I have Ubuntu 16.04 LTS and tried to install Virtual Box on my system. I downloaded setup for 16.04 directly from Oracle site, ran through Ubuntu Software of course, and I suspected already when it didn't start install on one click, I needed to click twice, then I got install icon on my dock, which didn't load for about 10 minutes. I restarted, then I got error message on picture.   Question 1: How to fix that error? Question 2: How do I get clear install of Virtual Box?
I have unistalled and reinstalled the Ubuntu Software Center as per info I found in a similar thread and I got the same response about line 91 or something like that.  I just tried to upload a screen shot but since I'm new it won't allow me to.  I also can not figure out how to cut and paste anything so I have to hand type what the error screen says, both when I attempt to open the software center and nothing happens, when I try to enter commands into the terminal to uninstall, reinstall, whatever I get the same following:  COULD NOT INTITIALIZE THE PACKAGE INFORMATION An unresolvable problem occured while initializing the package information Please report t:his bug against the 'update-manager' package and include the following error message: 'E: Malformed line 91 in source list/etc/apt/sources.list (dist parse)  E: The list of sources could not be read.,  E: The package list of status file could not be parsed or opened.   How do I report bugs?  What can be done about this.  I have searched and everything everyone says to do leads me back to the same line error message.  So, I don't know how to get to line 91 in the source list; to tell you what it says. Sorry, I'm really new to this. That is what I need is to find out how to get there and fix what it says. I would really like to NOT have to re partition my hard drive and start from scratch, so I'm really looking forward to getting this problem solved. I need to be able to install new software.
Problems with \input{table.tex}\hline after 2020 fall LaTeX release Since updating to the 2020 Fall release (MikTeX on Windows but also tested with TeXLive), I can no longer compile files where tables are imported from an external file using \input and followed by \hline (or \bottomrule). Things work perfectly with older releases. Note that it works if the last \\ is outside the file to be imported, but this is not a feasible option if the tables are created automatically from other softwares. Here is a MWE:  \begin{document}  \begin{table}   \caption{Table in text}   \begin{tabular}{lcc}     a &amp; 1 &amp; 2\\     b &amp; 1 &amp; 2\\     \hline   \end{tabular} \end{table}  \begin{table}   \caption{Table in other file 1}   \begin{tabular}{lcc}     \input{table1}     \hline   \end{tabular} \end{table}  \begin{table}   \caption{Table in other file 2}   \begin{tabular}{lcc}     \input{table2}\\     \hline   \end{tabular} \end{table}  \end{document}  with external files: table1.tex:     a &amp; 1 &amp; 2\\     b &amp; 1 &amp; 2\\  table2.tex:     a &amp; 1 &amp; 2\\     b &amp; 1 &amp; 2  Here is the log when it fails: This is pdfTeX, Version 3.14159265-2.6-1.40.21 (MiKTeX 20.10) entering extended mode (MWE.tex LaTeX2e &lt;2020-10-01&gt; patch level 1 L3 programming layer &lt;2020-10-05&gt; xparse &lt;2020-03-03&gt; (&quot;C:\Program Files\MiKTeX\tex/latex/base\article.cls&quot; Document Class: article 2020/04/10 v1.4m Standard LaTeX document class (&quot;C:\Program Files\MiKTeX\tex/latex/base\size10.clo&quot;)) (&quot;C:\Program Files\MiKTeX\tex/latex/l3backend\l3backend-pdftex.def&quot;) (MWE.aux) (table1.tex) ! Misplaced \noalign. \hline -&gt;\noalign                    {\ifnum 0=`}\fi \hrule \@height \arrayrulewidth \futurelet... l.18     \hline                 ! You can't use `\hrule' here except with leaders. \hline -&gt;\noalign {\ifnum 0=`}\fi \hrule                                           \@height \arrayrulewidth \futurelet... l.18     \hline                 ! Missing number, treated as zero. &lt;to be read again&gt;                     \futurelet  l.18     \hline                 ! Illegal unit of measure (pt inserted). &lt;to be read again&gt;                     \futurelet  l.18     \hline                 (table2.tex) [1{C:/Users/Gouel/AppData/Local/MiKTeX/pdftex/config/pdftex.map}] (MWE.aux) ) (see the transcript file for additional information)&lt;C:/Program Files/MiKTeX/fo nts/type1/public/amsfonts/cm/cmr10.pfb&gt; Output written on MWE.pdf (1 page, 14750 bytes). Transcript written on MWE.log.  