Find all primes $(p, q)$ such that $p^3 - q^5 = (p+q)^2$

After rearranging I got that, $p^2(p-1)=q(q^4+q+2p)$ and clearly $p>q$ So, $q|p-1$ Thus, $p-1=kq$ where $k$ is any integer Now putting it in the original equation,I get that $$k^3q^2+2k^2q+k-q^4-2kq-q-2=0$$ But now I don't know how to proceed from here...please give me some hints or correct me if I am wrong I am so sorry for my terrible mistake....it would be $q^5$ instead of $q^2$ .....really sorry(although i got some really good answers)


I need an alternative term for “master,” as in someone who has “mastered” a particular craft

I am writing for a fantasy setting, and there needs to be a similar concept of a “master” magician. There is a guild, “apprentice” and “journeyman” still work well, and then there needs to be a step above that for someone who has completed their training. Importantly, a “master” in this sense is just someone who has completed all the training and knows all the things you have to know. They aren’t necessarily the greatest or the best; they’re just just fully qualifed. In its original sense, “masterpiece” just meant something that demonstrated those qualifications, not the greatest work of one’s career (cf. magnum opus). The masterpiece is akin to a doctoral dissertation, a black belt, or what have you—a significant accomplishment, but one that should ideally be the beginning of your career, not its pinnacle. Except there are two problems:  “Masterpiece” is widely used to refer to the pinnacle of one’s career. “Magnum opus” would be better for that, but I can’t change the way people use words. Especially when “master” is paired with “masterpiece,” it leads many readers to thinking the person is among the best in the world, or of all time. I just want someone who is fully qualified and capable rather than a student.  “Master” is currently the subject of debate about its appropriateness, considering the relationship of a master to slaves.   Both of these are problems for me. I would like to avoid them if I can, but to do that, I need a good alternative. So, does anyone have any good suggestions for sentences such as these?    He was an apprentice to the local _____ wizard, Carl.     Upon completing his enchantments and demonstrating the new spell to the guild, she was awarded the rank of _____, able to properly call herself a magician now and sell her spellcasting services.    My goal is to write this story, describe this setting, in such a way that no one has any reason to question the word choice. I want something that captures the meaning I want, doesn’t lead readers astray, and doesn’t lead to anyone feeling uncomfortable or argumentative over something as simple as word choice. If all I have to do to make the story work better for more readers is find another word, I want to find the other word. For the sake of making this a useful question, “master” is off the table. It is patently obvious, I think, that I am aware of it as an option. The purpose of this question is to find other options, so that each may be considered. The word “master” is not an alternative to “master” and is therefore not a valid answer to the question.


Multiple lines one side of equation with a Curly Bracket

I am trying to write an equation that looks like this, everything should be left aligned on the right hand side.     I am using the following code to write this equation.    \begin{equation}   D_{it} = \Bigg\{if \ bank \ i \ issues \ ABS \ at \ time \ t \\   2 \ if \ bank \ i \ issue \ CBs \ at \ time \ t \\    \ 0 \ otherwise   \end{equation}   I am putting \\ for a new line but it does not work. Please guide how I can write the desired equation.


I am editing the following sentence, and having an issue with identifying the proper pronoun.      “Her and her husband’s journeys and careers have allowed them to travel extensively.”   I know the rule about taking away the other subject to determine the proper pronoun, and if I do that here, it’s clearly “her”. Her journey, her career. However, I just can’t shake the feeling that “she and her husband’s” just “sounds” correct. I often get this feeling about a sentence (and usually I’m correct), but can’t put my finger on the grammar rule that would back up my “feeling”.   Any help would be appreciated. I’m kind of going around in circles on this sentence.


I wanted to clarify whether comma usage was mandated, optional, or not allowed in cases where the phrase at the beginning could be moved later into the sentence. I realize this is not the best description so let me give two examples:  The next day [?] I went to the beach.   (I went to the beach the next day.)  Together [?] we drank juice.  (We drank juice together.)   In both cases, the section on the left can be moved into the sentence where a comma would definitely not be needed (and sound awkward).  My feeling is that for the sentences on the left, in both cases a comma is optional, but not necessary. Is this correct? If the first sentence was "The very next day", would it change things? I've heard for some phrases if the length is above three words then a comma is recommended.  EDIT: While someone has indicated this a possible duplicate, I feel the referenced article does not clearly answer my questions here. You can see from the comments in this post the answer is not trivial.


sudo add-apt-repository ppa:morphis/anbox-support security issues

Adding the anbox repository gives me these weird issues. i used the --allow-insecure-repositories but that only works for my update Please help. N: Updating from such a repository can't be done securely, and is therefore disabled by default. N: See apt-secure(8) manpage for repository creation and user configuration details. E: The repository 'http://ppa.launchpad.net/jconti/gnome3/ubuntu groovy Release' does not have a Release file. N: Updating from such a repository can't be done securely, and is therefore disabled by default. N: See apt-secure(8) manpage for repository creation and user configuration details. E: The repository 'http://ppa.launchpad.net/morphis/anbox-support/ubuntu groovy Release' does not have a Release file. N: Updating from such a repository can't be done securely, and is therefore disabled by default. N: See apt-secure(8) manpage for repository creation and user configuration details. E: The repository 'http://ppa.launchpad.net/peppermintos/p9-release/ubuntu groovy Release' does not have a Release file. N: Updating from such a repository can't be done securely, and is therefore disabled by default. N: See apt-secure(8) manpage for repository creation and user configuration details. W: GPG error: http://deb.fdmpkg.org bionic InRelease: The following signatures couldn't be verified because the public key is not available: NO_PUBKEY 38832685B6D09383 E: The repository 'http://deb.fdmpkg.org bionic InRelease' is not signed. N: Updating from such a repository can't be done securely, and is therefore disabled by default.```


Sudo: /usr/bin/sudo must be owned by uid 0 and have setuid bit set

Help I'm stuck. My login page was looping I checked online came here and most solutions didn't work for instance I didn't have the .Xauthority file listed when I ran the command ls -lah, so I stumbled on a solution which people said worked , chown -R $HOME:$HOME sudo so now if I type commands like ls -ld /usr /usr/bin I get drwxr-xr-x 10 Mickey Mickey and drwxr-xr-x 2 Mickey mickey, and my computer is in low graphics mode I can only access it through tty3. Please I don't want to loose my files.


Is there C++ destructor equivalent in Java?

In simplest form, following is the design:  class Session {   Timer t = new Timer();   // ... };   Whenever, Session is allocated, I start a timer inside it; the timer will be expired after 10-20 mins. Now, suppose if Session is destroyed before the timer can expire; then it's a scenario where I must stop timer. I don't know if is there any last method which is always called when Session is destroyed.  Is there some sort of C++ destructor equivalent in Java, which help me to cancel() the timer when Session is destroyed ? (without waiting for GC)  Edit: Please don't retag for C++. I wanted something of that equivalent. The Session is a phone session which is get destroyed when all the user connected to it are disconnected. Now, there is no Session method which is called lastly nor there is any exception.


how to format date in lightning components

I'm using lightning input of type date in my lighting component. Once the date is selected it is showing date as **Feb 12, 2019 ** But we want the date to be shown as MM/DD/YY. is it possible  Here is the code:

                                     <lightning:input type="date" aura:id="fieldId" label="Start Date of Travel"                                                      name="startDateOfTravel"                                                      value="{!v.startDateOfTravel}"                                                      required="true"/>


How to decide which university to study for PhD

I have seen many different research students that want to apply for a PhD or MSc program but they are so nervous about their choice. Sometimes they pay most of heir time, reviewing the websites of the universities, profiles of the professors and do their best to gather information and choose the best PhD program or university to apply for PhD but they are still nervous about their choice. Some students only think that the universities with higher rankings are best to apply for and they miss some middle-ranked universities which are so good at their majors. This way, their chance to apply for those high-ranked universities is so low and they may lose two or three years preparing and applying for those university. While in the same period of time, if they had applied for that middle-ranked universities, they had higher chance of applying and in this period of three years, they would have finished most parts of their PhD program. My question here is about these things:   To what extent a person should be realistic in choosing a university for his PhD program. A normal student may be more successful in a middle-ranked university than a higher-ranked university. I think that sometimes, normal students lose their confidence when they study at high level universities, while; if they study in good middle-ranked universities, their academic output may be much higher and they will be a more successful person. Does it worth that a person that has high chance to be accepted in a good second ranked university, wait for two or three years to modify his curriculum vitae and apply for a first level university? Which one is more acceptable and appreciated? A top student at a second ranked university or a poor and not so much successful student in a very good ranked well-known university?     I can not decide in this period of each persons' life, how he should make decisions. This also applies to other circumstances. For instance, working in good company with lower income or working in a not big company with higher level of income. Making clear how a person should make decisions like this may be so much helpful to me.


Prevent indexing of text loaded by javascript from XHR-ed JSON file

I have a web document, https://example.com/page.html, where a javascript, like


From jmeter I am trying get URL  I have this error: Expected closing bracket for IPv6 address at index 28  Somebody can give a help please.  PB


Calculating the Fourier transform of $f(t)=Ae^{-i\omega_0 t}$

I am trying to calculate the Fourier transform of $f(t)=Ae^{-i\omega_0 t}$  I'm getting an infinity which is giving me problems. Here are my steps:  $$F(\omega)=\frac{1}{\sqrt{2\pi}}\int_{-\infty}^\infty f(t)e^{i\omega t}dt$$ $$=\frac{1}{\sqrt{2\pi}}\int_{-\infty}^\infty Ae^{-i\omega_0 t}e^{i\omega t}dt$$  $$=\frac{A}{\sqrt{2\pi}}\int_{-\infty}^\infty e^{t(i\omega - i\omega_0)}dt$$ $$=\frac{A}{\sqrt{2\pi}(i\omega - i\omega_0)} |e^{t(i\omega - i\omega_0)}|_{-\infty}^{\infty}$$ $$=\frac{A}{\sqrt{2\pi}(i\omega - i\omega_0)}(\infty - 0)$$  Where am I going wrong? Thanks.


Why don't I have a password for "su"? Problems with "sudo"

I have installed Ubuntu using the GUI, giving myself a password and everything. I do not intricately remember the process. However, what worries me is that I don't know the following password:  $ su Password: <the only password I've ever created on this machine> su: Authentication failure   I just don't know what to do. I'm not in trouble, but I just want to know what's going on here. I can also lock myself out of directories:  starkers@ubuntu:~/Desktop$ mkdir foobs starkers@ubuntu:~/Desktop$ sudo chmod 777 -R foobs sudo: /var/lib/sudo writable by non-owner (040777), should be mode 0700 [sudo] password for starkers: <the only password I've ever created on this machine>  starkers@ubuntu:~/Desktop$ cd foobs bash: cd: foobs: Permission denied   I'm just a bit confused. How can I lock myself out like this? I think sudo is the key command here. But I'm making the foobs file as open as it can possibly be via the chmod, so why does it lock me out?


