When trying to launch steam, I get   Steam needs to install these additional packages:      libgl1-mesa-dri:i386, libgl1-mesa-glx:i386   Then it tries to install the packages and gives me   E: Error, pkgProblemResolver::Resolve generated breaks, this may be caused by held packages.
I have never used Ubuntu or any other Linux OS before last Friday. For all I know, I might have installed Ubuntu wrong and be missing a component. I would prefer if you use simplest terminology possible, but I'm OK with doing a bit of googling if need be. I just installed Steam for Ubuntu 16.04 but it won't open when I click on it in the launcher. The icon flashes for a few seconds, stops and then nothing happens. I looked in the system monitor and steam shows up there but ending the process and trying again does nothing. I heard trying to open apps that aren't working through the terminal tells you what the error is so I tried that and I got this:  Running Steam on ubuntu 16.04 64-bit STEAM_RUNTIME is enabled automatically Installing breakpad exception handler for appid(steam)/version(0) libGL error: unable to load driver: radeonsi_dri.so libGL error: driver pointer missing libGL error: failed to load driver: radeonsi libGL error: unable to load driver: swrast_dri.so libGL error: failed to load driver: swrast   Please help I just want to play CS:GO again.
insert code keywords inline What is the command to insert inline code words into the text like this?   I know there are packages for inserting snippets into the code, but I need to insert keywords within the main text. I was wondering if there is a more convenient way to do that. Convergence of the $\sum_{n=1}^{\infty}n^3b_n^3$ where $b_n=\int_{-\pi}^{\pi}f(t)\sin (nt)\ dt$. What's the regular expression that matches a square bracket? AWS dynamodb support for "R" programming language Does option "-h" for "ls" display size in MB or MiB and is it consistent over Unix-based systems? I can’t for the life of me figure out where to use a and where to use the — and where there is no article at all. Is there a simple rule of thumb to memorize?   The standard rule you always hear:     “If a person knows which item you are talking about then use "the"   . . . doesn’t clear things up for me, as I have no idea whether or not they know. How can I share a directory with an another user? I don't want the shared folder to be accessible by anyone on the system, I want it to be accessible just to a restricted set of users.  How to I do that? By taking courses, I have learned topic A. Through self-studying and discussion with others, I have explored topic B.    I also study topic A outside the classroom. What I want to emphasis is that topic B is not in my curriculum, but I study it on my own. Extracurricular activities can include both activities contributed to academic study although outside the normal curriculum, but also activities not contributed to academic study such as sports, volunteer work, etc. I want to emphasis the former activities. Do you say "outside classes", when mentioning study by yourself, i.e.      Outside classes, I have explored B.      If it were you, how would you rewrite the first quote for the same       meaning?    Thanks! How to get PHP 7.0 running with Apache2 I am totally new to Linux, servers and websites. I recently set up Apache2, Python, PHP, and MySQL for setting up a LAMP server. I am using Xubuntu 16.04 and PHP 7.0.11. I followed a guide and placed a PHP file named testing.php in it with:  &lt;?php phpinfo(); ?&gt;    It doesn't show anything on localhost/testing.php All it shows is the code itself. If two variables have 0 correlation, why are they not necessarily independent? Are zero correlated variables independent under special circumstances ?  If possible, I am looking for an intuitive explanation, not a highly technical one. How can I obtain an 'unbalanced' grid of ggplots? I'm using Ubuntu 16.04 and there's no fglrx! I'm using Ubuntu 16.04 and there's no fglrx! What happened? What's the blue pentagon for in Pokemon XY? On the Pokemon status screen, underneath the Pokemon and to the left of the custom markings, is a small blue pentagon:  This doesn't seem to be present on Pokemon obtained through the Pokemon Transporter from Gen V:  I've looked into it myself, and popular opinion seems to be that it's either some kind of &quot;Legitimate Pokemon&quot; mark or simply to indicate that the Pokemon originates from Gen VI. The latter seems far more likely to me, but do we know for sure what this blue hexagon means? Differential Equations: solve the system