Why a non-root user can delete files created by root?

Given a non-root user "joshua", as root I created a file called "foo" at joshua's home directory (/home/johsua/); it look like this:  -rw-r--r--  1 root   root       0 12-19 21:00 foo   and then delete it as joshua, i can delete it successfully.  I would expect that joshua doesn't have enough permission to delete it. Is it some kind of 'Permissions inheritance'?  My platform is Debian 5.0.7.


Syntax with templates in class functions with a binary search tree

So I am attempting to convert an int based binary search tree I created earlier into a templated binary search tree. I am struggling with how to type out my .cpp file.  In my .h file I have:  template <typename T> class BST { private:             struct node     {         T m_data;         node* m_left;         node* m_right;     };      node* m_root;     void AddLeafPrivate(const T& x, node* Ptr);     void PrintInOrderPrivate(node* Ptr);     node* ReturnNodePrivate(const T& x, node* Ptr);     T FindSmallestPrivate(node* Ptr);     void RemoveNodePrivate(const T& x, node* parent);     void RemoveRootMatch();     void RemoveMatch(node* parent, node* match, bool left);     node* CreateLeaf(const T& x);     node* ReturnNode(const T& x);     void RemoveSubtree(node* Ptr); public:     BST();     ~BST();     void AddLeaf(const T& x);     void PrintInOrder();     T ReturnRootKey();     void PrintChildren(const T& x);     T FindSmallest();     void RemoveNode(const T& x); };   In my .cpp file I am getting errors with the following functions:   template <typename T> template BST<T> :: node* BST<T>::ReturnNode(const T& x) {   return ReturnNodePrivate(x, m_root); }  template <typename T> template BST<T> :: node* BST<T> :: ReturnNodePrivate(const T& x, node* Ptr) { if(Ptr != NULL) {     if (Ptr -> m_data == x)     {         return Ptr;     }     else      {         if (x < Ptr -> m_data)         {             return ReturnNodePrivate(x, Ptr -> m_left);         }         else          {             return ReturnNodePrivate(x, Ptr -> m_right);         }            } } else {     return NULL; } }   I am getting the same 4 errors for each function and I am confused what I am doing wrong.   error: expected '<' before 'BST' for template BST<T> error: 'T' was not declared in this scope error: template argument 1 is invalid error: expected initializer before '*' token   Any suggestions on what I am doing wrong?


How do I find out which repository a package comes from?

Is there a method or command which can tell from which repository a package is coming from?


Formatting Textbox number on Leave event

I know this is simple but need some help in formatting a number in a textbox on Leave event. I am trying the below but I am getting incorrect results.   This is what Im expecting:  100 = 100  1000 = 1,000  10000 = 10,000  10000.25 = 10,000.25  2500000.432 = 2,500,000.432  txtAmount.Text = string.Format(System.Globalization.CultureInfo.GetCultureInfo("id-ID"), "{0:#,##0.##}", double.Parse(txtAmount.Text));


Why is FFmpeg video splitting of 595-600 seconds slow compared to 0-5 seconds?

I have to split a 4K 10 minutes video into 120 small video files, each containing 5 seconds of duration. I'm using ffmpeg for splitting the video. The splitting take a very very long time and the speed of the conversion gets slower as the duration of the splitting gets higher. For test use, I used the commands below in cmd and a) was a lot lot faster than b):  a) ffmpeg -i video.mp4 -ss 0 -to 5 split.mp4  b) ffmpeg -i video.mp4 -ss 595 -to 600 split2.mp4  As the commands executed, there was a time delay and then the splitting starts happening and the time delay of b) was a lot longer than a). Please help me   or advise me to prevent this time delay and help me speed up my conversion. Please don't give me any methods which will cause certain amount of video footage to disappear. Thanks  ADDITIONAL QUESTION:  Is there any way to make the ffmpeg video quality conversion, fps conversion and video splitting faster through the computer specs. As to do I need to have a  more powerful graphics card to make the ffmpeg conversions faster or any other computer parts?


This is my first question on the Photography stack. So please forgive me if I dont sound too technical.  I have a Nikon D5100 and a 18-50 mm F 1.8 Lens. I enjoy taking pictures of my 13 month old son who is constantly on the move as he just started walking. I usually try to use the Manual mode and set the aperture > F2.5 and shutter speed(usually 1/2 or 1/8) to suit the light. But I usually have a problem when I encounter low light. If I use the lowest F stop, I get blurry images owing to lower shutter speeds (I dont have a tripod yet). I have used the Sport mode with some good results, but I would like to have more control of my images.   My question is, what other modes I can use to remove the bluriness and if having an external flash would help.


Command and Conquer 3 exeption in exception handler

I have command and conquer 3 from Origin, but when I try to start it, I get the 'exception in exception handler' error and the game exits.   I've tried the Origin launcher fix as well as -runver to make the game run a different version (although this just says that it can't find any version). I run Windows 10 (I know, experimental) but this game worked at one point, and then stopped working suddenly - there wasn't even an update in between.   I suspect that it's got to do with Origin, but any help would be appreciated.


Can the empirical Hessian of an M-estimator be indefinite?

Jeffrey Wooldridge in his Econometric Analysis of Cross Section and Panel Data (page 357) says that the empirical Hessian "is not guaranteed to be positive definite, or even positive semidefinite, for the particular sample we are working with.".  This seems wrong to me as (numerical problems apart) the Hessian must be positive semidefinite as a result of the definition of the M-estimator as the value of the parameter which minimizes the objective function for the given sample and the well-known fact that at a (local) minimum the Hessian is positive semidefinite.  Is my argument right?  [EDIT: The statement has been removed in the 2nd ed. of the book. See comment.]  BACKGROUND Suppose that $\widehat \theta_N$ is an estimator obtained by minimizing $${1 \over N}\sum_{i=1}^N q(w_i,\theta),$$ where $w_i$ denotes the $i$-th observation.  Let's denote the Hessian of $q$ by $H$, $$H(q,\theta)_{ij}=\frac{\partial^2 q}{\partial \theta_i \partial \theta_j}$$  The asymptotic covariance of $\widehat \theta_n$ involves $E[H(q,\theta_0)]$ where $\theta_0$ is the true parameter value. One way to estimate it is to use the empirical Hesssian  $$\widehat H=\frac{1}{N}\sum_{i=1}^N H(w_i,\widehat \theta_n)$$  It is the definiteness of $\widehat H$ which is in question.


I'm currently trying to switch from OpenSUSE to Ubuntu as my main OS. While most of opensuse features is there in ubuntu, there is one feature that doesn't. In Opensuse, I can always use Ctrl+Up to autocomplete the command line using previously typed command. That feature is very useful for me as it allows me to work faster without having to retype long command.  Can anyone provide a way to enable this on Ubuntu?  Thank you


some webpages not opening in any browser

I have using ubuntu 12.04LTS with all available updates installed. Some websites are not opening in any browser, i have tried many browsers(firefox,chrome,chromium,arora,xxxtrem browser,Midori).  But yesterday i have install the ubuntu 12.04(the first release of this version) in my pen drive and use it. In USB booted ubutu, all websites are open properly or we can say that in older version of browsers websites are opening(in usb booted ubuntu firefox version is 11.0) but now in updated   ubuntu 12.04LTS websites are not opening .  I have read some solution about this problem but they are says to change dns server but i think this is not dns server problem because with same dns settings websites are opening properly in the windows and usb booted ubutu.  Please tell what will be solution?  website which i tried to open are   yahoo.com, skydrive.live.com, indiarailinfo.com


I am not an expert in this so I hope this doesn't sound so stupid: what is the common metric used when studying the Euclidean Group $\mathrm{E}(3)$. One could probably ask the same thing for (homogenous) transformation group $\mathrm{SE}(3)$. For the latter I have seen use of Riemannian metric. For both I am guessing (as this is not my field) that there are some kind of manifold structure involved, so I can't help to think that there are also good metrics (by good I mean metric that is considered "practical" when one considers rigid body motions).  Furthermore, is there a way to visualize the manifolds from $\mathrm{E}(3)$ and $\mathrm{SE}(3)$? Any good reference in this area?


Evenness of binomial co coefficients for power $2^n$.

I've noticed that all binomial coefficients, apart from first and last, for powers 1, 2, 4 and 8 are even numbers. This suggests, that it may be the case for any $2^n$.  In other words, is the following true?     $\binom{2^n}{k}$ is even for any natural $k<2^n$


How to remove a specific color in an image in Photoshop?

I am not an expert photoshop user but have been trying to use more of it in what I currently do.   I have a black and white image from which I am trying to remove all the white.   I cannot use the magic wand/delete because the white is in literally hundreds of places and in some cases very tiny.   Is there a method to strip the white off, leaving just the black?  Thanks in advance for your help.


View setEnabled() Error : NullPointerException

I tried to set views to Enabled(false), but it keeps giving me this error:  Caused by: java.lang.NullPointerException: Attempt to invoke virtual method 'void android.widget.Button.setEnabled(boolean)' on a null object reference   Something I don't understand is that the error didn't occur at ccl_stage11[][] but occured at vtl_stage11 and hrl_stage11[][] even though they're using same for in the same way.  I tried to unroll the 'for' loop at the setEnabled part, but it didn't work.  Can anyone help me to solve this problem? Here is the code related to this error.  public class Stage1Activity1 extends AppCompatActivity {      Button[][] ccl_stage11 = new Button[4][4];     Button[][] hrl_stage11 = new Button[4][4];     Button[][] vtl_stage11 = new Button[4][4];        @Override     protected void onCreate(Bundle savedInstanceState) {         super.onCreate(savedInstanceState);         setContentView(R.layout.activity_stage11);           buttonSettings(); }  protected void buttonSettings() {           int k = 0;         for (int i = 1; i <= 3; i++) {             for (int j = 1; j <= 3; j++) {                 ccl_stage11[i][j] = findViewById(R.id.ccl_stage11_11 + k);                 ccl_stage11[i][j].setEnabled(false);                 k++;             }         }         for (int i = 0; i <= 3; i++) {             for (int j = 0; j <= 3; j++) {                 vtl_stage11[i][j] = findViewById(R.id.vtl_stage11_00 + k);                 hrl_stage11[i][j] = findViewById(R.id.hrl_stage11_00 + k);                 k++;             }         }         for(int i=0;i<=3;i++){             for (int j =0;j<=3;j++){                 vtl_stage11[i][j].setEnabled(false);                 hrl_stage11[i][j].setEnabled(false);             }         }         ccl_stage11[1][3].setEnabled(true);         ccl_stage11[3][1].setEnabled(true);       }   The error occurs at   for(int i=0;i<=3;i++){     for (int j =0;j<=3;j++){         vtl_stage11[i][j].setEnabled(false);         hrl_stage11[i][j].setEnabled(false);     } }


What are those plastic clips delivered with my new bike?

I bought a new bike, online. It's a cube travel SLT, with belt drive, hydraulic brakes, alfine 11 hub.  In the box there were 2 of those plastic clips thingies, taken in the picture next to a set of hex keys for scale:   I have absolutely no clue what they could be used for, and google is not my friend here. What can/should I do with them?


In the Cricket and Soccer/Non-American Football World Cup, why do the players lead children during the beginning?

The title says it all, really. In the world cups for different sports, the player lead children on the field. Why?


