Not able to start mysql in Ubuntu 16.04
MariaDB won't start on Ubuntu: Can't lock aria control file
Understanding slice notation How to determine which form has been submited and to validate them in a servlet Feedback for The Loop - May 2020 May’s “The Loop” blog post was just posted, you can read it . A popular response last month to our post about how we receive, prioritize and implement feedback was a question around how this framework gets utilized in the practical sense. We thought that Dark Mode was a great feature to dig down into as it was so widely requested and anticipated.   We hope you enjoy this month’s post, please leave any questions or comments you have in this thread and we will respond ASAP. As a non-native speaker, I cannot grasp any difference between the expressions "here we go" and "there we go": both expressions seem to underline an event that is going to happen immediately.  Is there any subtle usage detail that I am missing? Why does $\sum_1^\infty \frac1{n^3}=\frac52\sum_1^\infty\frac{(-1)^{n-1}}{n^3\binom{2n}{n}}$? Apery's original proof that $$ \zeta(3) \equiv \sum_1^\infty \frac1{n^3} $$ is irrational starts from an alternating series  $$ \zeta(3) = \frac52\sum_1^\infty\frac{(-1)^{n-1}}{n^3\binom{2n}{n}} $$  There must be a way to see that those two series are equal, but I have tried various telescoping and other techniques and I just can't see it. Help me out:       Show (preferably by reasonably elementary means) that$$\sum_1^\infty \frac1{n^3}=\frac52\sum_1^\infty\frac{(-1)^{n-1}}{n^3\binom{2n}{n}}$$ Shape of confidence interval for predicted values in linear regression I have noticed that the confidence interval for predicted values in an linear regression tends to be narrow around the mean of the predictor and fat around the minimum and maximum values of the predictor. This can be seen in plots of these 4 linear regressions:    I initially thought this was because most values of the predictors were concentrated around the mean of the predictor. However, I then noticed that the narrow middle of the confidence interval would occur even if many values of were concentrated around the extremes of the predictor, as in the bottom left linear regression, which lots of values of the predictor are concentrated around the minimum of the predictor.  is anyone able to explain why confidence intervals for the predicted values in an linear regression tend to be narrow in the middle and fat at the extremes? When I try to print a Unicode string in a Windows console, I get an error . UnicodeEncodeError: 'charmap' codec can't encode character .... I assume this is because the Windows console does not accept Unicode-only characters. What's the best way around this? Is there any way I can make Python automatically print a ? instead of failing in this situation? Edit:  I'm using Python 2.5.  Note: @LasseV.Karlsen answer with the checkmark is sort of outdated (from 2008). Please use the solutions/answers/suggestions below with care!!  is more relevant as of today (6 Jan 2016). Evaluate the integral: $\int_{0}^{1} \frac{\ln(x+1)}{x^2+1} \mathrm dx$ Is it possible to use multiple desktop environments on same system? Is it necessary to dispose System.Timers.Timer if you use one in your application? I am using System.Timers.Timer class in one of the classes in my application. I know that Timer class has Dispose method inherited from the parent Component class that implements IDisposable interface. Instances of the class below are created many times during my application lifecycle; each of them has an instance of Timer class that generates Elapsed events continuously during the class's lifecycle. Should I implement IDisposable interface in the class that uses Timer class to dispose the timer object? (I have seen code that doesn't do this at all). I am afraid that some unmanaged resources will not be freed if I use the class below like this:  SomeClass someClass = new SomeClass(); someClass.DoSomething(); someClass = null;   The class:  using System.Timers;  public class SomeClass {     private Timer m_timer;      public SomeClass()     {                    m_timer = new Timer();         m_timer.Interval = 1000;         m_timer.Elapsed += new ElapsedEventHandler(m_timer_Elapsed);         m_timer.AutoReset = false;         m_timer.Start();                            }      public void DoSomething()     {      }      private void m_timer_Elapsed(object sender, ElapsedEventArgs e)     {         try         {             //Do some task         }         catch (Exception ex)         {             //Ignore         }         finally         {             if (m_timer != null)             {                 //Restart the timer                 m_timer.Enabled = true;             }         }     } } Is there a way to consistently increase the vertical spacing between equation lines in a gather (or gather*) environment from amsmath?  Specifically, I want to produce something like  \begin{gather*} a = b \\[2ex] c = d \\[2ex] e = f \end{gather*}   without having to write [2ex] at the end of each equation line.  I can think of some hacks that redefine \\ to automatically add the spacing, but is there some cleaner/better way to achieve this? Why can I feel my seven pound cat walking across floor of my home? The house is only 9 years old. (I am the second owner)   I know they settle but in the last year I can feel all movement across the floor- year ago I could barely feel anything but did notice that when someone walked across I could feel them go by.  But more recently the cat walking across to go to the chair I can feel that.  What is going on?  I know I should not feel the cat who is 7 lbs walking by or across the floor. Split level home 9 years old Minnesota location  Is anyone out there that can explain this? Relationship between $\operatorname{ord}(ab), \operatorname{ord}(a)$, and $\operatorname{ord}(b)$ Another homework problem from my Group Theory class.  Let $a,b$ be elements of a group, $G$.  Let $\operatorname{ord}(a)=m$ and $\operatorname{ord}(b)=n$. Let $a$ and $b$ commute. Prove: If $m$ and $n$ are relatively prime, then the $\operatorname{ord}(ab)=mn$.  So I am having trouble starting off on this problem.  Here is what I believe I know:  $a^m=e$ and $b^n=e$ [as defined by the order of the elements] which leads $a^m=b^n$  $\operatorname{ord}(ab)=mn=\operatorname{ord}(ba)=nm$ as defined by commuting.  $\gcd(m,n)=1$ as defined by $m,n$ being relatively prime.    I don't know how to start this proof. Do I want to to go the route of $a^mb^n=e$?  Then $(ab)^{mn}=e$?   Any tips to start this would be greatly appreciated!!! How does delete[] know it's an array? Weird future tense usage I am now reading  book and have noticed a couple of cases of weird (for non-native speaker) future tense usages.   The point of the kata is to train your fingers and your brain. I'll do a kata or two every day, often as part of settling to work. I might do it in Java, or in Ruby, or in Clojure, or in some other language for which I want to maintain my skills.`   The phrase about doing a kata or two every day looks perfect for Present Simple. Why does the authoer use Future Simple instead?   However, a professional also knows that there will be times when he will fail, his risk calculations will be wrong, his abilities will fall short; he'll look in the mirror and see an arrogant fool smiling back at him.   Shouldn't we use Present Simple after when/if in this kind of cases? I am especially curious about this case as sometimes I forget to switch to Present Simple after if/when and I thought it is a critical error (which I didn't expect to see in a book). Make "compact view" as a default directory view instead of "icon view" How can I make "compact view" the default for all directory views in File Manager, instead of "icon view" ? PhD Student : Publish Paper with Wife? Help me identify this insect from Bangladesh I have seen this insect flying literally everywhere in Dhaka city (Bangladesh) over the last two months. It's small -- around 1-1.5 inches long. It's not an agile flyer and can be easily grabbed by hand during flight. Mean Time to Failure (MTTF): When disk manufacturers post this, how should you interpret their numbers? Mean Time to Failure (MTTF) is usually given in terms of hours, and by doing some calculations, it seems that a disk should fail only after a good number of years have gone by.  It seems that disks need repair more often than that. Does anyone know why this is so?  I figured that there is something fishy about this metric. Am interpreting something wrong here? Are there any published details of Kenobi's communication with Lars family on Tatooine before ANH?