CSS - Add blank line between div elements
give space above and below a DIV
What amp rating of 24vac transformer for LM317T? I want to know what size transformer for LM317 at full 30 VDC. I know its a 24 VAC center tapped transformer but is 1 A or 5 A transformer best suited for a linear power supply of 1.5-30 VDC?  I will be using a standard LM317 variable power supply circuit with the 2200 uF 50 V smoothing and the 240 ohm drain resistor and potentiometer. I have a homemade oversized aluminum heat-sink that is quite large. Essentially, I wonder that if X is a plural noun, should we use a plural or singular verb in a sentence such as "X are a subject that [verb] ..."? I believe that we should always use the singular verb form there (for example, "Eatable flowers are a subject that comes up ..."). However, I was surprised to find this sentence on the  page:     Eatable flowers are a subject that come up in almost all cooking classes eventually and I am a big fan of them.   as well as this on Google Books:     Tools are a subject that come up at our house from time to time.   I think they are typos, but I would like a double check to be sure. Using Apple Script to Manage Sound Output Selection I am brand new here and I have an additional clarification or need additional help for an issue from this thread -   In my preference pane, in addition to Headphones and Digital out, I also have 2 apple monitors and would like the option of selecting one of them as out put (namely the first one in the list).   Basically I need help with adjust his solution to be able to select the third row or first monitor as sound output.  Or a way to accomplish this without knowing how to edit AppleScript for a different setup. How do I root my Nexus 7? I am wanting to gain root privileges on my Google Nexus 7 tablet, running Android 4.1-4.2.1. How can I do this? Please give me the proof for the following: Let $a_1,\,a_2,\,\dots\,a_n$ be $n$ positive real numbers whose product is equal to $1$. Prove that $$a_1+\cdots+a_n \geq n$$ and that the equality sign holds only if every $a_k$ is  equal to $1$. How do you reindex an array in PHP but with indexes starting from 1? I have the following array, which I would like to reindex so the keys are reversed (ideally starting at 1):  Current array (edit: the array actually looks like this):  Array (  [2] =&gt; Object     (         [title] =&gt; Section         [linked] =&gt; 1     )  [1] =&gt; Object     (         [title] =&gt; Sub-Section         [linked] =&gt; 1     )  [0] =&gt; Object     (         [title] =&gt; Sub-Sub-Section         [linked] =&gt;      )  )   How it should be:  Array (  [1] =&gt; Object     (         [title] =&gt; Section         [linked] =&gt; 1     )  [2] =&gt; Object     (         [title] =&gt; Sub-Section         [linked] =&gt; 1     )  [3] =&gt; Object     (         [title] =&gt; Sub-Sub-Section         [linked] =&gt;      )  ) I got a stomach flu or I got the stomach flu or I got stomach flu? Why does a light beam in a moving light clock follows a V shaped path? If I am standing on a platform moving along the X-axis and I throw a basketball vertically upward along the z-axis, the ball also travels along the x-axis. Does the same apply to a photon? According to a special relativity postulate  speed of light is not affected by the velocity of the inertial frame or the velocity of the emitter. If this postulate is true, shouldn't a photon fired vertically as above should travel only along the z-axis but not along the x-axis? C++ display stack trace on exception Nvidia graphics card no longer works in Windows 10 (error: Code 43) but works in Ubuntu Why is charge of the electron negative? Pointwise convergence of $h_n(x) = x^{1+\frac{1}{2n-1}}$ Okay, maybe I'm missing something obvious but consider $h_n(x) = x^{ 1+ \frac{1}{2n-1}}$ on the set $[-1,1]$. Now consider a fixed $x \in [-1,1]$, we have:  $$\lim_{n\rightarrow \infty} h_n(x) = x \lim_{n \rightarrow \infty} x^\frac{1}{2n-1} = x$$  But my book says it's $|x|$? Why? EDIT:  My question was poorly worded.   I wasn't asking about showing $\ln(1+x) &gt; \frac{2x}{2+x}$ for $x&gt;0$.   What I wanted to know is why the lower bound provided by $ \frac{2x}{2+x}$ was so tight for small positive values of $x$. This is addressed in robjohn's answer. 