I am  developing an iphone app which ask for one time set up details like user name in the first two screens when the user launches the app for the first time. I dont want these 2 screens to come up when I am launching the app once the user has given the details.   I tried getting the info from internet but I was not able to how to find it out. May be I am missing the technical term or wordings involved in doing this. Could any one please help in accomplishing this scenario. Any sample code would be very helpful.  Thanks for your time


Accessing a static member function of a nested class template

For academic purposes I'm reinventing the wheel a bit and try to write a HAL library. Now in designing it I encountered a compiler error that I do not understand. template< class DRIVER, class PORT, class PIN > class Instance {         Instance(){}     public:           static void set(const bool val)        {          DRIVER::GPIOPeripheral<PORT, PIN>::set(val);        }       // ... };  The idea is that a driver class defines the 'how' and an GPIO class defines the, well, GPIO interface abstraction. The driver class looks something like this: class SOC_xyz  {     SOC_xyz(){};  public:     template<class PORT, class PIN>     class GPIOPeripheral     {         static void set(const bool val){ /* ... */ };     } };  The call in the actual code looks like this: typedef Instance<SOC_t, PORT0_t, PIN0_t> GPIO0_0; GPIO0_0::set(1);  Now the compiler gives me a  error: expected primary-expression before ',' token  for the Instance::set function where the DRIVER::GPIOPeripheral<PORT, PIN> gets called. From my understanding it tries to tell me that the class-template-member addressing part is wrong but this is beyond my C++ knowledge. Is that, what I try to do, even possible?


Why has the color gone from the last seen timestamp?

The 'last seen' date on the profile page seems to have lost its color. This makes me sad. Let me illustrate:    I really like the color because it tells me stuff without me actually having to read. Please bring back color to mSE.


What is the proper way to punctuate this sentence? Colon, em dash, or comma?        Eating at a homeless shelter since March has provided me with a look into the thoughts of other people: both the homeless themselves   and their friends.    Eating at a homeless shelter since March has provided me with a look into the thoughts of other people — both the homeless themselves   and their friends.   Eating at a homeless shelter since March has provided me with a look into the thoughts of other people, both the homeless themselves   and their friends.      Also, is there supposed to be a comma between "themselves" and "and"?


Applying to Ph.D. programs in history when my degree is in a science field

I would like to apply for Ph.D. programs in history, but I am a graduate of a science program. Do I need another degree in order to apply to history Ph.D. programs?


Does Gríma have a surname? Wormtongue was a nickname/epithet and not his actual name - but did he have a genuine one?


Today is Thursday. Is "next" Saturday the day after tomorrow or nine days away?

Some people are telling me the day after tomorrow is "this Saturday", and "next Saturday" is a week later.  To others, "this Saturday" is synonymous with "next Saturday".  A few people claim that "this Saturday" is synonymous with "last Saturday", but I am reasonably certain those people are nuts.


App notifications don't dismiss when read on the site

I absolutely love the notifications on my device by the way; they are awesome.  It would be great however if they automatically went away when I took action on the notification in the website.  Scenario   A user's question receives a comment Notification appears on Android app User views the comment via the site, notification dismissed on the site Notification is still visible on the device    The principal: If I've dismissed something anywhere it should be dismissed everywhere


Examples/references for not changing tense when using reported speech

I'm sure people are familiar with the "rule" that the tense is moved backward when using reported speech i.e. "I am..." becomes "He said he was..."   However, there are many cases where it is OK not to change the tense e.g. "I'm going on holiday next week" being reported a short time later/the same day as He said he is going on holiday next week, which in my opinion invalidates the original rule as it is an unhelpful attempt to be prescriptive about English usage.   Can anyone offer an intuitive explanation as to why/when it is OK not to change the tense, or perhaps to explain what differences in meaning are implied when each is used?


Need help with holomorphic functions on a domain interval removed.

I want to prove that for a region $\Omega$ with interval $I=[a,b]\subset\Omega$, if $f$ is continuous in $\Omega$ and $f\in H(\Omega-I)$, then actually $f\in H(\Omega)$.  Is this problem related to the removable singularity? and are there some other sets that could draw same conclusion?


Using Menelaus’ theorem to show points are collinear

I need to prove the following statement and I really need some help. I can’t even visualize the image.      ”The external bisectors of the three angles of a scalene triangle met their respective opposite sides at three collinear points.”


Most pythonic way to check if an item is not a list then make it into a list?

I am writing a method that can take in a scalar or a list of items.  The first thing that I want to do in the method is to ensure that I am working with a list.  I want to know the most pythonic way of doing that.  Currently I am doing:  def print_item_or_list(list_or_item):     if not isinstance(list_or_item, (list, tuple)):         list_or_item = [list_or_item]      # Now I can consistently work with an iterable     for item in list_or_item:          print item   Is there a more idiomatic way?  Thanks!


Resizing the map item in QGIS print composer without changing scale?

Is it possible to lock the scale in the QGIS 2.0.1 print composer? Every time I resize the map, the scale is adjusted. This makes trying out different map layouts really annoying.


Discrete Math Proofs Involving Real Numbers

I am stuck on these two problems.   $1$. Prove that for every three positive real numbers a, b, and c that   $(a+b+c)*(\frac{1}{a}+\frac{1}{b} + \frac{1}{c}) \ge 9$.   $2$. Prove that for every three positive real numbers a, b, and c that  $a^2 + b^2 + c^2  \ge ab + bc + ac$.  I have tried direct proof and have not gotten anywhere significant. I won't put the work on there since it is way too long and I don't think it will help. There must be some sort of trick involved, but for the life of me, I cannot figure it out.


Some confusion with how commas work in C/C++

I've used SO for a while as a reference, but never asked a question before. I'm currently in a college C++ class and also reading Programming: Principles and Practice by Bjarne Stroutstrup just for my own benifit, as I saw an answer to a question here that really recommended it. We're covering operators at the moment in my class, and I just can't seem to wrap my head around how the comma operator works in a statement. One example is a sample question for the online portion of the class that I keep getting wrong, even if I write a C program and use GDB to get the result. The question is:  Assuming x==16 before the following expression, what is the value of the following expression (not necessarily the value of x)? x++, ++x, x+=x  I'm not interested in the correct answer so much as how to get the correct answer. I've read through a couple answers to similar questions, such as this one , but it seems like I'm missing how this applies when there is actually no assigment operator. Is this the same as saying int y = (x++, ++x, x+=x);  or int y = x++, ++x, x+=x;  or neither? Could someone please explain how the comma operator works, specifically in relation to a statement without an assignment?


Safe to add Debian Testing repos to Ubuntu 20.04

I am running Ubuntu 20.04 LTS. My question is about this: Is it safe to add the Debian Testing Repositories to Ubuntu 20.04? I want to have newer software available and software that is Ubuntu specific only (eg. Unity / Virtualbox). Will my system break? I added this to my /etc/apt/sources.list.d/debian-testing.list, am I missing a repo?: deb http://deb.debian.org/debian testing main # deb-src http://deb.debian.org/debian testing main  deb http://deb.debian.org/debian testing-updates main # deb-src http://deb.debian.org/debian testing-updates main  When I do sudo apt update and sudo apt upgrade, I receive the result that almost 1GB must be downloaded and that many packages "are no longer required". Is this ok? I dont want to remove those packages, as I need them! Is it safe to perform this upgrade? Will I loose my system?


I'm aware of the range iterators in boost, and as for , it seems there should be an easy way of doing what I want, but it's not obvious to me.  Say I want to represent a numerical range, 0 to 100 (inclusive or not), say range(0,100). I would like to do something like:  for_each(range<int>(0,100).begin(), range<int>(0,100).end(), do_something);   where do_something is a functor. This iterators shouldn't have the overhead of having an underneath vector or something like this, but to just offer a sequence of integers. Is this possible with the range implementation in boost? Possible at all with normal, standard STL iterators?


unable to turn on wifi in backtrack 5 r3 while booting from usb

i have hp pavilion 15 with RT3290 802.11bgn WIFI-ADAPTER in my laptop there is a shotcut key to turn on(white light)/off(orange light) wifi which works perfectly on windows.  i installed backtrack 5 r3 on usb drive to use it as a live usb, but while booting in bt5 i cannot use my wifi as its not turning on. The indicator is constantly showing orange light(as it is switched off). Due to this airmon-ng shows nothing like wlan0().  please tell me how to switch on my wifi in backtrack as soon as possible.


How can I record audio while it is playing?

Is it possible to record playing audio on an Ubuntu 16.04 laptop? I mean part of audio the from a video file or playing music.  As requested in comments:  Output of arecord -l  $ arecord -l **** List of CAPTURE Hardware Devices **** card 0: PCH [HDA Intel PCH], device 0: 92HD87B1/3 Analog [92HD87B1/3 Analog]   Subdevices: 1/1   Subdevice #0: subdevice #0   I tried   ffmpeg -f alsa -i hw:0 -t 360 na_re_full.wav   The output was just a blank file (of chosen length) with some random noise. Nothing was recorded from the streaming music :(  $ arecord -L default     Playback/recording through the PulseAudio sound server null     Discard all samples (playback) or generate zero samples (capture) pulse     PulseAudio Sound Server sysdefault:CARD=PCH     HDA Intel PCH, 92HD87B1/3 Analog     Default Audio Device front:CARD=PCH,DEV=0     HDA Intel PCH, 92HD87B1/3 Analog     Front speakers surround21:CARD=PCH,DEV=0     HDA Intel PCH, 92HD87B1/3 Analog     2.1 Surround output to Front and Subwoofer speakers surround40:CARD=PCH,DEV=0     HDA Intel PCH, 92HD87B1/3 Analog     4.0 Surround output to Front and Rear speakers surround41:CARD=PCH,DEV=0     HDA Intel PCH, 92HD87B1/3 Analog     4.1 Surround output to Front, Rear and Subwoofer speakers surround50:CARD=PCH,DEV=0     HDA Intel PCH, 92HD87B1/3 Analog     5.0 Surround output to Front, Center and Rear speakers surround51:CARD=PCH,DEV=0     HDA Intel PCH, 92HD87B1/3 Analog     5.1 Surround output to Front, Center, Rear and Subwoofer speakers surround71:CARD=PCH,DEV=0     HDA Intel PCH, 92HD87B1/3 Analog     7.1 Surround output to Front, Center, Side, Rear and Woofer speakers dmix:CARD=PCH,DEV=0     HDA Intel PCH, 92HD87B1/3 Analog     Direct sample mixing device dsnoop:CARD=PCH,DEV=0     HDA Intel PCH, 92HD87B1/3 Analog     Direct sample snooping device hw:CARD=PCH,DEV=0     HDA Intel PCH, 92HD87B1/3 Analog     Direct hardware device without any conversions plughw:CARD=PCH,DEV=0     HDA Intel PCH, 92HD87B1/3 Analog     Hardware device with all software conversions


Show that if $\sqrt{a}+\sqrt{b}\neq 0$, then   $\mathbb{Q}(\sqrt{a}+\sqrt{b}) = \mathbb{Q}(\sqrt{a},\sqrt{b}),  \forall a,b\in\mathbb{Q}$   It has something to do with $\sqrt{a} = -\sqrt{b}\implies a^2 = b^2$  The inclusion $\mathbb{Q}(\sqrt{a}+\sqrt{b})\subseteq \mathbb{Q}(\sqrt{a},\sqrt{b})$ is obvious  Now take $x\in \mathbb{Q}(\sqrt{a},\sqrt{b})$, that is: $x = c + d\sqrt{a} + e\sqrt{b} + f\sqrt{ab}$. I need to show that this is in $\mathbb{Q}(\sqrt{a}+\sqrt{b})$, that is, $x = g + h\sqrt{a} + i\sqrt{b}$, but I can't get that $\sqrt{ab}$ removed


Can I increase the thickness of an outlined path in Illustrator?

