Currently reading  and I really like the way theorems, definitions, etc. are emphasized by a lower right corner symbol (). For reference        I have tried recreating this formatting by manually inserting \hfill$\rlcorner$ in the following way  \documentclass[a4paper, 10pt]{article} \usepackage{amsmath, amssymb, amsthm} \usepackage[singlespacing]{setspace}  \theoremstyle{definition} \newtheorem{exam}{Example} \newtheorem{definition}{Definition}  \DeclareMathOperator{\im}{im}  \begin{document}  \begin{exam} A complex $$\cdots\longrightarrow M\overset\beta\longrightarrow N\longrightarrow0\longrightarrow\cdots$$ is exact at $N$ if and only if $\beta$ is an epimorphism.\par Indeed, the complex is exact at $N$ if and only if $\im\beta=$ kernel of the trivial homomorphism $N\to0$, that is, $\im\beta=N$.\hfill$\lrcorner$ \end{exam} \begin{definition} A {\it short exact sequence} is an exact complex of the form $$0\longrightarrow M\overset\alpha\longrightarrow N\overset\beta\longrightarrow0.$$\hfill$\lrcorner$ \end{definition}  \end{document}         Anyway, I am not happy with this solution as, on the one hand, it does not seem efficient and, one the otehr hand, I am not able to adjust the height of the second \rlcorner to match the excerpt (writing $$[Diagramm].\hfill\rlcorner$$ does not work).     Could someone help me out? I would prefer to declare this style within the preamble for all kinds of theorem enviroments at once.   Thanks in advance!

I have a question about making an ending symbol.  It is a LaTex-default that every proof environment has an ending symbol. I want to make every theorem-alike environment such as the example environment have also an ending symbol. But how to manually set this up? Specifically, I want to make all these environments ended by a square symbol.  \newtheorem{thm}{Theorem} \newtheorem{lem}[thm]{Lemma} \newtheorem{cor}[thm]{Corollary} \newtheorem{pro}[thm]{Proposition} \newtheorem{assump}{Assumption} \newtheorem{axiom}{Axiom} \newtheorem*{conj}{Conjecture} \theoremstyle{definition} \newtheorem{defi}[thm]{Definition} \newtheorem{exam}{Example} \newtheorem{exer}{Exercise} \newtheorem*{rem}{Remark} \newtheorem*{notation}{Notation} \newtheorem*{note}{Note}   I am looking for, with gratitude, a comprehensive setup.


I'm making a 2d rpg game with libgdx and java, and I'm wondering how I would organize different attack systems - magic, melee, etc. (it's not a turn-based rpg). I have a PlayerClass enum, a Player2D class(2d representation), and a Player class (for storing player data). Would I make an Attack class, with MagicAttack and MeleeAttack? Then have a method in Player2D like attack(Attack attack)? I've considered a few options, but I want to be sure. Thanks!

I am in the planning phase of a small RPG style game.   The character will have have a set of attributes, like strength, agility, etc which are represented as integers. The character also will have a set of attacks represented as an attack class.  On each attack I want it to do damage based on the characters attributes, eg: the attack "sword slash" will do 10 dmg + the value of the characters strength.   The way I was thinking to do this is to have an abstract attack class, which has an abstract Attack method, and for each attack I create one class that implements the Attack method.  public class SwordSlash:Attack {     public void Attack(Character attacker, Character defender)     {         defender.DoDamage(10 + attacker.Strength);     } }   I see that this will make it a nightmare to maintain.   Does anyone have an idea of how I can accomplish this in a nicer way?  What I think is the main problem is how to input the correct attribute, based on the attack.


Suppose I control  and . Each of these has an ability that triggers at the beginning of my upkeep.  Since I'm the controller of both of these abilities, can I choose the order in which they go on the stack, so that Hydra's Growth's ability resolves first (adding +1/+1 counters), this triggers Simic Ascendancy's other triggered ability (adding growth counters), and then Simic Ascendancy's original ability resolves (I win the game due to those growth counters)? This seems like it should be possible, but Arena doesn't allow it.

I had several humans on the battlefield.  On turn three, I played . On turn four, I played . On turn five, during my upkeep, this question came up.  At this point, I need to draw/reveal three cards. If I reveal a human, Descendants' Path will allow me to cast it without paying its mana cost.  So, does it matter when I draw the human?  The static abilities state "at the beginning up your upkeep..." which leads me to believe that those two draws/reveals would happen before my normal draw. If that's the case, does the draw order happen in the same order that I played the enchantments?  In the end, that's how we decided to do it. I drew first for Triumph of Ferocity, then I revealed for Descendants' Path, then I drew for my turn. Did we do it right?


