we want to show that a = e (identity of G). f(ab) = f(a)f(b) ⇒ f(ab) = e f(b) ⇒ f(ab) = f(b) ⇒ ab = b ⇒ a = e as required. For the backwards direction: want to show that if ker(f)={e}, then we have a monomorphism. f(a) = f(b) ⇒ (f(a))(f(b))^-1 = e ⇒ f(ab^-1) = e ⇒ ab^-1 ∈ ker(f) ⇒ ab^-1 = e ⇒ a = b. Thus, f is injective.

Let $f : G \longrightarrow G^\prime$  be a group homomorphism. Then $f$ is injective iff $\ker(f) = \{1\}$ where $1$ represents the identity of $G.$  First I tried to prove  that if $f$ is injective then $\ker(f) = \{1\}.$  Since $f$ is homomorphism, $f(1)=1^\prime$ (identity elt of $G^\prime$) then $1\in  \ker(f),$ so $\{1\} \subset \ker(f),$ and f is injective $\ker(f) = \{1\}$   For this part, I got help from professor but I can't exactly understand the bold and italic part.  This is my proof for other side ( if $\ker(f) = \{1\}$, then $f$ is injective. )  let $f(a)=f(b)$, then $f(a) * f(b)^{-1} = 1^\prime$ and $f(ab^{-1}) = 1^\prime$ so $ab^{-1}$ is in $\ker(f) = \{1\}$ then $a=b.$