I have downloaded some SVG icons from the web which are all outlined paths. In Illustrator I would like to make those paths thicker. Is there a way to do this? I know when a line is still in stroke-mode you can just adjust the size of the stroke, but once this has been converted to outlines I don't know if this is still possible?


Show that if $a\in R$ is not a zero divisor, then $a$ is unit.

Let $R$ be a commutative ring with 1 which has exactly 3 ideals$\{0\},J$, and $R$. If $a\in R$ is not a zero divisor then show that $a$ is a unit. My attempt: Suppose that $a$ is not a unit. Then, $R.a=R.a^2$. This implies $R.a-R.a^2=0$ i.e. $Ra(1-Ra)=0$. Since, $a$ is not a unit, then $1-Ra\neq 0$. This implies $Ra=0$. This is a contradiction. Anyone please suggest me mistakes in this proof. This is first time for me do solve these types of problems.


I want to switch 3D views in my presentation. I have read in the movie15 package that it is possible with the command: (dice example from movie15.pdf page 16)  \movieref[3Dviewindex=N]{dice}{Click here}   But in this case I have to click with my mouse on a button. It is possible to bind the command on a key or to call the button via a key or combine this with the command \pause ?  Regards,  Grandement.


Can a deterministic model of the universe account for an agent's free will?

If the divergence caused by an act of free will cannot be sustained temporally, then would a material-deterministic universe self-correct? Or am I just changing the frame of reference here to account for free will?   Also, if consciousness directs free will, then is consciousness a derived property above-and-beyond matter which material-determinism can never account for?


Convergence of improper integral $\int_0^{\infty} 1/(1+x^4 \sin^2(x)) \,dx$

I want to determine the convergence of the following improper integral:$$\int_0^{\infty} \frac{1}{1+x^4\sin^2x}\,dx.$$  I have tried comparison tests for the same. $$\int_0^{\infty} \frac{1}{1+x^4}\,dx$$ comes out to be convergent while $$\int_0^{\infty} \frac{1}{1-x^4}\,dx$$ comes out to be divergent. Thus we can't say actually anything about the convergence of this integral from these two comparisons. How can I proceed from here? Please suggest.


I get 1.0 Nm. But how to get 1.0 N.m   \documentclass{article} \usepackage{siunitx} \begin{document} \SI{1.0}{\newton\meter}\\ 1.0~N$\cdot$m \end{document}


Given the group $(\mathbb Z,+)$,then find $n\mathbb Z \cap  m\mathbb Z$ for arbitrary integers $n,m$.  From the definition we have: $$n\mathbb Z=\left\{nx:x \in \mathbb Z\right\}$$ $$m\mathbb Z=\left\{mx:x \in \mathbb Z\right\}$$ On the other hand : $a \in n\mathbb Z$ if and only if $n$ is a divisor of $a$: Proof: $\Longrightarrow$ From the definition $a \in n\mathbb Z$ if $a$ can be written as $a=nx$ for some integer $x$ and follows $n$ divides $a$. $\Longleftarrow$ If $n$ divides $a$ then there is some integer $x$ for which $a=nx$ does hold,from the construction of $n\mathbb Z$ easily follows $a \in n\mathbb Z$.  An element $a$ is in $n\mathbb Z \cap  m\mathbb Z$ if $ a\in n\mathbb Z$ and  $ a \in m\mathbb Z$,follows there is integers $x,x'$ such that :$a=nx$ and $a=mx'$ But I don't know how that helps to construct the elements of $n\mathbb Z \cap  m\mathbb Z$.


Quick check on function composition notation

Does $f^n(x)$ always mean $f(f(f(f(...f(x))))....)$ [n times]? i.e. $f^3(x)$ always means $f(f(f(x)))$? Does $f^0(x)$ mean $x$? [where $f\neq id$]  By always, I mean regardless of whether it's for proofs in computer science or for calculus.  Just want to be doubly sure so I don't make any unfounded leaps in my proofs by induction for computer science.  Apologies for this simian question. Many thanks!


Characterizing non-constant entire functions with modulus $1$ on the unit circle

Is there a characterization of the nonconstant entire functions $f$ that satisfy $|f(z)|=1$ for all $|z|=1$?   Clearly, $f(z)=z^n$ works for all $n$. Also, it's not difficult to show that if $f$ is such an entire function, then $f$ must vanish somewhere inside the unit disk. What else can be said about those functions?  Thank you.


How to eliminate if/elseif/else chain for SObjectType variables?

In a few places I have code of this nature:  private static void myMethod(SObjectType t) {     if (t == Claim__c.SObjectType) xyzForClaims();     else if (t == Account.SObjectType) xyzForAccounts();     else if (t == Contact.SObjectType) xyzForContacts();     ... }   for a great many SObjectTypes. It's a bit ugly, and if called a lot all the if/else if tests could become expensive.  It would be great if this was supported:  private static void myMethod(SObjectType t) {     switch on t {         case Claim__c.SObjectType { xyzForClaims(); }         case Account.SObjectType { xyzForAccounts(); }         case Contact.SObjectType { xyzForContacts(); }         ...     } }   but it isn't. The nearest thing I can think of (short of refactoring into multiple classes) is:  private static void myMethod(SObjectType t) {     switch on String.valueOf(t) {         case 'Claim__c' { xyzForClaims(); }         case 'Account' { xyzForAccounts(); }         case 'Contact' { xyzForContacts(); }         ...     } }   Am I missing a better approach here?


So I wanted to make a 'Ball' class that extends a 'Thing' class. I call the super command for variables that are shared (ex. x,y,sizeX) in the constructor. But when I try to use them (specifically in the jump function) it gives me the error 'MeTryingToMakeAGame.Thing.x is not visible'   Please note that the name of my project is 'MeTryingToMakeAGame.'  class Ball extends Thing {    Ball(int x, int y, int sizeX, int sizeY, int speed, int jumpheight) {     super(x,y,sizeX,sizeY);    }    void jump() {     x-=jumpHeight;   } }  class Thing {   private int x;   private int y;   private int sizeX;   private int sizeY;    Thing (int x, int y, int sizeX, int sizeY) {     this.x = x;     this.y = y;     this.sizeX = sizeX;     this.sizeY = sizeY;   } }


How to pass a variable's value in where clause in java?

I am trying to exexcute a sql query which contains where condition in it. But whenever I execute the query, it is giving me java.lang.NullPointerException. Please help me in this!  I am using mssql and java  dbURL = "jdbc:sqlserver://ip:portnumber;databaseName=abc";         username = "abc";         password = "abc";          //Load MS SQL JDBC Driver         Class.forName("com.microsoft.sqlserver.jdbc.SQLServerDriver");         con = DriverManager.getConnection(dbURL,username,password);          //Creating statement object         st = con.createStatement();         selectquery = "select * from abc where TradeType = '"+tradepair+"'";         rs = st.executeQuery(selectquery);          while (rs.next()) {              getpair = rs.getString("TradeType");             dbTradePair.add(getpair);          }         System.out.println("Pairs :-"+dbTradePair);   When "selectquery" is executed, i get "java.lang.NullPointerException". I hope i am executing sql query in proper format.Can anyone please help me out in this.?


I have if else question but I am not sure the answer is true?

I am running this on Linux:  $ number=4 $ test $number -eq 4 $ echo $? 0 $ test $number -lt 2 $ echo $? 1   Are the results (0 and 1) true ?


Catching exceptions from a constructor's initializer list

Here's a curious one. I have a class A. It has an item of class B, which I want to initialize in the constructor of A using an initializer list, like so:  class A {     public:     A(const B& b): mB(b) { };      private:     B mB; };   Is there a way to catch exceptions that might be thrown by mB's copy-constructor while still using the initializer list method? Or would I have to initialize mB within the constructor's braces in order to have a try/catch?


this TeX-source  \documentclass[a4paper,12pt]{book} \usepackage[usenames,dvipsnames,svgnames,table,x11names]{xcolor} \usepackage{fancyhdr} \pagestyle{fancy} \fancyhead[LO,RE]{} \fancyhead[LE,RO]{{\large{}\color{DarkRed}\rightmark}} \fancyfoot[C]{\thepage} \fancyfoot[LE,RO]{\color{DarkRed}\large{}\leftmark} \fancyfoot[LO,RE]{xxx} \renewcommand{\headrulewidth}{0.14mm} \renewcommand{\footrulewidth}{0.14mm} \setlength\headheight{6mm}  \begin{document} \markboth{A}{B}  Yadda yadda yadda yadda yadda yadda yadda yadda yadda yadda yadda yadda yadda yadda yadda yadda yadda yadda yadda yadda yadda yadda yadda yadda yadda yadda yadda yadda yadda yadda yadda yadda yadda yadda yadda yadda ...  \end{document}   when compiled with XeLaTeX, will cause this output:    as you can see, the red A is not properly aligned with the rest of the footer. naturally i first assumed that was because of the font size, but, surprisingly, changing  \fancyfoot[LE,RO]{\color{DarkRed}\large{}\leftmark}   to  \fancyfoot[LE,RO]{\large{}\leftmark}   gives me not only (naturally) a black A, but also a properly aligned one:    any hints why that should be so? any fixes?


Let $A=\mathbb R[X,Y]$. Is it easy to classify the $\operatorname{Spec}A$? I guess it contains at least $(0)$ and $(p)$ for primes $p\in A$ but maybe some else sets. Is it easy to classify those?  Edit. Yes. I forgot maximal ideals. I think those are given in  I'm not sure but I guess those can be written as $(p,q)$ where $p=X-a$ and $q=Y-b$ for $a,b\in \mathbb R$ or $p$ is linear and $q$ is $X^2+xX+d$ or $Y^2+cY+d$ where $c,d\in\mathbb R$ and $c^2<4d$.


Question: Can anyone shed some light on this formula? I can't find any information on it.  It has three corollaries that I also need to understand:


Sequence in Number Theory, at Madhava 2020

Let $a_{1} , a_{2},....$ be sequence of natural numbers, such that $gcd(a_{m}, a_{n})=gcd(m,n)$ for $m$ not equals $n$. Then show that $a_{n}=n$ for all natural numbers $n$.  I am looking for an alternative approach.   My approach. Suppose $r\geq 2$ then take $m=rn$ thus $n=gcd(rn,n)=gcd(a_{rn}, a_{n})$ thus $n|a_{n}$ now the idea is to show that $v_{p}(n)=v_{p}(a_{n})$ for every prime $p$ dividing $n$ or  $a_{n}$ as $n|a_{n}$ assume that $v_{p}(a_{n})\geq v_{p}(n)$ then take a $s$ large enough and then set $m=p^{v_{p}(a_{n})}s$ then  $p^{v_{p}(a_{n})} | gcd(a_{m}, a_{n})=gcd(m,n)$ thus  $p^{v_{p}(a_{n})}| n$ thus  $v_{p}(a_{n})\leq v_{p}(n)$ thus $v_{p}(n)=v_{p}(a_{n})$ and we are done.


Divisibility proof and its reverse implication

Suppose we have that prove that $mk|n \implies m|n \text{ and } k|n$. This is my idea so far. Since by definition of divisibility $m$ divides $n$ if there exists $q$ such that $n = mq$. Let $q = k$ (from assumption), then $m|n$. I can use similar argument for $k|n$ case. Is my reasoning correct? Also would the reverse implication be true? I think it would be false since i can use same arguement and show that even if $m|n$ and $k|n$ there is a chance that $mk > n$ and thus it wont be true. An example would be 2|4 and 4|4 but $(2\cdot 4) |4$ is not true


How to copy an entire directory except one file in each sub-directory via terminal?

