Cannot generate R File-Android
R cannot be resolved - Android error
Russian SE has a slightly longer and more storied history than Japanese SO Let $A_n$ denote an $n \times n$ tridiagonal matrix.  $$A_n=\begin{pmatrix}2 &amp; -1 &amp; &amp; &amp; 0 \\ -1 &amp; 2 &amp; -1 &amp; &amp; \\ &amp; \ddots &amp; \ddots &amp; \ddots &amp; \\ &amp; &amp; -1 &amp; 2 &amp; -1 \\ 0 &amp; &amp; &amp; -1 &amp; 2 \end{pmatrix} \quad\text{for }n \ge 2$$  Set $D_n = \det(A_n)$  Prove that $D_n = 2D_{n-1} - D_{n-2}$ for $n \ge 4$. Problem about angle in isosceles triangle Experimental Fractional scaling makes fonts dirty in Ubuntu 17.10 I updated to 17.10 from 17.04.   I activated the fractional scaling by running the following command.   gsettings set org.gnome.mutter experimental-features "['scale-monitor-framebuffer']"   Then, I changed 125% scale. The scale was changed, but the fonts and icons are so dirty.    The launcher icon and font in Google Chrome and other application except the system setting are dirty.  How can I resolve this problem?  For some reason, font in the system setting is not dirty... What's the difference between $\equiv$ and $\leftrightarrow$ in a formal proof? A question about eigenvalues of $5\times5$ matrix Show that if the Riesz map is surjective on $H$, then $H$ is a Hilbert space Let $H$ be a vector space equipped with an inner product $(\cdot, \cdot)$ and $f:H\to H',\ f(x)=(\cdot,x)$ surjective. Now, why $H$  is a Hilbert space? The other direction is clear by Riesz' representation theorem but what about this? If Chrome is already open, it opens new sites (e.g. from Windows shortcuts, application shortcuts, or from the Run dialog) in new tabs of the existing instance.   I'd prefer to open new sites in a separate window (a new instance of Chrome).   I don't see that in the options - is it possible? Detecting pattern at the end of a line with grep Why don't digital cameras shoot video at full sensor resolution, or do continuous drive at video framerates? I have seen some users show a picture of their network profile on the profile tab. How can I add this for my own account? Motivation behind standard deviation? Safest way to transport a laptop during flight I flew a long range flight carrying my laptop, a quite heavy one, inside a neoprene briefcase in the passenger cabin. The recommendation by the aircrew was to place it in the overhead compartment or under the seat in front of me. However, during take-off and landing, the vibrations on the plane are quite strong and, as a result, it received minor damage.   Placing them in the overhead compartment might be equivalent to placing it on the floor under the seat, with the added issue of additional luggage in the compartment shifting.  I considered the alternative of holding the laptop by the handle while sitting, so it won't be any contact with the aircraft's floor. This is impracticable during cruise, but I thought it could be better during the take-off and landing segments. Another option I considered is to wrap it with completely with bubble wrap before boarding the plane.   Which is the safest way to transport a laptop during flight? I'm working on a custom report (Visual Force) to generate specific charts(using apex:radar chart) to our client. The problem is that we have to export the information to PDF format. Using the technique of include "renderAs" property on APEX tag, the PDF is generated but the chart isn't included on the PDF and the apex tags, used to show detailed information in a table, seem to be unconfigured. Have anyone ever faced this kind of problem?     Thank you! Is a memory leak created if a MemoryStream in .NET is not closed? I have the following code:  MemoryStream foo(){     MemoryStream ms = new MemoryStream();     // write stuff to ms     return ms; }  void bar(){     MemoryStream ms2 = foo();     // do stuff with ms2     return; }   Is there any chance that the MemoryStream that I've allocated will somehow fail to be disposed of later?    I've got a peer review insisting that I manually close this, and I can't find the information to tell if he has a valid point or not. The number of labelled graphs with all vertices of even degree I have a graph exam tomorrow, and there is a problem that said number of graph with labeled vertices and all of them of even degree is $ 2^{n-1 \choose 2} $.  According to that topic, it means the number of cut spaces is $ 2^{n-1} $. Well, I don't understand what is cut space yet, and why its count is $ 2^{n-1} $ And don't  know why we should divide the total number of graphs by this! Prove that there are infinitely many primes and non-primes in the numbers $10^n+1$, where $n$ is a natural number. So numbers are 101, 1001, 10001 etc. How do I install drivers for a Canon LBP-2900 printer? I seen many times how people describe how to's about LBP-2900, and 10-12 steps from start to end of how to download, unpack, build driver, fix driver, make it work... Could be there some .deb package with ready-to-go driver for Ubuntu? This printer is very popular... As the title says, how can I make this shape without resorting to a Boolean operation?    This is obviously a very simple example, but I find myself needing to do something like this relatively often when modelling.  Despite using Blender for a couple of years, and considering myself an intermediate to possibly advanced user, I still know of no easy way to make this kind of indentation in an object.  Obviously, if you are looking to make an indentation in the middle of the surface, you can simply select a face and extrude down. As you will know, this does not work at the edge of the surface.  I can create this shape using loop cuts, deleting the faces and then using snap to edge to extrude the edges down to the same level (and then filling in the faces), but it feels cumbersome and a lot of work for what feels like it should be very simple. Unchained Flurry of Blows with Natural Weapons and Feral Combat Training using natural attacks as primary