How to get text above and below double harpoon (reversible reaction) symbols in an equation

I'm working on the Chemwiki Dynamic Textbook Project at UC Davis, California and I've run into a problem. I need to formulate a symbol containing double harpoons (as in a reversible reaction, e.g. \rightleftharpoons); however, I need to have text both above and below the harpoons. I have an image I can email, but I can't post with an image because I'm new to this.  I can find code for \overleftrightarrow and \underleftrightarrow, but that's not quite what I need. I need both, on the same expression. If anyone has a minute to help me, I would greatly appreciate it!


If chown can change groups, why was chgrp created?

So there's chown which lets you change the owner and group of files and/or directories. But there's also chgrp which only changes the group. Why was chgrp created? Isn't it redundant?


How to change items of second listwidget when I clicked first listwidget item

As I mentioned at title, I want to connenct two listiwdgets.(or it is ok to use combobox) What I want to make is that If I click a item of first listwidget, items of second listwidget are changed.  Try) I tried to connect two listwidgets as below   print clicked items check if printed text is same or not.   Problem) When I click a item in first listwidget, result is not what I want and fail to list-up new items in second listwidget.  from PyQt5 import QtCore, QtGui, QtWidgets  class Ui_Dialog(object):      def __init__(self):         self.list1 = ["a","b","c","d"]         self.list2 = ["alpha","beta","gamma","delta","epsilon","zeta","eta","theta","lota","kappa"]         self.list3 = ["alpha","beta"]         self.list4 = ["gamma","delta"]         self.list5 = ["epsilon","zeta","eta","theta","lota","kappa"]       def setupUi(self, Dialog):         Dialog.setObjectName("Dialog")         Dialog.resize(433, 509)         self.buttonBox = QtWidgets.QDialogButtonBox(Dialog)         self.buttonBox.setGeometry(QtCore.QRect(70, 450, 341, 32))         self.buttonBox.setOrientation(QtCore.Qt.Horizontal)         self.buttonBox.setStandardButtons(QtWidgets.QDialogButtonBox.Cancel|QtWidgets.QDialogButtonBox.Ok)         self.buttonBox.setObjectName("buttonBox")         self.listWidget = QtWidgets.QListWidget(Dialog)         self.listWidget.setGeometry(QtCore.QRect(20, 10, 256, 192))         self.listWidget.setObjectName("listWidget")         self.listWidget.addItems(self.list1)          self.listWidget_2 = QtWidgets.QListWidget(Dialog)         self.listWidget_2.setGeometry(QtCore.QRect(20, 230, 256, 192))         self.listWidget_2.setObjectName("listWidget_2")         self.listWidget_2.addItems(self.list2)          self.retranslateUi(Dialog)         self.buttonBox.accepted.connect(Dialog.accept)         self.buttonBox.rejected.connect(Dialog.reject)         QtCore.QMetaObject.connectSlotsByName(Dialog)          self.listWidget.itemActivated.connect(self.itemActivated_event)       def itemActivated_event(self, item):         print(item.text())         if print(item.text()) is "a":             self.listWidget_2.clear()             self.listWidget_2.addItems(self.list3)          elif print(item.text()) is "b":             self.listWidget_2.clear()             self.listWidget_2.addItems(self.list4)          else :              self.listWidget_2.clear()             self.listWidget_2.addItems(self.list5)        def retranslateUi(self, Dialog):         _translate = QtCore.QCoreApplication.translate         Dialog.setWindowTitle(_translate("Dialog", "Dialog"))   if __name__ == "__main__":     import sys     app = QtWidgets.QApplication(sys.argv)     Dialog = QtWidgets.QDialog()     ui = Ui_Dialog()     ui.setupUi(Dialog)     Dialog.show()     sys.exit(app.exec_())   What I really want is that,   Clicking item "a" in listwidget1, listwidget2 has new item "alpha, beta" When I click another item "b" in listwidget1, listwidget2 has clear items and has new item "gamma, delta"   There are so many problem because it is my first time to use python and pyqt5.


How do you write long division of a multivariable polynomial?

It is clear that when you have two polynomials f and g, there exist uniquely determined polynomials q and r such as $f=qg+r$ (1), where $\deg{r}\leq \deg{g}$.  But how do you extend this theorem for polynomials such as $f(x,y)$ which are being divided to $g(x,y)$ and also what if the two poynomials were $f(x,y,z)$ and $g(x,y,z)$.   This is what I mean: For example, let $f(x,y,z)=x^3+y^3+y^3-x^2-y^2-z^2$ and $g(x,y,z)=xy+yz+zx$. If you divide $f$ to $g$ then would there hold a relation similar to (1)? What if the polynomials were arbitrary?  After writing the general statement, could you also provide an example for some specific polynomials, please? Thank you in advance!


How does $cos(x) = \frac{\vec{v} \cdot \vec{w}}{|\vec{v}| \cdot |\vec{w}|}$ make sense?

In Multivariable Calculus, the professor said that in order to compute the angle $x$ between two vectors $v$ and $w$, we use the formula: $\cos(x) = \frac{\vec{v} \cdot \vec{w}}{|\vec{v}| \cdot |\vec{w}|}$  He also mentioned "Projection" but I didn't understand much of it. The only thing I got was that we can create a right triangle by drawing a perpendicular line from one vector to the head of the other and compute the angle like that using $\cos$, but I don't understand why we're multiplying vectors, or dividing by their magnitudes…how do those operations make sense?  Also, in the specific example, the result of $\cos(x) = \frac{\vec{v} \cdot \vec{w}}{|\vec{v}| \cdot |\vec{w}|}$ ended up being $1/2 = \pi/2$. Where does $\pi/2$ come from here? I can't understand how we go from $1/2$ to $\pi/2$.


Object Deploy fails with: "duplicate value found:  duplicates value on record with id"

When I try to redeploy an object that exists in source and destination orgs, the deploy fails with the cryptic and useless error message:  duplicate value found <unknown> duplicates value on record with id: <unknown>   This fails whether I deploy with Migration Tool or IDE. Note, individual fields are deployable, but not the object.


How to expand TeX's "main memory size"? (pgfplots memory overload)

I'm compiling one pretty simple LaTeX file with few dozen of pgfplots. Now, I can compile part by part, but am unable to compile it all at once. I really need good precision for all those plots (noise plots) and would like to avoid decimating graphs more. When I run compile, I get this error message:  [...] TeX capacity exceeded, sorry [main memory size=3000000].   Is there a way to avoid this message somehow? How am I supposed to use pgfplots if I can't plot couple dozen of figures with it without having TeX overloaded? How to expand TeX memory size, please?


Is it possible two graphical interfaces at the same time in different tty?

For example using in tty7 the default desktop and in other tty using another graphical session with other user.


If I need some program not in live installation, can I install the program without actually installing Lubuntu?

I downloaded Lubuntu 18.04 iso file into my flash drive and make the flash drive into a bootable device.  I inserted the flash drive into a laptop and booted into Lubuntu without actually installing it.  If I need some program not already in the Lubuntu 18.04 iso file, do I need to actually install Lubuntu on the laptop? Is it possible to install some programs like google chrome browser without actually installing Lubuntu on the laptop?  Thanks.  Which one below is the limit on the total sizes of the programs that I can install?  $ df -h Filesystem      Size  Used Avail Use% Mounted on udev            1.7G     0  1.7G   0% /dev tmpfs           340M  1.4M  338M   1% /run /dev/sdb        1.1G  1.1G     0 100% /cdrom /dev/loop0      968M  968M     0 100% /rofs /cow            1.7G  367M  1.3G  22% / tmpfs           1.7G   32M  1.7G   2% /dev/shm tmpfs           5.0M  4.0K  5.0M   1% /run/lock tmpfs           1.7G     0  1.7G   0% /sys/fs/cgroup tmpfs           1.7G  4.0K  1.7G   1% /tmp tmpfs           340M   20K  340M   1% /run/user/999


A Question On Euler's Proof Of the Basel Problem

I've studied the proof that Euler gave for the famous , and it would seem that while it is technically correct, he does not justify all of his steps properly. Namely, he assumes that   $$\frac{\sin(x)}{x}=\left(1-\frac{x}{\pi}\right)\left(1+\frac{x}{\pi}\right)\left(1-\frac{x}{2\pi}\right)\left(1+\frac{x}{2\pi}\right)\dots$$  simply because they have the same roots, which is really not a strong enough condition. How do you really show that the equality holds?  He then notices that if you use the above equality, and consider it against the Taylor expansion for $\frac{\sin(x)}{x}$, then you can equate the coefficients of the two infinite expansions at each order, and the result of the Basel problem follows. But how do you know that if you have two different expansions for a function, then their coefficients at each order must be equal?  I would really appreciate if someone could show me how to make these two intuitive, yet informal, steps rigorous.


Ways to remove/select scanning artifacts from document

I often receive scanned documents that has dots and grains in them. I often use the paintbrush in gimp to manually remove them, but it occurs to me that all the dots share so many similarities that a simple algorithm should be able to "white" them out automatically.   Take this example:   If blacks surrounded by whites in a given area is detected then select that said area for further processing:    Does anybody know of any scripting-way or plugin that can do such a thing?


I haven't finished writing this and im confused on how to do this. i need to output the averages together and indiviually(major,minor,other)-NOT FINISHED need input on what to do. you have to ask the user to continuing entering grades until they enter a negative number.  import java.util.Scanner;  public class GradingTwo {     public static void main(String[] args)     {         Scanner keyboard = new Scanner(System.in);         double grade = 0.0;         double majAvg = 0.0;         double minAvg = 0.0;         double othAvg = 0.0;         double catMaj = 0.7;         double catMin = 0.2;         double catOth = 0.1;         int count = 0;      while(grade>=0 && grade<=100)     {         System.out.println("Input a numeric grade from 0 to 100: ");         grade = keyboard.nextDouble();          if(grade<0)             break;          System.out.println("Input a grade category: ");         String gradeCat = keyboard.next();          if(gradeCat=="major")         {             majAvg+=grade;             count = count + 1;         }     else if(gradeCat=="minor")             minAvg+=grade;     else if(gradeCat=="other")             othAvg+=grade;           System.out.println();     }     System.out.println("Major Average       " + (majAvg/count)); }   }


How to prove $1+{x\over 2}-{x^2 \over 8}0$?

How to prove $1+(1/2)x-(1/8)x^2<\sqrt{1+x}$ for $x>0$ by Taylor Expansions up to $n$ order or Mean Value Theorem? I tried to apply MVT on $\sqrt{1+x}$ and get $\displaystyle \sqrt{1+x}=1+\frac{1}{2\sqrt{1+\xi}}x$ for $\xi\in (0,x)$. How to do next?


Null Pointer Exception While trying to Connect to FTP server

FTPClient mFTPClient;  mFTPClient = new FTPClient();  // connecting to the host  mFTPClient.connect(host, port);   After this line of code, the following exception thrown.     Method threw 'java.lang.NullPointerException' exception. Cannot evaluate android.system.StructAddrinfo.toString()


Why can't my program find the libraries in "/usr/local/lib"?