I have a folder named 'Java' which has 20 sub folders ('Day-01' to 'Day-20'). Each sub folder has one or two '.wav' files along with few other files. I want to copy the entire directory except the '.wav' files via terminal. How do I do this?


Active noise cancellation technology measurements

As you know the active noise cancellation technology used in many application such as protection of aircraft cabins and car interiors to reduce engine noise also some headphones use this feature to reduce unwanted ambient sounds.  Actually I don't know the details of how this feature works, but I do know that it has input (microphone) that receives noise waves, control unit that invert the incoming noise waves and output (speakers) to emit inverted noise waves and therefore they will cancel each other.  What I'm not understanding is that If we considered the sound waves are traveling in air, then the inverted noise waves emitted from the speaker will reach the listener before they combine with the original noise waves so they cancel each other while the inverted noise waves are traveling in a solid-media (components of the microphone, speaker, etc.) faster than the original noise waves traveling in air.    I'm I missing something or there is another feature they use to adjust the speed of sound in the active noise cancellation?


What is the correct way to treat operators that has "time" in QM?

I don't know if this question has already been resolved but considering that $i\hbar\partial_t$ is the energy operator, and $\partial^2_t$ is the waves operator (or helmholtz), I can't accept that $t$ itself isn't an operator  What is the argument here that says $t$ is not an operator?


How to move drupal site from remote server to localhost?

I have a drupal site running currently on bluehost. The site is big and I want to test every thing I change on local host before doing it on production site.  Unfortunately, I can not move it to from the remote server to local host.  Can someone give me the basic steps needed to move site from remote server to my local host (aquia dev desktop)?


Solve $x^2+2=y^3$ using infinite descent?

just so this doesn't get deleted, I want to make it clear that I already know how to solve this using the UFD $\mathbb{Z}[\sqrt{-2}]$, and am in search for the infinite descent proof that Fermat claimed to have found.  I've alaways been fascinated by this Diophantine equation $x^2+2=y^3$ in particular ever since I saw it, and I still have no clue how to attack it without $\mathbb{Z}[\sqrt{-2}]$. What's disappointing is that no one else seems interested in the hunt (an elementary proof using infinite descent). I know it's been studied extensively, and there have even been generalizations, such as Mordell's equation. However, I've never seen Fermat's original proof that $(x,y)=(\pm 5, 3)$ is the only integer solution. Obviously, Fermat probably knew nothing of UFD's, which is why I believe there has to be an infinite descent proof like he claimed. Has anyone apart from him actually seen this proof? People mention it all the time, yet I can't find anything about it. As I said, I know that it involved infinite descent, but I've never seen it anywhere and no one seems to have any idea about it.  Does anyone have ideas for this approach? I mean, infinite descent seems more effective for showing a contradiction, e.g. showing there are no solutions. But how could it work here? Also, why isn't it published anywhere in all this time? Could it really be that only Fermat knew his method of descent well-enough to make this problem submit to it?  Thanks!


Creating image with specific latitude/longitude positions using GDAL?

I have an ASCII file with latitude, longitude, and data_val in the following format.  35-13.643782N, 080-57.190157W, 118.6 ...   I have a GeoTiff image file, and I can easily view it.  I want to place a "pin" (can be a dot/flag/star or whatever is easiest) on the image at the specific latitude/longitude position found in the ASCII file.  Here is what I've managed to do so far:  My source image looks like this:  Driver: GTiff/GeoTIFF Files: /tmp/Charlotte SEC 100.tif Size is 16867, 12358 Coordinate System is: PROJCS["Lambert Conformal Conic",     GEOGCS["NAD83",         DATUM["North_American_Datum_1983",             SPHEROID["GRS 1980",6378137,298.2572221010042,                 AUTHORITY["EPSG","7019"]],             AUTHORITY["EPSG","6269"]],         PRIMEM["Greenwich",0],         UNIT["degree",0.0174532925199433],         AUTHORITY["EPSG","4269"]],     PROJECTION["Lambert_Conformal_Conic_2SP"],     PARAMETER["standard_parallel_1",38.66666666666666],     PARAMETER["standard_parallel_2",33.33333333333334],     PARAMETER["latitude_of_origin",34.11666666666667],     PARAMETER["central_meridian",-78.75],     PARAMETER["false_easting",0],     PARAMETER["false_northing",0],     UNIT["metre",1,         AUTHORITY["EPSG","9001"]]] Origin = (-365041.822331817995291,240536.419747152860509) Pixel Size = (42.334586069440391,-42.334898968590878) Metadata:   AREA_OR_POINT=Area   TIFFTAG_DATETIME=2016:06:24 12:46:45   TIFFTAG_RESOLUTIONUNIT=2 (pixels/inch)   TIFFTAG_SOFTWARE=Adobe Photoshop CS5 Windows   TIFFTAG_XRESOLUTION=300   TIFFTAG_YRESOLUTION=300 Image Structure Metadata:   COMPRESSION=LZW   INTERLEAVE=BAND Corner Coordinates: Upper Left  ( -365041.822,  240536.420) ( 82d48'55.43"W, 36d13' 4.92"N) Lower Left  ( -365041.822, -282638.262) ( 82d35'10.11"W, 31d30'17.00"N) Upper Right (  349015.641,  240536.420) ( 74d51'46.40"W, 36d13'26.16"N) Lower Right (  349015.641, -282638.262) ( 75d 4'55.60"W, 31d30'36.99"N) Center      (   -8013.091,  -21050.921) ( 78d50'12.11"W, 33d55'36.35"N) Band 1 Block=16867x1 Type=Byte, ColorInterp=Palette   Color Table (RGB with 256 entries)     0: 255,255,255,255 ...   Here is what I've managed to cobble together in Python:  from osgeo import gdal, osr  src_filename = '/tmp/Charlotte SEC 100.tif' dst_filename = '/tmp/foo.tiff'  # Opens source dataset src_ds = gdal.Open(src_filename) format = "GTiff" driver = gdal.GetDriverByName(format)  # Open destination dataset dst_ds = driver.CreateCopy(dst_filename, src_ds, 0)  # Specify raster location through geotransform array # (upperleftx, scalex, skewx, upperlefty, skewy, scaley) # Scale = size of one pixel in units of raster projection # this example below assumes 100x100 gt = [-365041.822, 100, 0, 240536.420, 0, -100]  # Set location dst_ds.SetGeoTransform(gt)  # Get raster projection epsg = 4269            # http://spatialreference.org/ref/sr-org/lambert_conformal_conic_2sp/ srs = osr.SpatialReference() srs.ImportFromEPSG(epsg) dest_wkt = srs.ExportToWkt()  # Set projection dst_ds.SetProjection(dest_wkt)  # Close files dst_ds = None src_ds = None   But, I can't quite figure out how to place a "red dot" at 35-13.643782N, 080-57.190157W  I'm having to learn some new details here (nomenclature about GIS).


Is there a tool to visualize a filesystem allocation map on Linux?

May you have ever used filesystem defragmentation tools (like Norton SpeedDisk or Piriform Defraggler) on Windows, you have probably seen such a diagram:    It displays a filesystem sectors map, painting (as for this particular example) sectors (sets of sectors actually, to fit the whole partition in the screen) occupied by non-fragmented (contiguous) files in blue, the opposite in red and free sectors in white (and some more colours for some more particular cases which can happen to be of interest). You can click on a "sector" and see what particular files "live" there.  Is there such a visualization tool for Linux?


Copying folders from MTP device using libmtp (over USB)

My question is very closely related to  question:  How do I download complete folders (not only single files) with libmtp from an Android device to my laptop? I'm on Debian 9.  There is a  claiming that you could do this with "mtp-connect --getfolder ..." but there is no such option on my system.


Protonmail-bridge install fails with unmet dependencies ttf-dejavu

I'm trying to install the  (so that I can get and send my Protonmail via Thunderbird) on my new Ubuntu 20.10 install. Unfortunately it states it has unmet dependencies: ttf-dejavu. Anybody got a tip how to correct this? ***@***:~/Downloads$ sudo apt install ./protonmail-bridge_1.4.5-1_amd64.deb  [sudo] password for ***:  Reading package lists... Done Building dependency tree        Reading state information... Done Note, selecting 'protonmail-bridge' instead of './protonmail-bridge_1.4.5-1_amd64.deb' 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.  protonmail-bridge : Depends: ttf-dejavu but it is not installable E: Unable to correct problems, you have held broken packages.


How to search for email of a particular date from years ago in Gmail

There are similar questions and several answers. I tried to follow the methods provided in the answers.  They did not work. So I am going to ask it again with more specifics.  I only knew the date of the email in the in-box in 2012 and the content of it but did not know the exact wording of the subject. Is it possible to find this email?


Can't install Python mysqlclient bindings

I'm running 64 bit Ubuntu 18.04. Although I got it working on my work machine (Ubuntu 18.10 64 bit), I simply cannot get the MySQL client Python libraries working on my personal machine. It's  online that you have to install it "twice": once with pip (the Python bindings) and once with apt (the actual C library). I've just installed a fresh copy of Ubuntu, and executed:  sudo apt install libmysqlclient-dev pip install mysqlclient   I've tried this with both python 2 and python 3 virtualenvs, and I get the same error in both cases:  x86_64-linux-gnu-gcc -pthread -DNDEBUG -g -fwrapv -O2 -Wall -g -fstack-protector-strong -Wformat -Werror=format-security -Wdate-time -D_FORTIFY_SOURCE=2 -fPIC -Dversion_info=(1,4,2,'post',1) -D__version__=1.4.2.post1 -I/usr/include/mysql -I/usr/include/python3.6m -I/home/jack/Code/Skylights/Operator/Env3/include/python3.6m -c MySQLdb/_mysql.c -o build/temp.linux-x86_64-3.6/MySQLdb/_mysql.o     MySQLdb/_mysql.c:37:10: fatal error: Python.h: No such file or directory      #include "Python.h"               ^~~~~~~~~~     compilation terminated.     error: command 'x86_64-linux-gnu-gcc' failed with exit status 1


I'd like to place two charts next to each other and have the y-axis scaled the same in both; that is, I'd like the y axis in this example to be from the minimum value, which is 10, to the maximum, 100, in both charts, so they can be more easily compared visually. Or would the best thing to be to put them in the same plot? If so, how can I separate the data visually?   (I got the code for doing the chart from )    \documentclass{article} \usepackage{pgfplots} \begin{document} \begin{tikzpicture} \begin{axis}[ xlabel near ticks, xtick=data, % Only put labels at positions of data points xticklabels={A,B,C}, % Provide text for labels xlabel={Type}, ylabel={Value}, ] \addplot [     only marks, % No lines between the points     mark=empty, % No marks at the points     error bars/y dir=plus,  % Error bars in the positive direction     error bars/y explicit,  % We provide the values for the error bars     error bars/error mark=empty,    % No markers at the end of the error bars     error bars/error bar style={thick}  % Use thick lines for the error bars ] table [     y error expr=\thisrow{Y2} - \thisrow{Y1} % Calculate the length of the error bars ] { X Y1 Y2 1 10  30 2 20 40 3 30 45 }; \end{axis} \end{tikzpicture} \begin{tikzpicture} \begin{axis}[  xlabel near ticks, xtick=data, % Only put labels at positions of data points xticklabels={D,E,F}, % Provide text for labels xlabel={Type}, ylabel={Value}, ] \addplot [     only marks, % No lines between the points     mark=empty, % No marks at the points     error bars/y dir=plus,  % Error bars in the positive direction     error bars/y explicit,  % We provide the values for the error bars     error bars/error mark=empty,    % No markers at the end of the error bars     error bars/error bar style={thick}  % Use thick lines for the error bars ] table [     y error expr=\thisrow{Y2} - \thisrow{Y1} % Calculate the length of the error bars ] { X Y1 Y2 1 60  80 2 70 80 3 90 100 }; \end{axis} \end{tikzpicture} \end{document}


Why can't the angular momentum vector be parallel or anti-parallel to the applied magnetic field?