I am asked to compute the limit of the function $(\cos x-1)/(x^2)$, as $x$ tends to $0$, without using L'Hospital. The only thing I am aware of in this case that I have (0/0) is to use DLH and so I found that the result is -1/2. But I am asked to compute it without L'Hospital.I would appreciate of your guidance.

$$\lim _{x \to 0}{1-\cos x\over x^2}={2\sin^2\left(\frac{x}{2}\right)\over x^2}={\frac{2}{x^2}\cdot {\sin^2\left(\frac{x}{2}\right)\over \left(\frac{x}{2}\right)^2}}\cdot\left(\frac{x}{2}\right)^2$$  now $$\lim_{x \to 0}{\sin^2\left(\frac{x}{2}\right)\over \left(\frac{x}{2}\right)^2}=\left({\sin\left(\frac{x}{2}\right)\over \left(\frac{x}{2}\right)}\right)^2=1^2$$  So we have $$\frac{2}{x^2}\cdot \left(\frac{x}{2}\right)^2=\frac{2}{x^2}\cdot \left(\frac{x^2}{4}\right)=\frac{1}{2}$$  Are the moves right?


How would I go about evaluating...  $$\int_{0}^{2}\int_{0}^{4-x^2} \frac{xcos(3y)}{4-y}dydx$$  I don't really have any work to show, since I don't even know how to start this problem, but I'll offer my thought process to show you what I've thought about and we'll see where to go from there.  I can't think of any particular reason why circular, spherical or cylindrical substitutions would make sense here. For this reason, I feel like a different type of substitution would be necessary...but...what? I don't know what type of substitution would make this easier. I couldn't just say that $ u = 4-y $, because in the numerator, I already have that nasty $ cos(3y) $ term.   Any help would be greatly appreciated.

Let $D$ be a region given as the set of $(x, y)$ with $$a \leq x \leq b\quad\text{and}\quad-\Phi(x) \leq y \leq \Phi(x)$$ where $Φ$ is a nonnegative continuous function on the interval $[a, b]$.  Let $f(x, y)$ be a function on $D$ such that $$f(x, y) = - f(x, - y)$$ for all $(x , y) \in D$.  Argue that $$\displaystyle \iint_D f(x, y) dA = 0.$$


Given a sample of $n$ iid variables  $$ \{X_i\}_{i=1}^{n} $$  distributed as a multinomial distribution $MN(p,1)$ where $$ p = (p_1,...,p_n) $$ I will have that each $X_i$ is a n-tuple with all zeros except a 1 in a certain (random) position. I have the following doubts:   Can I say that the j-th coordinate of each $X_i$ is a bernoulli with parameter $p_i$? If  $$ Y = \sum_i X_i $$ Can I say that the j-th coordinate of each $Y$ is a binomial with parameter $n$ and $p_i$, $B(p_i,n)?   The source of my doubt is the fact that assuming what written in the two question I have the impression of forgetting the fact that the various coordinates of $Y$ are not independent..

I wonder if single multinomial distribution (I will use the notation from JAGS/WinBUGS, but in fact, this is principial thing rather than of particular language)  x[] ~ dmulti(p[], N)   would give the same result as a sequence of binomial draws:  x[1] ~ dbin(p[1], N) x[2] ~ dbin(p[2]/(1 - p[1]), N - x[1]) x[3] ~ dbin(p[3]/(1 - p[1] - p[2]), N - x[1] - x[2]) ... x[K] <- N - x[1] - x[2] - ... - x[K - 1]   Is it totally equivalent? Or did I miss something?


If $3\sin A + 5\cos A = 5$, then prove that:      $$5\sin A + 3\cos A = ±3.$$

Another problem that I already wasted hours on. Given $$4\sinθ +3\cosθ  = 5$$  Find   $$4\cosθ -3\sinθ$$  Help me guys (PS:I'm not that good in maths)


Why the slope of a line isn't  the change in x divided by the change in y?

I understand that this is a reasonable definition and it shows how "fast" $y$ values change corresponding to $x$ values because it's a ratio, but what I'm asking is, couldn't the slope have been defined as the angle between the line and the positive $x$-axis for example? And it would have the same meaning; if the angle was large (but less than $90$) then that would mean the line is steep and $y$ values change fast corresponding to $x$ values...etc. Why is the first definition better? Is the second one even correct?