With an older release under Linux, it works perfectly: This is pdfTeX, Version 3.14159265-2.6-1.40.20 (TeX Live 2019/Debian) (preloaded format=pdflatex)  restricted \write18 enabled. entering extended mode (./MWE.tex LaTeX2e &lt;2020-02-02&gt; patch level 2 L3 programming layer &lt;2020-02-14&gt; (/usr/share/texlive/texmf-dist/tex/latex/base/article.cls Document Class: article 2019/12/20 v1.4l Standard LaTeX document class (/usr/share/texlive/texmf-dist/tex/latex/base/size10.clo)) (/usr/share/texlive/texmf-dist/tex/latex/l3backend/l3backend-pdfmode.def) (./MWE.aux) (./table1.tex) (./table2.tex) [1{/var/lib/texmf/fonts/map/pdftex/up dmap/pdftex.map}] (./MWE.aux) )&lt;/usr/share/texlive/texmf-dist/fonts/type1/publi c/amsfonts/cm/cmr10.pfb&gt; Output written on MWE.pdf (1 page, 13788 bytes). Transcript written on MWE.log. Determine file type of an image I'm downloading some images from a service that doesn't always include a content-type and doesn't provide an extension for the file I'm downloading (ugh, don't ask).  What's the best way to determine the image format in .NET?  The application that is reading these downloaded images needs to have a proper file extension or all hell breaks loose. In the 3rd and 4th editions of D&amp;D, there were explicit rules for determining if a character knew anything about a monster before them.  In 3rd edition, for example, use of the  skill with a general DC of 10 + the monster's HD allowed for determining one fact, plus one fact per 5 points over the check.  Looking at the Intelligence section of the 5e PHB, I don't see any similar notation.  Does 5e provide any guidance as to when a player could use their out-of-game knowledge about a monster, or when the player might be told things their character would probably know in-game? Show that $(L^{p},\|\|_{p})$ is a Banach space.  My approach: I prove the statement for $(L^{1},\|\|_{1})$, of the following way, first all, is easy show that $\|\|_{1}$ is a norm. So,  $(L^{1},\|\|_{1})$ is vector space. To show that is a Banach space, note that  Prop. 1: Let $(f_{n})_{n\in\mathbb{N}}\subset\mathcal{L}^{1}$ (where $\mathcal{L}^{1}=\mathcal{L}^{1}(X,\tau,\mu)$ is the space of all integrals function), such that $\sum_{i}{\|f_{n}\|}_{1}&lt;\infty$, then the sequences $\left(\sum_{n=1}^{N}{f_{n}}\right)_{n\in\mathbb{N}}$ converges almost everywhere to the integral function, that we called $\sum_{n\in\mathbb{N}}{f_{n}}$. Furthermore $$\sum_{n\in\mathbb{N}}{\int{f_{n}d\mu}}=\int{\sum_{n\in\mathbb{N}}{f_{n}d\mu}}\quad\lim_{N\to\infty}{\|\sum_{n=1}^{N}{f_{n}}-\sum_{n\in\mathbb{N}}{f_{n}}\|_{1}}=0$$ Prop. 2: Let $(E,\|\|)$ a normed vector space. Then $E$  is a Banach space if and only if for all $(e_{k})_{k\in\mathbb{N}}\subset E$ such that $\sum_{k\in\mathbb{N}}{\|e_{k}\|}&lt;\infty$, $\left(\sum_{k=1}^{n}{e_{k}}\right)_{n\in\mathbb{N}}$ converges in $E$  We take the proposition 2. Let $(f_{n})_{n\in\mathbb{N}}\subset L^{1}$ such that $\sum_{n}{\|\hat{f}_{n}\|_{1}}&lt;\infty$. Let $f_{n}\in\hat{f}_{n}$, then $\|f_{n}\|_{1}=\|\hat{f}_{n}\|_{1}$ and then $\sum_{n}{\|f_{n}\|_{1}}&lt;\infty$, by prop. 1, there exist $F\in\mathcal{L}^{1}$ such that $\|\sum_{n=1}^{N}{f_{n}-F\|_{1}}\to 0$, and then $\|\sum_{n=1}^{N}{\hat{f}_{n}-F\|_{1}}\to 0$. Finally note that $\hat{F}\in L^{1}$ is a Banach space. This was my answer for  $L^{1}$ space, but how I prove the general statement for $L^{p}$ (I want to do a similar response). Edit: I'm stuck in the problem, any idea or hint is appreciated.Thanks!! How can I strike through an expression (e.g. "2x") obliquely, e.g. from bottom left to top right, so as to indicate cancellation? With the \sout command from the ulem package, I can only strike horizontally. Google Analytics - Traffic Source - Search engine - (Not Provided) I am using Google Analytics, now here when I go to "Traffic Source Overview" under that it shows Keyword as "(Not provided)" which is almost 40% of my traffic source. Now more than 90% of search engine traffic is from Google and still out of that for more than 40% of keywords are "(Not provided)".  