This is the excerpt from my book, Arthur Beiser's Concepts of Modern Physics:      An atom with a certain value of $\displaystyle{m_l}$ will assume the corresponding orientation of its angular momentum $\mathbf{L}$ relative to an external magnetic field if it finds itself in such a field. However, we note that $\mathbf{L}$ can never be aligned exactly parallel or anti-parallel to $\mathbf{B}$ because $L_z$ is always smaller than $\sqrt{l(l + 1)\hbar}$ of the total angular momentum.   Why can't $\mathbf{L}$ be parallel to the applied magnetic field? I am not getting the reason showed by the author. Can anyone help me conceive the reason stated above?


How to derive $[x_i, F(\vec p)] = i \hbar \frac {\partial F(\vec p)}{\partial p_i}$

indicates that the following relation is "easily shown": $[x_i, F(\vec p)] = i \hbar \frac {\partial F(\vec p)}{\partial p_i}$, however I'm having some trouble showing it.  I think I'm just messing up the multivariable Taylor expansion (of $F(\vec p)$).  Can one of you walk me through it or link me to site that will?  Thanks.  Edit: Here's what I get (without using $x=i\hbar \frac \partial {\partial p}$ which I haven't proven yet): $$F(\vec p) = F(\vec 0) + \sum^3_{j=1} \frac {\partial F(\vec 0)}{\partial p_j}p_j + \frac 12 \sum^3_{k=1} \sum^3_{j=1} \frac {\partial^2 F(\vec 0)}{\partial p_k \partial p_j} p_j p_k + \dots$$ so $$(x_iF(\vec p) - F(\vec p)x_i)\psi$$ $$= x_i[F(\vec 0)\psi -i\hbar \sum^3_{j=1} \frac {\partial F(\vec 0)}{\partial p_j}(\nabla \psi)_j + \hbar^2\frac 12 \sum^3_{k=1} \sum^3_{j=1} \frac {\partial^2 F(\vec 0)}{\partial p_k \partial p_j} (\nabla \psi)_j (\nabla \psi)_k + \dots]$$ $$- [F(\vec 0)x_i\psi -i\hbar \sum^3_{j=1} \frac {\partial F(\vec 0)}{\partial p_j}(\nabla x_i\psi)_j + \hbar^2\frac 12 \sum^3_{k=1} \sum^3_{j=1} \frac {\partial^2 F(\vec 0)}{\partial p_k \partial p_j} (\nabla x_i\psi)_j (\nabla x_i\psi)_k + \dots]$$ where $$(\nabla x_i\psi)_j=\frac {\partial x_i}{\partial x_j}\psi + x_i\frac {\partial \psi}{\partial x_j} = \delta_{ij}\psi + x_i\frac {\partial \psi}{\partial x_j}$$ and $$(\nabla x_i\psi)_j(\nabla x_i\psi)_k=(\delta_{ij}\psi + x_i\frac {\partial \psi}{\partial x_j})(\delta_{ik}\psi + x_i\frac {\partial \psi}{\partial x_k}) = \delta_{jk}\psi^2 + x_j \psi \frac {\partial \psi}{\partial x_k} + x_k \frac {\partial \psi}{\partial x_j} \psi + x_i^2 \frac {\partial^2 \psi}{\partial x_j \partial x_k}$$ Thus: $$(x_iF(\vec p) - F(\vec p)x_i)\psi$$ $$=  x_i[F(\vec 0)\psi -i\hbar \sum^3_{j=1} \frac {\partial F(\vec 0)}{\partial p_j}\frac {\partial \psi}{\partial x_j} + \hbar^2\frac 12 \sum^3_{k=1} \sum^3_{j=1} \frac {\partial^2 F(\vec 0)}{\partial p_k \partial p_j} \frac {\partial \psi}{\partial x_j} \frac {\partial \psi}{\partial x_k} + \dots]$$ $$- [F(\vec 0)x_i\psi -i\hbar \sum^3_{j=1} \frac {\partial F(\vec 0)}{\partial p_j}(\delta_{ij}\psi + x_i\frac {\partial \psi}{\partial x_j}) + \hbar^2\frac 12 \sum^3_{k=1} \sum^3_{j=1} \frac {\partial^2 F(\vec 0)}{\partial p_k \partial p_j} (\delta_{jk}\psi^2 + x_j \psi \frac {\partial \psi}{\partial x_k} + x_k \frac {\partial \psi}{\partial x_j} \psi + x_i^2 \frac {\partial^2 \psi}{\partial x_j \partial x_k}) + \dots]$$ From here it doesn't look like those higher order terms are all going to cancel out.


What happens to the rest of the 95 percent in quarks?

Quarks are bound by gluons. Gluons have a mass of 0, while mass of quarks is only 5%. Where is the missing 95%?


text mode of a latex symbol \mathfrak s not found

hi i need the text mode of a latex symbol, in a reference pdf doc i found the exact symbol   which is categorized under "text" category. attached the screenshot of the pdf. i need a   different output of \mathfrak s


Which one is better: using ; or && to execute multiple commands in one line?

In tutorials and how-to's I often see commands combined. For instance,  sudo apt-get update && sudo apt-get install pyrenamer   There seem to be four possible connectors: &, &&, || and ;. Though the &  connector is clear to me (it sends a process to the background and leaves the terminal available), it is not clear what the difference is between && and ;. And I did not know of || until Kaya's comment.  The following questions deal with the difference between the two connectors, but do so mostly in the comments:        So here are a number of related questions:   What is the difference between ; and &&?  When should you use them respectively? It would be nice to see some use cases: if I want to run a command and then after it shutdown my computer, which connector should I choose? What are their advantages and dangers?  mentions in a comment to  that a command like cd /somewhere_else; rm -Rf * can have destructive consequences if the first element in the command chain fails, for instance. If relevant, where do they come from?


iterating over a list by a certain number

Suppose I have the following list:  ['id-1213fsr53', 'WAITING', '54-81-24-40', 'world', 'id-343252sfsg', 'WAITING', '54-41-06-143', 'hello']   the list can be subdivided into tuples in the following format:  (id, status, ip-address, name)   So, in other to check the status, I need to iterate over that list by those 4 element tuples, like:  for s in status:    (id, status, ip-address, name) = s # (s is a 4 element list)    # increment s by 4, and continue the loop   How can I achieve such behavior in python?


So, I'm not too physics savvy but I am curious to ask. Is there a finite amount of mass in the universe? or is there more and more being created from somewhere or something? If the universe is infinite, and there's a finite amount of mass, that just seems kinda weird I guess.   Hopefully this isn't too dumb a question...


Why and how do "bigger pixels" make a better picture?

This is going off of today's iPhone 5S announcement, when Phil Schiller said that "bigger pixels" is the key to a better picture.      What does this mean? Is it true or just a marketing ploy?


How to tell if terminal session is running within screen

When running a bash script, I would like to be able to tell if it is running within a screen. Is this possible?  I want this so that .bashrc can set the colour of the command prompt depending on whether the sessions is started within a screen or not.  Discovered this link once mine was answered:


Can Space-Time be Distorted by Anything Other Than Mass?

We know that mass distorts space-time. We also know that Einstein equated mass to energy. We believe that mass is energy and energy is mass.  Can space-time be distorted by anything other than mass? If energy can be transferred from point A to point B in space-time without the "delivery vehicle" of a moving body (mass), must space-time distort in order for that to be possible?


Could Riemann hypothesis solve certainly RSA?

I don't have the background for dealing with Riemann hypothesis but is well known that covers the prime distribution below a specified number.  In order to solve the RSA problem you have to factor the semiprime or calculate the totient itself, that's hard as factoring the modulus.  Question is, could Riemann hypothesis be used to calculate how many coprimes are below the modulus by counting the primes below $n$ and also counting how many products of those primes are below $n$, except those involving $p$ and $q$?  If the previous is negative, can someone clarify why some people say that Riemann hypothesis could "break" RSA?  Thanks for your patience and comprehension.


i want that when the give input in employee_address is Banglore and salary is more than 25000,i get all the details of employee

I have written this code but when i am giving input Banglore and 26000 it is not returning desired condition.  I want to get all employee details when the employee address is Banglore and salary is more than 25000.   import java.util.Scanner;  public class ContactManager {      public static void main(String[] args) {         // TODO Auto-generated method stub          @SuppressWarnings("resource")         Scanner s=new Scanner(System.in);          int employee_id;         String employee_name;         String address;         int mobile;         int salary;         String q;          System.out.println("empolyee_id:");         employee_id=s.nextInt();          System.out.println("employee_name:");         employee_name=s.next();          System.out.println("mobile:");         mobile=s.nextInt();          System.out.println("address:");         address=s.next();          System.out.println("salary:");         salary=s.nextInt();          q = "Banglore";          if(address==q && salary > 25000) {             System.out.println(employee_name);             System.out.println(employee_id);             System.out.println(address);             System.out.println(mobile);             System.out.println(salary);         } else {             System.out.println("Sorry");         }     } }


Estimating the number of bottles in a set

Say a distillery released a limited edition set of whiskey bottles but do not say how many have been released... If the bottles are individually uniquely numbered (bottle No.55, for example), is it possible to estimate the total number of bottles from a sample of bottle numbers?


I haven't touched any default permissions for views in my site but they disappear for anonymous and authenticated users. In permissions 'view published content' is enabled for the mentioned roles. I have even tried rebuilding the permissions but no use.  I also checked permissions in views i.e, Access option in Block Settings and tried all combinations of it's options but still no use.  All other contents (shown through print render($page['content'])) are fine and displays upon logout but it's only the views that disppear.  I'm using Drupal 7.  I don't know what seems to be the problem, and what else to try.


Deallocator of arrays in c++ after modification of pointer

Here is the code  int *p = new int[10]; ... delete[] p;   How does the program know how many elements were there when delete[] was called?  Suppose we inserted the following code in between:  p++;   Will the program try to free one more element? Will it just stop at the 10th element?


Very simple question, does the Flash (Barry Allen) have superhuman strength?  The reason I ask and just as one example of him appearing to be very strong is when he pushes the truck to save the villagers in in Justice League.                                  In my eyes it would take a very strong person to do what he does, such as push a truck that weighs that much as fast as he can run. OR , is it that he is actually slowed down when pushing the truck and the fact that he moves so fast makes us as the audience unable to tell that he is not running at full speed.   What I am trying to say is, that it is all relative, when a normal person pushes a truck, they do so at a slow speed and is very noticeable, but b/c the Flash uses the speed force it seems really fast to us, but in reality he is going really slow in comparison to his normal speed, like a normal human does. So he is in fact not using supper strength , just the speed force?   Or , does the speed force give him super strength?  I am not sure how the speed force works in cases like this, but any clarification would be great.  I would prefer if there was an answer for in the DC Extended Universe, but if not and canon answer on if the Flash has super strength?


How to HTTP POST a Blob to a different domain?

