How do I find out screen resolution of my Linux desktop (Ubuntu) from C# program running with mono?
Get and Set Screen Resolution
Refer to Sheet with value in Cell? The usual way to reference a sheet is  but how do you reference a sheet when the sheet's name is a value in a cell?  For example,   A1 = "Sheet number two" B1 = A1&amp;"!B4"   Here I want B1 to display the value in 'Sheet number two'!B4 but it's not working for me.  Any ideas? How to search only unanswered questions with an open bounty ? Lost USB BlueTooth Dongle for Keyboard and Mouse I lost my USB bluetooth dongle (from HP) which I used for a wireless keyboard and mouse. They came together in a set when I bought my last HP computer.  Are the keyboard and mouse useless now? or will any bluetooth dongle allow them to work? If I can just buy a new one - any recommendations on a replacement (good price, and perhaps works with Windows and Ubuntu out-of-the-box?   Forgive me if this is an easy question. I'm just not that familiar with wireless mice/keyboards. What is $\Delta t$ in the time-energy uncertainty principle? In non-relativistic QM, the $\Delta E$ in the time-energy uncertainty principle is the limiting standard deviation of the set of energy measurements of $n$ identically prepared systems as $n$ goes to infinity. What does the $\Delta t$ mean, since $t$ is not even an observable? There exist several implementations of the GBDT family of model such as:   GBM XGBoost LightGBM Catboost.    What are the mathematical differences between these different implementations?  Catboost seems to outperform the other implementations even by using only its default parameters according to , but it is still very slow.  My guess is that catboost doesn't use the dummified variables, so the weight given to each (categorical) variable is more balanced compared to the other implementations, so the high-cardinality variables don't have more weight than the others. It allows the weak categorical (with low cardinality) to enter to some trees, hence better performance. Other than that, I have no further explanation. Why didn't Isildur's Heir come forward sooner? Is it possible to restore a MySql database only using files from Data directory? I have a mysql installed inside a windows virtual machine. The hard drive was crashed and the system is not able to restore all again. But I can have access to entire c: ROOT. So I went to  c:/ProgramData/Mysql/Mysql Server 5.5/data/myDatabaseName    There I can see different files like: .frm, .opt, .trg and .trn. In a regular way, I could run a mysqldump to backup and restore all database from command line, but the system is not able to be restored. So I had to copy all these files and past inside inside the same  directory inside same database in another physical instance.   The issue is some tables are not been recognized by this new instance. So I think copy and past is not enough to restore the database.   What am I missing?    Note: Database has innoDb and Myisam tables. Suppose $u\in W^{1,1}$ and $\partial u$ is $C^1$. I want to prove the following: $$\int_{\partial\Omega}|u-\bar u|\leq A\int_{\Omega}|\nabla u|$$ where $\bar u=\frac{1}{|\Omega|}\int_{\Omega}u$ and $A&gt;0$. Note that unlike Poincar&eacute; inequality, the left integral is over $\partial\Omega$ and not $\Omega$. How can I do that?  I tried to prove in a similar way to Poincare inequality proof (arguing by contradiction), but with no success. I think I am missing something because of the  $\partial\Omega$ issue. To what extent are child actors exposed to the violent aspects of the movie they perform in? Some movies feature child characters put in violent situations. This can range from crude language to extreme horror (e.g. torture, gore, etc.). As an example,  and its sequel has plenty of those scenes. It looks like a paradox that children can be actors in movies that are definitely not for children.  Do the directors usually try and avoid exposing the very young actors to the violence of such scenes, e.g. by clever dubbing and editing? Are there laws that require them to do so, just like there are ratings that prevent children from seeing some movies? Reverse / invert a dictionary mapping Given a dictionary like so:  my_map = {'a': 1, 'b': 2}   How can one invert this map to get:  inv_map = {1: 'a', 2: 'b'} What counter balances gravity here? Lets consider a stone tied to one end of a massless and unstretchable string... Now if i'll start rotating, it will form a conical pendulum &amp; then the equilibrium is achived when the pendulum attains horizontal circular motion.... Now to maintain that state we give a constant force to string.... Here, which force counterbalances gravity? Is it the torque due to applied force cancels out the torque due to gravity?  The angle θ changes from 0 to 90° This should be a very easy question but it might just be that I'm confusing myself. So we have the definition of a function $f$ on $S$ being continuous at $x_0$:     For any $\epsilon$>0, there exists $\delta&gt;0$ such that: whenever $|x-x_0|&lt;\delta$, we have $|f(x)-f(x_0)|&lt;\epsilon$   And I assume the negation is     There exists $\epsilon$>0 such that for all $\delta&gt;0$, $|x-x_0|&lt;\delta$ yet $|f(x)-f(x_0)|\ge \epsilon$.   Now I want to show that the function $f(x)=\sin(\frac{1}{x})$ together with $f(0)=0$ cannot be made into a continuous function at $x=0$. So I need to show that there exists $\epsilon&gt;0$ such that for all $\delta&gt;0$, $|x|&lt;\delta$ yet $|f(x)|\ge\epsilon$.  Let $\epsilon = \frac{1}{2}$. Then no matter what $\delta$ we choose, let $|x|&lt;\frac{1}{2}$. It is certainly possible that $|f(x)|\ge \frac{1}{2}$, because, well, $\frac{1}{x}$ can really take on arbitrarily large value as $x$ is small.  Now, what confuses me is that, as $x$ gets small, $f(x)$ can certainly be greater than $\frac{1}{2}$ for infinitely many times, but it will be less than that infinitely many times, too. But I suppose it doesn't really matter. So I think there's something wrong with my negation but I couldn't figure out where.  Update: The correct version can be found . Watch for Lemma 4.6 How do I remove a file named "NUL" on Windows? I have a Windows XP box (NTFS filesystem) on which I found a file named NUL. I have not been able to remove this file in any usual way. The file appears to be owned by Administrator in the SYSTEM group, unlike any other file in the same directory (the other files are owned by my user id).  How do I get rid of this file? Where did it come from? I don't know the command to set our spawn in Minecraft 1.12.1.  Is it /set spawn? I honestly can't figure it out. Thanks! share login/logout sessions across two installs? What is a word that means "someone who pretends to be your friend but is actually your enemy?" How do I install VMware player on a Mac os X? I went to their site, and downloaded a .bundle which automagically turned into a .txt file after downloading.   Long story short, I can't run the txt file because I guess Mountain Lion Mac os X isn't a strict Linux box and is missing some core components to do that type of installation.  Does anyone know how to install VMware? So I just started using linux/ubuntu today and I've been getting problems with my wifi, ive tried the solutions on this page:  When im really close to my router, its fine, i can see wifi signals, but when i go just a few steps back it disappears right away. Im using the latest version of ubuntu 17.10  Any suggestions would be nice! :) I understand that this command attempts to write to nowhere or a null device but what does 2&gt;&amp;1 mean here?  wget -q -O - http://yourwebsite.com/wp-cron.php?doing_wp_cron &gt; /dev/null 2&gt;&amp;1 Suppose you have 2 circles that intersect each other in such a way that each circle passes through the other's center. What is the area between the circle(or common area) i.e. area between the centres of the circles?