Hilbert's operator $$H f(x)= \int_0^{\infty} \frac{f(y)}{x+y}\, dy \quad\text{ for all } f \in {L}^2(0,+\infty) \text{ and } x \in(0,+\infty),$$ is regular integral operator on $L^2(0,+\infty)$ with norm $\pi.$   Using Cauchy-Schwarz inequality on space $L^2(0,+\infty)^2$ and Fubini's theorem for every $f,g \in L^2(0,+\infty)$ it's valid estimate for associated norm of sesquilinear form:  $$\begin{align*} |\langle Hf,g \rangle | &= \left|\int_0^{\infty} \int_0^{\infty} \frac{f(x)\overline{g(x)}}{x+y} \, dx \, dy\right| \\ &=\left|\int_0^{\infty}\int_0^{\infty} f(y) \sqrt[4]{\frac{y}{x(x+y)^2}}\,\,\overline{g(x)} \sqrt[4]{\frac{x}{y(x+y)^2}}\, dx \, dy\right|\\ & \leqslant \sqrt{\int_0^{\infty}\int_0^{\infty}\frac{|f(y)|^2}{x+y}\sqrt{\frac{y}{x}}dx\, dy}\sqrt{\int_0^{\infty}\int_0^{\infty}\frac{|g(x)|^2}{x+y}\sqrt{\frac{x}{y}}dy\, dx} \\ &=\pi \sqrt{\int_0^{\infty} |f(y)|^2 \,dy}\sqrt{\int_0^\infty|g(x)|^2 \, dx}=\pi \| f \| \| g\|. \end{align*}$$  We find that $\| H \| \leqslant \pi$, but how to prove that $\| H \| = \pi$?  We used that $$\int_0^{\infty} \frac{1}{x+y} \sqrt{\frac{y}{x}} \, dx = 2 \int_0^{\infty} \frac{1}{1+\left(\sqrt{\frac{x}{y}}\right)^2} \frac{d\sqrt{x}}{\sqrt{y}} = \pi \quad \text{ for every } y \in (0,+\infty).$$

Show that the linear operator $T$ given by $(Tf)(x) = \frac{1}{\pi} \int_0^{\infty} \frac{f(y)}{(x+y)} dy$ is bounded on $L^2(0, \infty)$ with norm $||T|| \leq 1$.   The professor also wrote, $``$In fact, you should observe that $||T|| = 1$, where $$||T|| = \sup\limits_{f\neq 0}\frac{||Tf||_2}{||f||_2}."$$


Let $a_1=\frac 2 3 , \ a_{n+1}=a_n-a^2_n$ for $n\ge 1$, $a_n$ is monotonically decreasing and bounded: $0\le a_{n+1} \le 1$ and $\displaystyle\lim_{n\to\infty} a_n=0$. Is there a uniformly continuous function $f:\mathbb R \to \mathbb R$ such that $a_{n+1}=f(a_n), \ \forall n\in \mathbb N$ ?  I don't know how to start here but I'm pretty sure there is such function since $a_n$ is converging then from the definition of uniform continuity, we'll have $\forall \epsilon >0 :\exists \delta >0: \forall n,m\in \mathbb N: |a_n-a_m|<\delta\Rightarrow |f(a_n)-f(a_m)|<\epsilon$ $a_{n+1}=f(a_n)=f(a_{n-1}-a_{n-1}^2)$ so I need to find a function that will "push the index" by 1, like $f(x)=x+1$ and is uniformly continuous, but I have no idea how to find such function.

$a_{n+1} = a_n - a_n^2$, $a_1 = 2/3$. for $n\ge1$         a) Show the series converges and find its limit.   b) find a uniformly continuous $f:\mathbb{R}\rightarrow \mathbb{R}$ such that: $a_{n+1}=f(a_n) \forall n \in \mathbb{N}$.     section (a) is very technically, I proved $\{a_n\}$ is monotonically decreasing and bounded bellow, And using limits arithmetic found $L=0$.    section (b) is quite tricky for me. I'd be glad for help. Thanks!


I.e., can two photons completely overlap and propagate in the same direction?

Why is it that if I have two torches, each shining rays in perpendicular directions at perpendicular screens, such that the beams cross, then the images on the respective screens are independent of whether the alternate torch is switched on? In other words, why does light seem to pass through itself without interacting?  Apologies if this question is basic, and apologies if there is a similar question somewhere on the site but I haven't managed to find an answer.   Thanks,  A.