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 $n \ge 4$. I'm trying to recall the title of a young adult-targeted book. It was probably published by Scholastic, or at least sold through their take-home pamphlets, which means it was probably published before I started high school in 1996. It's about a group of teenagers who receive invitations to play a game at an invitation-only arcade. When they go there, they are put in an immersive VR game in which they must learn to survive on an alien planet. I believe the game ends and they wake up back in the real world after they fall asleep on the alien one. They are invited back the the game a couple times, and then it turns out…      …they go to play the game again, but they are unable to exit it. Eventually they realize that they actually are on an alien planet now, and that the previous game-playing sessions were just training for the real thing. I believe the epilogue states that all of the players have coupled up and the females have become pregnant, and they are optimistic about populating the new planet.   I think it was told in the first-person perspective of a female player. I don't think there was a real protagonist or strong conflict; just the group of players learning how to survive in the game. One of the other players had a photographic memory and used it to map the planet's surface. I think the cover art featured of a girl wearing a VR headset over her eyes, with her hair being blown back and her mouth open in surprise. WiFi Adapter AX201 Not Found: Ubuntu 18.04 Please note that this question is specific to Intel WiFi adapters.  My laptop is an HP ENVY with an Intel AX201 Wifi Adapter. I've dualbooted Ubuntu with Windows.  AX201 WiFi adapter is not supported by latest Ubuntu 18.04 version, because Ubuntu 18.04 comes with Linux Kernel 5.0, whereas support for AX201 comes built-in in Linux Kernel 5.2+. Canonical claims that Ubuntu 18.04 will get Linux Kernel 5.3 sometime next year. However, I wont be able to wait that long.  I tried downloading and installing Kernel 5.2.14, but I cant go beyond Grub: I get the error:     error: you need to load the kernel first.   Other option is to download the Intel Backport Driver, which I tried. That didn't seem to work either. As per the tutorials, I've restarted frequently, but that didnt work either.  Also I'm not quite sure if Intel IWLWIFI Backport driver supports AX201 in the first place.  WiFi works while I'm booted in Windows.  What should I do?  Thanks in advance!  UPDATE  I tried out @Pilot6's answer, and it worked. Thanks!  I have one last question: I've read that if you upgrade the Kernel beyond what Ubuntu 18.4 supports, its kinda unsafe (which I read as prone to system crashes).  I dont want system crashes because I have only one partition (root) for Ubuntu, and any crash would likely mean all my data is lost. One method forward would be to split my Ubuntu partition into root and home.  So if I want to access WiFi on my device safely without risking any crashes, what should I do?  My understanding of Ubuntu and Linux may be wrong as they are built on forum answers only. Please correct me if Im wrong anywhere. Why is the ampere a base unit and not the coulomb? I always thought of current as the time derivative of charge, $\frac{dq}{dt}$. However, I found out recently that it is the ampere that is the base unit and not the coulomb. Why is this? It seems to me that charge can exist without current, but current cannot exist without charge. So the logical choice for a base unit would be the coulomb. Right? Why isn't the gamma function defined so that $\Gamma(n) = n! $? As a physics student, I have occasionally run across the gamma function  $$\Gamma(n) \equiv \int_0^{\infty}t^{n-1}e^{-t} \textrm{d}t = (n-1)!$$  when we want to generalize the concept of a factorial.  Why not define the gamma function so that   $$\Gamma(n) = n!$$  instead?  I realize either definition is equally good, but if someone were going to ask me to choose one, I would choose the second option.  Are there some areas of mathematics where the accepted definition looks more natural?  Are there some formulas that work out more cleanly with the accepted definition? My child has chickenpox, am I infectious? My 3-year-old has had chickenpox for about 2-3 days, but a close friend has just had a baby and I want to go and help. Is it possible that I am infectious, despite not having the illness? I had it as a child, so (hopefully) can't actually get it myself. Thanks! Difference between == and === in JavaScript