Two principal ideals coincide if and only if their generators are associated

Suppose we have a ring $R$ and $(a),(b)$ are both ideals of $R$. Is it always true that $(a)=(b)$ if and only if there exists a unit $c$ such that $a=bc$ (i.e., $a$ and $b$ are associate)?    I have already verified that the forwards direction is true. But I have no idea on the backward direction. If it is true, can someone provide a proof to me?  Backward direction: Suppose that there exists a unit $c \in R$ such that $a=bc$. This implies that $(a)\subset (b)$. By using the same thing, (i.e., $b$ and $a$ are associate), there exists a unit $d \in R$ such that $b=ad$. This implies that $(b) \subset (a)$. is this correct?


Is a force acting on a freely falling body?

Albert Einstein in his equivalence principle stated that a freely falling body does not experience force, but if I let a ball free fall its velocity increases periodically (it accelerates). How is this possible without a force being involved?


I am trying to complete my "Build your first Unlocked package" step in the "unlocked Packages for Customers" Badge  While doing it, I am getting the following error:    It says:     ERROR running force:package:install:  Invalid alias or ID:   dreamhouse@3.0.0-5. Either your alias is invalid or undefined, or the   ID provided is invalid.   Can somebody please help me through this?


How to change the attribute using jquery?

I have this tag
some text
   How can I change the attribute so that it is
some text


Prove that $2^{3^n}+1$ is divisible by $3^{n+1}$

I'm stuck on the induction step where substitution is difficult.


Python double for loop over finite iterable running indefinitely

In my code below, 'single' refers to a finite list. I then need to get all possible pairs from this list; however, the program didn't finish executing. After messing around with some print statements, for some reason, despite 'single' having a finite number of elements (13122; I checked with len()) the for loop was running forever, until I but a break statement in which forcibly ends the loop when the index gets too high. Initially I thought this was because I was referencing over 'single' twice; however, even when I replaced 'single' with copy.deepcopy(single), the same problem occurred, and my fix no longer worked. If it is of any help, the elements of 'single' are themselves lists. ''' for index1, i in enumerate(single):     for index2, j in enumerate(single):         return_list.append([i,j])                  if (index1 > length):             break  '''


Trigonometric integral involving the fractional part function

I have tried the $u$ substitution yet I could not move forwards on this problem. Could you calculate in closed-form this integral? $$\int_{0}^{\pi/2}\bigg\{\csc(x)\bigg\}\mathrm{dx}$$


Why are Files mysteriously showing up in Windows 8.1 Recycle Bin?

PROBLEM: In the past couple of weeks - around mid-May 2015, I found a folder named "Hacked" in my Recycle Bin and in another recent case, several Files and shortcuts that I had previously emptied from my Recycle Bin show up back in my Recycle Bin.  Up until a few weeks ago, I have not had this problem or any other problem.   ACTIONS: I emptied my recycle bin when the "Hacked" folder showed up and emptied the recycle bin when the previously deleted files showed up and the folder & files were removed.    QUESTIONS:  1. Why did this "Hacked" folder end up in my Recyle Bin and why are these previously deleted files showing up in my Recycle Bin? 2. What can I do to prevent this type of behavior from happening again?  3. What can I do to determine if my system has been hacked and in need of a cleaning?  I run a full McAfee scan regularly - at least weekly if not more.   SYSTEM: I have an HP - Pavilion 23" Touch-Screen All-In-One Computer - AMD A6-Series, running Windows 8.1 and has had McAfee installed from day 1.  The system was purchased in April of 2014.  I use this system for email and web browsing.  I do not goto suspicious sites (i.e. porn) and don't consciously download files or open email from unknown sources.   Thank you for any replies.


What's the cardinality of $\{ (i,j,k) : i+j+k=10, i,j,k \in \mathbb{N} \}$ ? General case.

How many triples of natural numbers are there of sum equal to 10? What about the cardinality of   $$\{ (n_1,...,n_K) : \ n_i \in \mathbb{N} \ \wedge \sum_{i=1}^{K} n_i=N \ \} \ ?$$  Is there an intuitive way of thinking about this? I'm looking for a simple argument how to count this.


Is there a word for Condescending , Fake Empathy?

I am looking for a word to describe the situation :  A poor person describes his struggles of poverty, while a middle-class (economically speaking) lady is faking her empathy to the man – and the conversation goes in the lines of "Do not despair, keep hoping, work = reward... " etc. All these words very often repeated to the poor person, but his state does not change due to certain unchanging social situations. The lady is aware of it.  Nevertheless, just to virtue-signal, the lady who never experienced the struggles of the other – goes on making empty, often condescending remarks to the guy, without genuine empathy, just mechanically repeating the statements everyone else does.   She even goes on to invent some silver lining, such as the positive effects of poverty is that you will not have to manage a big house..  My question Is there a word to describe the remarks of the lady? Patronizing does not quite hit the nail, and condescending does not quite capture the part in italics. Are there any words to describe what I am looking for?   Example:       [Name] at this point is truly tired of continuous _______ from every 4th middle-class . The last thing he'd appreciate now is pity.   Part of Speech: Noun; I searched thesaurus for patronizing and condescension  A single word would be better than a phrase .


How does k-fold validation affect the model coefficients?

My question on k-fold is not about evaluations of the model, but rather the coefficients that are returned by it.   In the R code below, I am performing 3-fold cross validation, which is to say the model is trained and tested three times. The keyword I am looking at is "trained".  My question is... how do the coefficient values get set? Is it an average of the three folds or another method?  library(caret)  formula <- nos_yn ~ phone_conf_yn + nos10iact  train_control <- trainControl(method = "cv", number = 3, summaryFunction = twoClassSummary, classProbs = T)  model <- train(formula, data=training, trControl=train_control, method="glm", metric = "ROC", family=binomial(link="logit"))  data.frame(summary(model)$coefficients[,1])                                  summary.model..coefficients...1. (Intercept)                                           -2.1853334 `phone_conf_ynBad Phone Number`                        0.7364689 phone_conf_ynConfirmed                                -1.2032336 `phone_conf_ynNull/Other`                             -0.6636189 nos10iact                                              0.3016733


Model selection and cross-validation: The right way

There are numerous threads in CrossValidated on the topic of model selection and cross validation. Here are a few:    @DikranMarsupial's  to    However, the answers to those threads are fairly generic and mostly highlight the issues with particular approaches to cross validation and model selection.   To make things as concrete as possible, say for example that we are working with an SVM with an RBF kernel:  $K(x, x' ) = (\gamma \, \vert x - x'\vert)^2$, and that I have a dataset of features X and labels y, and that I want to    Find the best possible values of my model ($\gamma$ and $C$) Train the SVM with my dataset (for final deployment) Estimate the generalization error and the uncertainty (variance) around this error   To do so, I would personally do  a grid search, e.g. I try every possible combination of  $C$ and $\gamma$. For simplicity, we can assume the following ranges:   $C \in \{10, 100, 1000\}$ $\gamma \in \{0.1, 0.2, 0.5, 1.0\}$   More specifically, using my full dataset I do the following:   For every ($C$,$\gamma$) pair, I do repeated iterations (e.g. 100 random repetitions) of $K$-fold cross validation (e.g. $K=10$), on my dataset, i.e. I train my SVM on $K-1$ folds and evaluate the error on the fold left, iterating through all $K$ folds. Overall, I collect 100 x 10 = 1000 test errors. For each such ($C$,$\gamma$) pair, I compute the mean and the variance of those 1000 test errors $\mu_M, \sigma_M$.   Now I want to choose the best model (the best kernel parameters) that I would use to train my final SVM on the full dataset. My understanding is that choosing the model that had the lowest error mean and variance $\mu_M$ and $\sigma_M$ would be the right choice, and that this model's $\mu_M$ are $\sigma_M$ are my best estimates of the model's generalization error bias and variance when training with the full dataset.  BUT, after reading the answers in the threads above, I am getting the impression that this method for choosing the best SVM for deployment and/or for estimating its error (generalization performance), is flawed, and that there are better ways of choosing the best SVM and reporting its error. If so, what are they? I am looking for a concrete answer please.  Sticking to this problem, how specifically can I choose the best model and properly estimate its generalization error?


C# - how can I get owner's name for a Mutex

I have a shared mutex between 2 applications. I want to create an administration console that shows the current owner's name of the mutex.  How can I get the application name that currently owns the Mutex?


It seems to be related to the mesh texture~


Can I travel from Serbia to Budapest with just my Czech Republic ID?

Does the train from Beograde to Budapest stop at the border or does the passport controller come into the train?


Question on existence of square root function!

I have a relation $f$ defined as   $$ f=\{(x, y) \mid y=\sqrt{x} \;\text { and }\; y, x \in \Bbb R\} $$  Now this relation is a function.  But how? A function is a relation whose every element in domain have only one image in codomain. Now if I have $4$. Then  \begin{align} \sqrt{4}=\pm 2 \end{align}  So I have two ordered pairs whose second element is square root of first element:  \begin{align} (4,2) \quad \text { and } \quad(4,-2) \end{align}  Now you can observe that 4 has two images. Therefore relation $f$ must not be a function. But it is! How this is possible?


How to install Jupiter on Ubuntu 14.04 LTS?

I have made some research how to install Jupiter on Ubuntu 14.04:  In therory:   download the program (noarch.rpm) from  convert .rpm into .deb, by using alien program; add missing jupiter group to Ubuntu; install recently converted deb package;   In practic:  sudo apt-get install alien sudo groupadd jupiter cd ~/Downloads sudo alien -k jupiter-0.1.11-1.noarch.rpm --scripts sudo dpkg -i jupiter_0.1.11-1_all.deb   ...in general, it works (it appears in ps aux | grep jupiter list), but there is still missing jupiter indicator. Someone knows how to get this done to work properly?


Summarizing flatness of county with statistic Elevation variance per square mile

I need to classify every county in the US as either hilly, moderately hilly, or flat. Accuracy is not critical, just a rough classification. I used R and followed the advice in  answer to import elevation and counties and calculated the zonal variance. This was inherently biased towards larger counties since they have more surface for hills, so I need to divide by area. If I divide variance by square miles does that reasonably represent hilliness? The preliminary results seem decent, with the highest values being places like Colorado, Hawaii, Montana, etc.


I need a validate a textbox for numbers only alongwith a few special conditions. The allowed values are:   decimal numbers >= 0 [E.g. 25] floating point numbers [E.g. 25.83] decimal numbers with comma [E.g. 1,800]     I tried this regex method. but it is obviously not the correct regex for all the conditions. Please help in getting this fixed.  function validateText(text) {          var regex = new RegExp('^[0-9]+$');         return regex.test(text);     }


Why does it not like my arrays of TextFields, hBoxes, and Labels?

