I freshly installed ubuntu 17.10.1 on my hp and my wifi seems to be not working. I searched for solution then i found apt-get linux-generic-hwe-16.04 it throws an error package not found  i run this command   lspci -vnn | grep Network   output  02:00.0 Network controller [0280]: Realtek Semiconductor Co., Ltd. Device [10ec:d723]   `
How do I install Wi-Fi drivers for Realtek RTL8723DE device in Ubuntu 16.04?  lspci -v | grep -i network 02:00.0 Network controller: Realtek Semiconductor Co., Ltd. Device d723
Let $R$ be a commutative ring with 1 then why does $a\in N(R) \Rightarrow 1+a\in U(R)$? Let $R$ be a commutative ring with 1, we define  $$N(R):=\{ a\in R \mid  \exists k\in \mathbb{N}:a^k=0\}$$  and  $$U(R):=\{ a\in R \mid a\mbox{ is invertible} \}.$$  Could anyone help me prove that if $a\in N(R) \Rightarrow 1+a\in U(R)$?  I've been trying to construst a $b$ such that $ab=1$ rather than doing it by contradiction, as I don't see how you could go about doing that. How to Export this animation as a gif file for powerpoint presentation Sorry to start a subjective question, but want to understand "own.sty" file.  Other than all \usepackage{} what sort of other commands can be added to the makeyourown.sty file.  Can you include \let command, and \newcommands in it.   What sort of precaution / structure newbies should follow. I am programming with normal pointers, but I have heard about libraries like Boost that implement smart pointers. I have also seen that in Ogre3D rendering engine there is a deep use of shared pointers.  What exactly is the difference between the three, and should I stick on using just a type of them? Question:   Answer:   The question was closed at 11:57:57 (according to the hover-over-"x-mins-ago" bar) and the answer was posted at 12:16:35. It's a fairly lengthy answer, so it's possible that it was started to be written before it was closed but I swear I've started to answer a question then I got a banner along the top saying "this question has been closed" and the answer was no longer post-able. Digitally selectable filter I have asked a  but I did not get an answer, as it was too specific. So I will build on it but make it a bit more broad spectrum.  I would like to make a digitally selectable BPF using transistors to select a component in the filter; resulting in the center frequency being changed.  I have used FilterPro to generate quick second order filters and get a rough filter response.  For all the designs, a Multiple-feedback was selected:  In the first picture, a center frequency at 108KHz with a bandwidth @ -3dB of 103K to 113KHz is given.    For the second, a center frequency at 117.5KHz with a bandwidth @ -3dB of 112.8K to 122.2KHz is given.    The only difference between these two circuits is R3.  If I were to implement a circuit as shown below, would it work and what transistor would be recommended? I have selected the  as the Opamp in the circuit design as that is what was used for the .    For the transistors, I was thinking of using the MOSFETs (2N7002) used in the ST7590 design as well. Homotopy equivalence of universal cover As part of am exam question (Q21F ), I'm trying to prove that if $X$ and $Y$ are path-connected, locally path-connected spaces with universal covers $\widetilde{X}$ and $\widetilde{Y}$, respectively, then if $X \simeq Y$ then $\widetilde{X} \simeq \widetilde{Y}$.  My attempt might be correct, but it seems too complicated and amongst the jumble I may have made some incorrect assumptions. So what I'm looking for is (a) verification or correction; and (b) ideas as to how I could simplify my argument.    My argument:  Let $p:\widetilde{X} \to X$ and $q:\widetilde{Y} \to Y$ be the covering maps, and let $X \overset{f}{\underset{g}{\leftrightarrows}} Y$ be a homotopy equivalence.  Fix a point $\widetilde{x} \in \widetilde{X}$, let $x=p(x) \in X$ and $y=f(x) \in Y$, and fix $\widetilde{y} \in q^{-1}(\{y\}) \subseteq \widetilde{Y}$. Also let $x' = g(y) \in X$ and fix $\widetilde{x'} \in p^{-1}(\{x'\}) \subseteq \widetilde{X}$.  Define a map $\widetilde{f} : \widetilde{X} \to \widetilde{Y}$ as follows. For $\widetilde{z} \in \widetilde{X}$ let $\widetilde{u}:[0,1] \to \widetilde{X}$ be a path from $\widetilde{x}$ to $\widetilde{z}$. Let $z=p(z)$ so that $u=p\widetilde{u}$ is a path in $X$ from $x$ to $z$. Let $v=fu$, so that $v$ is a path in $Y$ from $y$ to $f(z)$. Lift $v$ to a path $\widetilde{v}$ in $\widetilde{Y}$ with $\widetilde{v}(0) = \widetilde{y}$. Define $\widetilde{f}(\widetilde{z}) = \widetilde{v}(1)$.  Notice that $q\widetilde{v}=v$ so that $q\widetilde{f} = fp$.  Define $\widetilde{g}:Y \to X$ analogously: For $\widetilde{z} \in \widetilde{Y}$ let $\widetilde{a}:[0,1] \to \widetilde{Y}$ be a path from $\widetilde{y}$ to $\widetilde{z}$. Let $z=q(z)$ so that $a=q\widetilde{a}$ is a path in $Y$ from $y$ to $z$. Let $b=fa$, so that $b$ is a path in $X$ from $x'$ to $g(z)$. Lift $b$ to a path $\widetilde{b}$ in $\widetilde{X}$ with $\widetilde{b}(0) = \widetilde{x'}$. Define $\widetilde{g}(\widetilde{z}) = \widetilde{b}(1)$.  Likewise, notice that $p\widetilde{g}=gq$.  Claim: $\widetilde{X} \overset{\widetilde{f}}{\underset{\widetilde{g}}{\leftrightarrows}} \widetilde{Y}$ is a homotopy equivalence.  We have $p\widetilde{g}\widetilde{f} = gq\widetilde{f}=gfp \simeq p$ and $q\widetilde{f}\widetilde{g} = fp\widetilde{g} = fgq \simeq q$.  This shows that $\widetilde{g}\widetilde{f}$ and $\widetilde{f}\widetilde{g}$ are covering translations (deck transformations) and are therefore homotopic to the respective identity maps. So we have a homotopy equivalence.    