I'm on Ubuntu 10.10, and I've just upgraded opencv to 2.4.2.   The problem is that each time I open a new shell and try to compile and run, it compiles but doesn't run due to the following error:  ./a.out: error while loading shared libraries: libopencv_calib3d.so.2.4: cannot open shared object file: No such file or directory   As far as I can see, this file is located in /usr/local/lib/!   I can get it to run by running the following beforehand:  export LD_LIBRARY_PATH=/usr/local/lib   How can I fix this issue?


I have installed Opera browser but an older version. Because, the most recent version does not play Netflix and some more platforms videos. This issue is related with libffmpeg.so file and WidevineCDM. However, I solved this issue using an older version of Opera. Now, I want an exception for Opera. I want it to be not updated when I enter the command sudo apt-get update. How can I do that? Thanks.


How to request Moderator elections in a Beta site?

The Project Management SE is well populated and considered useful to those of us that frequent it but the moderation is sparse and we have had examples recently of  and threads from lack of Moderator oversight.   How can we increase the amount of Mods and force an election to supplement the current moderators on the site since many of the power users from the past hardly frequent the site any more.  I don't want to be a Mod myself particularly but I can think of several who would be well suited to do so.


I want to read GPX track points with their time stamps into QGIS. I try GPS Tools, GPX Conversions, Waypoints from a track.  This fails on my PC at office (QGIS code revision d94c044). Sometimes QGIS stalls with high CPU usage, but most times I get an error "The layer C:/Daten/CurrT.gpx?type=waypoint is not a valid layer and can not be added to the map".  It works on my Laptop at home (QGIS code revision ebebdf3), but the created features don't contain timestamps. Fields are name, elevation, comment, description, source, url, url name.  How should I proceed?  BTW both versions of QGIS insist "You are running the current version of QGIS" and don't offer updates. Is it reasonable to re-install the (apparently) same version of QGIS from time to time?


Does Loop Quantum Gravity predict general relativity in semi-classical Limit?

Recently i read about Loop Quantum Gravity in Wikipedia and found this below statement .     Presently, no semiclassical limit recovering general relativity has been shown to exist.    But i also came across a paper in  whose abstract claims that Einstein's equations arise as a result of Semi-Classical Limit from Covariant Loop Quantum Gravity.     In this paper we explain how 4-dimensional general relativity and in particular, the Einstein equation, emerge from the spinfoam amplitude in loop quantum gravity.    So is the Wikipedia article outdated or is the paper's idea falsified?


smallest number of cells classified in a raster

I am using ArcGIS 10.3 and I ran con statement in the ModelBuilder within ArcGIS. I have an output raster (2m*2m) classified into four different classes. The raster has small pockets of 4 classes. I want to know what is the smallest number of cells that ModelBuilder has been able to categorize into a particular class.   Is there any specific command to figure this out or randomly we can say it can pick even a single cell that falls into a separate class?


Can 32-bit drivers be loaded into 64-bit Windows 7?

I am using Windows 7 32-bit on a Dell Vostro 1014 (Intel Core 2 Duo T6670 CPU) and now I want install a 64-bit version of Windows.  My questions:   How can I be sure that my laptop is compatible with 64-bit Windows 7? On the Dell website, I only see drivers for Windows 7 32-bit. Will Windows 7 64-bit supply its own drivers for my laptop, or will I be unable to use the 64-bit version due to the unavailability of 64-bit drivers from Dell? If I try to install 32-bit drivers on Windows 7 64-bit, will the 32-bit drivers work?


How to determine which logins have sysadmin?

How can you determine through T-SQL which logins have sysadmin?  Thanking you


How do you give a name, lore, and enchantments in Minecraft using a single Command Block? (Bedrock Edition 1.16)

Here's a quick backstory as to why I'm making this post. If you don't want to read it, skip to the bold. I've just recently picked up Minecraft after a couple years and started playing around with it. After I got comfortable messing around with it, I noticed that they implemented command blocks into the game and I wanted to see if I remembered how to use them. I messed around with command blocks for a while before I wanted to give myself a weapon. I did a little bit of research on command blocks, tried several different commands, but nothing can get me what I want. So I thought to ask you guys, after all, some of the commands I tried were on here. This is where you start reading I want a netherite sword with the title >The Legendary Sword of Power< (How original) and the lore being >The Ancient Ones used this weapon to kill the powerful Wither.< On top of that, I wanted to give it a couple overpowered enchantments. If anyone could help me with this (or just give me a command), that would be highly appreciated. Thank you!


A point $(X,Y)$ is chosen uniformly at random from the unit square ($(X,Y)\in [0,1]^2$) and the random variables are $X$ - the x coordinate and $Y$ - the y coordinate.  Now of course X and Y have uniform distributions but how can we find the density of the random variable $X+Y$?  I've been struggling on this.


Pick an urn and pick two balls from the urn

There are 5 urns, the nth urn contains n − 1 red balls and 5 − n green balls (in total 4 ineach urn). We pick an urn at random and take 2 balls out of it without replacement.  (a) What is the probability the second ball is green?  (b) What is the probability the second ball is green given the ﬁrst is green?  (c) What is the probability we picked either the ﬁrst urn or second urn given both balls are green?  for (a), I did:   P(2nd ball is green) = 5*[{P(i th urn picked) * P(first ball drawn red/ ith urn picked) P(2nd ball drwan green/first ball red)}+ {P(i th urn picked) * P(first ball drawn green/ ith urn picked) P(2nd ball drwan green/first ball green)}]  = 5*[[{1/5 * (n-1)/4 * (5-n)/3 } + {1/5 * (5-n)/4 * (4-n)/3}] = 5* [{(n-1)(5-n)/60} + {(5-n)(4-n)/ 60}]  =[(n-1)(5-n) + (5-n)(4-n)]/12 = (5-n)(n-1+4-n)/12 = (5-n)*3/12 = (5-n)/4  And for b): 5*{P(i th urn picked) * P(first ball drawn green/ ith urn picked) P(2nd ball drwan green/first ball green)} = 5*{1/5 * (5-n)/4 * (4-n)/3} =(4-n)(5-n)/12  c), P(1st urn or 2nd urn/ both are green) = [ [P(1st or 2nd]* (4-n)(5-n)/6 ] / [{P(1st or 2nd]* (4-n)(5-n)/6} + {{P(3rd or 4th]* (4-n)(5-n)/6}] = {(4-n)(5-n)/15} /  2*{(4-n)(5-n)/15} = 1/2  But I am really uncertain about my solutions. If anyone has different solution or easier way to get the answer please let me know! Thanks a lot!


Where does Windows store its current wallpaper?

I created an image for a desktop wallpaper and set the image directly in Windows (not from a browser). However, the image file I made is no longer on my computer, but the wallpaper is still there. How can I retrieve this wallpaper? It has to load from somewhere.


javafx NullPointerException in the for loop

I'm placing images inside hbox where the hbox located inside the vbox  FileInputStream seats_fileInputStream = new FileInputStream("seat.png");     Image seats_image = new Image(seats_fileInputStream,50,50,false,false);      ImageView[] seats = new ImageView[30];      for(int i = 0;i<30;i++){     seats[i] = new ImageView(seats_image);     }      HBox seatsRaw_hbox[] = new HBox[4];     VBox seatsLine_vbox = new VBox();      for(int i=0;i<5;i++){              for(int j=0;j<6;j++){            seatsRaw_hbox[i].getChildren().addAll(seats[j]);                           }             seatsLine_vbox.getChildren().addAll(seatsRaw_hbox[i]);      }    in should display 6 images in each hbox where there is 5 hboxes it total and place them into the vbox. But I keep getting       java.lang.NullPointerException runtime error in the line      seatsRaw_hbox[i].getChildren().addAll(seats[j]);


An entire function satisfying $Im(f(z)) > 0$ for all $z \in \mathbb{C}$ is constant

This particular question was part of a multiple choice question asked in my quiz. I contradicted other $3$ options but this one is true and I have no idea how to prove it.  Assume that $f$ is entire and satisfying $Im(f(z)) > 4$ for all $z \in \mathbb{C}$. Then show that $f$ is constant.  Kindly shed some light on which result I should use to solve this problem.


Food safety concern - storing medium rare steak overnight

I hope this is an ok first question to ask. So, yesterday my partner and I had steaks at a pub, and he saved half of his medium rare one. We came home and put it in the fridge, but he decided to leave it overnight and cook it into pilaf this evening. I was ... sort of horrified about it to be honest, but he seems to think it's completely fine. It's now cooked through and not rare anymore, he boiled it in the pilaf for a good amount of time. Still, I'm convinced this is pretty bad practice and I'm worried he'll get food poisoning. Thoughts?


Towards the end of The Last Jedi, Luke enters a room. The first one to notice Luke's arrival is the droid C-3PO and the others turn to see what C-3PO is looking at. However...      we later see that Luke never left Ahch-To Island but rather was projecting a Force illusion of himself. The Force connects and influences organic beings so I'm having trouble understanding how C-3PO could've been affected by what is essentially an incredibly advanced mind trick.   How then could C-3PO see Luke?


How can I set the least significant bit of an integer in C. For example, I have a 4 data with the following bits  [0] Decimal: 131    Binary: 10000011 [1] Decimal: 11     Binary: 00001011 [2] Decimal: 115    Binary: 01110011 [3] Decimal: 236    Binary: 11101100 [4] Decimal: 245    Binary: 11110101 [5] Decimal: 75     Binary: 01001011 [6] Decimal: 74     Binary: 01001010 [7] Decimal: 116    Binary: 01110100   and I have to change all those four data to be updated with 12 (integer) or 0000 1010 in bits.  So the new updated list would be:  [0] Decimal: 130    Binary: 10000010 [1] Decimal: 11     Binary: 00001011 [2] Decimal: 114    Binary: 01110010 [3] Decimal: 237    Binary: 11101101 [4] Decimal: 244    Binary: 11110100 [5] Decimal: 74     Binary: 01001010 [6] Decimal: 74     Binary: 01001010 [7] Decimal: 116    Binary: 01110100


How to print Euro (€) character on an UTF-8 file?

I have a .php file saved as UTF-8 and I would like to let it print out a character like €  How can I do it?  This is the source code of the example:  <?php header('Content-Type: text/html; charset=UTF-8');  echo "€"; ?>   The file was saved with notepad++ as UTF-8 but when I execute the file it just prints me out "?"    Answer  While the answer provided here  fullfills various aspect of UTF-8, i found the answer to my question inside  comment.  The .php file was saved as UTF-8 but WITH BOM. Within Notepad++ i choosed Format-> "UTF-8 without BOM" and the script worked.


Canadian parent gifting adult child in the US

My wife was born in Canada but now has her US citizenship and resides with me in the US. She still has Canadian Citizenship but, as you know, the US does not recognize dual citizenship.  One of her Canadian parents wishes to gift her money. We know what the exemptions are if the gift was a US parent to US adult child; however, we are confused as to how the gifting from a "foreigner" would work. We are also confused about whether to open a bank account in Canada for the gifting of the funds as my wife still holds Canadian Citizenship.  We have been told that there are no gift taxes in Canada for cash and have also been told that the US IRS looks unkindly on people having more than $10,000 USD in a foreign bank account.   So, in essence, what is the best path here to allow the gift to incur as little taxes (within the laws) to giver and receiver and where should the money be received, in Canada or to the US?