I am using JavaFX and this is my code. I am trying to make a column of five labels, textfields and hBoxes.       Label[] lblTask = new Label[5];     TextField[] taskTF = new TextField[5];     HBox[] hb = new HBox[5];      for(int i = 0; i < 5; i++) {         hb[i].getChildren().addAll(lblTask[i],taskTF[i]);         hb[i].setSpacing(10);         hb[i].setLayoutX(30);         hb[i].setLayoutY(120+(60*i));         root.getChildren().add(hb[i]);     }   It is giving me a java.lang.reflect.InvocationTargetException, and java.lang.RuntimeException and a java.lang.NullPointerException on the line that I set the spacing!


I'm stuck on the following question and want to know what it is that I'm doing wrong.  Consider a communication source that transmits packets. After each transmission, the receiver sends a signal indicating if the transmission was successful or unsuccessful. If a transmission is unsuccessful, the packet is resent. Assume that the results of successive transmissions are independent of each other and that the probability of a transmission being successful is p=0.9. Let X be the number of times a packet is transmitted. a. Determine the PMF of the random variable X = number of times a packet is transmitted. b. Find the expected number of times a packet is transmitted. c. Find P(x=4)   I feel like for part a the general formula would be the following.  a. $\frac {.9^x}{x} $ for x > 0  0 otherwise  b. Isn't part b asking the same as part a pretty much? Here is where I'm getting confused since it seems to me as though a packet has a chance of 1 - $\frac {.9^x}{x} $ to fail.  c. $P(x=4) = \frac {.9^4}{4} $


Vowel is to diphthong as consonant is to?

While reading about diphthongs in a different question today, I noticed that while the word "diphthong" doesn't seem to contain any actual diphthongs, it does contain 3 sets of consonant groupings.  When I was younger, I used to think consonant groupings actually were called diphthongs. I know now that I was mistaken, but I do wonder - is there a single word that describes consonant groupings?  After doing some searching on Google, Wikipedia and this site, I'm unable to find a definitive answer besides "consonant cluster" or "consecutive consonant". Those terms may be the only accurate ones available, but I would be mildly disappointed.


Light diffusion from coloured surface emitting light (Blender 2.8X)

Similar to these questions (, , ), I wish to emit light from some of the atoms in my model. I've randomly generated some atoms to be glowing and blue. I've followed a lot of the methods of these questions in generating my own material. However, I'm not observing (rendered) any light diffusion from the blue atoms onto other atoms and their surfaces. Clearly the light source I've created is working well and creating these shadows.  All spheres share roughly the same material properties, although I'm giving any emission from the magenta atoms and so using a different material node set. I've ramped up the emission strength for this image just to show it's not diffusing properly of neighboring atoms, although ideally I have this lower so there's still some aspect of the atom curvature relative to the main light source observable. I was wondering if using Blender 2.8 might have changed some of these properties from previous versions, as I'm fairly inexperienced. What am I missing, to observe light diffusion from neighboring atoms?


As per the title, what is this new feature?


Home folders accessible to other users and should not be, how to fix?

Why are my home folders accessible by other users on the same system by default?  I understand that I can change the permission of the home folders but want to know why this happened?  I have done nothing to make the folders "shareable" and yet I can easily navigate to any users home folder using Nemo 2.4.5 and see all their contents.  This is quite a privacy and security flaw and I'm not sure why it has defaulted this way on my system.  Under Users and Groups (items checked =) (both are administrator accounts)  User 1 = adm, cdrom, dip, lpadmin, plugdev, sudo  User 2 = User 2, sudo  Also of note is why User 2 has User 2 clicked but User 1 does not have User 1 clicked.  Both accounts appear to behave exactly the same.  Thank you for any tips in this matter.


How do I convert a number from bytes to GB and round to 2 decimal places?

I need a script that converts a number from bytes to GB (not GiB) and rounds the result to 2 decimal places. How would I go about doing this?  Thanks.


How is * interpreted on bash command lines?

What would be output if we type something like this in our terminal  /home/user/some character with *  e.g. /home/renga/i*  I pass a variable (home/renga/i*) like this in my script, in run time the value was passed along with a file name instead of /home/renga/i*.


is there a PRODUCT function like there is a SUM function in Oracle SQL?

I have a coworker looking for this, and I don't recall ever running into anything like that.  Is there a reasonable technique that would let you simulate it?  SELECT PRODUCT(X) FROM (     SELECT 3 X FROM DUAL     UNION ALL      SELECT 5 X FROM DUAL     UNION ALL     SELECT 2 X FROM DUAL )   would yield 30


Where do I ask a question about W3C standards and their status?

I wanted to know what some of the W3C standards meant from here,    and Web Components.  But I don't know where to ask it.  Where should I ask it?


Which file has basic commands features such as rm, cd etc.?

I am having problem to find a file has basic commands like rm, ls, cd, etc. I need the file path in Ubuntu to edit them. I checked on web but just found UNIX file locations (/usr/bin).  So, here it is what I mean,  # cd /usr/bin # ls -lh rm -r-xr-xr-x   1 root   bin   14K May  1  2007 rm # chmod 4555 rm # ls -lh rm -r-sr-xr-x   1 root   bin   14K May  1  2007 rm # chmod 2555 rm -r-xr-sr-x   1 root   bin   14K May  1  2007 rm   I want to change the privileges of rm. Inclusion of any suggestions or documentations are welcomed.


How do I delete pictures of my iPhone which wont delete?

My iPhone 5 has an album which has been saved onto it through iTunes from another laptop, when I try and delete the album through iTunes it doesn't seem to give me the option to do so. If anyone could be able to inform me on how to complete the action of deleting the album I would appreciate it, Thank you.


Difference between a light wave in space and a wave in a pond

Apart from their nature and the medium utilized, what are the differences between an EM wave and a wave we see in a pond?  When we throw a stone into a pond, can we imagine we are observing light propagating through space or are we missing something?


TikZ: difference between \node and \coordinate?

What is the  difference between \node and \coordinate in TikZ? Exchanging them does no visual effect in my (to be honest: still simple) pictures.  When to use what?


Baked normals in substance painter doesn't look correctly in blender

Some edges look sharp, but I haven't made them sharp. Auto Smooth - 57.3° (the same issue with any value) After applying the baked normal maps from Substance painter in blender, the model looks like this:  In Substance painter:  Material nodes:  Wireframe and sharpen edges in blue:


I'm trying to solve the following exercise from the book A Textbook of Graph Theory by R. Balakrishnan and K. Ranganathan     Show that for a simple bipartite graph, $m\leq \frac{n^2}{4}$   $m$ is the size of the graph.  $n$ number of vertices.  I was considering the following cases:  Let $X$ and $Y$ be a partition of the set of vertices of $V(G)$ and I tried to verify some cases accordingly to the cardinality of the each set. If $|V(G)|=n$ and $|X|=|Y|=\frac{n}{2}$ it is easy to see, but I got stuck trying to show the case when the cardinalities are $|X|<|Y|$  Any help will be greatly appreciated!  Thanks!


rename multiple directories by adding one character

I have multiple folders named as follow:    Name1   Name2   ...   Name9   Name10   Name11   ...     I need to rename them using mv command into:    Name01   Name02   ...   Name09   Name10   Name11   ...     Any ideas?


rc.local file is missing in Kubuntu 18.04

I tried to edit my rc.local file in order to use a script with parameters on startup but it doesnt exist. I am using Kubuntu 18.04. Has it been removed?


Ubuntu 18.04 workspaces and switch between windows

I moved from 17.04 to 18.04 but there is a lot of changes in windows switching and workspaces. On 17.04 I had to use windows+S key to open all workspaces and then navigate via arrow keys to select. Plus each window was visible in its workplace, it wasn't accessible from other workspaces.  If I have two windows of terminal or code editor, I was able to open them via alt+tab long press and then I had to select the window between. Now it’s like press alt+tab, then press down key for selection between same application windows.  It’s extremely annoying, please suggest a solution.


Why is the phrase "Winter is coming" so significant in Game of Thrones?

I am curious as to what the phrase "Winter is coming" might mean in Game of Thrones.   I know about the thing with the White Walker. Is there anything I am missing? What actually is going to happen when the winter comes? Does the winter signify the season or is it something different?


Use of "I am having" on Stack Exchange sites

I use Stack Overflow a lot and have noticed a certain trend that I myself got caught up in at one time of using the phrase "I am having a problem" in place of "I have a problem."  I would use this phrase for an event in the future, for example, "I am having a steak dinner tonight," but for a problem that I need solved and am asking for a solution, I'd use "I have a problem..."   What would force us to use this phrase? Is it even valid English for the present tense?


What is the difference between egrep, fgrep, find and grep commands?

i know i can use grep to find files however i am wondering what the particular difference between these common commands ? They all seems to be equal in meaning to me.   egrep  fgrep grep  find locate   as windows search and find command.


How do I prevent yum from updating a particular RPM?

For certain reasons I have to keep a slightly older version of a particular RPM installed on my box (Fedora 11). The problem is that every time I do a package update yum (or one of its GUI equivalents) wants to update this RPM to the latest version, which is annoying - especially when I update it by mistake.  Is there a way to 'pin' this version so that yum knows to never try and update it?


How do I do a contour integral in complex analysis

I want to do the integral sign over the sign gamma (integrating around a path gamma)


Proper Way to Combine Feature Selection and Hyperparameter Tuning?

Been doing reading on feature selection and hyperparameter tuning but I'm getting lost on how to properly code/set up the experiment. I am doing a classified ML experiment, I have 1200 samples and 400 features, and would like to optimize my models. My plan is to do a stratified k-fold analysis, use RFE for feature selection and do hyperparameter tuning for models where applicable. My understanding is that both the feature selection + hyperparameter tuning should occur at each fold of the looping process? I was wondering how that would be done in python. My instinct is that I have to use some combination of RFE (or RFECV) and GridSearchCV?  Does this thought process make sense?   Split the data into training/test set, discard the test set for now. Using the training set, use GridSearchCV to do the cross-validation w/ stratified K-fold, and embed RFE within the loop Select the best model Fit to Test set   OR   Split data in training/test K-Fold RFE selection for a given model Select those features identified by RFE Then perform hyperparameter tuning on those features   Does this make sense? Could someone provide an example code so I can see it laid out?  Thanks!


How to fix " Could not compile `user32-sys" error in Rust

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


Do Klingons believe that William Shakespeare was Klingon?

From Wikipedia  :      In a scene from the film Star Trek VI a dinner is held for the Klingon   chancellor, Gorkon. He makes a toast to "the undiscovered   country...the future". Spock, recognizing the quotation, responds,   "Hamlet, Act 3 Scene 1", to which Gorkon replies with his statement   about the "original" Klingon text of Shakespeare. Though Gorkon does   not quote from the "original" Klingon text, another character, Chang   quotes the Klingon words "taH pagh taHbe'" (To be, or not to be). The   film is filled with other quotations and references to Shakespeare                                   Was the "original" Klingon text mentioned by Gorkon implying that Shakespeare was Klingon?


how to use drush commands for a live site?

I am using drush in my localhost. I am new to drupal and i want to execute some commands in drush for a live site. can anyone know how to use drush for a live site...?


If I have 5% 100k resistors but wanted 1% precision, can I use 4 of them in series parallel to improve on the 5% precision?