Solve the following system:   $$dx/dt=-.2(y-2)$$ $$dy/dt=.8(x-2)$$  This is what I have so far, but I got stuck.. $$\begin{eqnarray} dx/dt&amp;=&amp;-.2y-.4\\ x'&amp;=&amp;-.2y-.4\\ x'+.4&amp;=&amp;-.2y\\ y&amp;=&amp;-x/2'-2\\ y&amp;=&amp;-x''/2-2\\ \\ dy/dt&amp;=&amp;.8(x-2)\\ dy/dt&amp;=&amp;.8x-1.6\\ y'&amp;=&amp;.8x-1.6\\ -x''-2&amp;=&amp;.8x-1.6\\ -x''&amp;=&amp;.8x+.4\\ x''+16x+.8&amp;=&amp;0 \end{eqnarray}$$  when I used the quadratic formula I got stuck. Is this correct so far? Can someone finish it off for me? Problem on Extremal Graphs: three independent paths The problem states that:     A simple (or strict) graph with $n$ vertices and $m&gt;\dfrac{3(n-1)}{2}$ edges, has two vertex   joined by three independent paths.   Any hints, ideas or useful results, to attack this problem? Existence of a local geodesic frame Let $(M,g)$ be a Riemannian manifold of dimension $n$ with Riemannian connection $\nabla,$ and let $p \in M.$ Show that there exists a neighborhood $U \subset M$ of $p$ and $n$ (smooth) vector fields $E_1,...,E_n \in \chi (U),$ orthonormal at each point of $U,$ s.t. at $p,$ $\nabla_{E_i}E_j(p)=0.$  What I've found so far;  Let $V$ be a normal neighborhood at $p.$ Let $(W,x(x_1,...,x_n))$ be a local coordinate system at $p$ s.t. $x(W) \subset V.$  Let $\{X_i:=\frac{\partial}{\partial x_i}\}$ be the standard basis of $T_pM.$ By Gram-Schmidt, there exists an orthonormal basis $\{E_i\}$ of $T_pM.$ Consider the orthonormal frame $E_i(t),$ by parallel transporting $\{E_i(0)=E_i\}$ along a  a geodesic $\gamma :I \to M$ starting at $\gamma(0)=p$ and ending in $\gamma(1)=q,$ where $q \in V.$ This gives us an orthonormal frame at each point of $V.$ To satisfy the second condition, let $E_i(t)=\sum_{l}a_{li}X_l$ and  $E_j(t)=\sum_{s}b_{sj}(t)X_s.$ Then   $$\nabla_{E_i}E_j=\sum_{k}(\sum_{l,s} a_{li}(t)b_{sj}(t)\Gamma^k_{ls}+E_i(b_{kj}))X_k,$$  where $\Gamma^k_{is}$ are Christoffel symbols.   To have $\nabla_{E_i}E_j(p)=0,$ we must have $\sum_{l,s}a_{li}(0)b_{sj}(0)\Gamma^k_{ls}+E_i(b_{kj})(p)=0$ for each $k.$      How can I conclude the argument? Help me identify this insect from Bangladesh I have seen this insect flying literally everywhere in Dhaka city (Bangladesh) over the last two months. It's small -- around 1-1.5 inches long. It's not an agile flyer and can be easily grabbed by hand during flight. Selectively disable iCloud keychain syncing for WiFi passwords I have iCloud Keychain sync enabled, but I want to stop it syncing WiFi passwords.  I have a portable WiFi hotspot which I use for my laptop and iPad, but I don't want my iPhone to connect to it since it has it's own 3G  Because iCloud is syncing the settings, within about 30 seconds of connecting my laptop to the 3G hotspot, my iPhone will connect itself. If I go into wifi settings on the iPhone and manually disconnect, about 30 seconds later my laptop will disconnect too. It seems with iCloud wifi sync on, I can’t connect my laptop to WiFi without my phone also connecting.  The only way to get around it seems to be disabling Keychain sync in iCloud. I’ve tried Googling, but got no real help on how to disable it without turning off Keychain, which is what I’ve done at the moment.  I also don't want to enable 'Ask before joining networks' on my iPhone, since I'll be manually re-connecting it constantly. Inequality with complex numbers Consider the following problem.  Fix $n \in \mathbb N$. Prove that for every set of complex numbers $\{z_i\}_{1\le i \le n}$, there is a subset $J\subset \{1,\dots , n\}$ such that   $$\left|\sum_{j\in J} z_j\right|\ge \frac{1}{4\sqrt 2} \sum_{k=1}^n |z_k|.$$  I believe I proven have a stronger statement. Is this proof correct, and if so, what is the optimal constant?  My proof. Consider all the $z_i$ with positive real part. Call the real part of the sum of these numbers $X^+$. In a similar way, form $X^-$, $Y^+$, and $Y^-$. Without loss of generality, let $X^+$ have the greatest magnitude of these.  Note that because $|\operatorname{Re}(z)|+|\operatorname{Im}(z)|\ge |z|$, we have  $$ \left(\sum_{k=1}^n  |\operatorname{Re}(z_k)|+|\operatorname{Im}(z_k)| \right) \ge \sum_{k=1}^n |z_k|.$$  But note that $\sum \limits_{k=1}^n  |\operatorname{Re}(z_k)|+|\operatorname{Im}(z_k)| = X^+ + |X^-|+ Y^+ +|Y^-|$, so we have  $$ 4X^+ \ge \sum_{k=1}^n |z_k|.$$ By choosing $J$ to be the set of complex number with positive real part, this proves a stronger statement, because the factor of $1/\sqrt 2$ isn't needed. Getting "'file' is different from the same file on the system" when I attempt to update through synaptic