Weak Mathematical Induction for Modulo Arithmetic $8\mid 3^{2n}-1$

Using Weak Mathematical Induction, I have to show that, for all integers $n \geq 1$,  $8|3^{2n} -1$  I really don't know how to go about solving this problem. Currently I only have the base case and the Inductive Hypothesis:  Base Case: For $n = 1$ $$8|3^{2(1)}-1 = 8|8 = 0$$  Inductive Hypothesis: Assume true for $n = k$ $$8|3^{2k}-1$$  Inductive Step: I want to show that the statement is true for $n = k+1$ so $$8|3^{2(k+1)}-1$$  This is where I am currently stuck. Any help would be really helpful. Thanks


The expected number of n types of coupons have appeared at least once?

There are n different types of coupons and each item must contain one coupon. So what is the expected number of items needed to buy for all n types of coupons have appeared at least once?


I am looking at the travel arrangements for flights from Bangkok to St Martens as the individual will be working in the British Virgin Islands. She has her visa to work and will be requiring a flight at the end of September.  The most economical way of getting her to St Martens is via Miami but because of the visa restrictions this is not an option as she has not applied for a US visa. The next option is via either Amsterdam or London. The latter is an option as she will have a BV visa. Would she need a visa just to transfer through Amsterdam?


MySQL: Data type and length for hashed password?

Possible duplicate:   To save password, I am trying to use SHA2() in MySQL.  But when saving the hashed password SHA2(CONCAT(pwd_salt, pwd), 512), why does this need binary(128), not binary(64)? (512 bit => 64 (=512/8) bytes).  I guess that MySQL might save the hashed data into string, not binary data.  When I put  SELECT SHA2('some password with random salt', 512);   , it gives 128 words like  414c33de702e93bad92529973d651c7e4c5811ebe4a7f74775386245c0cfbc2b 3cf57260a833a4a6ad923bb9e13c9f8da768ad4d435b90b54f2c4c75ee3b22e4   I tried  SELECT CAST(SHA2('some password with random salt', 512) AS BINARY(64));   But this just truncate the data into 64 words like  414c33de702e93bad92529973d651c7e4c5811ebe4a7f74775386245c0cfbc2b   What am I doing wrong?


Sometimes, when I answer a question on Stack Overflow, I have two different answers that are equally valid. This happens most when answering architectural questions where there are many valid ways to solve a problem.  Is it better to put each alternative into a single answer, or put each alternative in its own answer?  Posted each alternative separately will allow the voting system to float the best answer to the top, but I don't want to be accused of rep whoring by "flooding" a question with answers.  What's your opinion? One or two answers?


Why does the equation $x^2\equiv2 \pmod 5$ have no solutions?  I did a remainders table and found that $$x^2\equiv0;1;4\pmod 5$$  But is there any way to justify this besides that?  The original equation was $2x^2\equiv9\pmod 5$ but I got it to the form above.


How to show that the centralizer formed by $g\in A\cap B$ where $A$ and $B$ are 3-Sylow subgroups contains $A$ and $B.$

Problem Setup:  We want to show that a group $G$ of order $180$ is not simple. We do this by contradiction.   Thus we first observe that $n_3(G) = 10$, which means that the number of $3-$Sylow subgroups is $10.$ Next, we try to show that the $A\cap B = \{e\}$ where $A\neq B$ and $A,B$ are $3-$Sylow subgroups.  For this, we assume that $g\in A\cap B$ such that $g\neq 1$ then we consider $C(g) =\{h\in G:gh=hg\}.$ Then we can observe that $C(g)$ is subgroup of $G.$   I want to show that $C(g)\supset A$ and $C(g)\supset B$ and that $|C(g)| = 18.$ Apparently this should lead to a contradiction implying that $A\cap B =\{e\}.$  My Attempt:  Here is what I have so far. We know that $A$ and $B$ are conjugates of each other and therefore there exists $y\in G$ such that $A = y^{-1}By.$ Next, if $a\in A$ then in order for it to be in $C(g)$ it must satisfy $ga=ag$ or $g=aga^{-1}$ which implies that  $$y^{-1}gy=aga^{-1}\implies gya =yag\implies ya\in C(g).$$  But I can't see how to work backward and show that $A\subset C(g).$  However, if we assume that $C(g)\supset A$ and $C(g)\supset B$ then we observe that $|C(g)| \in \{9, 18,36,45,90,180\}$ since it contains subgroups of order $9$,  namely $A$ and $B.$ Now $|C(g)|\neq 9$ since that would mean that $C(g) = A=B$ which is impossible. If $|C(g)| = 180$ then $C(g) = G$ but I am not sure why this would cause a problem.   I think to obtain further reduction I will have to use the fact that $|G|$ divides $[G:Z(g)]!$ since otherwise $Z(g)$ would contain a non-trivial normal subgroup [index theorem] which will be a contradiction. So if we have $|C(g)|\in \{18,36,45,90\}$ then I can show using the index theorem that $|C(g)|=18.$ Although, I don't see how this could lead to a contradiction.  Note:  This is different from the question asked  since I am asking a question that refers to a very specific step in the proof that is used to show that the group is not simple. Furthermore, the way that I have to prove this fact is different from the way used there.


Practical way to disable/enable internet connection for an app in Windows 10

What do you advice as the most practical way to fastly disable/enable internet connection for an specific app in Windows 10? Thanks!


I am looking to upgrade to 16.04 but the updater will not detect it. Tried many mirrors, checked all the possible update icons. BTW, I am running 14.04 LTS


I am pretty new in WordPress and I know just a litle about jQuery and Javascript and I have the following problem:  Into my functions.php file I load jQuery, the jQuery FlexSlider pluging (that create a slideshow) and another personal jQuery scripts file, in this way:  /* Function automatically executed by the hook 'load_java_scripts':  * 1) Load all my JavaScripts  */ function load_java_scripts() {      // Load jQuery:     wp_enqueue_script('jquery');     // Load FlexSlider JavaScript     wp_enqueue_script('flexSlider-js', get_template_directory_uri() . '/assets/plugins/flexslider/jquery.flexslider.js', array('jquery'), 'v2.1', true);     // Load scripts.js:     wp_enqueue_script('myScripts-js', get_template_directory_uri() . '/assets/js/scripts.js', array('jquery'), '1.0', true); } add_action('wp_enqueue_scripts', 'load_java_scripts');   Ok so the FlexSlider neeeds jQuery and in the last scripts-js file I have the following JavaScript:  /* Slider */ $(window).load(function() {  $('#main-slider').flexslider({      animation: "slide",      useCSS: false,      pauseOnHover: true  }); });   I don't know very well jQuery but I think that this script create my FlexSlider slideshow into the #main-slider div of my theme, this one (correct me if I am wrong):  <div id="main-slider" class="flexslider">     ...........     ...........     ........... </div>   The problem is that if I execute the previous scripts into a simple pure HTML website all work well but if I put these scripts into a WP theme the slide show is not shown  After a few hours of panic I found this documentation about the jQuery no conflict mode in WP:   So I have change the previous script that create my slideshow in this way (replacing the $ with the explicit jQuery function):  jQuery(window).load(function() {  jQuery('#main-slider').flexslider({      animation: "slide",      useCSS: false,      pauseOnHover: true  }); });   and now all work fine and the slideshow is shown.  Reading the jQuery documentation related to how avoid conflict() it seems to me that exist some other JavaScript framework different from jQuery that also use the $ character and that the safe mode disable the use of $ to avoid interpretation conflicts between Jquery code and other library code. And if I can't use $ in my code I have to replace it using the explicit namespace*jQuery*.  Ok, in this WP documentations:   show how continue to use $ even if jQuery is set in safe mode, and it do the following example:  ORIGINAL JQUERY FUNCTION THAT USE $:  $(document).ready(function(){      $(#somefunction) ... });   This function can't work if jQuery is setted in safe mode  So if I want to use $ and I don't want replace all $ with jQuery in my code I can do:  jQuery(document).ready(function($) {     // Inside of this function, $() will work as an alias for jQuery()     // and other libraries also using $ will not be accessible under this shortcut });   So it means that I have to replace the first $ (before my ready() function) and the pass the $ symbol as parameter on my definied function, so in this function I can still use $ without replace it? Is this one the correct meaning?


Given the identity matrix $I_n$ and a matrix $J_n$ with only 1's as every element.  I must prove that if $n>0$ then $(I_n - J_n)^{-1} = I_n - \frac{1}{n-1} J_n$  I'm trying to understand if there is some sort of theorem that states that $(I_n - J_n)^{-1} = I_n^{-1} - J_n^{-1}$ or something like that?


I tried deleting a folder in my /opt/ file that I had created but got the message   rm: cannot remove '/opt/*': Is a directory   I created this folder, so why am I getting that message?  Thanks again for any help with this!


Moving from acceleration- gravity equivalence to general relativity

Einstein's happiest thought of his life led to so called acceleration-gravity equivalence by simply imagining a man free falling. This simple thought led Einstein to formulate his general theory of relativity. But I want to know how mathematically he came up with the conclusion such as gravity is interpreted as a curvature in the fabric Of space and time using this principle.


My brother cannot connect to my Minecraft LAN world

I have tried many times to play with my brother. We are on the same Wifi, with different accounts.  I start up Minecraft 1.7.9, create a new Survival world, click Esc->Open To Lan. It tells me the port (which seems to be a random number) in the chat.  My brother tries to connect to the world. On the Multiplayer screen it searches for the LAN world forever and it never shows up. Is it supposed to only have the port or it also need the IP like 192.168:{port} but for me I dont even have the IP.  Notes:   We both use Windows 8 Same Wifi Different minecraft account Same House We try switching which side hosts a Lan server, and we get a different port


I'm searching the 5 bottles in The Legend of Zelda: A Link Between Worlds, but I've just found the one in the empty house. Where are the other bottles?


Decrypting SSL traffic in Wireshark. Only headers get decrypted

I'm trying to decrypt SSL traffic in Wireshark, and it partially works because I'm able to view the decrypted headers. The problem is that I don't see any of the packet contents, only their headers. Is there an explanation for this behaviour?  A bit more detail: we used openssl to generate keys and certificates with the command:  openssl req -config *.cnf -new -x509 -extensions v3_ca -keyout *.key -out *.crt -days 1825  and then to decrypt the private key to a PKCS#8 format, which wireshark supposedly supports, we issued this command: openssl pkcs8 -nocrypt -in *.key -informat DER -out *.key -outformat PEM  In Wireshark we issued the following parameters in SSL decryption section: 10.10.10.10,443,http,*.key - where 10.10.10.10 is the client we're trying to MITM using sslsniff. We have also tried localhost and servers IP with no success. Any suggestions?


What is the difference between #!/bin/bash and #!/usr/bin/env bash?

In tutorials for Ubuntu scripting I see as first line of a script either #!/bin/bash or #!/usr/bin/env bash. What is the difference between those?


Should I use two "where" clauses or "&&" in my LINQ query?

When writing a LINQ query with multiple "and" conditions, should I write a single where clause containing && or multiple where clauses, one for each conditon?  static void Main(string[] args) {     var ints = new List<int>(Enumerable.Range(-10, 20));      var positiveEvensA = from i in ints                          where (i > 0) && ((i % 2) == 0)                          select i;      var positiveEvensB = from i in ints                          where i > 0                          where (i % 2) == 0                          select i;      System.Diagnostics.Debug.Assert(positiveEvensA.Count() ==                                           positiveEvensB.Count()); }   Is there any difference other than personal preference or coding style (long lines, readability, etc.) between positiveEvensA and positiveEvensB?  One possible difference that comes to mind is that different LINQ providers may be able to better cope with multiple wheres rather than a more complex expression; is this true?