I made an error on ordering and am receiving a shipment of 5% 100K resistors when I wanted 1%.  This is for a voltage divider circuit.  Would it help improve the precision if I put two each in parallel then put them in series to achieve the 100K?  Or would the extra parts be worse for the circuit than simply using a DMM to find the most accurate one and use that?  Please excuse me if this sounds like a dumb question.  The order was wrong.  It is a simple case of the computer doing what I told it to do instead of what I wanted.  (Old joke, I know).  Thanks in advance for your answer(s).


A graph which is not a single block has at least two leaf blocks.    According to the Intro. to Graph Theory by D. West:    Block: A maximal connected subgraph of $G$ that has no cut-vertex. Leaf block: A block that contains eactly one cut-vertex of $G$.   I have not well understood this statement. Would you elaborate on this statement.   Edit: Can we say this:      The block-cutpoint graph of a connected graph is a tree where its leaves denote the blocks of $G$. Since a tree has at least two leaf blocks hence the graph has at least two leaf blocks if it is not a single block.


Repeating determiners: “the X and (the) Y”

I have a problem with the use of "the" after "and" where you would basically be connecting words. For example, which of the following is better:     The table and the chairs?   The table and chairs?   Or are both okay? What is the rule, and are there exceptions to it? Or is the rule just contextual and may vary between the sentences and meanings?


Whenever I try to do anything at all that requires my password it returns this:  u7ur7l3@ubuntu:~$ sudo sudo: /usr/lib/sudo/sudoers.so must be owned by uid 0 sudo: fatal error, unable to load plugins u7ur7l3@ubuntu:~$   So I can't install anything from the Software Center / package manager or run any commands in terminal that require my password. I can log in, but that's pretty much it.  I accidentally changed the permissions of some files, then changed some more trying to fix it :/. Now I'm completely lost as to what to do.  This is what happened when I tried to get sudo working again using pkexec:  u7ur7l3@ubuntu:~$ pkexec chown root /usr/lib/sudo/sudoers.so Error getting authority: Error initializing authority: Error calling StartServiceByName for org.freedesktop.PolicyKit1: GDBus.Error:org.freedesktop.DBus.Error.Spawn.ExecFailed: Failed to execute program /usr/lib/dbus-1.0/dbus-daemon-launch-helper: Success   u7ur7l3@ubuntu:~$ sudo ls sudo: /usr/lib/sudo/sudoers.so must be owned by uid 0 sudo: fatal error, unable to load plugins   And to change permissions I was using Root Actions as a dolphin service/ plugin thing, so history doesn't show me the permission changes.  I just realized that sounds don't work at all anymore. When I go into Phonon my default settings and playback devices aren't even there. Also I don't have the option to shutdown, I can only log out or leave.


Prove that "injective function $f:X\to Y$ exists" and "surjective function $g:Y\to X$ exists" is logically equivalent.

Prove that   injective function $f:X\to Y$ exists surjective function $g:Y\to X$ exists   is equivalent.$(x,y\neq \emptyset)$   My approach  First,prove left to right.  If injective function $f:X\to Y$ exists, a set A can be defined like this. $$A=\{f(x):x\in X\}$$ then it is sure that $A\subset Y$, and $|A|=|X|$  And, if we define function $g$ like $$g(y)=\begin{cases}x & \text{if $y\in A$ and } f(x)=y,\\x_0& \text{if }y\notin A.\end{cases}$$ ($x_0$ is a fixed element of $X$)  Then, $g$ is a surjective function, so surjective function $g:Y\to X$ exists.  Now,prove right to left.  If surjective function $g:Y\to X$ exists, $\forall x \in X$, we can select a element $y\in Y$ that $g(y)=x$, which is clear that we can pick a different $y\in Y$ for $\forall x \in X$  if we define function $f$ as $f(x)=\text{one element in Y that g(that element)=$x$}$, f is a injective function, so injective function $f:X\to Y$ exists.    But, I am not sure that my approach is right, especially on proving right to left. Please check whether my approach is right, ways to improve it,  and some other ways of proving this question.


Android Null Pointer Exception on My Database

My insert function  public void AddBakim(){     btn_bakimkaydet.setOnClickListener(new View.OnClickListener() {         @Override         public void onClick(View view) {             db.insertBakim("1","2","3");         }     }); }   My database function   public boolean insertBakim(String bAd,String bFiyat,String bTarih){ /*String FK_aID*/   SQLiteDatabase db = this.getWritableDatabase();   ContentValues deger = new ContentValues();   deger.put(COLUMN_bAdi,bAd);   deger.put(COLUMN_bFiyat,bFiyat);   deger.put(COLUMN_bTarih,bTarih);   //deger.put(COLUMN_FK_aID,FK_aID);   long sonuc = db.insert(TABLE_BAKIMLAR,null,deger);   if (sonuc== -1)       return false;   else       return true; }   My other insert method doesn't work and is giving me the following error. Please help me friends.  Caused by: java.lang.NullPointerException: Attempt to invoke virtual method 'void android.widget.Button.setOnClickListener(android.view.View$OnClickListener)' on a null object reference       at com.bakim.synergy.bakimson.BakimKayit.AddBakim(BakimKayit.java:42)       at com.bakim.synergy.bakimson.BakimKayit.onCreate(BakimKayit.java:38)


Is there a way to derive Principle of Least Action from Newton's laws instead of other ways around?

If we start from  $ m\ddot{x} = -\frac{dV}{dx} $  How could one derive/construct principle of least action? i.e. find out that this quantity  $ S = \int_{t_0}^{t_1}dt\left(\frac{m\dot{x}^2}{2} - V(x) \right)$  needs to be minimized. Assuming it's true and then proving it is is very easy and it's written in every textbook but that's not what I'm asking for. I want to go in other direction, not assuming I know the answer. All I know are Newton's laws and that $ F = -dV/dx$.  I thought of simply inverting the steps of derivation of Euler-Lagrange equation but they seem unintuitive and the reasoning behind them is unclear except that I know the answer in advance (which I want to assume that I don't).  I guess this is inverse of optimization problem? Given a solution finding out what does it optimize?


I have a solution containing 13 projects. The solution is configured to start multiple projects. A lot of these project need to go to shared databases and web services.  My app.config and web.config files now contain a lot of duplication. Eg when I want to change a database I need to change all the configuration files in the projects (app.configs) that access that database.  I wonder what the best approach is to tackle this? Is there a way to define solution wide configuration settings in .NET?


Why is insulting other users and giving sarcastic comments such a huge part of the culture on SO? It's the complete opposite of projects like Wikipedia where everybody is exceedingly friendly and helpful.  For example: This response comes from a user with 13k reputation to a question about an interview problem:     There are a fair number of undergraduate CS students who can see this solution       immediately, and it seems they were looking for those students.      If you have any ambition as a C++ programmer, and aren't already intimately       familiar with the data structures and algorithms provided by the STL, you       should learn them now. It seems your competition already has.   This was in response to a genuinely extremely difficult interview problem that did not even ask for a solution using the STL. This seems to me like an unnecessarily unfriendly thing to say. This is just one example of what I think is a major trend.


Textbook reads:     All logarithms are natural logarithms: $\log = \ln$.   Does this mean $n\log(n) = n\ln(n)$?


To show: $\det\left[\begin{smallmatrix} -bc & b^2+bc & c^2+bc\\ a^2+ac & -ac & c^2+ac \\ a^2+ab & b^2+ab & -ab \end{smallmatrix}\right]=(ab+bc+ca)^3$

I've been having quite some trouble with this question. I'm required to show that the below equation holds, by using properties of determinants (i.e. not allowed to directly expand the determinant before greatly simplifying it).  $$\begin{vmatrix} -bc & b^2+bc & c^2+bc\\  a^2+ac & -ac & c^2+ac \\ a^2+ab & b^2+ab & -ab \end{vmatrix}= (ab+bc+ca)^3$$  I tried everything:   $R_1\to R_1+R_2+R_3$ and similar transformations to extract that $ab+bc+ca$ term, but to no avail. $C_2\to C_1+C_2$ and $C_3\to C_3+C_1$ seemed to be a good lead, but I couldn't follow up.  How can I solve this question?


I set up a fail2ban system on my server to restrict SSH access. It works fine, except that after entering the username on the unit, if I enter the password incorrect 3 times (my maxretry value), it continues to allow the user to attempt to log in. But if I remove exit from trying to log in as that user, and open a new session, I am now banned.   When using putty, I enter the target address (but not it's username  login as: user user@address's password: 1234 Access Denied user@address's password: 1235 Access Denied user@address's password: 1324 Access Denied user@address's password: 1234 Access Denied user@address's password: 1235 Access Denied user@address's password: 1324 Access Denied   In theory it should not let me log in after the 3rd try, but instead it lets me go through 6 tries, after which I get a popup about having too many authentication failures. If I then go back, fail2ban has properly blocked the device from access.   How can I get it set up so that I am kicked off right after the 3rd try?   Edit: I am aware of  question. However, I believe this is different because the poster there asks why it is not blocking at all. I am more worried about why it does not block login attempts that are already in progress.


Firewall configured to allow 25/tcp but still cannot telnet into server on that port

I've got postfix and dovecot running on ports 25, 110, 587, 465, 993, 995 for the usual mail protocols. I can telnet into all ports except port 25 which you can see below. Any ideas on what's going on?  Remotely Telnet to port 25 (fails)  # telnet 192.168.1.100 25 Trying 192.168.1.100 ... telnet: connect to address 192.168.1.100: Operation timed out telnet: Unable to connect to remote host   Locally Telnet to port 25 (success)  # telnet localhost 25 Trying 127.0.0.1... Connected to localhost. Escape character is '^]'. 220 example.com.au ESMTP Postfix   Firewalld rules:  # firewall-cmd --list-all public (default, active)   interfaces: eth0   sources:   services: dhcpv6-client dns http https imaps pop3s smtp ssh   ports: 110/tcp 465/tcp 5432/tcp 587/tcp 143/tcp 2288/tcp 25/tcp   masquerade: no   forward-ports:   icmp-blocks:   rich rules:   My postfix main.cf has   inet_interfaces = $myhostname, localhost    and ss -plnt |grep :25 returns   LISTEN     0      100                       *:25                       *:*      users:(("master",30844,13)) LISTEN     0      100                      :::25                      :::*      users:(("master",30844,14))


No doubt an easy question: I'm trying to follow Wikipedia's (second) proof of the irrationality of $\sqrt{3}$ and it relies on the notion that since $3n^2 = m^2$ is divisible by 3 then so is $m$. Why is this so and can you help me prove it?


My network icon is always a question mark but I have acces to internet

My network icon is always a question mark in both wired and wireless connection but everything network related works correctly.