Any comments would be appreciated. How can I cure lycanthropy? I really want to get rid of it. I've been through the whole companion’s quest line and cured Kodlak's. I killed all 5 witches and have 4 of the heads left in my inventory.  I've been back to that same flame and tried to use it with the head, but nothing going; activating it does nothing. I've heard this is how you cure it; however I have not heard a first-hand account of anyone actually curing it.  If you have, can you explain what you do? Do you go to the same tomb where you fought Kodlak's beast form? Do you do something special with the witch head in your inventory, or just have it in there and activate the harbinger flame or whatever? "no public key available" on apt-get update What are these rays that appear in photograph of sun? In many images of light emitting objects we see such rays. Why do they appear ? What is the math behind their number and direction? given that $f$ is an analytic function with real part $u$ is a polynomial in the variable of $x,y$, $z=x+iy$, we need to show $f$ is a polynomial in $z$, I am kind of puzzled to see the problem, first I would like to say:any hint please Marshal "char *" in C# Given the following C function in a DLL:  char * GetDir(char* path );   How would you P/Invoke this function into C# and marshal the char * properly. .NET seems to know how to do LPCTSTR but when I can't figure out any marshaling that doesn't cause a NotSupportedException to fire when calling this function. Title of short story: God granting immortality to others to find a way to kill himself HUD is not working after upgrade My HUD is not working after I upgraded from 11.04 (and or 11.10).  It prompts for command and it tries loading for 4 seconds then gives up. I'm looking for a class in java that has key-value association, but without using hashes.  Here is what I'm currently doing:   Add values to a Hashtable. Get an iterator for the Hashtable.entrySet(). Iterate through all values and:   Get a Map.Entry for the iterator. Create an object of type Module (a custom class) based on the value. Add the class to a JPanel.  Show the panel.   The problem with this is that I do not have control over the order that I get the values back, so I cannot display the values in the a given order (without hard-coding the order).  I would use an ArrayList or Vector for this, but later in the code I need to grab the Module object for a given Key, which I can't do with an ArrayList or Vector.  Does anyone know of a free/open-source Java class that will do this, or a way to get values out of a Hashtable based on when they were added?  Thanks! I have to compute this integral $$\int_{0}^{\infty} \frac{dt}{1+t^4}$$ to solve a problem in a homework. I have tried in many ways, but I'm stuck. A search in the web reveals me that it can be do it by methods of complex analysis. But I have not taken this course yet. Thanks for any help. Table with 100 % width and vertical / horizontal alignment I want to draw the following table in LaTeX. In the first column the text should be left aligned. The text in all other cells should be centered. The first problem occurs with D in the first row. If I write a \centering in front of D, I get a LaTeX error. The second problem is, that I want to vertically align the text in all cells but I don't know how. I have found a solution but it doesn't work if the width of the first column is specified.  \documentclass{article} \usepackage{blindtext} \usepackage{tabularx}  \begin{document}   \begin{tabularx}{\textwidth}{|p{4cm}|X|X|X|X|}     \hline                &amp; \centering A &amp; \centering B &amp; \centering C &amp; D\\     \hline     \blindtext &amp; 123 &amp; 123 &amp; 123 &amp; 123\\     \hline   \end{tabularx} \end{document} What will be the value of the following Infinite Product :   $$\displaystyle \prod_{k=0}^\infty \left(1+\dfrac{1}{2^{2^k}}\right)$$  It would be nice if anyone could spare the time and boil down to the absolute basics and tell how they reached the solution. How do I use SQL's GETDATE() and DATEADD() in a Linq to SQL expression? If I have a Linq to SQL expression like this:    from subscription in dbContext.Subscriptions  where subscription.Expires &gt; DateTime.Now select subscription   I want this to to use the SQL Servers GETDATE() function instead of the time of the machine running the C# program.  The next question would be how to translate this:  DateTime.Now.AddDays(2)   to this:  DATEADD(dd, 2, GETDATE()) Creating Users on secondary server in log shipping I have a production Server say ServerA I have setup log shipping to ServerB which is left in read-only mode. The purpose of this log shipping is to lower the load on production server for some expensive queries (painful reports).   Now if I have to create some logins using our domain accounts. I cannot do this because the secondary database is in standby mode.   I thought if I create these logins on Primary server it will be copied over to secondary server then the logs are restored there but this isnt the case.   I have done a lot of research online finding a way around to this. I found the following resources for this. I tried every method suggested in this articles but none of them seems to work.   1)   2)   3)   Has someone experienced the same issue? what did you do? Is there any way around for this issue? Any suggestions any pointer please.