An object reference is required for the non-static field, method, or property 'Component.gameObject'

using System.Collections; using System.Collections.Generic; using UnityEngine; using UnityEngine.UI; public class Death : MonoBehaviour {     private void OnTriggerEnter2D(Collider2D collision)    {         if (collision.gameObject.tag == "koza")         Time.timeScale = 0;         if (Time.timeScale < 1)         Canvas.gameObject.SetActive(true); //error is here    } }  I need a canvas like death screen I am new at unity and c# and know nothing, Thank you for your time.


How can a person trapped in a box figure out, without looking outside, whether the box is stationary or moving with a constant velocity?  Is it even possible, considering the fact that the box is an inertial frame of reference? (since acceleration, and thus net force, is zero)  Additional question: Assume that the box is moving with a constant velocity. When a ball is thrown at a wall, will the time taken by the ball to reach the wall be any different from the time taken when the box is stationary? (If I picture myself in a closed room, I don't see why this should be possible - yet I can't convince myself that this is the case. If the wall is moving away from the ball, it seems reasonable that the time taken should be more. Likewise, it feels reasonable to think that the ball should take less time to reach the wall that is moving towards it.)


What communication can be intercepted by network I'm connected over VPN to?

I have to connect to client's network over VPN, and I was wondering if the client can intercept (and read) my Google Talk messages (or any other IM communication) while I'm VPN-ing.  My main concern is them having access to our internal conversations.  Suggest workarounds if you have any.


I love stack exchange and its mobile app however I feel it is missing the ability to use the chat in the mobile app. Everytime I want to chat I have to go to my mobile browser and sign in again and even still the chat is a little buggy.  Why can't you chat in the mobile app? Is it not possible or is there a reason it is not included?


Converting the text to time and calculating average time on that?

15 h 11 m 59  s 48 h 11 m 59  s   I need to convert the above text to "48:11:59"(Time format) and apply the average function on that. Can any one help on that?


Can't use the official unmodified Minecraft Launcher

I have tried anything that came into mind: Reset modem, add Minecraft to exception list etc. Now this is the launcher that claims it doesnt need Java, is that true or not? because as far as I know the latest version of Java is on my PC. I can play Minecraft Vanilla just fine with FTB and Technic but Voxelmap needs Liteloader and it claims that Minecraft Vanilla from Technic doesnt have a Launcher Profile so I had to resort to using the official one.


How to print original variable's name in Python after it was returned from a function?

I have enum and use the variables like myEnum.SomeNameA, myEnum.SomeNameB, etc.  When I return one of these variables from a function, can I print their names (such as myEnum.SomeNameA) instead of the value they returned?


Recommended books for advanced undergraduate electrodynamics

What books are recommended for an advanced undergraduate course in electrodynamics?


If I install Ubuntu in C-drive containing windows using option ' Erase disk and Install Ubuntu' will my personal files,folders,photos, music will be lost?  It's ok that windows will be removed from my desktop. Please help me out


I'm trying to understand tensors, but I've come across the following question:        Let $T^{\mu\nu}$ by a $(2,0)$ tensor. Give the definitions of $T_\mu^{\,\nu}$, $T_{\mu\nu}$, and $T^{\mu}_{\,\nu}$. Then give explicit formulas for the following components in terms of components of $T^{\mu\nu}$: $T_{00},\,T_{10},\,T_{12},\,T_0^{\,1},\,T_1^{\,1},\,T_0^{\,0},\,T^1_{\,1}$   $$T_\mu^{\,\nu}\equiv\eta_{\mu\sigma}T^{\sigma\nu} \\    T_{\mu\nu}\equiv\eta_{\sigma\mu}\eta_{\rho\nu}T^{\sigma\rho}\\   T^\mu_{\,\nu}\equiv\eta_{\sigma\nu}T^{\mu\sigma}$$      I'm finding it hard to understand these definitions. I really don't know what these tensors represent or what it means when both the indices are raised? Also are these standard definitions in special relativity or is it more likely that they are just made up by my professor for this assignment? I've always thought that things with two indices are matrices in general.


So I've always thought that "$\Delta$" when applied to an n-tuple or scalar was the change of that n-tuple or scalar relative to a previous state in time and proportional to the amount of time or $\Delta \bf{x}=\frac{\bf{x_u}-\bf{x_i}}{t_u-t_i}$ so I always wrote the acceleration of a mass as $\Delta^2 M_p$ but now I am unsure whether this is in fact correct. My question is: What are all of the different ways Delta can be used as well as am I using it correctly?


Proving a formula for the derivative of the determinant of an $n\times n$ matrix

This time I'm having trouble proving the following question: Assuming that the elements of an $n\times n$-matrix $Y(t) = (y_{ij}(t))_{i,j=1,...,n}$ are differentiable, I need to show the following equality: $$\frac{d}{dt}(\det(Y(t))) = \sum\limits_{1=1}^n \det\left(\begin{array}{ccc}         y_{11} & \cdots & y_{1n}\\         \vdots &  & \vdots \\         y_{i-1,1} & \cdots & y_{i-1,n}\\         y'_{i,1} & \cdots & y'_{i,n}\\         y_{i+1,1} & \cdots & y_{i+1,n}\\         \vdots &  & \vdots \\         y_{n1} & \cdots & y_{nn}\\     \end{array}\right)$$ And as a hint I'm told that one way of proving this equality is to use the formula of determinant with n!, however I'm not sure I know this formula, and the only one I could think of was the one with  Levi-Civita symbol: $$\det(Y(t)) = \frac{1}{n!}\sum\limits_{i_1,...,i_n = 1; j_1,...,j_n = 1}\epsilon_{i_1,...,i_n}\epsilon_{j_1,...,j_n}\alpha_{i_1j_1,...,i_nj_n}$$ which I don't know how to derivate. Could anyone help me derivate this determinant ? any lue to start would be welcome, I didn't find anything related to my problem on mathstack.


Open Terminal at Startup and run Java application

Here am I again after successfully installing Ubuntu MATE 14.04 with the help of AskUbuntu (thanks a bunch!)  What am I trying to achieve now is the following:   Launch a Terminal with root privileges at startup Change the working directory to Desktop Execute Jar file with the "java -jar filename.jar" command   What is the easiest way to do this, preferably without installing any third parties?  EDIT: I am not only looking how to run a script at startup, but also launching a command line and executing a command.


I want to upgrade my 12.04LTS to 14.04LTS. I have tried update-manager-d , and in update manager settings I have set something like : "Notify when new LTS version...". But I don`t get message that new Ubuntu is available . Update manager shows that no, updates available.


Can I enable the Windows 7 Start menu in Windows 10?

I've upgraded from Windows 7 to Windows 10 and now I only find this new slower Start menu with all the tiles in it   (picturesource: )  Can I enable the older Windows 7 one again which suites my needs more?


Can a iOS user join a world with a PC user?

I can't figure out if the PC version user can join an iOS version's user world. I tried connecting, but I don't know if I have to click Join Via Steam or Join Via IP.


Upper limits for jerk and higher derivatives in physics

Is there an upper limit for  jerk in physics? What about higher derivatives?   A consequence of  special relativity is that no material body can reach or exceed the speed of light in vacuum (due to the relativistic mass increase, or the Lorentz contraction).    I am not interested in obtaining these upper limits  based on postulates (and following mathematical implications), like the postulate  of the constancy of speed of light in special relativity.    I would like to know whether there are experiments that would lead to these upper limits, as a matter of consistency with empirical evidence. For the speed of light in vacuum we have Maxwell's equations. As far as I know, it was established experimentally that the constant that appears in Maxwell's equations is the speed of light in vacuum.  For acceleration,  there is a previous question on StackExchange, , where in an answer it is discussed Caianiello's maximum acceleration (the result is linked to Heisenberg's uncertainty principle, that's the type of answer that I am interested in, as an example).   So for speed and acceleration,  I understand that there is  experimental evidence that tells us that in order to have consistency (with the empirical evidence),  then we must accept that there is a maximum speed and acceleration in physics.  I am not interested in arguments involving the Planck system of units, since these arguments would be sensitive to the choice of normalization.   What about jerk in physics, and higher order derivatives. Is there any experimental data that would force us to accept upper limits for these quantities? Would it be useful to imagine experimental scenarios that would force us to accept these upper limits?  I will reformulate the question,  for clarity. I will not focus on the chronological emergence of the mathematical models that explain the experimental data.  In physics, maximum speed can be linked to Maxwell's equations. Maximum acceleration can be linked to Heisenberg's uncertainty principle. Does this trend continue,  for jerk and higher derivatives? Because  intuition tells me that in physics there must be upper limits/bounds for all of them, and there is a countable infinity of these quantities.


why Spring security getPrincipal is giving NullPointer

i'm trying to get the logged in user to show its informations in jsf index page which you need to be logged in to access it , i can't access the login page because the exception preventing the project from working, like the title says i'm getting nullpointer exception , i'm using spring 4 , java 7 . Managed bean :     @PostConstruct public void init() {     Object principal = SecurityContextHolder.getContext().getAuthentication().getPrincipal();     if (principal instanceof UserDetails) {        login = ((UserDetails)principal).getUsername();     } else {        login = principal.toString();     }  web xml :          <listener>         <listener-class>             org.springframework.web.context.ContextLoaderListener         </listener-class>       </listener>       <listener>         <listener-class>             org.springframework.web.context.request.RequestContextListener         </listener-class>       </listener>         <!-- CONTEXT  -->             <context-param>                     <param-name>contextConfigLocation</param-name>                     <param-value>/WEB-INF/ApplicationContext.xml , /WEB-INF/spring-security.xml</param-value>                    </context-param>        <filter>         <filter-name>springSecurityFilterChain</filter-name>         <filter-class>org.springframework.web.filter.DelegatingFilterProxy</filter-class>     </filter>     <filter-mapping>         <filter-name>springSecurityFilterChain</filter-name>         <url-pattern>/*</url-pattern>     </filter-mapping>  Spring security xml :   <http      authentication-manager-ref="jdbc-auth"       use-expressions="true" >                          <intercept-url pattern="/loggedout.xhtml" access="permitAll" />                  <intercept-url pattern="/login.xhtml" access="permitAll" />             <intercept-url pattern="/denied.xhtml" access="isAuthenticated()" />                          <intercept-url pattern="/member/**" access="isAuthenticated()" />             <intercept-url pattern="/admin/**" access="Administrateur-portail" />                                <form-login  login-page="/login.xhtml" login-processing-url="/j_spring_security_check"               username-parameter="username" password-parameter="password" authentication-failure-url="/denied.xhtml" />     <csrf disabled="true"/>      </http>


What is the correct word for "dependee"?    In other words, what is the word for something that is depended upon? The relationship here is in the context of software engineering


What is the difference between C++ and Visual C++?   I know that C++ has the portability and all, so if you know C++ how is it related to Visual C++? Is Visual C++ mostly for online apps? Would Visual Basic be better for desktop applications?


