I have Windows 10 and Ubuntu 16,04.  I did an update on Windows and after the update I had to restart my computer. After restarting I have an error   Error : no such partition. Entering rescue mode... grub rescue&gt;   How can I fix it?
I installed Windows 7, which ate Ubuntu's boot file. When starting up the computer, it now goes straight to Windows, without giving me the option of booting Ubuntu.   How can I get Ubuntu back?
Predicting count data with random forest? Schengen visa refused from German embassy How can I take a photo with everything in focus with my DSLR? I am quite new to DSLRs and one of the first things I noticed was the incredible focus points and appearance of depth that you can achieve. That is great in a lot of scenarios, but not in all. When filming a landscape as a whole, I do not want to have the focus on that single tree, but on the whole skyline.  Is there a way by which you can sort-of "disable" the focus, so that the raw image is recorded without any added blur? I suppose something as simple as this is only a small function you can turn off, but I can't seem to find it in the manual of my camera. If $\Gamma$ is satisfiable then $\Gamma$ is consistent We say that $\Gamma$ is consistent if for no $\phi$, then both $\Gamma\vdash \neg\phi$ and $\Gamma\vdash\phi$. We say that $\Gamma$ is satisfiable if there is a structure $M$ s.t. $\models_M\gamma[s]$ for alle $\gamma\in\Gamma$.  I want to show that if $\Gamma$ is satisfiable, then $\Gamma$ is consistent.  I'm thinking we assume that $\Gamma$ is not consistent, and then show that $\Gamma$ is not satisfiable. So if $\Gamma$ is not consistent then both $\Gamma\vdash \neg\phi$ and $\Gamma\vdash\phi$ for some $\phi$. But by soundness theorem then $\Gamma\models\neg\phi$ and $\Gamma\models\phi$, meaning for structure $M$, we have $\models_M\neg\phi[s]$ (whereas $\not\models_M\phi[s]$) and $\models_M\phi[s]$. So would this mean that $\Gamma$ is not satisfiable? I'm a little confused, because wouldn't this instead be a contradiction? Where can I find documentation on how to use the \nolinebreak command?  The  at  never makes mention of \nolinebreak  The  states that \nolinebreak is implemented by multiplying its input parameter penalty by (-1) and passing the result into \nopagebreak.       I haven't found documentation on how to use the command. I am new to the glmnet package, and I am still unsure of how to interpret the results. Could anyone please help me read the following trace plot?  The graph was obtaining by running the following:  library(glmnet) return &lt;- matrix(ret.ff.zoo[which(index(ret.ff.zoo)==beta.df$date[2]), ]) data   &lt;- matrix(unlist(beta.df[which(beta.df$date==beta.df$date[2]), ][ ,-1]),                   ncol=num.factors) model  &lt;- cv.glmnet(data, return, standardize=TRUE)  op &lt;- par(mfrow=c(1, 2)) plot(model$glmnet.fit, "norm",   label=TRUE) plot(model$glmnet.fit, "lambda", label=TRUE) par(op) Make terminal use pageup/pagedown instead of shift-pageup/shift-pagedown? I've grown quite weary of shift-pgup to page up in gnome terminal, the command line, terminator, and guake, etc.  Any way to easily make these apps use the straight page-up and page-down keys for paging around? How to convert Wubi install into regular install? I tried writing $y=x^{\sin x}$, so $\ln y=\sin x\ln x$. I tried to rewrite the function as $\ln(x)/\csc x$ and apply l'Hopital to the last function, but it's a mess.   Is there a by hand way to do it? Add warning when changing display name The policy on changing one's display name :  only one display name change is allowed every 30 days  However, there is no warning whatsoever when actually changing one's display name.  Thus, it came as quite a bit of a shock to me when I found out today that I might be stuck as &quot;Unicorns are Yummy&quot; on Stack Overflow for the next freakin' month. I would like to recommend that a warning be added to the &quot;Edit Profile&quot; page to warn people. Or, at least make the policy concerning display name changes more obvious. Workaround I was able to change my display name back (phew!) by copying my profile from Meta Stack Overflow. I still think a warning should be implemented, though. Introduction to proofs with a fair amount of hand-holding? Lately I've gotten a friend of mine interested in mathematics. He has no college-level education to speak of, but is well employed as a software engineer. So I feel he's competent to learn this stuff on his own.  He asked me recently if there was a 'mathematical' version of .  The point being, if there was an "introduction to proofs" book which took a more hand-holding approach. He's also expressed fondness for the .  However, metamath's proofs are obviously a bit too low level to learn anything serious.  At one point in our conversation, I mentioned the dependently typed programming language , but I felt it's not quite as helpful until he at least gets some experience with  (for which the target audience of Agda is Haskell programmers, hence the similarity in syntax).  Anyone have any good suggestions on a book? Can I change directory to a Windows drive in Ubuntu Bash on WSL? I am a super newbie for Ubuntu and basically need Ubuntu for a Python package.  I would like to run a Python file in say e:/username/folder1/folder2/python.py. I tried every method online and the only reply is bash: cd./e: No such file or directory. I am not sure whether it is because of the bash windows or virtualenv.  When I use bash on Ubuntu on Windows, ls, it says VIRTUALENV_DIR. cd, it says /home/username. The cd .. etc changes the directory a little, but not another drive, nor the folder I would like it to find. Prove that $\binom{m+n}{m}=\sum\limits_{i=0}^m \binom{m}{i}\binom{n}{i}$ I need to proof this following equality :  $$\binom{m+n}{m}=\sum_{i=0}^m \left(\binom{m}{i}\binom{n}{i}\right)$$  This is what I did combinatoric proof:  Left : subset with $m$ members from $m+n$  Right : $\binom{m}{i} \rightarrow$ The number of subsets in set $m$ could also be written as $2^m$ AND $\binom{n}{i} \rightarrow$ the number of subsets with $m$ members from set $n$  In case $ n \leq m \implies \binom{n}{i}=2^n$  So this is what I came up with I still can't see why those expression are equal.  Any ideas? Thanks. How do I check the health of a SSD? Only charge capacitor when button pushed then turn on LED momentarily with capacitor when button released I am trying to make circuit to turn on an LED momentarily. I would like to charge the capacitor when the button is pushed, then when released turn on the LED momentarily with the capacitor. How do I brew an X potion? Before upgrading to 14.04 when I clicked on a file in the dash, it opened the file.   This still happens on my 12.04 machine.  In 14.04 when I click on a file in dash search results, it offers me 3 options: 'Email', 'Open' and 'Show in Folder'.  How can I get back the previous behaviour - i.e. to immediately open the files on the first click? How do I calculate the closest power of 2 or 10 a number is? Cast Double to Integer in Java If a car hits a wall at a speed of $v$, and an identical car hits a wall at a speed of $2\,v$, with the kinetic energy equation $E_K = \frac{1}{2}mv^2$ (the speed goes from $v$ to $0$) the second car will lose 4 times the energy, and therefore cause 4 times the damage, but with the force equation $F = ma$ (the car hits the wall and decelerates), it will hit with 2 times the force, and cause 2 times the damage.  How can this be explained?