I have some Blob() object. I want to upload somewhere else (a website that handle user upload through forms).  I can put them in a FormData and send them through an XMLHttpRequest object, but then I can't read the ajax response, because I'm blocked by the  of the ajax call.  How can I get around this? Is there some way to do a regular upload without using ajax? Is there a way to deal with that "same origin policy" that will work on recent versions of Chrome and Firefox?  edit: Not sure this is a duplicate: I don't control the server being posted, so I'm not OK with just "setting the same origin policy on both domains".


I have a GET request to a jsp page. The contents of the JSP page is below:  <%@page language="java" import="java.sql.*,java.util.*" %> <%@page import="javax.servlet.*, java.util.*,java.util.Date, java.text.*"%> <jsp:useBean id="workM" class="test.concept" scope="page" /> <jsp:useBean id="userM" class="test.learning" scope="page" /> <jsp:useBean id="checkM" class="test.check" scope="session" /> <% if (checkM.checkUser()) //For auto loading user's most used search engine. Note: Only if the difference between top two is very big {     String user_id = checkM.getUser();     ResultSet RS6=workM.executeQuery("select top 1 searchEngineUsed,count(*) as number from UserSearchEngineSearch where user_id='"+user_id+"' group by searchEngineUsed order by number desc;");     while (RS6.next())     {          String name = RS6.getString("searchEngineUsed");         if (name.equals("google"))         {             out.print("1");         }         else if (name.equals("yahoo"))         {             out.print("2");         }         else if (name.equals("bing"))         {              out.print("3");         }         else if (name.equals("baidu"))         {              out.print("4");         }         else if (name.equals("yandex"))         {             out.print("5");         }         else if (name.equals("askcom"))         {             out.print("6");         }         else //by default just display google         {             out.print("1");         }     } } else //user not login {      out.print("1"); } %>   However, the content of the GET webpage is contains 5 lines of new line followed by a 4 (which means "baidu" was selected). How do I remove the 5 lines of new line spacing?


Blob is not a Valid UTF-8 String - Only after "–"

I created a CSV parser that parses CSV's from static resources.   I am returned with a Blob is not a Valid UTF-8 String error when parsing the character: "–" different from "-". The "–" is apparently still a unicode character:  .   The sheet is being saved as UTF-8 CSV and the data was exporting from Salesforce using data loader 38.0.   Can someone explain why this character is returning the Blob is not a Valid UTF-8 String even though the character appears to be a UTF-8 character?   CSV:     HEX with bad character:   00:00:00:XXX USER_DEBUG [XX]|DEBUG|4f626a6563742c437573746f6d5f446563696d616c5f5f632c437573746f6d5f5f632c42726f6b656e5f4669656c645f5f630d0a4d794f746865724f626a6563745f5f632c312c412c5858209620546869732068797068656e206973206275737465640d0a   HEX without bad character:   00:00:00:XXX USER_DEBUG [XX]|DEBUG|4f626a6563742c437573746f6d5f446563696d616c5f5f632c437573746f6d5f5f632c42726f6b656e5f4669656c645f5f630d0a4d794f746865724f626a6563745f5f632c312c412c58582020546869732068797068656e206973206275737465640d0a   ||||||Update:   Upon opening the file in Notepad, it appears the file was encoded in ANSI, even though excel states the file is encoding in UTF-8 when I open it. After saving at UTF-8 in Notepad, that resolved the symbol issue.   This did not work:     This did:     With this being said are there any capabilities within the blob class or another class to convert the file from ANSI to UTF-8 within Salesforce as opposed to relying on customers to ensure the file is in the correct encoding?


Flying Turkish Airlines, what are credit card rules?

I have return tickets flying out of SFO on Turkish airlines for the whole family. The credit card I used to book the tickets has since been replaced by the bank with a new card.   In order to board, can I present the new credit card (same name) at the checkin counter, or must I present the original credit card (which is no longer valid and has been discarded)?  By 'discarded' - I mean cut up and thrown away in trash. It was no longer valid, since it was replaced with a new card. So can I use the new card to travel on a booking that was made using the original card?    The new card has a new number; and the ticket was purchased through an agent.


Is there an Apex code formatting standard?

Are there any documents out there that talk about proper formatting in apex? I have not been able to find too much on this subject (maybe my google skills are weak).  Some examples:   //comment with no space  // comment with space   if (something == something) { String foo = "keep it in one?"; }   if(something==something)       String foo="Or do it this way?";   I realize that this is probably based off of the user's preference, but I'm wondering if there is a standard to do things a certain way in apex? Would writing the syntax one way or the other affect the performance?


Custom item in context menu when I right-click on folder

Has this been asked before? I want a custom item in the context menu when I right click on a folder. I know you're supposed to do it through the registry, but I don't know how. I will manage what it executes. Thanks.


In CWM Mac Lane uses the term $\mathbf {ENS}$  for a category having as objects the subsets of a given set and as morphisms the functions from these sets to these sets. What is abbreviated by the letters ENS?


So when I do sudo -s in my terminal I get into root mode, and after I do whatever I wanted to do, I do 'exit'. Now If I do 'sudo -s' again, the terminal does not ask for any password and enters root mode directly. Is this a normal behavior? I use ubuntu 16.04.  as I remember this was not the case 3-4 days ago,I think something has changed today,cant figure out what.  If this is not normal, how do i rectify it.


Why are Vandermonde matrices invertible?

A Vandermonde-matrix is a matrix of this form:  $$\begin{pmatrix}  x_0^0 & \cdots & x_0^n \\ \vdots & \ddots & \vdots \\  x_n^0 & \cdots & x_n^n \end{pmatrix} \in \mathbb{R}^{(n+1) \times (n+1)}$$.  condition ☀ : $\forall i, j\in \{0, \dots, n\}: i\neq j \Rightarrow x_i \neq x_j$  Why are Vandermonde-matrices with ☀ always invertible?  I have tried to find a short argument for that. I know some ways to show that in principle:   rank is equal to dimension all lines / rows are linear independence determinant is not zero find inverse   According to , the determinant is  $$\displaystyle V_n = \prod_{1 \le i < j \le n} \left({x_j - x_i}\right)$$  There are two proofs for this determinant, but I've wondered if there is a simpler way to show that such matrices are invertible.


For every point $(a,b)\in \mathbb{R}^2$, such that $a + b = 1$, find the limit: $$\lim_{(x,y)\to(a,b)}\frac{y\sin\pi x}{x+y-1}$$ We have three cases, $a = 0 $ and $ b=1,$ $b=0$ and $ a=1$, and finally $a, b\not\in\{0,1\} $. I solved the first case, there was no limit, but I have no idea how to tackle the rest of them.


When I bought a new laptop it had 4 GB RAM. Then after 1 month I added 4 GB RAM in the second slot. And it shows 7.88 GB RAM usable. After some time it showed 6.4 GB RAM usable and 1.4 GB hardware reserved. So I formatted and installed Linux. Now in Linux it shows only 6.2 GB RAM usable. I have talked to Dell customer care. And read many forum. I searched Google a lot, but nothing helped me.


I was playing in one of the snapshots for 1.9 in my survival world i think it was 15w49b and all the sudden my game crashed so i load back my launcher and the worlds not there but when i went to my saves folder its still there and im not sure why it wouldn't be showing i have a backup but it's from like 2 months before it crashed so it's not going to do me any good. Here is a picture of what the inside of my world folder looks like  please help!


Say I've got the following pipeline:  cmd1 < input.txt |\ cmd2 |\ cmd4 |\ cmd5 |\ cmd6 |\ (...) |\ cmdN > result.txt   Under certain conditions I would like to add a cmd3 between cmd2 and cmd4. Is there a way to create a kind of conditional pipeline without saving the result of cmd2 into a temporary file? I would think of something like:  cmd1 < input.txt |\ cmd2 |\ (${DEFINED}? cmd3 : cat ) |\ cmd4 |\ cmd5 |\ cmd6 |\ (...) |\ cmdN > result.txt


How do I fix unexpected inconsistency run fsck manually without prompt?

It says:  /dev/sda1: UNEXPECTED INCONSISTENCY; RUN fsck MANUALLY. (i.e., without -a or -p options) _  Then it only stays like that, I can't even type something to FIX it. What can I do because it doesn't show any prompt so that I can solve the problem. How can get the prompt.


I just installed Ubuntu 12.10 (amd64), and want to install a recent version of MySQL 5.6.  If possible, I would like to install (not upgrade) it the "Debian Way' (i.e., using apt-get or dpkg).


How to convert a normal distribution to a truncated normal distribution?

Is it possible to transform a normally distributed variable into one that defined by a truncated normal distribution? I am currently using a KL transform to generate Gaussian random fields. I would like to transform these fields into truncated normally distributed fields with a specified mean and std. As I am using these random fields with the Polynomial Chaos Expansion (PCE) method to compute the low order statistics of the system, I don't know it mathematically correct to simply truncate my Gaussian fields. For context, at the moment I am able to transform the Gaussian fields into  uniformly distributed fields in the range [a,b] by using the following transformation: $x_{uni} = a + (b-a)\phi[x_{norm}]$ where $\phi[\cdot]$, is the gaussian cumulative distribution function. Is there a similar transformation that I can apply to convert the Gaussian field into a truncated normal field? Thanks in advance!


So, I understand how to target a specific menu using the following to add a custom code.  <?php  wp_nav_menu(  array(   'menu' => 'Project Nav',   // do not fall back to first non-empty menu   'theme_location' => '__no_such_location',   // do not fall back to wp_page_menu()   'fallback_cb' => false  )  );  ?>   Question I have is the following.  Let say I have a menu called "primary". Within this menu, there are 4 menu items (picture below).    One of the items is called "Profile".  I want to replace the word "Profile" with the following code which shows user profile photo instead of the word "Profile".      <?php global $my_profile; ?>     <?php if (is_user_logged_in()) : ?>
<?php echo get_avatar( get_current_user_id(), 64 ); ?>
     <?php endif; ?>   So, the final result would look like this:    Now, how can I specifically target a menu item title?   EDIT:  So, I got the following based and I am not sure why it is not working.  function nav_replace_wpse_189788($item_output, $item, $args) {  //var_dump($item_output, $item);  if( $args->theme_location == 'primary' ){   return $items;     if ('royal_profile_menu_title' == $item->title) {     global $my_profile;      if (is_user_logged_in()) {        return '
'.get_avatar( get_current_user_id(), 64 ).'
';         }     }   }    return $item_output;  }  add_filter('walker_nav_menu_start_el','nav_replace_wpse_189788',10,2);   Here is my logic. First target the "primary" menu, then look for item title "royal_profile_menu_title" then replace the word title with the output  (My menu title is "royal_profile_menu_title": Picture below)   Any


Prerequisites for classical mechanics by Susskind

So I am an undergraduate in Electrical Engineering. We had a course on Physics in our freshman year which is equivalent to Classical Mechanics I as taught in MIT. I am interested in studying advanced classical mechanics (which includes Lagrangian formulation and other stuff) as equivalent to Classical Mechanics lecture by Susskind. I wanted to know are they any prerequisites which I should know about before taking this course.   In general what are the prereqs for this course?


In the minted package, how do I enforce straight single quotes?

Basically I want  \mint{python}|'banana'|   to produce straight single quotes, rather than the curly ones it normally produces (in pdflatex).


Is there any way to run file explorer as administrator under Windows 10

After install Windows 10, it seems that I lost the ability to run explorer.exe as administrator with a user in administrator group.   The reason I want to do that is, in our team's development environment, we are using a C# exe to do some environment configuration which will start command prompt under administrator mode and subst a drive. As a result those substed drives are not visible within the file explorer since it is run not as administrator. That will be kind of inconvenience and sometimes make mistakes.   I was able to run explorer.exe from task manager with the option "create with privileges" checked and then I can see all the drives in explorer. But now this is not working anymore.   I knew there are other options to workaround this workflow, but just want to make sure that if it is now totally impossible under Windows 10?  Any comment is appreciated.