How to evaluate $\int_{0}^{+\infty}\exp(-ax^2-\frac b{x^2})\,dx$ for $a,b>0$

How can I evaluate $$I=\int_{0}^{+\infty}\!e^{-ax^2-\frac b{x^2}}\,dx$$ for $a,b>0$?  My methods:  Let $a,b > 0$ and let $$I(b)=\int_{0}^{+\infty}e^{-ax^2-\frac b{x^2}}\,dx.$$ Then $$I'(b)=\int_{0}^{\infty}-\frac{1}{x^2}e^{-ax^2-\frac b{x^2}}\,dx.$$  What the other methods that can I use to evaluate it? Thank you.


Zip folder without including path to folder and require only one argument

I'm trying to make a zip function that'll do all the steps I typically do when zipping a file or folder. Say my current directory is ~, and I want to zip a folder named Folder1, whose file path is ~/Folder2/Folder1.  Issuing  cd ~/Folder2 && zip -r Folder1 Folder1 && cd -   does exactly what I want. Namely, it zips so that the output Folder1.zip does not contain folders that lead up to the folder I'm zipping (namely, /home/user/Folder2), it zips recursively, and it takes in the first argument of zip with the exact name as the file or folder I'm zipping (Folder1.zip).  So I want to make a function in my .zshrc something akin to  coolerzip() { cd /path/to/file && zip -r file file && cd - }   where it need only take in one argument, which in this case, it will be ~/Folder2/Folder1. Then Folder1 will be the name for both files in coolerzip, and I will cd right into ~/Folder2 so Folder1 lies in my current directory before zipping. Is there any way I can achieve this so that coolerzip only requires one argument rather than three?


English isn't my native language. I need some help. I look for a word to name a sound.  This sound you can hear when you bend your finger in opposite site. This sound you can hear in your knees when you are doing squats.  I am trying to say something like this: "I hear in my wrist (here name of this sound) when I am doing something"


A mother spends much time with her children in comparison to the father.  A mother spends much time with her children in comparison with the father.    I don't have an idea which preposition to chose. I thought that I would get help online, but could not get what I wanted. However there is one blog post of Oxford English Living Dictionaries site under the title of ; the title contains the words "compare to" rather than comparison, thus is not akin to what I am asking here.


How to know which App architecture is installed on my device? 32bit and 64bit

I've researched a lot about this,  found how to know if the APK is 32bit or 64bit   I tried going to the developer area in my phone => process manager and still couldn't see running apps' architecture.  tried installing a couple of task manger apps too, still no luck.  I think Google play automatically detects CPU architecture and installs the correct version      and apparently since 2019 August, Google play requires all apps to have a 64-bit version.   but when I go to Chrome => chrome://version, it shows 32-bit  so I'm looking for a universal way to find out whether the installed app on my phone is 32bit pr 64bit.  I'm using Android 9


How to remove unused textures and materials

I have a lot of materials and textures in my scene that I don't use, but idk how to delete them. Could someone help me and tell me how to do that? 'Cause it eats up a lot of memory and crashes (._. ) Every time I import an object it creates a few copies of the same material\texture, for some reason...


Show that there are infinitely many positive integers $N$ that cannot be written in the form $a^n+b^n+c^n$ where $a,b,c$ are positive integers and $n \geq 2$.   I thought about considering solutions such that $$a^n+b^n+c^n < N^n.$$ Thus $a,b,c < N$. Thus there are less than $N^3$ positive integers expressible in the required form that satisfy the above inequality. Therefore, there are at least $N^n-N^3$ that aren't for a given $n$. I didn't see how to continue from here since the exponent $n$ can vary.


Possible bug in Badge Progress Window? (wrong next step)

In my Badge Progress window I can see I edited 73 posts and it says the next step will be 500, to reach "Copy Editor" badge, bypassing the actual next step that is "Strunk & White", reached after 80 post edits.  I wonder if it's a bug or a desired behaviour? The other progress bars seem to indicate the next step, not the last one.


I am very new to blender still.  I want to simply change the color of an object in the video.  I want to know if there is good way to do this.  I am including what I have to test.


A partial update of Ubuntu 20.04 broke texlive. Can't reinstall

A partial update (sent by  Ubuntu) of Ubuntu 20.04 broke my existing installation of texlive.  After unsuccessfull attempts to install various parts of it I used apt to purge and remove it. Now I still can't install texlive or any parts of it.   This is the result: (Trying other parts give "similar" results.) 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: texlive : Depends: texlive-latex-base (>= 2019.20200218) but it is not installable texlive-base : Depends: texlive-binaries (>= 2019.20190605) texlive-latex-recommended : Depends: texlive-binaries (>= 2019.20190605) Depends: texlive-latex-base (>= 2019.20200218) but it is not installable E: Unable to correct problems, you have held broken packages. What are my options? (One might be to go back to Slackware.)


Windows ignores GPT disk and converts to MBR during installation

I have followed these steps to install windows 7 home premium x64 on a 3tb drive (asus z87-z motherboard):    In the console window, diskpart, I ran:  select disk <disk number> clean convert gpt   Then when using the GUI to partition the disk to install windows, it always reverts back to MBR (list disk shows no asterisk under gpt).  I tried again, in this case cleaning and converting the disk, then pointing windows at the partitioned disk and letting it install.   By going to Control Panel-Administrative tools-Computer Managment-Storage-Disk Managementand checking the properties of the disk I can see that it is now a MBR.  Is there something I have missed? Could there be something in my setup incompatible with GPT that is causing this?


Ubuntu 16.04. Best way to disable apport?

I have been searching for ways to do this in 16.04, but most instructions that I've found are for 14.04. I don't think it will work, since Ubuntu 16.04 uses systemd. Can someone please guide me?


I have recently found out about slide rules from a  and I like them very much. However, I have never got access to a real slide rule. So I made my own slide rule using my printer with the help of . However, the slide rule that I have made does not have many scales whereas real slide rules , have a lot of scales.  So I thought that maybe I will be able to make a better one using TikZ. I started making it and got stuck here:  \documentclass{article}  \usepackage{amsmath,amsfonts,amsthm} \usepackage{tikz} \usepackage[a5paper,margin=0pt]{geometry}  \begin{document} ~\vfill \centering  \begin{tikzpicture} \draw (0,0) rectangle (14,20); \draw (8.75,0) -- (8.75,20); \draw [dashed] (1.75,0) -- (1.75,20); \draw [dashed] (7,0) -- (7,20); %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% \foreach \x in {2,...,18}{\draw (0,\x) -- ++(0.15,0);} \node [rotate=90] at (0.5,1.5) {C}; %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% \end{tikzpicture}\\  \vfill \end{document}   The problem is that I don't know how to make a logarithmic scale in TikZ. So please tell me just the basic syntax to create the logarithmic scale. I will do the rest.


The time hierarchy theorem states that turing machines can solve more problems if they have (enough) more time. Does it hold in some way if the space is limited asymptotically? How does $\textrm{DTISP}(g(n), O(s(n)))$ relate to $\textrm{DTISP}(f(n), O(s(n)))$ if $\frac{f}{g}$ grows fast enough?  I am especially interested in the case that $s(n) = n$, $g(n) = n^3$ and $f(n) = 2^n$.  In particular, I considered the following language: $ L_k := \{ (\langle M \rangle, w) \; : \; \text{M rejects } (\langle M \rangle, w)  \text{ using at most } |\langle M \rangle, w|^3 \text{ time steps}, $ $ k * |\langle M \rangle, w| \text{ cells and four different tape symbols} \} $  However, $L_k$ could be decided in $n^3$ steps by using $(k+1)n \in O(n)$ space.  Without limiting $M$ to four tape symbols and thus allowing to compress $O(n)$ cells into $n$ cells, we get space issues when simulating an $M$ with too many tape symbols. In this case, the language is not in $\text{DSPACE}(O(n))$ anymore. The same happens when setting $k = h(|w|)$ for some $h$ that can be computed fast enough.  This question is basically a rephrase of my question .  Edit Summary: Changed $\textrm{DSPACE}(s(n)) \cap \textrm{DTIME}(f(n))$ to $\textrm{DTISP}(f(n), s(n))$, however, I think the intersection is also worth to think about.


I am trying to solve the following exercise of Dummit and Foote Book(page # 551).   Let $a>1$ be an integer. Prove for any positive integers $n,d$ that $d$ divides $n$ if and only if $a^d-1$ divides $a^n-1$. Conclude in particular that $\mathbb{F}_{p^d}\subseteq\mathbb{F}_{p^n}$ if and only if $d$ divides $n$.  I did the first part and I know that for all $\alpha\in \mathbb{F}_{p^d}$, $\alpha^{p^d}=\alpha$. How can I apply the first part for the second? Any help is greatly appreciated. Thank you.


Is the word “etymology” correct when looking for the origins of a phrase?

I wasn't sure, so I looked it up, and it would seem it's specific to single words.           1.) the derivation of a word.   Synonyms: word origin, word source, derivation, origin.      2.) a chronological account of the birth and development of a particular word or element of a word, often delineating its spread from one language to another and its evolving changes in form and meaning.   Synonyms: word history, word lore, historical development.      3.) the study of historical linguistic change, especially as manifested in individual words.   Obviously the following sentence would be easily understood, but is it technically correct?  Or is there a better way to ask the following question?  “What is the etymology of the Baseball term 'meat hand'?”  As in a first-use, or how the phrase came to be, or what made it popular – etc.  What I think of as “etymology”, but perhaps that word is more technical, and specific to the linguistic breakdown and origins of individual words.


Why is the result of signal() cast to (void)?

Some questions tackle with this problem for general instances; however, in this case, all I see is just a value returned by a function. See by yourself:  The third line, (void) signal (SIGALRM, myAlarm); is supposed to execute the system call signal, which - if I understood correctly - returns a pointer to a function. Being it the general case, I can see why a function pointer is being cast to void; however, apart from C's implicit casting, that line itself does exactly nothing to the returned value "in memory" as it's simply a value. Am I missing something? Does (void) actually do anything in the third line (and for the rest of the program)? Even if the function pointer were to be of a different type than void, wouldn't the third line act only on the returned value, instead of a (hypothetically) stored one? In a few words, is it necessary or is it a redundancy?


How does knowing a function as even or odd help in integration ??

So, I am learning Fourier Series and it involves integration. I am not too good at integration. Now, the resource I use is . In the opening video he says that knowing whether the function as even or odd will greatly simplify the integration process.    So, I have two questions: 1. What is even/odd function? 2. How will that simplify integration ?


Help with proof by induction of inequality

I am studying for an exam and going through various earlier tutorial sheet questions. For the question below, I have tried and just can't figure out how to prove that $x$n$ $ < $ 3$ by mathematical induction. Does anyone know how to prove this?     The question is:     Let $x$1 = 1, and for each $n \in  \mathbb{N}$ let $x$n+1 = $\frac{2}{3}x$n$ $ + $ 1$. Then $x$n$ $ < $ 3$ for all $n \in \mathbb{N}$.


Flexible Array Member (Zero Length Array)

In reference to  explanation:  This is particularly useful in the case when a struct is a header for a variable-length object. This is exactly my case. Furthermore, I am concerned with the alignment of my structs in the heap.  In this case, I still really do not understand what's useful about zero length arrays. How are they related to this particular situation?  EDIT:  Is it that I can put as much "data" as I want in there?