I installed additional 8 Gb of RAM on a system recently. Everything was running fine before I observed that the system randomly froze, I don't know what the proper term is, but the screen just hangs up on a static frame, and the PC, just hangs up. And it usually happens when I am playing games on it;  I took following steps to check what is wrong: Updated all the drivers Clean OS install  Removed the newly installed RAM sticks Removed the old ones and checked with the new ones only  Removed any additional peripheral  Memtest, with no errors  Check disk, no errors System file verification, no errors  One thing strange thing happens, when the system hangs up, my keyboard just powers down, and it's a Logitech G510, and with power downs I mean that it goes blank, and that is rare since even during crashes, usually the keyboard backlight is there.  The specs of PC are:  Windows 7 professional x64 Intel core i3 3rd generation(3240) Intel Z75 based m-ATX motherboard(Intel DZ75ML-45K) Nvidia 550ti  2*2gb ram sticks @1333(corsair) 2*4gb ram sticks @1333(transcend) Microsoft wireless combo  Logitech G510 keyboard  450w cooler master smps  Htpc cabinet   The temperatures are within range during load; they rarely cross 70C  GPU stress test sometimes crashes the system, and sometimes goes on for hours without any crash.  Any guess what might be wrong?  (Sorry for not being able to give exact specifications of PC, and I hope this is the right section for asking such questions)

I built a desktop computer a couple years back with the following specs:  CPU: Intel  Yorkfield 2.5GHz 6 MB L2 Cache LGA 775 95W Quad-Core Processor BX80580Q9300 Motherboard:  LGA 775 NVIDIA nForce 680i SLI ATX Intel Motherboard Video Card: Two  GeForce 8600GT SCC 256 MB 128-bit GDDR3 PCI Express x16 SLI Supported Video Card PSU: SeaSonic S12 Energy Plus  ATX12V V2.3 / EPS12V V2.91 SLI Certified CrossFire Ready 80 PLUS Certified Active PFC Power Supply Memory: Two G.SKILL 4 GB (2 x 2 GB) 240-Pin DDR2 SDRAM DDR2 800 (PC2 6400) Dual Channel Kit Desktop Memory   Since its inception, the machine has periodically locked up, the regularity having varied over the years from once a day to once a month. Typically, lockups happen once every few days. By "lockup" I mean my computer just freezes. The screen locks up, I can't move the mouse. Hitting keys on my keyboard that normally turn LEDs on or off on the keyboard (such as Caps Lock) no longer turn the LEDs on or off. If there was music playing at the time of the lockup, noise keeps coming out of the speakers, but it's just the current frequency/note that plays indefinitely. There is no BSOD. When such a lockup occurs I have to do a hard reboot by either turning off the computer or hitting the reset button. I have the most recent version of the NVIDIA hardware drivers, and update them semi-regularly, but that hasn't seemed to help. I am currently using Windows 7 x64, but was previously using Windows Server 2003 x64 and having the same lockup issues. My guess is that it's somehow video driver or motherboard related, but I don't know how to go about diagnosing this problem to narrow down which of the two is the culprit.  Additional information re: cooling Regarding cooling... I've not installed any after-market cooling systems aside from two regular fans I scavenged from an older computer. The fan atop the CPU is the one that shipped with it. One of the two scavenged fans I added it located at the bottom tower of the corner, in an attempt to create some airflow from front to back. The second fan is pointed directly at the two video cards.  SpeedFan installation and readings Per studiohack's suggestion, I installed , which provided the following temperature readings:  GPU: 63C GPU: 65C System: 76C CPU: 64C AUX: 36C Core 0: 78C Core 1: 76C Core 2: 79C Core 3: 79C   Update #3: Another Lockup :-( Well, I had another lockup last night. :-( SpeedFan reported the CPU temp at 38 C when it happened, and there was no spike in temperature leading up to the freeze. One thing I notice is that the freeze seems more likely to happen if I am watching a video. In fact, of the last 5 freezes over the past month, 4 of them have been while watching a video on Flickr. Not necessarily the same video, but a video nevertheless. I don't know if this is just coincidence or if it means anything. (As an aside, each night before bedtime my 2 year old daughter sits on my lap and watches some home videos on Flickr and, in the last month, has learned the phrase, "Uh oh, computer broke.")  Update #4: MemTest86 and 3DMark06 Test Results: Per suggestions in the comments, I ran the MemTest86 overnight and it cycled through the 8 GB of memory 5 times without error. I also ran the 3DMark06 test without a problem (see my scores at ). So... what now? :-) Any further suggestions on what to check? Is there some way to get a stack trace or something when the computer locks like that? Resolution I have never did figure out the particular problems, but based on the suggestions here and elsewhere, I'm presuming it was a motherboard issue. In any event, I recently upgraded my system, buying a new motherbeard, PSU, CPU, and RAM, and that new rig has been working splendidly the past several weeks. I am using the same graphic cards as in the old setup, so I think it's safe to reason that they weren't the cause of the problem.