How to show that $\displaystyle{\cot z-\frac{1}{z}}$ is bounded on the given circle

$$f(z)=\cot z - \frac{1}{z}=\frac{z \cos z - \sin z}{z ~ \sin z}$$ having poles at $z=n \pi$ with residue $1$ at each pole. Also $f(z)$ has a removable singularity at $z=0.$ All these are asked to calculate and I've done that. If $C_N$ is the circle enclosing all the poles having the center at the origin and radius $R_N,$ how can I show that $f$ is bounded on $C_N$ for a suitable $R_N$ ?  Any help is much appreciated.   Edit: Note that


Is there a complete list of defaults / plist settings for the dock?

I know that most of the defaults settings for macOS components are probably hidden or undocumented, but I'm curious if there is someone who has compiled a complete list or if there is a way to discover what options are available?  In particular, I've become annoyed by how quickly the dock seems to follow my mouse to my 2nd monitor (but seems to delay coming back to primary), so I'm looking to see if there are any settings which could influence the behavior of this.


Are there tools that I can use to obtain a snapshot of terminal or pty state?

Please stop marking this question as a duplicate, it's not a duplicate. Thanks. Consider the sequence of a, followed by \x1b[D ("cursor back"), followed by b. This would produce an output of just b.  I am looking to experiment with and create TUI applications (examples: less, vim), e.g. using ncurses style libraries or with raw application of escape sequences. I've found that as a tmux user, tmux offers a very useful capture-pane feature which could be a good basis for a test framework that can use this as a form of "screenshot" functionality for test verification purposes. For example, rather than manually testing the output for correctness and, say, establishing a test that runs the program under test for a specific window size and then comparing the output with a rigid string compare, I could instead run it under tmux through a wide range of window dimensions and check the rendered state to satisfy requirements in a practical way. Anyway, the point is that this seems to be the only way I know of to "resolve" a terminal byte stream into a terminal screen buffer. As great and versatile as tmux is, I'm somewhat hoping for a tool that provides this specific capability. Since I read some more today about what ptys are and how they work , it does seem to me that this aspect of the system is in the purview of the terminal emulator, and something like tmux is rather unique in that it has to do it while not being a GUI application (which is a plus here).


In Ksh shell, my below command runs okay. test "$(($(date +%W)%4))" -eq 2 && echo "yes" > /u/crmprod/test  but it doesn't run in crontab using below. How to solve this please? 34 00 * * 2 test "$(($(date +%W)%4))" -eq 2 && echo "yes2" > /u/crmprod/test


What is the error in this fake-proof of the complex number i?

The error is from the 3rd step to the 4th step. But why is this an error? Can't $i$ be interchangeable with $\sqrt{-1}$?  $-1 = i\cdot i = \sqrt{-1}\cdot \sqrt{-1} = \sqrt{(-1)(-1)} = \sqrt{1} = 1$


Do different versions of the same feat stack?

The reason I ask this is because there are several different versions of the Spell Sniper feat, and all of them double range for ranged spells with attack rolls. Most feats that are like this specify they don’t stack, but not Spell Sniper.  I'm not asking how you'd rule it, I'm asking if the base rules allow it. I can't find anything on this. I'm hopeful because this would mean that a sorcerer + warlock could eventually have a range of 9600 feet with eldritch blast.


Klein's $4$ group, $\{1\}$ and $A_4$ are three normal subgroups of $A_4$. I want to know about any other normal subgroups of $A_4$. Do these exist?


My should-be-cool table has a malicious dot

This table is meant to have three sections that appear to float: the to row, the left column, and the body. This is the best I could do; however, when zoomed in near the top-left corner, you can see an undesirable dot. Any fix I can think of makes things worse. Do I have to live with this dot or is there something I can do? \documentclass[12pt]{article}  \usepackage{fontspec} \setmainfont{Arial}  \usepackage{hhline}  \begin{document}     \begin{tabular}{|l||c|c|c|}         \hhline{~|---}         \multicolumn{1}{l|}{} &  &  &  \\         \hhline{-::===}          &  &  &  \\         \hhline{-||---}          &  &  &  \\         \hhline{-||---}          &  &  &  \\         \hhline{-||---}     \end{tabular} \end{document}  Please note that I am unable to take screenshots, so…


Induction proof. Explain in detail why it’s incorrect

Can somebody give a clear explanation why this is incorrect? thank you     Theorem 1:   All positive integers are equal.   Proof: We show that any two positive integers are equal, from which the result follows. We do this by induction on the maximum of the two numbers. Let $P(n)$ be the statement “if $r$ and $s$ are positive integers and $\max \{ r, s \} = n$ then $r = s$.”  Clearly $P(1)$ is true. Suppose that $P(n)$ is true and let $r$ and $s$ be positive integers whose maximum is $n + 1$. Then $\max \{ r − 1, s − 1 \} = n$. By the inductive hypothesis, $r − 1 = s − 1$ and hence $r = s$. Thus $P(n + 1)$ is true.  The result is now proved by mathematical induction.


I´m having problems with url parameters (req.requestURI) in my test class.  This is my code.  REST CLASS:  @RestResource(urlMapping='/Accounts/*') global class StoreController {       @HttpGet     global static String getAccounts() {           integer pageNumber=integer.valueof(RestContext.request.params.get('page'));         string  ptime=RestContext.request.params.get('time');         string  hash=RestContext.request.params.get('hash');      }   REST TEST CLASS:  @isTest private class StoreControllerTest {      static testMethod void testGet() {       //do request     RestRequest req = new RestRequest();      RestResponse res = new RestResponse();      req.requestURI = 'https://dev-my-my.cs14.force.com/mine/services/apexrest/Accounts?page=0&time=1390296387&hash=1wer2547';         req.httpMethod = 'GET';     RestContext.request = req;     RestContext.response = res;          String results = StoreController.getAccounts();      } }   When i run test class i get the error:  System.NullPointerException: Argument 1 cannot be null    for line :  integer pageNumber=integer.valueof(RestContext.request.params.get('page'));   Looks like parameters are not taken from url ''  when i run the test class.Please can you help me with this?


On an AC-DC adapter, what is the use of the mA number printed on it?

releted to  I wonder what the use of the number of mA printed on an AC-DC adapter/converter means.  I am charging a Bluetooth headset, which came with a AC-DC adapter, over USB using a "DIY-hybrid-cable" and it is working. The original AC-DC plug (which I've cut) has 450mA printed on it and the USB standard AC-DC plug, to which my "hybrid-cable" is connected, has 1.0A printed on it.     Does the mA number has any relevance? Why? I feel I am missing important knowledge.


Comma placement for a parenthetical after "and"?

I find myself writing sentences like this often:     A. Here's a summary of our discussion, and if needed, more detail can be found at www.website.com.   I'm not sure if the commas there look quite right. Assuming that "if needed" is in fact a parenthetical, then I'd thought it needed a pair of commas (or parentheses, em dashes) to separate it:     B. Here's a summary of our discussion, and, if needed, more detail can be found at www.website.com.   This continues to separate the two independent clauses with a comma (the one after "discussion"), but that's a lot of commas. Alternately, there's this one.     C. Here's a summary of our discussion, and if needed more detail can be found at www.website.com.   But this reads awkwardly to me: it feels as though there's a "you" missing after the "if."  I'm looking to understand the core issue with comma placement for this particular sentence structure. So, here are my questions:    Is "if needed" a parenthetical statement?  Without rewording the whole sentence, what comma placement is grammatically best?


Is there a way to "rescue" mesh that has very bad topology?

I have a mesh with tons of ngons, non-manfold stuff, poles, and a decent amount of tris. Should I just give up on the mesh, or can I somehow rescue it?


I try resize my devtmpfs size, by add a row to /etc/fstab.  This is my fstab file :  # <file system> <mount point>   <type>  <options>       <dump>  <pass> # / was on /dev/mmcblk0p2 during installation UUID=6e7b65b0-f9ce-4a0d-97fd-73374d0a8492 /               ext4    errors=remount-ro 0       1 # /boot was on /dev/mmcblk0p1 during installation UUID=26c4e594-31fe-49ab-844a-a2e7e195ea36 /boot           ext2    defaults        0       2 0       0 # Define devtmpfs size udev /dev   devtmpfs  rw,relatime,size=102400k,nr_inodes=217992,mode=755  1  0   But during reboot machine I get these rows :  EXT4-fs (mmcblk0p1): mounting ext2 file system using the ext4 subsystem EXT4-fs (mmcblk0p1): mounted filesystem without journal. Opts: (null) [....] Mounting local filesystems...mount: udev is already mounted or /dev busy failed.   What I make wrong ?


Boolean Not Working The Way I Think It's Supposed To

So When I do a Boolean Modifier on the Sphere, and select a torus surrounding that sphere, I expect it to do what it first did in the middle, but it just cuts a hold straight through it.


"Open in browser" crashes when Android app is set as default

This is a follow-up to .     When I click a link to an SE site in the Android app, it gives me an "open with" pop-up that has two options:         Chrome   Stack Exchange         I can then choose to open SE posts like this "Just once" or "Always."      The problem is that when I set the SE app to "always," and I click "open in browser,"   Except, the app crashes when trying to open it in browser.  LogCat (just right after selecting "Open in browser")  01-22 18:03:36.354: E/AndroidRuntime(16064): FATAL EXCEPTION: main 01-22 18:03:36.354: E/AndroidRuntime(16064): Process: com.stackexchange.marvin, PID: 16064 01-22 18:03:36.354: E/AndroidRuntime(16064): java.lang.NullPointerException: Attempt to invoke interface method 'int java.util.List.size()' on a null object reference 01-22 18:03:36.354: E/AndroidRuntime(16064):    at com.stackexchange.marvin.utils.Helpers.getNonMarvinViewIntent(Helpers.java:452) 01-22 18:03:36.354: E/AndroidRuntime(16064):    at com.stackexchange.marvin.ui.question.QuestionDialog$1.onClick(QuestionDialog.java:39) 01-22 18:03:36.354: E/AndroidRuntime(16064):    at com.android.internal.app.AlertController$AlertParams$3.onItemClick(AlertController.java:1108) 01-22 18:03:36.354: E/AndroidRuntime(16064):    at android.widget.AdapterView.performItemClick(AdapterView.java:310) 01-22 18:03:36.354: E/AndroidRuntime(16064):    at android.widget.AbsListView.performItemClick(AbsListView.java:1145) 01-22 18:03:36.354: E/AndroidRuntime(16064):    at android.widget.AbsListView$PerformClick.run(AbsListView.java:3066) 01-22 18:03:36.354: E/AndroidRuntime(16064):    at android.widget.AbsListView$3.run(AbsListView.java:3903) 01-22 18:03:36.354: E/AndroidRuntime(16064):    at android.os.Handler.handleCallback(Handler.java:739) 01-22 18:03:36.354: E/AndroidRuntime(16064):    at android.os.Handler.dispatchMessage(Handler.java:95) 01-22 18:03:36.354: E/AndroidRuntime(16064):    at android.os.Looper.loop(Looper.java:148) 01-22 18:03:36.354: E/AndroidRuntime(16064):    at android.app.ActivityThread.main(ActivityThread.java:5417) 01-22 18:03:36.354: E/AndroidRuntime(16064):    at java.lang.reflect.Method.invoke(Native Method) 01-22 18:03:36.354: E/AndroidRuntime(16064):    at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:726) 01-22 18:03:36.354: E/AndroidRuntime(16064):    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:616)   I suspect it's related to , but not sure.  Specs:   Device model: Nexus 5 Android version: Android 6.0.1 SE app version: 1.0.82 (beta) Installed browser: Chrome 47.0.2526.83 (latest at current writing)


Prove that the following polynomial has no multiple roots

Prove that the following polynomial $$p(x) = \sum_{k=0}^n x^k$$ has no multiple roots  Hint: consider the polynomial $(x-1)\times \sum_{k=0}^n x^k$  I have tried finding the derivative of the polynomial and trying to reach a contradiction by supposing there is a root such that p(x) = p'(x) = 0 but I can't reach any conclusions. The hint leads me nowhere, I don't know how to use that information  Thanks in advance


How to create virtual block devices from file?