Proving that $1_{\limsup A_n}=\limsup1_{A_n}$.

Proving that $$1_{\limsup A_n}=\limsup1_{A_n}$$  $$1_{\limsup A_n}= \begin{cases}1, x \in \bigcap_{n=1}^{+ \infty}\bigcup_{k=n}^{+\infty}A_n \\ 0, x \notin \ldots\end{cases}$$  or that $x$ is in infinitely many $A_n$. And also:  $$\limsup1_{A_n}=\inf_{n\geq1}\{\sup_{k \geq n}\{1_{A_n}\}\}$$ this function seems to be $1$ when $x\in A_n$ (just one set). I clearly am not understanding this $\inf\{\sup\{\ldots\}\}$ definition correctly. Can someone enlighten this for me. I have a test very soon.


I have an object in which there are two fields i.e Phone no. & email. The combination of these fields should be unique Right now I can create just one unique field But I want their composite to work like a unique field.   I know that I can create composite key in SQL but I dont know how to achieve this in salesforce.


my Java (libgdx) application/game throws me java.util.ConcurrentModificationException.  My code:  for (Lod lod : lode) {     if (!pause){         lod.move();     }     if (lod.isDestroyed()){         lode.remove(lod);     } else {         lod.draw(game.batch);     }        }


get previous month from a string but return last 2 months

Below code I expected 12 but I get 11:    public static int previousMonth(String format, String value) {         SimpleDateFormat sdf = new SimpleDateFormat(format);         Date date = null;         try {             date = sdf.parse(value);         } catch (ParseException e) {             e.printStackTrace();         }         Calendar calendar = Calendar.getInstance();         calendar.setTime(date);         calendar.add(Calendar.MONTH, -1);         return calendar.get(Calendar.MONTH);     }       int actual = CommonUtil.previousMonth("yyyy-MM-dd", "2021-01-01");     int expected = 12;     assertEquals(expected, actual)  ;


How are you planning on handling the migration to Python 3?

I'm sure this is a subject that's on most python developers' minds considering that Python 3 is coming out soon.  Some questions to get us going in the right direction:   Will you have a python 2 and python 3 version to be maintained concurrently or will you simply have a python 3 version once it's finished?   Have you already started or plan on starting soon?  Or do you plan on waiting until the final version comes out to get into full swing?


Query mysql with word with tilde in where clause does not generate result in PHP but if in phpmyadmin

today I have a problem which does not make sense and I cannot figure out how to do it, it consists in that when making a query in phpmyadmin which in its where clause has a word with tilde it generates its respective results but when doing it in php with mysqli does not generate anything, and I do not understand why since the where clause works with special characters like the 'ñ' since I have tested it and it works but with tilde no, the column count is in utf8_general_ci so that it can handle all kinds of special character, I have changed its collation to utf8_spanish_ci to see if it was the collation that did not accept accents but no, even so with this last collation it still does not generate results the same as with the previous collation in php but if in phpmyadmin without any inconvenience I do not understand why the php does not generate the results and the phpmyadmin if  Note: there is no problem with the results of the query since I have validated that in none of them it returns a special character  Php code:  <?php $conexion = mysqli_connect("localhost", "admin", "123", "school"); $consulta="select * from users where localidad='Cúcuta'"; $resultado=mysqli_query($conexion,$consulta); while($registro=mysqli_fetch_array($resultado)){     echo 'Successfull'; } mysqli_close($conexion); ?>


I have two vector layers as seen below, one is a landcover map showing the different habitats in a region and one is a grid of 4 x 4 km squares that covers the region.   I have to extend this grid to cover the whole landcover layer as currently it does not cover it properly, I could also create a new one but I need the current squares to stay in the same place. I can't find anything on expanding this layer or to create a new one based on the old one


A particle with mass $m$ moving with constant velocity $v$ has a total energy $T$ equal to its kinetic energy. If we consider the reference system (inertial) moving with the particle, the velocity is 0, so the total energy is 0. Where is the energy gone? What about energy conservation law?


what's a better way to design this code for efficiency?

the question is simply a design question.. i mean how to restructure this piece of code into something that simple and efficient.  So lets take the following code for example.  class D{      var a;  }  class C{      D d;     //uses d.a  }  class B{      C c;  } Class A{      B b;     //needs d.a  }   here class A needs to access the variable "a" in D and classes B And C don't store variable "a" (even though C uses "a" i doesn't store it as it only needs it for initialization). Is there a way to make this code more cleaner.  right now i have made both classes B and C store variable "a". but it seems like it's not the correct way to do it. i mean i am thinking of cases where this chain is longer and the last class needs some variable in the first class. so how should i deal with it.


Prove that ML estimate of a function of a parameter, $g(\theta)$ is the function of its ML estimate $g(\hat{\theta})$

As titles say, given $\hat{\theta}$ is the Maximum Likelihood estimate of a parameter $\theta$, how to prove that Maximum Likelihood estimate of $g(\theta)$ is $g(\hat{\theta})$. Additionally, is this property applied to Bayesian estimate? I think given that $\hat{\theta}$ is the Maximum Likelihood estimate of function $f(x_1, x_2, ..., x_n)$, then $\frac{\partial f(x_1, x_2, ..., x_n)}{\partial \theta}|_{\theta=\hat{\theta}}=0$. Then we can continue proving that $\frac{\partial g(f(x_1, x_2, ..., x_n))}{\partial g(\theta)}|_{g(\theta)=g(\hat{\theta})}=0$


Which one is best approach class or structs? In c++

Suppose you have to develop an application for XYZ bank with the following features. 1)The application must be secure 2)For transactions, proper interfaces will be provided to the customers. 3)The application must be reusable. 4)The application must be efficient in terms of speed and memory  usage. You can use either structs or class in order to achieve the above mentioned features. So which programming construct (class or struct) will you select for application development.  Please help me out here. Thanks


When would it be that Ubuntu 15.XX is released?

I just bought new laptop which is Lenovo ThinkPad E455 posted on the H/W partner.  And it is found that 14.10 has kernel 3.16 which is older than currnet release.  It is wanted to know if Ubuntu 15.XX with new kernel would be released SOON  Thank you.  HELLOVENUS Fantagio


QGIS: why doesn't the "graduated" classification work for my column?

I'm new to QGIS so bear with me. I need to show something on a map using the "graduated" classification. The thing is the program doesn't give me this option. I believe it's been reading the column as text instead of numbers, but how can I change that?


'Thank you for taking your time writing' or 'Thank you for taking your time to write' ?

A person gave me an answer on English.SE and I commented:     Thank you for taking your time writing this wonderful answer!   Now, looking at the sentence in retrospect, even though I am not a native English speaker (duh, otherwise I wouldn't be asking a question on ELL.SE), I find the sentence a bit odd.  To get my point across, let me rephrase the sentence:     Thank you for taking your time to write this wonderful answer!   With my relatively little knowledge and understanding of English, I feel that using 'writing' (as I did in the original sentence) emphasizes the very process of writing the answer, whereas using 'to write' emphasizes the mere fact that an answer has been given, and a wonderful one at that.  This is exactly why I feel the original sentence is a little bit awkward and the second, revised one would have been more apt.  Am I correct or are the quoted sentences virtually synonymous?


Count triangularizations of convex polygons such that each triangle created by triangularizations have atleast one side as polygon side.

Let    $n$  be  an  integer greater than four,  and let $P_1,P_2,\dots, P_n$ be   a   convex  $n$-sided    polygon.    Zach     wants  to  draw    $n-3$ diagonals    that    partition the region    enclosed    by  the polygon into    $n-2$ triangular   regions and that    may intersect   only    at   the    vertices    of  the polygon.    In  addition,   he  wants   each    triangular  region  to  have    at  least   one side that   is  also    a   side    of  the polygon.    In  how many    different ways  can Zach     do this?


Preposition with 'line' when quoting from a text (prose or poetry) with numbered lines?

When referring to a line or lines in/from (?) a text with numbered lines, is it    "the idea expressed in line 25 is such and such"; "in line 25, the word 'lisp' is a clear indication that…"  or "the idea expressed on line 25 is such and such"; "on line 25, the word 'lisp' is a clear indication that…"  ?


javascript: get object item in real order

i need to get real order of simple javascript abject, but i get incorrect answer from this code:    var Obj={"x":"z", "2":"a", "1":"b"}; for(i in Obj)     document.write(Obj[i]+"<br>");   I expect to see z, a, b as answer, but i get b, a, z See the code in action:


What happens to Klingons who die on Starfleet ships?

In the TNG episode Heart of Glory, Worf states that once a Klingon has died their body becomes an empty shell, and should be treated as such.  What exactly does this mean for the crew? Organic waste can be recycled into the replicator system or ejected from an airlock, but would they feel comfortable doing that? Would they respect Klingon tradition, and if so what does that entail?


I came across this question in a Microsoft Practice Test and I got confused. Here is the question:     Which of the following C# code samples   is the proper way to raise an event,   assuming that the Alarm event, the   AlarmEventArgs class, and the   AlarmEventHandler delegate have been   declared?   Here is the "correct" answer they provided:  AlarmEventArgs e = new AlarmEventArgs(1, 2); AlarmEventHandler handler = Alarm;  if (handler != null)  {      handler(this, e); }   However, there is also another answer which seems correct.  AlarmEventArgs e = new AlarmEventArgs(1, 2); if (Alarm!= null)  {      Alarm (this, e); }   I personally, always use the second method. It works just fine. Can someone please tell me why I should use the first method instead of second?


Use more complex AND/OR structure with PAM

PAM allows to use sufficent and required for some logic, like  auth sufficient pam_a.so auth required pam_b.so auth required pam_c.so   which would mean "either a is true, or b must be true and then c must be true".  Is it possible to do more complex operations? like "(a or b) and (c or d)" or "(a and b) or (c and d)"? Possibly with even more layers of parenthesis.


Add an "Or do you believe this should actually be closed?" link/button when failing Close Vote audits

Far too often I end up failing close vote reviews like  which I genuinely believe should be closed (in this case for "demonstrate a minimal understanding of the problem being solved"). When this happens I'm greeted with a message titled:  STOP! Look and Listen!  This is a pretty rude message to receive when you already were paying close attention to the question at hand. To make it worse I then have to click out of the review section to go into the question to cast the close vote I'd just attempted to add. As someone who has obtained the silver Reviewer medal for Close Votes, could an "Or do you believe this should actually be closed?" link/button be added within the failed Close Vote audit message? This would allow us to cast a close vote after failing an audit like this instead of forcing us to leave the review process to do so.


How do I install a Windows OS given only a ISO file and an external hard disk?

There is a new machine that need to install a Windows OS. However, you are given an ISO file (that contains the Windows OS) and an external hard disk only.   How do I go about to install it?  Please note that you are not provide any blank CD or DVD to burn the ISO file.


Is the closed interval $[-\dfrac{\pi}{2}, \dfrac{\pi}{2}]$ homeomorphic to $\mathbb{R}$?

The open interval $(-\dfrac{\pi}{2}, \dfrac{\pi}{2})$ is well known to be homeomorphic to $\mathbb{R}$ through the homemorphism $f(x) = \tan(x)$  Is the closed interval also homeomorphic to the real line?   It seems to be the case until you hits the end points, which is undefined by $f(x) = \tan(x)$ so that seems to ruin everything.  Also, is the closed interval homeomorphic to open interval given any intervals?