How to find the intersection(/s) of two curves(non-linear and linear) in excel

I have two plots using scatter plot of which one is non linear and the other one is linear. And I require the intersection of these curves. How should I proceed ?  Edit: The plots are done by using a set of values in excel.  Curve 1:  x: 0, 0.5, 1, 1.5, 2, 2.5, 3, 3.5, 4, 4.5, 5, 5.5, 6, 6.5, 7, 7.5, 8  y:8.43, 8.76, 8.27, 7.87, 7.69, 7.76, 8.46, 8.85, 8.34, 7.92, 7.73, 7.79, 8.42, 8.76, 8.27, 7.87, 7.69  Curve 2: y=8.168  Thanks  Edit-2: In the other question  a trend line is made and then the intersection of those are dealt, which is clearly not possible for mine and not a duplicate  for the question you are referring to.


how to downgrade moto g 2nd gen from lollipop to kitkat without root

I am having a problem while gaming on my new android update on moto g (2nd gen). So, i want to downgrade the android version please help me out.


how to boot into safe mode in windows 10?

I've been sifting through google search results and can't find the answer.  It seems F8 is not an option anymore.. however everything else shows how to boot into safe mode - when you're already in windows.. argh... that makes no sense, why do I need safe mode if windows is already working properly?  What I need is a way to boot straight into safe mode in window 10.. how can I do this? My screen is not working and i need to uninstall the graphics drivers - the regular "Type blindly your password" solution to this "Black Screen of Nothingness except a mouse cursor after windows 10 upgrade" problem is not working for me.. so I need to boot into safe mode and uninstall the nvidia drivers.  I don't have a windows CD since I upgraded from the internet. So I can't boot from that either.  So what's the official (or any) way to boot straight into safe mode ? thanks


Allow users under 50 rep to post one or two comments daily

I have seen many new users posting comments as an answer, which is wrong. Some new users have good knowledge but they can't add comments because they don't have 50 reputation.    I agree that some users post comments that are not related to the topic; to deal with that, other users can raise "not an answer" flags.  My question is: Why don't we provide a limit of 1 or 2 comments to the new users on a daily basis?  To help new users write more useful comments the community can give some suggestions to the new user in additional comments.  I read , but it doesn't prevent many new users from writing comments in the answer section because they need more information in order to offer an answer.   Suggestions:   New users should be permitted a limited number of comments. The community can give suggestions to a new user for avoiding wrong comments.  The comments become visible after a review and acceptance by another user with enough reputation.


What is the name of this plant with 4-5 lobed leaves?

Location is India, It has 4-5 lobed leaves with flowers & pointy seed pods.    I am thinking it is Wild raddish.


How much resources does MySQL (MariaDB) use vs. Apache/PHP-FPM on my server?

I host about 60 client sites on this server: AMD EPYC 7401P 24 Cores "Naples" (Zen) 128GB DDR4 ECC RAM NVMe storage. Centos7  All sites are PrestaShop 1.7 sites with each their own PHP 7.1 PHP-FPM pool as well as one MySQL (MariaDB) database for each site.  The speed is good, but I am considering to migrate to one separate MySQL server and one web-server.  I have NO IDEA how much resources MySQL uses vs Apache and PHP-FPM.   Let's say I keep Apache and PHP-FPM on my current server and buy a new server for MySQL. What server should I get? Half the RAM and CPU compared to the webserver? Double, same?   My guess is that the answer is: it's hard to say without real data, so a followup would then be: how can I get this data, preferably resource usage over time? Is this data hidden in the system allready or do I need to install some statistics tool?


Trying to render the default scene.  Have set my user preferences to have Render Output go to F:\Blender\BStills\ - and this is what's listed in Properties panel as well.  If I try to render an animation, things work fine. If I try to render a single, still image, I'm not getting any output (even though the render looks like it runs fine within blender).  Also, is there a simple way to attach .blend files so people can look at those directly to help with troubleshooting?    Thanks for any help.


How to find out who deleted some data SQL Server

My boss had a query from a customer yesterday asking how they could find out who deleted some data in their SQL Server database (it is the express edition if that matters).  I thought this could be found from the transaction log (providing it hadn't been truncated) - is this correct? And if so how do you actually go about finding this information out?


Can't figure out why I'm getting this NullPointerException

I'm trying to create a card game. It has 3 classes, "PlayingCard", "DeckOfPlayingCards" and "Game".  public class PlayingCard {      private String rank;     private String suit;      public void setRankAndSuit(String rank, String suit) {         this.rank = rank;         this.suit = suit;     }      public String getRankAndSuit() {         return rank + " of " + suit;     } }     public class DeckOfPlayingCards extends PlayingCard {      // Array of playing card objects     static PlayingCard[] deck = new PlayingCard[2];      DeckOfPlayingCards() { // This is my line 11 BTW         deck[0].setRankAndSuit("1", "S");         deck[1].setRankAndSuit("2", "S");     } }     public class Game extends DeckOfPlayingCards {      public static void main(String[] args) {          DeckOfPlayingCards newDeck = new DeckOfPlayingCards(); // This is my         // line 6         System.out.println(deck[0].getRankAndSuit());     } }     Everything compiles fine, but when I run it, I get a Exception in thread "main" java.lang.NullPointerException at DeckOfPlayingCards.<init>(DeckOfPlayingCards.java:11) at Game.main(Game.java:6)  As I understand, this exception is thrown when I'm trying to access something which is null. I simplified the program to see where the problem is, but I still can't figure it out. I initialized the array of 2 elements before I called them, so I don't know what is wrong. Please help me


For example, William Bank head was the 47nd Speaker of the House for the 74th congress.    Is there a word to describe 47 and 74?


How exactly do Bayesians define (or interpret?) probability?

Part of a series of trying to understand Bayesian vs frequentist:         I think I get the difference of how Bayesians and frequentists approach , but I'm not quite sure if or how that is supposed to explain to me how they view probability.  From what I understand, according to , a frequentist "defines" probability as follows:  Given probability space $(\Omega, \mathscr{F}, \mathbb{P})$, $\forall A \in \mathscr{F}$, $\mathbb{P}(A) \approx \frac{n_A}{n_t}$, where $n_t$ is the number of trials conducted and $n_A$ is the number of times A has occurred in those trials.  Furthermore, $\mathbb{P}(A) = \lim_{n_t \to \infty} \frac{n_A}{n_t}$.  Okay, so how do Bayesians define probability? The above seems to be one approach to computing probability of an event in addition to defining a probability.  Bayesians seems to assume a prior probability, conduct some trials and then update their probability, but that doesn't really seem to explain how they define what probability is.   says 'Bayesian probability is a quantity that we assign for the purpose of representing a state of knowledge, or a state of belief.'  What exactly does that mean? Is state synonymous to degree? For example, Walter's state of belief that a particular coin is fair is represented with the number 0.1 while Jesse's state of belief that the same coin is fair is represented with the number 0.2. Given new information, Walter's state of belief could become 0.96 while Jesse's state of belief could become 0.03. So, initially, Walter was less inclined to believe the coin is fair, but later on Jesse was more inclined to believe the coin is fair?  I'm hoping for something in terms of  like the frequentist one above.  Same Wiki page says 'The Bayesian interpretation of probability can be seen as an extension of propositional logic that enables reasoning with hypotheses, i.e., the propositions whose truth or falsity is uncertain.', it seems like Bayesian and frequentist probability are analogous to fuzzy and Boolean logic, respectively.


Why isn't my quill stem controlling the front wheel of my bike?

Please excuse me if some of my terminology is off. I don't know much about bikes.  When I came home from college I noticed that the seat of my bike was way to high and the headset was really low, I have a old style quil stem head set,. So I decided to raise the headset. When I raised the headset I did not know that I was not supposed to completely remove the headset stem bolt. I tried screwing it back in but it doesn't work. So now the headset does not control the front wheel, and I have no idea how to fix it. Can someone PLEASE help me!!! I also have a question, why is it that when I hit the bicycle stem bolt with a hammer it fixes it but only for a short time period?


If i have two 's on the battlefield and I attack with both. If I use the ability, "{B}:Vector Asp gains infect until end of turn", do I have to pay twice (once for each attacking Vector Asp) or only once?


MySQL adds broken comment script after each line

Every time I try to create a table using MySQL Workbench 6.3 CE it adds "broken" comments at the end of the script.  Example:  I am trying to create a table called "user". This is what the table should look like:   However when I click the apply button, the script generates incorrectly:  CREATE TABLE `user` (   `userid` INT NOT NULL AUTO_INCREMENT COMMENT '',   `record_status` INT NOT NULL DEFAULT 1 COMMENT '',   `createdby` VARCHAR(75) NOT NULL COMMENT '',   `createddate` DATETIME NOT NULL COMMENT '',   `updatedby` VARCHAR(75) NULL COMMENT '',   `updateddate` DATETIME NULL COMMENT '',   `username` INT NOT NULL COMMENT '',   `password` VARCHAR(75) NULL COMMENT '',   `firstname` VARCHAR(75) NULL COMMENT '',   `lastname` VARCHAR(75) NULL COMMENT '',   `email` VARCHAR(75) NULL COMMENT '',   `facebook_userid` VARCHAR(75) NULL COMMENT '',   `email_verified` VARCHAR(75) NULL COMMENT '',   PRIMARY KEY (`userid`, `username`)  COMMENT '');   The comment in this line should not be there, so the code should be:   PRIMARY KEY (`userid`, `username`));   and the code executes when I paste it into an editor and remove this comment. However I create massive databases daily. (Each with +- 15 tables). I can't keep doing this for each table as it is time consuming.  How can I disable this feature that adds the comments to the script? I don't need them in my databases


Assuming $f(x,y) = 1$, $0<x<1$, $0<y<1$, obtain the density of $Z = X-Y$.


Can we deduce two contradictory statements from a wrong statement?

In the proof that $\sqrt{p}$ is irrational where $p$ is a prime number:  We first assume $\sqrt{p}$ is rational.  From this we deduce $\sqrt{p}=\dfrac{a}{b}$, where $a$ and $b$ are co-prime.  Then using other reasonings we deduce $a$ and $b$ are not co-prime.  That is from the wrong statement (i.e. $\sqrt{p}$ is rational), we deduced two contradictory statements.  From a statement, if we apply correct reasonings, we may deduce two results which contradict each other. How can this be reasonable? Can anyone explain with simple examples?  Anyway; from a statement, if we apply correct reasonings, we may deduce a result which contradicts another established result. This seems reasonable to me. And this shows that the statement is wrong.


The famous 'Hat Check Problem' goes like this, 'n' men enter the restaurant and put their hats at the reception. Each man gets a random hat back when going back after having dinner. The goal is to find the expected number of men who get their right hat back. To calculate the expected value from is definition, we have to compute the probability with which 'k' men would get their correct hat back.    How to compute this probablity? I know that this problem can be solved by using 'Linearity of Expectation' in a much simpler way, but i would like to know the way to compute this probablity.


which is more grammatically correct on date 26/6 or in date 26/6?

which is more grammatically correct to say on date 26/6 or in date 26/6 ?  I am using the on as a preposition and I feel not sure about that.


Let $n\in\mathbb{N}$ and $(a,b)\in \mathbb{Z}^2$. Show that:   $$n|a^n-b^n\Longrightarrow n|\frac{a^n-b^n}{a-b}$$   I’ve tried an induction, but I gave up. Is there a direct proof?  To admin: Please open this post and wait one day before closing it since we are looking for new perspectives.


