Linear Algebra Matrix to the third power is the identity
Linear Algebra: If $A^3 = I$, does $A$ have to be $I$?
Ubuntu 16.04 software center doesn't have many apps Record screen, microphone and web camera in Ubuntu 17.10 (Wayland Session) Libraries module. Where to extract? I tried Libreoffice, but its Import option while pasting in the cell is very  annoying.I also tried Gnumeric but I am not able to paste using middle button.Parcellite to make copy paste faster and middle button pasting is not working with Gnumeric. Is there any simple table maker app available that can accept only simple unformatted text? All these software are very complicated for this simple work. Book recommendations How can I completely remove ecryptfs from my system and delete .Private? Few days back I have installed ecryptfs, created a private directory using it. Now my Ubuntu login became super slow. I have tried removing ecryptfs from Synaptic. I found It, it can not be deleted that way. Somewhere I have read about this command  ecryptfs-setup-private --undo   But this command displays a rather confusing list of commands on terminal. I don't want to mess up my installation, neither want to loose my administrator account.  Now my question is, how can I safely remove /home/user/Private (.Private) and remove ecryptfs encryption ? Can I use one of my attacks to cast a cantrip? In the D&amp;D campaign I am currently participating in, I am playing as a level 5 high elf champion (I actually just reached level 5 at the end of the last session).  As a High Elf, I got a free cantrip at first level, and chose the firebolt cantrip.  Here's what I'm wondering now: for the purposes of the extra attack feature, does firebolt (and similar cantrips) count as an attack? How to call the method correctly in Preference.OnPreferenceChangeListener() Beta regression of proportion data including 1 and 0 Is there a higher register word that means to criticize something highly specific and inconsequential? Any synonym I can think of seems a little too vernacular, e.g. "to split hairs", "to nitpick". What's a more professional/academic way of saying this? I'd prefer a single word if one exists. Arrive steering behavior diagram software for Ubuntu? how to permanently disable ubuntu updates & hide install updates button pic included how to permanently disable ubuntu updates pop up &amp; hide or remove Install Updates button pic included see below: What exactly is the singleton class in ruby? I understand that for resistors in series we need to add R for each resistor to get the equivalent resistance, where R is resistance. I also understand the mathematical manipulations that show that for resistors in parallel we need to add the 1/R for each resistor to get the equivalent resistance. However I have a couple of questions that have to do with the physical interpretation of the mathematical manipulations involved.   First, I am trying to understand why in the case of parallel resistors we have to add 1/R's instead of adding R's as in the case of resistors in series i.e. could it be thought that the current in the wire is like a sort of water flow in the pipe that has two horizontal parallel pipes positioned one on top of the other and in between connected by a number of vertical pipes that have a tap each that could be adjusted to represent different resistances. Then at the top of each vertical pipe the water pressure P exists and at the bottom the pressure will be reduced by P*R.   For example, suppose we have three vertical pipes, so then the pressure at the bottom of each (after the tap) is P*R for the total of 3*P*R so why is the equivalent resistance not 3*R*P but 1/R = (1/R1 + 1/R2 + 1/R3) and how can I be able to visualize this relation? Distribution of $-\log X$ if $X$ is uniform. Why am I allowed to turn my focusing ring beyond infinity? For some reason, I can no longer access the Winterbash 2015 page--when I try, I get redirected to the  instead, just like Winterbash is over. Except, we should still have almost another two weeks. Also, I can no longer see hat-related features on SE sites. What happened to the hats?!  UPDATE: The hats seem to be back now. But the question still remains, why did they disappear, and is it going to happen again? I don't follow understand what this theorem is saying: "Every function $f: A \to{\cal P}(A)$ is not surjective."   Is this saying so for example let A = {1,2,3} then the power set of A is {},{1},{2},{3},{1,2},{1,3},{2,3},{1,2,3} Is this saying that there is no surjective function that takes every element in each of its power sets to atleast 1 element in A?  Is my understanding correct? SQL Server compatibility with New TLS Standards The major browsers are moving beyond SSL3.0 and TLS1.0 . The PCI Security Council has declared an end-of-life date for these protocols to be considered sufficiently strong encryption.   We need to move away from these protocols, to use newer and stronger ones. On Windows servers, you can very easily disable these old protocols, and instead offer only TLS1.1 or greater.  However, as noted , Microsoft SQL Server 2008 R2 and SQL Server 2012 (Standard, at least) both will not start if those lower protocols are disabled.  However, there are a growing number of versions of MS SQL Server.  There are SQL Server Standard, Business Intelligence, Enterprise, Express, Web, and Compact editions.  And of course there is SQL Server 2008, 2012, 2014, and (in pre-release) 2016.  Which of these editions support or will support the use of only TLS1.1 or greater protocols?