I'm really struggling to vertically centre my div, which is currently serving as a container for two text areas. I have two text areas within my div, positioned side by side how I want it, and I would like them to retain their relative position to eachother, but, be vertically in the very middle of the screen. How can I do this?  App.js  class App extends React.Component {   state = {     character: null   };   render() {     return (

           <TextBox           />

           <textarea             className="Box"             placeholder={"English translation"}             value={this.state.english}           />

     );   } }  export default App;   App.css  .Box {   height: 100px;   width: 98%;   padding: 1%;   border: solid 1px orange; }  .Centre {   width: 800px;   height: 400px;   margin: 0 auto; }  .Left {   width: 300px;   height: 200px;   float: left;   border: red; }  .Right {   width: 300px;   height: 200px;   float: Right;   border: red; }   textbox.jsx  class TextBox extends React.Component {   render() {     return (       <form>         <textarea           className="Box"           placeholder="Type in Spanish"           value={this.props.equation}           type="text"           name="equation"         />       </form>     );   }

I have a div with two images and an h1. All of them need to be vertically aligned within the div, next to each other. One of the images needs to be absolute positioned within the div. What is the CSS needed for this to work on all common browsers?

testing...


Apologies if this is the wrong group.  I did look for a "Ask Differerent" group that is for Windows user rather than Mac users, to no avail.  If there's a better group, please point me that way.    How do I get rid of the annoying Chrome window that comes up periodically.  It might happen on Edge and Explorer too, but I use Chrome 95% of the time.  I did some research that suggested it was browser independent and to try Malware.  I did so, without luck.    A little research reveals that if you call the number, they will ask you for remote access to to your computer and "fix" the problem for a small fee.  Probably not the best solution :).  I'm using AVG virus protection (free version) if that is relevant.  I'm assumming there is some sort of program to look for in Add/Remove programs or a registry setting to modify, but I've had no luck so far. Thanks, Dave

What should I do if my Windows computer seems to be infected with a virus or malware?  What are the symptoms of an infection? What should I do after noticing an infection? What can I do to get rid of it? how to prevent from infection by malware?   This question comes up frequently, and the suggested solutions are usually the same. This community wiki is an attempt to serve as the definitive, most comprehensive answer possible. Feel free to add your contributions via edits.


what is difference between analog supply and digital supply for microcontroller, i mean if we want to give 5VA and 3.3VD to ADC, then how to do it?

Currently I have start working on MSP430 Controller and found that there are 4 pins for the supply voltage viz. AVcc, DVcc, AVss, DVss. These are used as analog supply voltage and Digital supply voltage. What are the purpose of providing these twins pins? How can I use these pins during designing of supply section.


I would like to find a book on ARDl not part of a general time series book, but focused on ARDL primarily (I have read books on time series and articles on ARDL already - I want an extensive treatment of the topic). I would prefer it not to deal with cointegration which ARDL does not require (the variables do not have to be integrated of the same order even). I am particularly interested in bound testing; I don't work in economics and there is no certainty at all in my field that there is cointegration. ARDL is nice in not requiring it exist. The books in the duplicate link have little to do with my interest as best I can tell.

Please suggest books/references on ARDL model and ARDL bounds test approach to study.


In the movie RED, according to , when surrounded by FBI agents,       The terminally ill Joe pretends to be Frank, walks outside, and is  killed by sniper from the Vice President's personal hit squad.   I watched that scene again and did not find anywhere a hint about the shooter. Is this explained somewhere else?

While Joe and Frank are at Dunning's house, the FBI (or maybe the CIA, or maybe both!?) surrounds them. Victoria tells them they are surrounded and there is no clean exit, but she can cover them to the woods, if they can create a distraction. Frank tells Cooper he is surrendering and coming out, and Cooper swears that he will be safe. He issues a no-shoot order.  As Frank (Joe pretending to be Frank) leaves the house he is shot instantly.    Who shot him and why?