I have my server running Ubuntu 18.04 LTS, I used it to host my personal stuff, stream media, bots and doing android builds. A month ago I saw some errors while executing the envsetup.sh script that is where it prepares the environment to start the build. Link to the . This is the output:  miguel@mike-machine:/home/builds/sources/PixysOS$ . build/envsetup.sh  bash: build/envsetup.sh: line 1: syntax error near unexpected token `$'{\r'' 'ash: build/envsetup.sh: line 1: `function hmm() {   I tried executing it in my other machine (Manjaro 18 KDE) and didn't have problems, thats where I have been building temporarily. I think it is a bash problem, but I sudo apt-get install --reinstall bash, but I still get the same.


How does one prove probability integral transform? So when $Y = F_X(X)$ where $X$ has a continuous distribution for which the cumulative distribution function is $F_X$, why does $Y$ have a uniform distribution? And what would Y's relationship with $\text{uniform}(0,1)$ distribution?


I need to select an element from a drop-down menu.  The dropdown menu has two value and I need to select the second "sponsor.com"  <select tabindex="1" name="userDomain" onchange="javascript:doWFAction('ReloadUser');">   <optgroup label="Selected">     <option value="0" selected=""></option>   </optgroup>   <optgroup label="Other">     <option value="261">sponsor.com</option>   </optgroup> </select>   What I have tried but doesnt work (I am a beginner, actually my first project)    driver.find_element_by_xpath("//select/option[@value='261']").click()     driver.find_element_by_xpath("//select[@name='userDomain']/option[text()='Other']").click()     select = Select(driver.find_element_by_name('userDomain')) select.select_by_visible_text('Other') select.select_by_value('261').click()     if I do this command  driver.find_element_by_name('userDomain').click()   I can click on the drop-down menu but don't know how to select sponsor.com


What triggers a lycanthropic change in the Potterverse?

In most fiction I've read or encountered, the change occurs as a simple consequence of the lunar cycle. Though from what I know of Harry Potter, the change that takes place is due to sighting the full moon (as occurs in the third movie, Prisoner of Azkaban) where the gang, plus Lupin, Severus, Sirius and Pettigrew emerge from the Whomping Willow and upon sighting the full moon he begins to change.  Is this the trigger for werewolves in the Potterverse? If not, why did he (Lupin as an example, though for any werewolf in general) not change whilst in the shrieking shack that night?  Edit: This  addresses Lupin's change but I'm after more general information about werewolves.


I have a long literature.bib file. It has been running without a problem, suddenly it seems to not run further: INFO - Logfile is 'main.blg' INFO - Reading 'main.bcf' INFO - Found 27 citekeys in bib section 0 INFO - Processing section 0 INFO - Globbing data source 'literature/literature.bib' INFO - Globbed data source 'literature/literature.bib' to literature/literature.bib INFO - Looking for bibtex format file 'literature/literature.bib' for section 0 INFO - LaTeX decoding ... INFO - Found BibTeX data source 'literature/literature.bib'  It stays there and never generates the literature in the text nor shows an error.


Please give me a definition of . A textbook I have defines it to be - "A fundamental property of matter, which determines whether the matter will receive an electric flow or liberate one" I don't find this convincing enough. Any help would be appreciated.


Multivariable Delta Epsilon Proof $\lim_{(x,y)\to(0,0)}\frac{x^3y^2}{x^4+y^4}$ --- looking for a hint

I have the limit $$\lim_{(x,y)\to(0,0)}\frac{x^3y^2}{x^4+y^4},$$ and would like to show with an $\epsilon-\delta$ proof that it is zero. I know with a situation like $$\left|\frac{x^4y}{x^4+y^4}\right|\leq y$$  or something similar, but I can't find a way to do the same thing here, as no single term in the numerator is of sufficient degree, although I think I could get this with a small hint.


Here is the proof:  let a = b a² = ab a²-b² = ab-b² (a-b)(a+b) = b(a-b) a+b = b 2b = b 2 = 1   Now, of course Problem must lie on the line (a-b)(a+b) = b(a-b), as it seems like multiplying by 0 on both side but does algebraic rule allow that step? Anyway, where is the error in this proof?


Evaluate: $\int_0^{\pi} \ln \left( \sin \theta \right) d\theta$

Evaluate: $ \displaystyle \int_0^{\pi} \ln \left( \sin \theta \right) d\theta$ using . Given hint: consider $f(z) = \ln ( 1 +z)$. EDIT:: I know how to evaluate it, but I am looking if I can evaluate it using Gauss MVT. ADDED:: Here is what I have got so far!! $$\ln 2 = \frac{1}{2 \pi } \int_0^{2\pi } \log(2+e^{i \theta}) d\theta = \frac{1}{2 \pi } \int_0^{2\pi } \log(2+e^{-i \theta}) d\theta$$ Hence, $ \displaystyle 2 \ln 2 = \frac{1}{2 \pi } \int_{0}^{2 \pi} \log(5 + 4 \cos \theta )d \theta  = \frac{1}{\pi} \int_0^{\pi} \log(1 + 8 \cos^2 \theta) d \theta$,  now to problem is how to reduce it to the above form?


Examining each connected pixel to select its neighbors to separate clusters using ArcGIS for Desktop?

I am trying to develop a methodology for separating pixels from one another to determine whether they belong to a city cluster or not. Starting at the center pixel of the city I want to select all pixels that fall under a certain pixel neighborhood. I want to examine a few different ones 3x3, 4x4, etc.. The selection would expand outward, examining each connected pixel to select its neighbors, and so on, until there are no neighbors for any of the pixels. I have tried focal statistics in arcgis, but I cannot find out if there is a way to use the tool on just one pixel. The picture below shows the issue. I cannot tell if the pixels circled in black are actually connected to the center pixel. This is the output of focal statistics showing number of neighbors in 3x3 rectangular neighborhood. I would prefer a python solution if possible.


Cycles Final Render is Black in Blender 2.91.0

I need some help with one of my Blender projects. I was making this simple interior design render with the help of fspy. I made some simple objects and some materials. I didn't check before if I can render an image as a preview. I only relied on the rendered view while making the scene. If I were to hit F12 and render an image, it just renders pitch black. I tried many ways to fix this by researching other forums and questions but, none of them worked. One weird thing I found is when I render and allow it to denoise, I can see a faint light from where the window is supposed to be. I appreciate any help to fix this. I uploaded the .blend file to my google drive:  Thank you very much!


Time Manager to animate time series in multiple columns?

I have a vector file of Africa containing all its countries. I have a CSV file containing a time series of monthly precipitation per African country. Is there a way to use Time Manager (or anything else) in computing a series of images containing all countries with their corresponding precipitation value over time?  So what I would like to achieve is an image of Africa with all countries having a different color based on a precipitation-value, and this for every month over a period of about 30 years. Obviously I would like to avoid having to make 12 x 30 separate images myself.      Tutorials that I find only show how to use Time Manager with a CSV that contains spatial data, which is not the case for me. If I add all the precip-data as columns to the attribute table of the Africa shapefile, I have the problem of only being able to select one column for Time Manager to run. If I do it the other way around I can only do it for one country in stead of all countries simultaneously.  Any suggestions as to how I can achieve this?


One of the question at HW in Number Theory was calculating $$147^{147}\mod 13$$ We didn't see much about the modular properties yet, so I am kind of stuck. Could someone give a hint or a direction how to approach it?


implementing the hashcode of a pojo in an efficient manner in java

In an interview it was asked from me to show the implementation of hashcode and equals method in an efficient manner so i have constructed the below pojo but the interviewer said that this is not the correct and the best implementation as it can result in an collision , can you please advise is the below implementation of hashcode is correct or not   public class Emp  {      String name, job;     int salary;      public Emp(String n, String j, int s) {         this.name = n;         this.job = j;         this.salary = s;      }      public int hashcode() {         return name.hashCode() + job.hashCode() + salary;     }      public boolean equals(Object o) {          Emp e1 = (Emp) o;         return this.name.equals(e1.name) && this.job.equals(e1.job) && this.salary == e1.salary;     }     }


I have a COC level 36 account and I'm playing on my tablet. I downloaded bluestack to my computer and installed COC so that I can play with both my computer and tablet. However, after I linked my level 36 account to the new level 2 account, I lost my level 36 account. I have used my tablet and computer with 1 Google account. How do I get back my level 36 account?


Show that the sequence converges and what is it limit?$x_{n+1}=\frac{1}{2}(x_{n}+\frac{a}{x_n})$

The sequence is: $x_{n+1}=\frac{1}{2}(x_{n}+\frac{a}{x_n})$ for$ , n \in \mathbb{N}_{0}$, $a>0$ and $x_{0}=a$  Hint: Show at first that $x^{2}_{n+1} - a \ge 0$ and than take $x_{n+1}-x_{n}$  I tried this way: $\frac{a}{x_0}$ is not negativ, so the sum of $x_{0}+\frac{a}{x_0}$ and $\frac{1}{2}(x_{0}+\frac{a}{x_0})$ is also not negativ.  I guess that I should prove it for $x_{n}$ that it's not negativ with induction.


Reject and Improve buttons are too close

The buttons are too close (especially on high resolution) and I tend to hit Improve instead of Reject 1 out of 20 times or so.  Most times I simply cancel and reject the edit, but when it's a "test" I fail it and now I'm banned for 2 days of review.  It would be much easier if the Improve button was the rightest one.


what is the meaning of "had they used their gift"? does it conditional?does "as D.D. Home used his" means that he should followed the advise?

what is the meaning of "had they used their gift"? does it conditional? does "as D.D. Home used his" means that he should followed the advise of the author?     To realize their position one has to remember that they were little   more than children, poorly educated, and quite ignorant of the   philosophy of the subject. When a man like Dr. Kane assured Margaret   that it was very wrong, he was only saying what was dinned into her   ears from every quarter, including half the pulpits of New York.   Probably she had an uneasy feeling that it was wrong, without in the   least knowing why, and this may account for the fact that she does not   seem to remonstrate with him for his suspicions. Indeed, we may admit   that au fond Kane was right, and that the proceedings were in some   ways unjustifiable. At that time they were very unvenal themselves,   and had they used their gift, as D.D. Home used his, with no relation   to worldly things, and for the purpose only of proving immortality and   consoling the afflicted, then, indeed, they would have been above   criticism. He was wrong in doubting their gift, but right in looking   askance at some examples of their use of it.   from


