When I update my machine I get the following error message. E: The repository 'http://ppa.launchpad.net/webupd8team/java/ubuntu groovy Release' does not have a Release file.  How can I update my machine?
When updating, I get the following error message:   W: The repository 'http://ppa.launchpad.net/mc3man/trusty-media/ubuntu xenial Release' does not have a Release file.   Here, I find another statement on this error:   This recommends removing certain PPAs; and, I'm not sure if I should do that since it might mean not getting the updates that I need.    Is this what I should do?
I've seen many people who say:     This is a HTML page.   Yet I've also seen many people who say:     This is an HTML page.   Are both usages equally correct?  Or, which is the grammatically correct one?       Possible Duplicates: Let's say I have a video running in an application.  If I hover my mouse over the taskbar, it shows a little popup windows that diplays the video  (aero peek).  Sometimes I'm running a maximized window and I want to have this little screen always popped up.  (Kind've like when your using the TV Guide menu, you still see a little clip of the video) I have two servers (both servers are on Windows OS):   Server_A running Oracle 12c Server_B running SQL Server 2014   I want these servers to be able to see each other, so I can SELECT anything I want in Server_A from Server_B and vice versa.  I only want the ability to run SELECT queries (not INSERT, UPDATE, DELETE or any DDL queries), and also if possible to EXECUTE procedures.  What options or technologies we have for achieving this issue and which one is better?    Tell me if any software I have to install or any configuration have to be set on each of servers. I appreciate explaining the instructions step by step. Chromatic polynomial properties I have some properties which I do not understand how to form a proof for. Most of them are by induction, which is not my strong point Any help would be fantastic.   Looking at the chromatic polynomial $$P_G(k)=P_{G-e}(k) - P_{G/e}(k)$$  Properties   1.If G has n  vertices then $ P_g(k)$ has degree n and the coefficient of $k^n $ is 1   The signs of $P_g(k) $ alternate If G has q components the smalles non-zero term of $P_g(k)$ is the term in $k^q$ Generic solution to prevent a long cron job from running in parallel? I am looking for a simple and generic solution that would allow you to execute any script or application in crontab and prevent it from running twice.  The solution should be independent on the executed command.  I assume it should look like lock &amp;&amp; (command ; unlock) where lock will return false if there was another lock.  The second part would be like if it acquired the lock, run command and unlock after command is executed, even if it returns error. I'm fitting a multiple linear regression model between 4 categorical variables (with 4 levels each) and a numerical output. My dataset has 43 observations.  Regression gives me the following $p$-values from the $t$-test for every slope coefficient: $.15, .67, .27, .02$. Thus, the coefficient for the 4th predictor is significant at $\alpha = .05$ confidence level.  On the other hand, the regression gives me a $p$-value from an overall $F$-test of the null hypothesis that all my slope coefficients are equal to zero. For my dataset, this $p$-value is $.11$.  My question: how should I interpret these results? Which $p$-value should I use and why? Is the coefficient for the 4th variable significantly different from $0$ at the $\alpha = .05$ confidence level?  I've seen a related question, , but there was an opposite situation: high $t$-test $p$-values and low $F$-test $p$-value. Honestly, I don't quite understand why we would need an $F$-test in addition to a $t$-test to see if linear regression coefficients are significantly different from zero. How to avoid nested With[]? $\dim(U_1+U_2) = \dim U_1 +\dim U_2 - \dim(U_1\cap U_2).$  I want to make sure that my intuition is correct. Suppose we have two planes $U_1,U_2$ though the origin in $\mathbb{R^3}$. Since the planes meet at the origin, they also intersect, which in this case is a one-dimensional line in $\mathbb{R^3}$. To obtain the dimension of $U_1$ and $U_2$, we add the dimensions of the planes (4), and the subtract the dimensions of the line (1), which results in (3).   *additional question(s):   Can we generalize this notion to $\mathbb{F^{n}}$?  Suppose we have an additional case where $U_1$ and $U_2$ are planes in $\mathbb{R^3}$, but $U_1 \subseteq U_2$. In this instance, $dim(U_1 + U_2) &lt; 3$, because the first two-dimensional plane is contained in the second and as a result, the dimensions of the subspaces when summed cannot exceed two. Since both subspaces $U_1,U_2$ are two dimensional and $U_1 \subseteq U_2$, then their intersection is also two-dimensional, concluding $dim(U_1+U_2)=2+2-2 = 2$.  Is this proper intuition? Why do I always hear remote train horn at night? This is definitely not an illusion, as many people have the same experience. I have usually lived in places miles away from train stations, which makes it unlikely to hear any train horns during the day. However at night, occasionally train horns can be heard. I hope if any one can explain the physics of this effect, like possibly sound travels faster at low temperature. Proving Eigenvalue squared is Eigenvalue of $A^2$ The question is: Prove that if $\lambda$ is an eigenvalue of a matrix A with corresponding eigenvector x, then $\lambda^2$ is an eigenvalue of $A^2$ with corresponding eigenvector x.  I assume I need to start with the equation $Ax=\lambda x$ and end up with $A^2 x=\lambda^2 x$ but between those I am kind of lost. I have manipulated the equations several different ways and just can't seem to end up where I need to be. Help would be greatly appreciated as I believe this will be on a test tomorrow. How can I query SEDE for tags I've created? How can I query the  for tags I've created? What does "xmlns" in XML mean? What do we mean by hyperparameters? Can anyone give me full details about what we mean by hyperparameters, and what in the Dirichlet distribution are called hyperparameters? A practice example for the estimation of those parameters would also be useful. RSA when N=pq and p = q Setting up different application instances under one DNS How to install applications to a separate hdd? I was so good with windows, now I’m feeling like a complete idiot.  I have an SSD for ubuntu and want to install the majority of my programs to a separate HDD but I have no clue how. All searches I have tried only turn up with dual-boot installations.   (RESOLVED -> ) I am also having trouble locating "/etc/". Specifically, to modify Conky. Searching for this term only turns up instances where people are telling you to access this file, not how to get to it. I have to compute this integral $$\int_{0}^{\infty} \frac{dt}{1+t^4}$$ to solve a problem in a homework. I have tried in many ways, but I'm stuck. A search in the web reveals me that it can be do it by methods of complex analysis. But I have not taken this course yet. Thanks for any help. In the following is it better to use a possessive noun with an apostrophe or an attributive noun without an apostrophe?     The following list details the assumptions that have been made in   conjunction with the Dell Company’s staff.   Or      The following list details the assumptions that have been made in   conjunction with the Dell Company staff.   Assume Company is the name of a company, such as Dell. How to understand the Ubuntu file system layout? Does it make any difference to SEO ratings what-so-ever if your url has a trailing slash:  http://www.example.com/some/slug/paths/   as opposed to one that does not:  http://www.example.com/some/slug/paths