Let's have unknown disk drive uncompressed raw image (created for example by dd if=/dev/sda of=image) in single file. If we knew the disk layout, we could mount particular partitions from the file as the loop devices via skipping some offsets. Let's suppose we don't know the layout. Can we somehow "mount" the whole disk drive image, which process would create virtual block devices according to the disk layout? For example having 2 partitions in the image would result in creating 3 devices (/dev/sdx, /dev/sdx1, /dev/sdx2). We could then mount such devices as usual.


Proof of for-all / there-exists "negation"?

I was recently playing around with delta-epsilon proofs for limits, which, when true, have the following form:  $$\forall \epsilon > 0, \exists \delta>0 , p \implies q$$  Where $p = (\text{for all $x$, }0 < |x-a| < \delta)$ and $q = (|f(x) - L| < \epsilon)$ (this isn't directly relevant to my question, just showing what these... events? Statements? Propositions? I don't know the word -- what they look like).  I didn't include the actual thing being shown true above about $f(x)$ (I don't know where it'd go), but the more informal statement is "The limit of $f(x)$ as $x$ approaches $a$ is equal to $L$ if for all $\epsilon > 0$ there exists a $\delta>0$ such that for all $x$, $0 < |x-a| < \delta$ implies $|f(x)-L|<\epsilon$."  I wanted to prove a scenario where the limit was knowingly false ahead of time, and it took me some time to notice that this was the new statement to show in order to prove a limit false:  $$\exists \epsilon > 0, \forall \delta>0 , p \not\implies q$$  Now it's something more like, "The limit of $f(x)$ as $x$ approaches $a$ is not equal to $L$ if there exists an $\epsilon > 0$ such that for all $\delta>0$, for all $x$ $0 < |x-a| < \delta$ does not imply $|f(x)-L|<\epsilon$."  My questions:   Is there a formal proof or understanding as to why negation changes for-alls into there-exists and vice-versa? I'm a little unsure why De Morgan's laws don't seem to apply between the "statements" (apologies for my imprecision, I don't know what any of these things are called). For instance could we not think of it as $(\forall \epsilon > 0) \land (\exists \delta>0) \land (p \implies q)$ as in, all of these things must be true -- the epsilon condition must be true AND the delta condition must be true AND $p$ must imply $q$. Then if we negate it, why doesn't it become something like $(\exists \epsilon > 0) \lor (\forall \delta>0) \lor (p \not\implies q)$ as in, the epsilon condition must be true OR the delta condition must be true OR $p$ must not imply $q$. I know intuitively this isn't the case but I don't know why, since the original statement makes sense to me as a chain of ANDs but the negation... still feels like it should be a chain of ANDs whereas De Morgan's laws normally have you invert them to ORs.


I have:  public class MyUserControl : WebUserControlBase <MyDocumentType>{...}   How do I get the TypeName of MyDocumentType if I'm in another class?


Is it now impossible to build a reputation on Stack Overflow?

I recently tried to answer I few questions on Stack Overflow. By doing so, I noticed that almost every single time people post a wild draft and edit the post afterwards. It seems to be a common practice to include everything that might be helpful from other answers as well. It has the feeling that it is not about sharing knowledge and help people - it is all placing your answer on top - and ultimately about reputation. I am definitely not the only  one .  Moreover, I noticed that some classic questions like char[] or String for passwords  long time ago. Now a few people generate more and more reputation points from these answers.  Don't get me wrong. Whenever I have a problem I know that I can find the answer probably on Stack Overflow - or at least someone who knows the answer.  However, am I simply too late?


Short story about underwater aliens with 2-stage life cycle and 3 kinds of "gametes" who combine to make adults

A while back I read a short story about this alternate dimension story where these aliens had figured out how to trade resources with our earth by shunting materials across dimensions...on earth's side their material manifests as tungsten, I believe, although I remember there were side effects of the shunting that were potentially dangerous. I think they had also figured out how to communicate...I can't remember a lot of the details. The aliens were some kind of underwater creature but it doesn't go into a lot of detail about their immediate environment. The story describes them floating around but omits other details.  Most of the story surrounded these 3 sort of "gamete" children/adolescents. These aliens had three types of young that, when "joined" after maturity (a sort of pseudo-sexual union of the 3 types of gametes), formed an adult. After a trial period of temporary joinings the gametes fuse permanently and complete the life cycle (I can't remember if the adults produce gametes asexually or what). The adult alien's consciousness is wholly independent of the gametes, who lose consciousness when joining and disappear as independent entities once joined. Adults keep the truth of "joining" secret from the young, who believe they merely grow into adults individually.  A main feature of the plot is that the particular gametes of the story have heard about a "new adult" that was some sort of genius and who was up to no good with respect to trading with the human world, and they never discover that the "new adult" is actually the product of their own joining. The last time they fuse (for good), the reader discovers that they, in fact, are this "new adult" they've been learning about and trying to sabotage.  Anyway, I was trying to describe the plot to my fiancee and I can't remember the title or the author, and searching for it on the internet is not fruitful.


How to integrate $\int x\sin {(\sqrt{x})}\, dx$

I tried using integration by parts twice, the same way we do for  $\int \sin {(\sqrt{x})}$ but in the second integral, I'm not getting an expression that is equal to  $\int x\sin {(\sqrt{x})}$.  I let $\sqrt x = t$ thus, $$\int t^2 \cdot \sin({t})\cdot 2t dt =  2\int t^3\sin(t)dt = 2[(-\cos(t)\cdot t^3 + \int 3t^2\cos(t))] = 2[-\cos(t)\cdot t^3+(\sin(t)\cdot 3t^3 - \int 6t \cdot \sin(t))]]$$  which I can't find useful.


$\{e^{ik}\mid k\in \Bbb N\}$ is dense in $S^1$

I wanted to {$e^{ik}|k\in N$} Is dense in $S^1$ My Attempt:  On the contrary, assume that it is not dense in $S^1$. So there exists a point in $S^1$ which is not a limit point, say $e^it $ for some $t\in R$ That means $\exists \epsilon >0$ such that $\forall k\in N ,|e^{ik}-e^{it}|>\epsilon $ that is $|e^{i(k-t)}-1|>\epsilon $ I was expecting some contradiction to occur. But I am not able to see. Any help will be appreciated


Does having 2 memory of 512 MB improve performance over a single 1 GB Mem?

Besides , I want to upgrade my RAM of my Laptop which is a Compaq Presario v 2000 model . I already have a 512 MB RAM in it and the performance of the Laptop is decent for my browsing work etc . Should I go for a new 1 GB RAM or would a additional 512 MB ( new ) give good performance ? I dont want to spent much on old laptops , just need decent performance . Just want to know ur opinion .


Two pairs from a standard deck of 52 cards

You are dealt $5$ cards from a standard deck of 52 cards. A standard deck of 52 cards has 13 ranks in each of four suits.) How many ways can you be dealt the $5$ cards so that they contain two cards of one rank, two cards of another rank, and a fifth card of a third rank? We say that such a hand has two pairs. For example, the hand QQ225 has two pairs. (Assume that the order of the cards does not matter.) I'm not sure how to start.. Seems like permutations, but I'm not sure. Any help would be appreciated, and thank you in advance.


What would you say vs. How would you say

I want to ask a question what someone would say in or about a certain situation.  Here's a question.  "How would you say when you had a great time?"  And I'm expecting the answer,  "It was fun."  Should I say "How would you say when ~?", "How would you say it when~?" or "What would you say when~?" Which one sounds better?


Why do arrival and departure cards exist?

When I clear passport control in every country I've visited so far, one of the first things the officer does is scan my passport and pull up my info on his computer.  He then collects an arrival card from me that contains exactly the same info as what's in my passport, plus some info about my trip (duration of stay, address, etc.).  When I go to leave the country, I am (usually) required to then submit a departure card, which – unlike the arrival card – is 100% redundant with what's in my passport.  These pieces of paper are considered so important that travelers are not permitted to enter/leave the country without them.  What is their purpose, if most (all?) of the information on them can be collected from the passport?


Integration by Substitution: substituting variable with complex functions

I'm learning integration by the method of substitution. While doing sums, I encountered a case in which I got this expression in the denominator: $$\sqrt {a^2 + x^2 } $$  Now, I wanted to substitute  $x$ as $a i \sin \theta$ where $i = \sqrt  {-1} $. My idea was to take $a$ outside the root, and obtain $\cos \theta $ from the root.  Although I've reached the answer, I couldn't find any complex function substitution example in my book, which makes me wonder whether my substitution is correct.  Can I substitute a variable with a complex function in integration?


Why long int and int has same maximum value in my computer

I am learning C programming language and I stumbled on something while playing with some code. I was led to believe that an int has 4 bytes, and therefore has a maximum value of +2147483647(The problem was the long int). But when I tested that in my computer with GCC compiler, the result is different. I tried the same with long int, It gave the same maximum size. Can you please expain this behavior to me ? Other questions didn't help me understand the underlying reason. Let me add some examples I tried to find out what is happening.    Code sample:  #include <stdio.h> #include <limits.h> int main(void){      int a = 1, i;      printf("int limit: %d\n", INT_MAX);     printf("long int limit: %li\n", LONG_MAX);     for (i = 0; i < 10; i++){         a *= 10;         printf("A: %d\n", a); // To see when a is corrupted.     }         return 0; }


Is it ok to store many null values in my table?

I am creating a table for bookmarks in my database as the following picture, the bookmark can be on a place or an event,  then it can be be regular user or by business user:  e.g.  business user with id (1) made a bookmark on place id (1) e.g.  business user with id (2) made a bookmark on event id (6)  in such a way my table contains the following indexes to allow only for single bookmark for place or event by any user.  Table structure with indexes   but then the table looks like this when I insert values for bookmarks:    my question is what is the effect on storing a table like this on database, can I improve the table structure without making many small tables of it?


Does the flagging history summary need improvement?

It is not easy form me to understand the . I think it needs  a separator (border or underline) to differentiate the total number and breakdown of that total.        As suggested by Stijn it should be something like this


Notes app search is not finding some notes

I am using my notes app on OSX 10.11.5 and iOS 8. For the most part, things are working, but I am noticing that many of my older notes are not searchable. When I type something in the search box, these older notes do not appear in search results even if there is a match. However, if I edit a note or create a new one, it is fully searchable.  My guess is that somehow the search indexes for my notes got corrupted. Is there any way to fix this or rebuild the indexes?


What exactly is the Probability Integral Transform?

I've been going back over my notes from Stats class and came across the Probability Integral Transform.  From my limited understanding, the basic idea is that from a cdf in terms of one variable, can be transformed into another cdf in terms of different variable:    i.e. from $F_x(x)$ to --> $F_y(y)$   Is this understanding correct?  What is the purpose behind this?  Finally, is there a general procedure in performing the transformation?