Error creating onClickListener for map marker

E/AndroidRuntime: FATAL EXCEPTION: main     Process: com.iot.maptesting, PID: 11741     java.lang.RuntimeException: Unable to start activity ComponentInfo{com.iot.maptesting/com.iot.maptesting.MapsActivity}: java.lang.NullPointerException: Attempt to invoke virtual method 'void com.google.android.gms.maps.MapFragment.getMapAsync(com.google.android.gms.maps.OnMapReadyCallback)' on a null object reference         at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2913)         at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:3048)         at android.app.servertransaction.LaunchActivityItem.execute(LaunchActivityItem.java:78)         at android.app.servertransaction.TransactionExecutor.executeCallbacks(TransactionExecutor.java:108)         at android.app.servertransaction.TransactionExecutor.execute(TransactionExecutor.java:68)         at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1808)         at android.os.Handler.dispatchMessage(Handler.java:106)         at android.os.Looper.loop(Looper.java:193)         at android.app.ActivityThread.main(ActivityThread.java:6669)         at java.lang.reflect.Method.invoke(Native Method)         at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:493)         at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:858)      Caused by: java.lang.NullPointerException: Attempt to invoke virtual method 'void com.google.android.gms.maps.MapFragment.getMapAsync(com.google.android.gms.maps.OnMapReadyCallback)' on a null object reference         at com.iot.maptesting.MapsActivity.onCreate(MapsActivity.java:39)         at android.app.Activity.performCreate(Activity.java:7136)         at android.app.Activity.performCreate(Activity.java:7127)         at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1271)         at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2893)         at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:3048)          at android.app.servertransaction.LaunchActivityItem.execute(LaunchActivityItem.java:78)          at android.app.servertransaction.TransactionExecutor.executeCallbacks(TransactionExecutor.java:108)          at android.app.servertransaction.TransactionExecutor.execute(TransactionExecutor.java:68)          at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1808)          at android.os.Handler.dispatchMessage(Handler.java:106)          at android.os.Looper.loop(Looper.java:193)          at android.app.ActivityThread.main(ActivityThread.java:6669)          at java.lang.reflect.Method.invoke(Native Method)          at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:493)          at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:858)


How do you set a dynamic aura attribute default value like current userinfo instead of hardcoding. See below.  The harcoding accountid works, not dynamic contactid/not supported.   <aura:attribute name="lookupcase" type="Case" default="{      'sobjectType': 'Case',      'ContactId': '{!v.userInfo.ContactId}',                                                     'AccountId': '0012D000002oAkt'  }"/>


I have a script which uses pexpect to start a CLI program. It works a bit like a shell where you get a prompt where you can enter some commands.  The problem I have, I think, is that this program uses a coloured prompt.  This is what I do   import pprint import pexpect  1 a = pexpect.spawn('program') 2 a.expect("prompt>") 3 print "---------start------------" 4 print(a.before) 5 a.sendline("command") 6 a.expect("prompt>") 7 print "---------before------------" 8 pprint.pprint(a.before) 9 print "---------after------------" 10 pprint.pprint(a.after)   This is the output:  > python borken.py ---------start------------ A lot of text here from the enjoying programs start-up, lorem ipsum ...   ---------before------------ ' \x1b[0m\x1b[8D\x1b[K\x1b[1m\x1b[34m' ---------after------------ 'prompt>'   For some reason the first prompt colour coding borkens up things and a.before at line 8 is garbled, normal print does not work,  even if I see that the command at line 5 actually produced a lot of output.  Does someone know what the problem could be, or is it possible to set the terminal type in pexpect to avoid the colours?  I am using tcsh shell


WIFI does not work after new installation 18.04.1

Short version: I downloaded Ubuntu from my Windows PC, made a bootable usb stick and installed it on an Acer Aspire laptop (which had windows before). Now my WIFI does not work and I am completely lost as I need to download everything via Windows PC (But what do I need in this case? As I understand too little I would need to start with random solution like try another Ubuntu version, ...).  Some details after research on the web:  ethtool => not found ifconfig => not found lsb_core => not found iwlist scan lo       Interface does not support scanning enp1s0f1 Interface does not support scanning iwconfig lo       no wireless extension enp1s0f1 no wireless extension   I use a "normal installation" and "installed third-party software".  From lshw: Ethernet interface RTL8111/8168/8411 PCI Express Gigabit Ethernet Controller Realtek Name enp1s0f1   As said: I am new to Ubuntu and more information can be shared if I know for what I must look... Any help is highly appreciated!  lspci -nnk | grep 0280 -A3 02:00.0 Network controller [0280]: Broadcom Limited BCM43142 802.11b/g/n [14e4:4365] (rev 01)         Subsystem: Foxconn International, Inc. BCM43142 802.11b/g/n [105b:07e]         Kernel modules: wl  lspci -knn | grep Net -A3; rfkill list 0: acer-wireless: Wireless LAN         Soft blocked: no         Hard blocked: no 1: acer-bluetooth: Bluetooth         Soft blocked: no         Hard blocked: no 2: hci0: Bluetooth         Soft blocked: no         Hard blocked: no   Work in progress:  sudo apt install bcmwl-kernel-source Paketlisten werden gelesen... Fertig Abhängigkeitsbaum wird aufgebaut.        Statusinformationen werden eingelesen.... Fertig bcmwl-kernel-source ist schon die neueste Version (6.30.223.271+bdcom-0ubuntu4). 0 aktualisiert, 0 neu installiert, 0 zu entfernen und 319 nicht aktualisiert.


Good evening.  I'd like to know, in your opinion, what would be the best fundamental physics book for a freshman?  I want to start all over again.


When you click on someone's profile tags, it shows a search of posts by that user on the selected tag. However, the tag description appears twice in the page and there's not much left for the actual content you want to see.      The image was taken from my profile. Also not sure why it shows me a user id instead of my username.


Primary decomposition of an ideal (exercise 7.8 in Reid, Undergraduate Commutative Algebra)

I would like to understand how to use geometry to solve the problem 7.8 from Reid's book Undergraduate Commutative Algebra. The problem is the following     Let $k$ be a field and consider the ideal $I = (xy, x - yz) \subset k[x,y,z]$. Find a primary decomposition of $I$.   So the vanishing locus $V(I)$ is the two axis $Y$ and $Z$, and if $I = q_1 \cap \cdots \cap q_n$ with all $q_i$ being $p_i$-primary, we could guess that we can take $p_1 = (x,z)$ and $p_2 = (x,y)$. Moreover, the vanishing of $xy$ is the $Z$-axis, but with double multiplicity (is this true ?), so we could guess to take $q_2 = (x,y)^2$, but we need $x - yz$ to be in there, so I think that $q_2 = (xy, y^2, x - yz)$ and $q_1 = (x,z)$ would give a decomposition into primary ideals ($x^2$ is automatically in $q_2$, don't need it).  Question 1 : How to make sure that these primes $p_1$ and $p_2$ are the only ones ? We can compute them by $\operatorname{Ass}(k[x,y,z]/(xy,x - yz))$, but wasn't able to do it.  Question 2 : Is $(x,z) \cap (xy, y^2, x - yz)$ a primary decomposition of $I$ ?  Question 3 : What is a better way to get to this answer with geometric intuition and not algebraic brute-force ?  Thanks


Linear regression: Unbiased estimator of the variance of outputs

I'm having trouble understanding something from the linear regression chapter of .  We have a fixed $N\times p$ matrix $\mathbf{X}$ ($N$ inputs with $p$ predictors)  that gives us the observations $\mathbf{y}$ which are "uncorrelated and have constant variance $\sigma^2$." Our predictions $\mathbf{\hat{y}}$ are given using the standard least squares solution, $\mathbf{\hat{y}}=\mathbf{X}\hat{\beta}=\mathbf{X}(\mathbf{X}^T\mathbf{X})^{-1}\mathbf{X}^T\mathbf{y}$. Apparently, an unbiased estimator of the variance  $\sigma^2$ is given by:  $$ \hat{\sigma}^2 = \frac{1}{N-p-1}\sum_{i=1}^N(y_i - \hat{y_i})^2 $$ Or the residual sum of squares divided by the degrees of freedom. This leads to: $$ (N-p-1)\hat{\sigma}^2 \sim \sigma^2\chi^2_{N-p-1} $$  I'm familiar with Bessel's Correction, but I still couldn't reconcile these two. Proof that the first one is an unbiased estimator or that the similarity in the second one is true would be greatly appreciated!


Prove that three points are collinear using their corresponding vectors.

Let $a = \begin{pmatrix}x_a\\y_a\\z_a\end{pmatrix}$, $b = \begin{pmatrix}x_b\\y_b\\z_b\end{pmatrix}$, and $c = \begin{pmatrix}x_c\\y_c\\z_c\end{pmatrix}$. Show that $(x_a,y_a,z_a)$, $(x_b,y_b,z_b)$, and $(x_c,y_c,z_c)$ are collinear if and only if $$a \times b + b \times c + c \times a = 0.$$    I was thinking of proving that the area of the triangle formed by the three points is 0.  I thought the box product, $|(a \times b)\bullet c|$, would be helpful but I don't know how to relate that to the equation.  All help is greatly appreciated.


Get text between start pattern and end pattern based on pattern between start and end pattern

I am trying to get everything between startStr and endStr for case bbb. I understand how I can get all occurrences between startStr and endStr using sed. I do not see how I would constraint it just to the one instance where bbb occurs.  Sample input:  fff startStr aaa bbb ccc endStr xxx yyy startStr ddd endStr ddd bbb   Required output:  startStr aaa bbb ccc endStr   This is what I have:  $ sed -n -e '/startStr/,/endStr/ p' sample.txt startStr aaa bbb ccc endStr startStr ddd endStr


Show that $$\lim_{n\to \infty}\left(\frac{1}{n+1}+\frac{1}{n+2}+\cdots+\frac{1}{6n}\right)=\log 6$$ Here I need to use the definition of integral but I  faced problem in range . Please help.


How to install ubuntu in my laptop?  Where from I can get it? Is it free?  What apps or software are required? I am using HP pavilion with Windows 8.1 Original Ver.


How to show that If a is relatively prime to n, then multiplication by a permutes the elements 1,2,3,....,n-1?

Lemma#3: If a is relatively prime to n, then multiplication by a permutes the elements  1,2,3,....,n-1. I didn't understand what permutes means here. If I consider $\mathbb{Z_n}$ then any element a relatively prime to n has the same order as 1 and also it generates $\mathbb{Z_n}$. Thats the maximum I know. Please I need help to understand this.Thank you.


I have a table as follow:  ID  User  Activity  PageURL    1  Me    act1      ab       2  Me    act1      cd       3  You   act2      xy       4  You   act2      st   I want to group by User and Activity such that I end up with something like:  User  Activity  PageURL   Me    act1      ab, cd      You   act2      xy, st   As you can see, the column PageURL is combined together separated by a comma based on the group by.  Would really appreciate any pointers and advice.


Problem requiring/including plugin files with plugin_dir_path( __FILE__ )

I am trying to write a WordPress plug-in. In my project I have three PHP files.   My plug-in file Widget for the plug-in Data installation   I need to install data table on plug-in activation. For that sake I wrote code to create table for my plug-in in data installation file. But I am not able to create data table using this file.  My code for include data installation file and widget file in my plug-in file is  define ( 'OTHER_FILES_PATH', plugin_dir_path( __FILE__ ) ); require_once( OTHER_FILES_PATH . '/data_installation.php' ); require_once( OTHER_FILES_PATH . '/plugin_widget.php' );   My problem is when I put my data installation code in my plug-in file it's working fine but when I put it in separate file (data installation) I am unable to create tables for my plug-in.  Please let me know if I am making any mistake.


How to calculate difference in hours between two time fields

I have two time-formatted cells and I need to calculate the difference (e.g., 2.75) in hours between the two.  10:30 AM   |   1:15 PM   Simply   =B1-A1   will not do the trick.