Hilbert, Gödel, and "God equations" - a 19th century lesson for 21st century physicists?

It seems there are a lot of respected physicists appearing on pop-sci programs (discovery channel, science channel, etc.) these days spreading the gospel of   Three examples, quickly: 1) Many programs feature Michio Kaku saying that he is on a quest to find an equation, "perhaps just one inch long," which will "describe the whole universe."  2) Max Tegmark has come out with  in which he expresses the gut feeling that "nothing is off-limits" to science.  The subtitle of this book is My Quest for the Ultimate Nature of Reality.  3) In the series  there is talk about a search for the "God equation."  (A good counter-example would be Feynman, but his self-described "non-axiomatic" or "Babylonian" approach does not seem popular with physicists today.)  Is there any sense among physicists that it might be impossible to articulate the "ultimate nature of reality" in equations and formal logic?  It seems to me that physicists are following in the footsteps of the 19th century mathematicians (led by Hilbert) who were on a similar quest which was put to rest by Gödel's incompleteness theorems in 1931.  Is there any appreciation for how the Incompleteness Theorems might apply to physics?  Has any progress been made on  for the 20th century?  Shouldn't this be addressed before getting all worked up about a "God equation?"


This page has an interesting video of beads 'syphoning' out of a glass beaker:    The host has a few explanations for the effect, but none of them sound plausible to me. The beads are in 'perpetual motion'? 'Shock wave'? What could cause an entire bead chain to syphon out of a beaker like water does out of a syphon? It certainly does not look to me that there was enough initial investment in energy to move the chain as is done. On the other hand, considering that only a small portion of the chain is moving at any one moment in time, the whole system could be considered to be moving very slowly thus meeting the initial energy investment requirement (very low velocity).


How to replace a word , special character present inside multiple files of a certain file extension using a single windows command only

How to replace a word , special character present inside multiple files using windows command only. I have tried using multiple commands, but it doesn’t work.


I am learning Blender and currently building a simple low poly model. Trying to follow reference picture I realize that it is very difficult to build a model such that all faces are perfectly planar. I can use flattening tool but some quads are never brought to perfect flatness. When tested wih 0.1 deg limit they show nonplanarity.   Even when I scale one face of a standard cube (in its own plane) it is enough to show nonplanarity above 0.01 deg. Similary scaling and/or rotating simple plain is enough to create nonplanarity above 0.02 deg.   I am guessing that this is related to the finite accuracy of numerical representation of the location of vertices. Clearly it makes sense to disregard this level of nonplanarity.   But how about 0.1 deg? 1deg?


I tried to create a remote filesystem folder with sshfs, it did not work and now I cant remove the folder  ls returns: d?????????  ? ?     ?            ?            ? remote and when I try sudo rm -fvr remote: rm: cannot remove 'remote': Is a directory


Convergence in probability with a maximum value

Let X1, X2,...,Xn be i.i.d. continuous random variables of the uniform distribution $Unif(0, \beta$), $\beta>0$. Consider Mn = max1≤i≤n Xi. Prove that Mn converges in probability to $\beta$. I know how to prove a sample $\bar X$ converges in probability to an expected value $\mu$ with the Chebyshev's inequality $P(|\bar X-\mu|> {\epsilon})\le \frac{{\sigma}^2}{{\epsilon}^2}$ with (in this case) E(Xi) = ${\mu}=\frac{\beta}{2}$ and Var(Xi) = $\frac{\beta^2}{12}$, but the new concept of Mn = max1≤i≤n Xi added to this confuses me a lot. Can someone explain this to me? Thank you!


Find the limit of $\begin{equation*} \lim_{x \rightarrow 4} \frac{\sqrt{1 + 2x} -3}{\sqrt{x} - 2} \end{equation*}$

Find the following limit: \begin{equation*} \lim_{x \rightarrow 4} \frac{\sqrt{1 + 2x} -3}{\sqrt{x} - 2} \end{equation*}   I have tried to divide the numerator and denominator by $\sqrt{x}$, but it did not work.  I have tried to multiply by the conjugates of the numerator and denominator simultaneously but it did not work.   I have tried to multiply by the conjugates of the numerator only but it did not work.  So what shall I do?


How can I protect my creations from Endermen?

Whenever I build something out of expensive blocks (like emerald blocks), a silly Enderman walks past and steal a block. Is there any way to prevent this, without ruining the creation (putting water around it, and spamming torches everywhere)?


When do you gain tag wiki edit suggestion privileges?

Empirically it seems that I just gained tag wiki edit suggestion privileges (ability to add a suggestion to the review queue, not to get my changes approved without peer review) in Stack Overflow when my reputation got over 500 points. However,  suggests there is a completely different logic involved, but it doesn't seem to match my personal experience. As far as I can tell the current logic is not explained in the  or on SO's own , although there is a lot of content in both and I might have missed something. I did see somewhere a note that anyone can suggest edits to the tag wikis, but I've misplaced where that was (somewhere within the linked FAQ pages, possibly?), and at least personally I couldn't suggest tag wiki edits in SO last week when my reputation was 495. I assume that this could be one of the many cases where SO does things a bit differently than most sites, but if so, is the limit in SO truly 500 reputation or some other milestone that I happened to hit over the weekend? Edit: there was no 'Edit tag info' button at all when I tried on Friday, but now there is.


Error at startup on Linux after computer shutdown during Ubuntu 18 update

I tried to update my laptop to Ubuntu 18.04 (from 16.04) last night, but I had a power outage and I believe it was interrupted in the middle. As I woke up and noticed that the power was out, I panicked, and, yeah, system corrupted as the laptop ran out of power.  Can anyone give some instructions on how to repair the system?    Full StartupError Message:   [     1.271631 ] Kernel panic - not syncing: VFS: Unable to mount root fs on unknown-block(0,0) [     1.271695 ] CPU: 0 PID: 1 Comm: swapper/0 Not tainted 4.15.0-36-generic #39-Ubuntu [     1.271753 ] Hardware name: ASUSTEeK Computer Inc. G74Sx/G74Sx, BIOS G74Sx.202 08/15/2011 [     1.271820 ] Call Trace:  [     1.271873 ]    dump_stack+0x63/0x8b [     1.271924 ]    panic+0xe4/0x244 [     1.271974 ]    mount_block_root+0x1f6/0x2da [     1.272025 ]    ? set_debug_rodata+0x17/0x17 [     1.272075 ]    mount_root+0x38/0x3a [     1.272126 ]    prepare_namespace+0x139/0x18e [     1.272186 ]    kernel_init_freeable+0x224/0x251 [     1.272189 ]    ? rest_init+0xb0/0xb0 [     1.272191 ]    kernel_init+0xe/0x110 [     1.272193 ]    ret_from_fork+0x35/0x40 [     1.272243 ] Kernel Offset: 0x24400000 from 0xffffffff81000000 (relocation range: 0xffffffff80000000-0xffffffffbfffffff) [     1.272505 ] ---[ end Kernel panic - not syncing: VFS: Unable to mount root fs on unknown-block(0,0)


I run Ubuntu 16.04 on Vmware box version 12.5.2. Trying to install Vamware tools using these commands:  VM->Install vmware tools copy whole VMWare Tools directory to ~ run sudo ./run_upgrade.sh   But nothing is happening and no error messages appear? How can I install vmware tools in the correct way?


Why didn't Harry die in the Forbidden Forest?

In the Forbidden Forest, did Harry fall on top of the Resurrection Stone after being hit with Voldemort's Killing Curse?  Would this have made him the 'Master of Death'?  Is that why he didn't die?


the meaning of 'waiting on Beyonce' part in this sentence

I have seen the sentence like 'I have been waiting on Beyonce to call me.' on the internet. And I can't understand the meaning of 'waiting on Beyonce' part. What is the meaning of the sentence 'I have been waiting on Beyonce to call me.' Please tell me.


Handling non understandable behaviour of Java date formats.

As I am not expert in handling of dates in java but I am unable to understand this behaviour.Here is my code  Date from = new SimpleDateFormat("dd/MM/yyyy").parse("05/07/2013"); System.out.println(from);     which gave me this output    Sat Jul 05 00:07:00 PKT 2013   And this is 2nd another code snippet   Date from = new SimpleDateFormat("dd/mm/yyyy").parse("05/07/2013"); System.out.println(from);    which gave me this output: Sat Jan 05 00:07:00 PKT 2013   Now the thing which is considerable is format. This format dd/MM/yyyy which have MM gave me correct output but this format dd/mm/yyyy which have small mm gave me wrong output (always give jan in month).I read the doc where it is mentioned that samll m is for minutes and capital M is for month My question is Can I never use small m here? if no , then why it is giving the result and on which basis it is giving jan everytime I know this is a basic question but after searching and after not finding any understandable thing , I posted it.Thanks


What does the "$\cdot$" mean in an equation

I am trying to solve an equation for a project that I am undertaking. The equation is very long and its probably not necessary to show it all here. Most of the equation is fairly straightforward; i.e., $1+(\frac{w}{W})(\frac{d}{t})$, etc. but at the very end it reads $\left(1+\frac{w}{W}\right)\left(\frac{D}{T}\right) \cdot \frac{1}{T}$.        $w$, $W$, $D$, and $T$ are all either constants or variables that I have solved already. My question is, what is the "$\cdot$" symbol asking me to do?  In the equation in the book, the "$\cdot$" is in the centre of the dividing line between $1$ and $T$, as opposed to down low like a period or full stop. I appreciate that I have phrased this question in an awkward manner, but as is obvious, I am no maths expert.  Here is a photo of the equation in the book:


I wonder what these shortcuts mean and since I already can figure out that "shortcut" is not the right word for it, I don't even know what to google so I'll just strike a question here.  Here's the screenshot:   So, what does M, A, ? and all other shortcuts mean exactly ?


Can you find the Duke 'o' Death in GTA 5 on xbox 360 when you start the game with no updates?


Run JQuery in the context of another frame

The client I am working with has a frameset like so...  <frameset rows="100,*, 0">   <frame name="theFrame" id="theFrame" src="blah.html" >   <frame name="theSecondFrame" id="theSecondFrame" src="foo.html" >   <frame name="importantFrame" id="importantFrame" src="myFrame.html" > </frameset>   When a certain action takes place I need my frame (importantframe which is currently hidden) to mostly take over the page and block any interaction with the other frames. I'm planning on blocking interaction using the jquery block UI plugin.  The problem is I can't actually change the foo.html or blah.html files. So the JS code cannot live there. What I need to do is execute my jquery code in the context of those frames. So just to recap, I need my JQuery code to live in myFrame.html but execute in the context of the other frames. How can I do that? Hope that makes sense.  Thanks CDR


Why does this regex with no special character match a longer string?