Can anyone explain me what is going wrong here or how can I get that data? Because that comes as 1st option and is biggest keyword in the list. Will that be some crawler or secure google search? What is the difference between '->' (arrow operator) and '.' (dot operator) in Objective-C? I can get the element like this $("#txtEmail") but I'm not sure how to get the actual value. Suppose $f$ and $g$ are entire functions, and $|f(z)| \leq |g(z)|$ for all $z \in \mathbb{C}$, Prove that $f(z)=cg(z)$.   My try :  I consider $h(z)=\frac{f(z)}{g(z)}$. If I prove that $h(z)$ is entire, using the fact that $|h(z)|\leq 1$, the result follows immediately from Liouville's theorem.  To prove that $h(z)$ is entire, I have to prove that $h(z)$ has removable singularities at possible zeros of $g(z)$.  Suppose $g(z_0)=0 \Rightarrow |g(z_0)|=0 \Rightarrow |f(z_0)|=0$, BUT what if $z_0$ be a root of of order $k$ of $g(z)$ (i.e. $f^{(n)}(z_0) = 0 $ for all $ 0 \leq n \leq k-1$) and be a zero of order $m$ of $f(z)$ and $k&gt;m$ ?  And if that's not the case, how to rigorously show that $z_0$ is a removable singularity ?  Thank you all in advance. If I click to open achievements from a question when I click the X to close the achievements view I end up on the answers tab of the question, I assume because the X is over the tab and it's tapping through.    It appears if I hit the X it's ok, but if I tap anywhere else in the top row (where the X is) then I can switch to the question or answer tab. Changing the value of an element in a list of structs I have a list of structs and I want to change one element. For example :  MyList.Add(new MyStruct("john"); MyList.Add(new MyStruct("peter");   Now I want to change one element:  MyList[1].Name = "bob"   However, whenever I try and do this I get the following error:     Cannot modify the return value of   System.Collections.Generic.List.this[int]‘ because it is not   a variable   If I use a list of classes, the problem doesn't occur.  I guess the answer has to do with structs being a value type.  So, if I have a list of structs should I treat them as read-only? If I need to change elements in a list then I should use classes and not structs? Proof the Legendre polynomial $P_n$ has $n$ distinct real zeros What are these  error below ?  Package natbib Warning: Citation `Krishna2014' on page 16 undefined on input li ne 502.  [16 &lt;./figure/aks smr.png&gt;] [17] [18] ! Undefined control sequence. l.560 \Bibliography                    {figure/bib} Immigration check between Northern Ireland/Republic of Ireland and Great Britain Do immigration checks exist between Northern Ireland and England/Scotland? (not just for flights but also ferry/bus/train) Do immigration checks exist between the Republic of Ireland and England/Scotland? PlotRange precision limit? This is a very basic query I can't figure out....  Let's say I have a two column table like this:  userid  |  roleid --------|--------    1    |    1    1    |    2    1    |    3    2    |    1   I want to get all distinct userids that have roleids 1, 2 AND 3.  Using the above example, the only result I want returned is userid 1.  How do I do this? Is it possible to include the tag-wiki associations in the Data Explorer? To do this would require two additional columns in the postTags table that associate a tag wiki excerpt and a tag wiki to their tag.  The tag wiki data is already available in the posts table. But there is no way to associate this data with its tags. The SEDE schema lacks the required columns to link the tag excerpt and the tag wiki to the tags table.  Additionally, the postTypes table only lists three posts types. It makes no mention of tag-wiki and tag excerpt posts. Perhaps the postypes table can be updated to reflect the additional post types? Preserving signatures of decorated functions How to center column values in a table? How can I center the column values in this code?  \documentclass[conference]{IEEEtran} \begin{document} \begin{table}   \centering   \begin{tabular}{|p{2.5cm}|p{2.5cm}|p{2.5cm}|}     \hline     Reconstruction strategy &amp; aa          &amp; bb( \%) \\ \hline     Classic                 &amp; 3342 voxels &amp; 68 \%   \\ \hline     VC                      &amp; 4296 voxels &amp; 87 \%   \\ \hline     V m=7                   &amp; 4745 voxels &amp; 96 \%   \\ \hline   \end{tabular}   \newline\newline    \caption{title}\label{tab1} \end{table} \end{document} How does DC work with natural 20?