The 'grub-efi-amd64-signed' package failed to install into / target/. Without the GRUB boot loader, the installed system will not boot
Ubuntu 16.10 Dual Boot error - 'grub-efi-amd64-signed' package failed to install
What's the best way to build a string of delimited items in Java? Which is correct: "the below information" or "the information below"? I frequently see statements that refer to something later in the text that use a phrase such as "the below information". Is it more correct instead to say "the information below" (or "the following information")? Dark Energy / Accelerating universe: naive question How to calculate relatedness in haplodiploid organisms (mainly full sisters and full brothers)? I have tried to calculate the relatedness for haplodiploid organisms, but cannot understand the calculations behind full sister and full brother.  (taken from  I have managed to solve the other cases. Since female will have ZZ:  female will share 1/2 of her genes with daughter female will share 1/2 of her genes with son female will share 1/2 of her genes with mother female will share 1/2 of her genes with father  Since male will have only Z:  male will share 1 (100%) of his genes with his daughter male won't share anything with his son (unfertilized eggs leads to male in haplodiploidy system) male will share 1(100%) of his genes with his mother male won't share anything with his father (unfertilized eggs leads to male in haplodiploidy system)  Even though I figured out how others work, I wasn't able to calculate r for fullsister fullbrother? How can it be 3/4,1/4,1/2,1/2? If $A$ is a square matrix and $A^2 = 0$ then $A=0$. Is this true? If not, provide a counter-example. Example of non-flat modules Let $R = \mathbb{C}[t]$ be a ring of polynomials in variable $t$ with coefficients in the field of complex numbers $\mathbb{C}$ and let $$N = R[x]/(tx-t).$$  I claim that $N$ is not a flat $R$- module. If we consider the exact sequence $$0 \rightarrow(t) \rightarrow R$$ such that the ideal $(t)$ is viewed as an $R$-module.   We know that the above sequence exact iff the map $(t) \rightarrow R$ is injective. Let us assume that N is flat then this means that $N \otimes  (t) \rightarrow N \otimes R$ has to be injective. How do I go from here?   Thanks. Does existence of $\gcd$ implies PID? How to make document custom page dimensions? Stuff like polls, recommendations based on subjective constraints, puzzles, webcomics etc. do not belong on the serious main SE sites, where professionals should be considered at work and having just a few spare minutes ("code's compiling") to answer questions, so they should not be distracted by such things. However, I'd also like to have a home for these things still using the SE engine. For the reason I mentioned before, this needs to be a separate place though. Let's call it four.[sitename-here].com. What is a "hat"? What exactly is a hat?  I have seen a lot of people arguing the significance of hats and the limited edition hats. I know the hats are sort of linked to the Winterbash stuff, but what exactly is a hat, what does it do, how do I get one?  Is there a full list of hats? I've got a huge list of date-times like this as strings:  Jun 1 2005  1:33PM Aug 28 1999 12:00AM   I'm going to be shoving these back into proper datetime fields in a database so I need to magic them into real datetime objects.   This is going through Django's ORM so I can't use SQL to do the conversion on insert. Could not get lock /var/lib/apt/lists/lock when I try to apt-get update I'm getting the below error,  E: Could not get lock /var/lib/apt/lists/lock - open (11: Resource temporarily unavailable) E: Unable to lock directory /var/lib/apt/lists/ How does water evaporate if it doesn't boil? When the sun is out after a rain, I can see what appears to be steam rising off a wooden bridge nearby. I'm pretty sure this is water turning into a gas.  However, I thought water had to reach 100 degrees C to be able to turn into a gas.  Is there an edge case, for small amounts of water perhaps, that allows it to evaporate? Why is `[` a shell builtin and `[[` a shell keyword? Evaluating $\int_{0}^{\infty}\frac{\sin^{2n+1}x}{x}\mathrm{d}x$ I was generalizing the following integral: $$\int_{0}^{\infty}\frac{\sin^{2n+1}x}{x}\mathrm{d}x \hspace{40pt} n\geq 0$$ We can start by noting that $\sin x =\dfrac{e^{ix}-e^{-ix}}{2i}$ and thus $\displaystyle \sin^{2n+1}x=\frac{(-1)^n}{2^{2n}}\sum_{r=0}^n (-1)^r \binom{2n+1}{r}\sin(2r+1)x$. This implies $$\begin{aligned}\displaystyle \int_{0}^{\infty}\frac{\sin^{2n+1}x}{x}\mathrm{d}x &amp;=\frac{(-1)^n}{2^{2n}}\sum_{r=0}^n (-1)^r \binom{2n+1}{r}\int_{0}^{\infty}\frac{\sin(2r+1)x}{x}\mathrm{d}x \\ &amp;=\frac{(-1)^n\pi}{2^{2n+1}}\sum_{r=0}^n(-1)^r\binom{2n+1}{r} \\ &amp;=\frac{(-1)^n\pi}{2^{2n+1}}\sum_{r=0}^n\left((-1)^r\binom{2n}{r}-(-1)^{r-1}\binom{2n}{r-1}\right)\end{aligned}$$ Where I have used the well known  $\displaystyle \int_{0}^{\infty} \frac{\sin(2r+1)x}{x}\mathrm{d}x=\int_{0}^{\infty}\frac{\sin x}{x}\mathrm{d}x=\frac{\pi}{2}$ and the property of binomial coefficients that $\displaystyle \binom{n}{r}+\binom{n}{r-1}=\binom{n+1}{r}$ Since the above sum telescopes, we have $$\displaystyle \int_{0}^{\infty}\frac{\sin^{2n+1}x}{x}\mathrm{d}x=\frac{(-1)^n\pi}{2^{2n+1}}(-1)^n\binom{2n}{n}=\frac{\pi}{2^{2n+1}}\binom{2n}{n} ~\forall ~ n\in \mathbb{Z^{+}}$$ I would like to know other methods for evaluating this integral. Print composer problems Qgis 2.8 Wien with Google Satellite I am having serious problems in exporting a map (Google satellite map) linked to QGIS.   Using the print editor I clearly see the part of the map I want to print and also in the right scale, but when I save it as jpeg, the result is: the correct map in a circle in the middle of the page, and all around it seems that Qgis is zooming at different scale on another part of the map [see attached file].  Any suggestion about it ? I don't want to save it as simple screenshot  because I need an HD file.   ] Convert short[] into a grayscale image I just installed Ubuntu 14.04 Server and cannot get wifi configured correctly to work with WPA2 personal and could use some help.    There was a simple wizard during install where I selected my SSID from a list and entered my passphrase and that worked great.  Now that the install is done I am having trouble configuring wifi.  My Access Point is setup to WPA2 Personal TKIP or AES. Any advice would be greatly appreciated.  I have been messing around with WPA supplicant ant my /etc/network/interfaces file with no luck.  Thanks How do I fork a process that doesn't die when shell exits? Shortest path from points in one layer to points in another layer via roads in QGIS