I am using this method to try find a match, in an example:  Regex.Match("A2-TS-OIL", "TS-OIL", RegexOptions.IgnoreCase).Success;   I got a true result. I am confused. I think this should return false since there is no special characters in the pattern. If I use ".+TS-OIL", true should be returned (. for any and + for more than 1). How should I do to get what I need?


What is the maximum possible length of a .NET string?

What is the longest string that can be created in .NET? The docs for the String class are silent on this question as far as I can see, so an authoritative answer might require some knowledge of internals. Would the maximum change on a 64-bit system?  [This is asked more for curiosity than for practical use - I don't intend to create any code that uses gigantic strings!]


In phonegap how to cancel an ajax request in program, I would like to set cancel button for control the request when it's too slow  $.ajax({     type: "GET",     url: url,     success: function(m) {         alert( "success");     } });


Which of the following is grammatically correct?  I am having OR I have. We/they/you are having OR we/they/you have.  For eg.  I have/ We have a problem that I/we can't seem get rid of.  OR  I am having/ We are having a problem that I/we can't seem get rid of.


Is there a Term to describe the relationship between two people when they share an Alma Mater?  For example; Neil Armstrong is an alumnus of Purdue University. I am an alumnus of Purdue University. Both Neil and I are alumni of Purdue University, which is to say we share an alma mater. So, I'm looking for a term to describe my relationship to to Neil with out needing to explicitly reference the university. Is co-alumni a real term? Is it appropriate to say that Neil and I are co-alumni? Is there something better? Further, is there a way to specifically describe the relationship between two people from the same graduating class?  Thank You in advance!


How do I disable the the charms bar? I am surprised there is no easy way to disable the feature.  Here's what I've done so far:  1.) Disabled right edged swipe gesture in my touchpad settings. Part of the problem is solved as this was probably the most common way the charms bar would pop up. But there are still many other ways it can pop up.  2.) Used regedit and added the key "EdgeUI" with "DisableCharmsHint" set to 1 in HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\ImmersiveShell\  This stopped it from popping up whenever I moved the cursor to the top right or bottom right of the screen. I mean who ever needs to move his/her mouse there? (sarcasm)  But there's ANOTHER WAY it pops up: when I move the cursor to the top right of the screen followed by moving it downwards OR when I move the cursor to the bottom right of the screen followed by moving it upwards! How do I disable this method of invoking the charm bar?


Given measure zero $X \subset [0,1]^2$, find dense $Y \subset [0,1]^2$ s.t. no absolute differences of pairs are in $X$

Given measure zero $X \subset [0,1]^2$, is there a dense subset $Y \subset [0,1]^2$ such that for all distinct pairs $y,y' \in Y$, we have $(|y_1 - y'_1|,|y_2 - y'_2|) \notin X$ ?   This generalizes a question which asks to find dense $Y \subset [0,1]^2$ such that no two points in $Y$ lie on a common horizontal or vertical line. In that case, $X = \{(0,a) : a \in [0,1]\} \cup \{(a,0) : a \in [0,1]\}$, which has measure zero.


got LNK2019 and LNK1120 when compiling BST source code

This code is aim to create a binary search tree class.   #pragma once #include "Dictionary.h" #include "BSTNode.h"   template <typename Key, typename E> class BST : public Dictionary<Key, E> { private:     BSTNode<Key, E> * root;     int node_count;      void ClearHelp(BSTNode<Key, E>*);     BSTNode<Key, E>* InsertHelp(BSTNode<Key, E>*, const Key&, const E&);     BSTNode<Key, E>* DeleteMin(BSTNode<Key, E>*);     BSTNode<Key, E>* GetMin(BSTNode<Key, E>*);     BSTNode<Key, E>* RemoveHelp(BSTNode<Key, E>*, const Key &k);     E FindHelp(BSTNode<Key, E>*, const Key&) const;     void PrintHelp(BSTNode<Key, E>*, int) const; public:     BST() { root = nullptr; node_count = 0; }     ~BST() { ClearHelp(root); }      void Clear() override { ClearHelp(root); root = nullptr; node_count = 0; }     void Insert(const Key& k, const E& e) override     {         root = InsertHelp(root, k, e);         node_count++;     }     E Remove(const Key& k) override     {         E tmp = FindHelp(root, k);         if (tmp != 0)         {             root = RemoveHelp(root, k);             node_count--;         }         return tmp;     }      E RemoveAny() // Delete min value     {         if (root != nullptr)         {             E temp = root->Element();             root = RemoveHelp(root, root->key());             return temp;         }         else return 0;     }      E Find(const Key &k) override { return FindHelp(root, k); }     int size() override { return this->node_count; }     void Print() const     {         if (root == nullptr)             std::cout << "The BTS is empty!\n";         else             PrintHelp(root, 0);     } };   I got these errors after trying to compile the code in VS2017:     1>main.obj : error LNK2019: unresolved external symbol "private: void   __thiscall BST::ClearHelp(class BSTNode *)" (?ClearHelp@?$BST@HH@@AAEXPAV?$BSTNode@HH@@@Z) referenced in function   "public: virtual __thiscall BST::~BST(void)"   (??1?$BST@HH@@UAE@XZ)       1>main.obj : error LNK2019: unresolved external symbol "private: class   BSTNode * __thiscall BST::InsertHelp(class   BSTNode *,int const &,int const &)"   (?InsertHelp@?$BST@HH@@AAEPAV?$BSTNode@HH@@PAV2@ABH1@Z) referenced in   function "public: virtual void __thiscall BST::Insert(int   const &,int const &)" (?Insert@?$BST@HH@@UAEXABH0@Z)      1>D:\05Development\04 C_C++\C\Algorithm\BTS\Debug\BST.exe : fatal   error LNK1120: 4 unresolved externals


I'm running  on a Windows 7 (RTM) 64-bit host. When I create a new virtual machine and try to install 64-bit Windows 7 on that VM, I get "this CPU is not compatible with 64-bit mode."  Is there a way to create 64-bit virtual machines?


How do two-leaded color changing LEDs work?

I have a few 3mm color-changing LEDs which I harvested from a toy. They fade in between all different colors, and then after a little while, they blink crazily between all the colors. After a few moments, the cycle repeats.  What is interesting about them (and what I wasn't expecting) is that they only have two leads, like a normal hobbyist LED.   I understand that, like an RGB LED, they have multiple elements (probably not the right word) inside. But how do they achieve the color changing and cycling?  Here is a picture of the LED in question:    Notice the little bit of black material inside the LED. Could this possibly be a tiny chip?


Can't install R with sudo apt-get install r-base

When I try to install R with sudo apt-get install r-base, it says  Reading package lists... Done Building dependency tree        Reading state information... Done Some packages could not be installed. This may mean that you have requested an impossible situation or if you are using the unstable distribution that some required packages have not yet been created or been moved out of Incoming.   The following information may help to resolve the situation:  The following packages have unmet dependencies:  r-base : Depends: r-base-core (>= 3.2.1-4vivid0) but it is not going         to be installed       Depends: r-recommended (= 3.2.1-4vivid0) but it is not going to be installed       Recommends: r-base-html but it is not going to be installed E: Unable to correct problems, you have held broken packages.


Too slow to select application to open a download file in Firefox

For unknown reason, some of downloaded pdf files in Firefox are opened by default by gedit, and some are by default by evince.  For those which will be opened by default by gedit, I want to select the executable file /usr/bin/evince when I initiate the download. But it always takes very long to show the many files under /usr/bin/, and sometimes forever. (See the picture below. Actually it should be "Open with" selected, not "Save File".).  I wonder what I can do to make it faster to select evince to open a pdf file when finish downloading it?  Thanks.    In my Firefox preferences:


How to install Ubuntu on Windows machine while still maintaining seamless boot to Windows?

I am currently running Windows 7 as the only OS and I am wondering if it is possible to install Ubuntu as secondary OS, which would only be accessible via some explicitly called boot menu - by that I mean that after I am done with installing Ubuntu and setting this up, if I restart PC it would boot exactly like it does now, when only Windows 7 is installed. If I would want to access Ubuntu, I would have to press some key to bring up boot menu before Windows loads (or just go straight to Ubuntu without any menu actually).  Is this possible?


I have list of book titles and I have to list chapters like this.  Title 1         Chapter1        Chapter2        Chapter3        Chapter4 Title 2         Chapter1        Chapter2   So, I have list inside a list. I can get list of books (and titles) but when i reference their chapters i get nothing. well, how can I do that?  <% foreach (var item in Model) { %>

             	                              <%= Html.Encode(item.Text) %>
          <% foreach (var chapters in item.Chapter){%>
                              <%=Html.Encode(chapters.Number)%>             	                              <%=Html.Encode(chapters.Text)%>
         <% } %>
          <% } %>


I'm trying to write a bash script that will go into a directory loop through the .gz files and delete them if they are empty (ie the uncompressed file contained within in empty.  I've got a couple of questions:   Is there a standard file size of a compressed (gz) empty file I can check for? Or is there a better way to check if a gz contains an empty file without decompressing it with a bash script?   I was trying to use the following code to acheive this but it relies on the filesize being 0 i think.  for f in dir/* do     if [[ -s $f ]]     then         do_file_creation     fi done


13.04 will not show up as an upgrade on my update manager

My update manager on 12.04 will not find the upgrade to 13.04. I would like to know why I can't see it.


I was wondering, given an $n \times n$ square matrix, let function $\det : \left(a_1,a_2,\ldots,a_{n^2}\right) \to \textbf{R}$ give the determinant, where $a_{k}$'s are the entries of the $n \times n$ matrix.  Is this function (determinant) a differentiable kind?  If so, is the derivative continuous? That is, is $d\left(\det\right)$ a continuous function?  Furthermore, if so, to what differentiability class does this $\det$ function belong?   Thanks in advance.


The Ocelot won't tame In the Windows 10 PC Version

I'm having the same trouble with the Ocelot. It was walking towards me and I right clicked it lots of times with the raw fish in hand, but it still only goes into breeding mode and it won't tame them at all.


How can I copy/transfer games via external hard drive?

I have successfully transferred "Killing Floor" from my brother's laptop to my own via external hard drive. The problem, now that I have all the files, is that I don't know how to launch the game through Steam. All I did was copy files from his Laptop to the hard drive, then from the hard drive to my laptop, then I put the files in the "Steamapps" folder under "Steam" in my laptops hard drive. So the question is, how do I start up the game through Steam?


Call javascript from Iframe to aspx page

I have two pages a.aspx and b.aspx. a.aspx have an Iframe and I load the b.aspx page in that Iframe. Is it possible to call a javascript from b.aspx to a.aspx? Thanks in advance


So I am making a script that adds two numbers (decimal numbers) together, which I have encountered a problem.    I made the script, it turns out pretty good:  0.1 + 0.5  //0.6 0.2 + 0.3  //0.5   But soon I see:  0.1 + 0.2  //0.30000000000000004 0.01 + 0.06  //0.06999999999999999   And it does not look right to me. I know it is a shortcoming of using float point with finite bits, but I can't find a way to fix that.  Math.ceil   //No Math.floor  //No .slice      //No   UPDATE  Is it possible to multiply the numbers by 1000 first, then add them then divide it by 1000?


I have email addresses encoded with HTML character entities. Is there anything in .NET that can convert them to plain strings?


In the US, we have 4 options for cellular plans (AT&T, Verizon, T-Mobile & Sprint).  To get a comparison, who are the top 3-4 companies that I have to choose from in London? and which one has the largest coverage outside of London i.e. Verizon has the largest coverage in the US?


prove that $$(\frac{n}{3})^n<n!<e\cdot(\frac{n}{2})^n$$  I tried to prove by the induction that $(\frac{n}{3})^n<n!$ and $n!<e\cdot(\frac{n}{2})^n$, but I failed  my assumption $n^n<n!*3^n$  $$(n+1)^{n+1}<(n+1)*3^{n+1}$$ $$\frac{(n+1)^n}{9}<n!*3^{n-1}$$


I get a long list of such arrays  {     "id": "byu6g6c4cjys5mdkg5znh8ju8c",     "create_at": 1511875272294,     "update_at": 1511875272294,     "delete_at": 0,     "display_name": "BMA",     "name": "BMA",     "description": "",     "email": "aleksandar.ivanov@random.com",     "type": "O",     "company_name": "",     "allowed_domains": "",     "invite_id": "gdgz1tbxuinntx1fbr1ax7kehy",     "allow_open_invite": false,     "scheme_id": null   }   I want to get by JQ only the ID where the name is BMA. At the moment I parse " jq -r '.[]["name"]" and I can filter the output from curl by name and I will get "BMA" and also 100 other names, but I need to filter only the ID where name is =BMA. Any ideas?


High school quadratic inequality question

Any help with the following question would be very much appreciated.     The equation $2x^2 + ax + (b + 3) = 0$ has real roots. Find the minimum value of $a^2 + b^2$.   Please note that, unfortunately, the question provides no clarification regarding the nature of $a$ and/or $b$.


I am trying to install software in Ubuntu and getting error 404 Not Found [IP: 91.189.95.83 80]

When I run sudo apt-get update  I get this error:     **404  Not Found [IP: 91.189.95.83 80]**     Err:5 http://in.archive.ubuntu.com/ubuntu focal InRelease                                Could not connect to in.archive.ubuntu.com:80 (2403:8940:ffff::f). - connect (113: No route to host) Could not connect to in.archive.ubuntu.com:80 (103.97.84.254), connection timed out     Err:6 http://in.archive.ubuntu.com/ubuntu focal-updates InRelease       Unable to connect to in.archive.ubuntu.com:http:     Err:7 http://in.archive.ubuntu.com/ubuntu focal-backports InRelease       Unable to connect to in.archive.ubuntu.com:http:     Reading package lists... Done     E: The repository 'http://ppa.launchpad.net/webupd8team/java/ubuntu focal Release' does not have a Release file.     N: Updating from such a repository can't be done securely, and is therefore disabled by default.     N: See apt-secure(8) manpage for repository creation and user configuration details.`  Please help to fix it.


Proving two entire functions are constant.

Let $f$ and $g$ be entire functions such that $f^n+g^n=1$, where $n\geq 3$ is an integer. Prove that $f$ and $g$ are constant.  I suppose I should somehow prove that either $f$ or $g$ is bounded so that I can apply Liouville's Theorem, but I don't see how. I tried setting the derivative of the left hand side equal to zero and work with that but that did not seem to work.


Can only Extrude or move vertices/edges in a pre-set distance

I just started using blender yesterday to model a character. I got through most of the head but now, every time I want to move vertices/edges or extrude, I cannot do it properly. If I try, it moves at a pre-set length that I can't seem to get away from. Please help!  You can see the file here ()


Is there any consensus on the capitalization of theories?

Should the name of theories be capitalized? Does this depend on convention, the particular theory itself, or whether or not it contains a proper name?   I appreciate any input, thank you!


In a modern SPFx Web Part, how do I check if a URL exists?

I am creating a Web Part that shows a video that might or might not be in another Document Library.  If the video exist, I should display it.  If it doesn’t, I should display another video.  How can I create a _videoExixts function in typescript?  In javascript I would do something like this:  function _videoExixts(url) {     var http = new XMLHttpRequest();     http.open('HEAD', url, false);     http.send();     return http.status!=404; }


Is there a short way to say $f(f(f(f(x))))$?  I know you can use recursion:  $g(x,y)=\begin{cases} f(g(x,y-1)) & \text{if } y > 0, \ \newline x & \text{if } y = 0. \end{cases}$


Tag excerpts from 'obligatory' tags on per-site metas do not appear in the 'all tags' page?

Tag excerpts from 'obligatory' tags (e.g. ) and 'moderation' tags (e.g. ) on per-site metas do not appear in the  page. However, in Meta Stack Exchange they do (see picture below).    I have used Cross Validated SE and GIS SE as examples. Notice that excerpts for such tags do exist (for example, [discussion] -->  and , respectively).   This happens probably because while in Meta SE the excerpts have a history (were edited at least once) on the per-site metas which I cited as examples still have the system's default excerpt.   Nonetheless, I think we should take advantage that there are excerpts for such tags an enable them in the 'all tags' page.


How do you politely ask for someone's gender?

If you, for example, have to add a person to an application whilst that person is on the phone, how do you politely ask for that person's gender if the voice and/or name has not proven decisive?  To clarify why I posted this question on this site: I was looking for an answer within the context of the English language and usage. The given answers have proven that this question really isn't off-topic, other languages know different distinctions that are relevant to addressing this issue.


Find all prime numbers $p$ and $q$ such that $p^{q+1} + q^{p+1}$ is a perfect square.  Number theory problems like these are always difficult for me. So please insert the topics under which this problem has been asked and also I welcome your solution.


Can you easily export a .blend to a previous version of Blender?

I have 2 versions of Blender, 2.79 and 2.9. I edited a .blend file that was made in 2.79 today in 2.9, then saved. Now, I cannot open it in 2.79 anymore (it just crashes Blender). However, there are plugins in the 2.79 version that I haven't yet installed, or might not exist in 2.9. And I have to deliver some files. I now that all Adobe apps allow you to export documents to a previous version if you need, but I couldn't find anything about Blender. I would prefer not to have to redo textures, etc. Can I export the file from 2.9 to 2.79 easily?


Why is using "have" or "have had" necessary?

Just one example I recently saw, I also hear people talking this way, and wonder why. Washington Post title today reads, "Many who have received the coronavirus vaccine wonder..." Another news title reads, "People who have had the vaccine..." Why is it necessary to add "have" or "have had" instead of simplifying the statement with, "Many who received the coronavirus vaccine wonder..."? Just seems like adding extra words, which looks/sounds wordy instead of getting to the point.


In The Empire Strikes Back as Han Solo leaves to look for Luke Skywalker a rebel worker says     Your tauntaun will freeze before you reach the first marker.   Han replies     Then I'll see you in hell!   Is there a concept of heaven and hell in the Star Wars mythology? If not, to what is he referring?


I have an old assembled PC with    2.6 GHz Intel core2 Duo  4 GB ram and  Nvidia Gforce 7100 GS Graphic card.   I tried to Install Ubuntu 14.04. When I tried it before installing it worked smoothly , however when I installed and ran it, the screen was sluggish from the time of login and the mouse cursor took a lot of time to move from one point to another.   When I ran ubuntu 12.04 or lower there were no such issues. Any idea what could be the problem and solution for this ?


Wrong site icon showing up in hot questions feed

I recently saw a few instances of the wrong site icon showing up to certain questions in the "hot network questions" feed. Here are a few of the more, er, interesting ones:        The Workplace SE seems to be disproportionately affected, and hovering over the site icon displays the correct site name (all of the above are actually on Worldbuilding).  I can't provide steps to reproduce, but my environment is Firefox 61.0.1 on Ubuntu 16.04.


Buy a second seat in order to bring an extra bag?

We're trying to get from Krakow to London in order to fly home on Virgin this summer. AFAIK all the intra-Europe flights share the same luggage policy: 20-25kg max luggage weight per passenger, with a overweight charge of 5-12 euros per kilo and no option for a second bag.  We'd like to bring an extra suitcase of personal effects.  Lacking any other reasonable options, I had the bright idea of flying EasyJet to London and just buying an extra $122 ticket so we could bring one more suitcase.  But I'm not sure if that's even possible, and not sure if EasyJet is still going to hold me to the 20 kilos per person.    Would this strategy work?  Update  What we ended up doing was flying first from Krakow to Frankfurt on Lufthansa, and then buying a completely separate ticket from Frankfurt to London (not even on the same itinerary). KraKow isn't big enough to have a lot of international options, and going to London leaves the Schengen zone.  Trying to get directly from Krakow to London had too few choices.  And Lufthansa has a reasonable baggage policy.


Should I choose shutter speed or aperture first?

I am learning about photography and in process of that reading few books and online resources to get some basics.  Currently i am reading "Understanding Exposure" by Bryan Peterson.While going through book, i came across few sections where he first choose "shutter speed" in place of the "aperture".  I am not sure how relevant this question is  , but i am curious to know about these decision. Is there any thumb of rule for these decisions, when to go with aperture or when to go with shutter speed or it just a decision based on experience.  In All cases Camera was set in Manual mode


Polynomial Long Division Algorithm: question on wiki examples

I was  the algorithm on  for polynomial long division works for $\mathbb{Q}, \mathbb{R}, \mathbb{Z}$.  Using  I now understand it over $\mathbb{Q}, \mathbb{R}$, however am having challenges using the same steps over $\mathbb{Z}$.   I will provide an example with questions.  has another base-2 code example that shifts bits and also has a recurrence relation $r_{j+1} = B r_j - q_{n-(j+1)} b$ where $r_j$ is the partial remainder, $B$ the base, $q_{n-(j+1)}$ digit of the quotient, $n$ number digits and $b$ divisor.  I'm assuming $r_0 = 0$.  I don't understand why $b$ is in the first term. For such a widely used algorithm, there are many step by step explanations on "how to do it" but very little algebraic explanation with explicit proof of what is occuring.  So I appreciate your guidance. QUESTIONS  Can anyone describe algebraically or with set theory the integer algorithm?  Perhaps using the recurrence relation above?  Maybe I'm overlooking something. I'm curious for the base-2  algorithm.  Does anyone know why it shifts higher order bits numerator to low order in the denominator? An example follows where I'm getting stuck using  suggested algorithm which seems suited for $\mathbb{Q},\mathbb{R}$.  Does anyone know where I'm going wrong?  Example Using  algorithm. $bq + r = a$ $a = 1*10^1 + 8*10^0, b=9*10^0$ The first steps is to divide the highest degree terms $\frac {1*10^1}{9*10^0} = 0$ because we are over a field of $\mathbb{Z}$.  Now $r = a = 1*10^1 + 8*10^0$.  This process seems to continue forever with $q = 0$.


Why is the voltage across a PN junction 0 v when it is in open circuit conditions?

Why is the voltage across a PN junction 0 v when it is in open circuit conditions ?