The difference between page background color and progress on golden badges is so miniscule that I find it hard to see it at all. I see progress on bronze and silver badges just fine, but the contrast of gold badges is so small that I need to check numbers to know where to look.    My sight is far from perfect and I'm protanomalous colorblind, but I don't think this affects the contrast enough. Let's do the math.  Bg color   R   G   B   H    S    L page     255 255 255   0   0% 100% bronze   209 166 132  26  46%  67% silver   180 184 188 210   6%  72% gold     255 250 230  48 100%  95%   The lightness value of bronze and silver badge progress backgrounds is around 70%, while lightness of gold is 95%, which is displayed on pure white background with 100% lightness. This is probably a mistake as numbers are clearly inconsistent.  This applies to all websites, both to badges displayed directly in profiles and to the popup for choosing a badge to track.  P.S. Even if protanomaly affects the contrast, it's one of the weakest types of color blindness, so people with other types of color blindness will be affected even more. Also slight differences in contrast are very dependent on monitor settings. Almost nobody has perfectly calibrated monitors.  [Edit] While this question turned out to be a dupe, it's higher quality than the first one, has more info and more upvoted already, so I'd rather close the other way.  [Edit 2] Considering this question is  in  and the other one is , I find it counter-productive to close this question instead of the other one ().

Update #2: Seems that it was my secondary screen the one that didn't show the color! Tried with another screen and I could see the progress clearer... perhaps a stronger color will make it easier to see across different devices?  Update: Seems to be an issue in Firefox, as I tried on Chrome and the progress is visible.    I just noticed that the badge progress on your user profile had it's style changed (don't know when but it seems that recently).  However, seems that the progress of gold badges is not working properly. If we see the Bronze and Silver badges, they are "filled with color" as you progress on the badge, however golden ones are not colored (just the border).   Here a picture illustrating what I say:    Is there a reason for this behavior?


I'm looking for a book with variety of combinatorics exercises specially enumerative problems.  I have found some lecture notes but they were not coherent.  What do you advise?

What is your recommendation for an in-depth introductory combinatoric book? A book that doesn't just tell you about the multiplication principle, but rather shows the whole logic behind the questions with full proofs. The book should be for a first-year-student in college. Do you know a good book on the subject?  Thanks.


A few moments ago I deleted one of my own answers here:   I am logged in to the site, and am a 10K+ user, yet within my deleted answer I see:     add comment (requires 50 reputation)   Clicking this does nothing.  I do not recall the ability to add a comment to a deleted answer.  Is this a bug?

So I recently saw add comment (requires 50 reputation) on a deleted answer. After looking around a bit, it seems to be on all deleted posts now (only deleted posts, normal posts still say just add comment).  I'm sure it wasn't there before (I think it just said add comment (unclickable) or possible nothing).  It is also on , presumably the root cause is the same.  And yes, I do have more than 50 reputation (in case anyone was wondering).  Just to clarify, requires 50 reputation obviously shouldn't be there for users with 50 or more reputation. Choices:   Display nothing Unclickable add comment - probably not ideal Unclickable add comment (disabled for deleted posts) or something along those lines   FYI - You may be somewhat confused right about now if you can't  yet.


I tried to explain how those force work but I can hardly figure it out. I exerted a force on the trolley and there will be a force on trolley on me as well. This is the newton's third law. But why the trolley will move? Where's the force come from

Given Newton's third law, why is there motion at all? Should not all forces even themselves out, so nothing moves at all? When I push a table using my finger, the table applies the same force onto my finger like my finger does on the table just with an opposing direction, nothing happens except that I feel the opposing force. But why can I push a box on a table by applying force ($F=ma$) on one side, obviously outbalancing the force the box has on my finger and at the same time outbalancing the friction the box has on the table? I obviously have the greater mass and acceleration as for example the matchbox on the table and thusly I can move it, but shouldn't the third law prevent that from even happening? Shouldn't the matchbox just accommodate to said force and applying the same force to me in opposing direction?


Suppose $R$ and $S$ are integral domains. And let $\phi:R[x]\longrightarrow S[x]$ be an isomorphism between their polynomial rings. Is it possible that $\phi|_R$, the restriction of the isomorphism to $R$, is not an ismorphism between $R$ and $S$?

This is a very simple question but I believe it's nontrivial.  I would like to know if the following is true:      If $R$ and $S$ are rings and $R[x]$ and $S[x]$ are isomorphic as rings, then $R$ and $S$ are isomorphic.    Thanks!  If there isn't a proof (or disproof) of the general result, I would be interested to know if there are particular cases when this claim is true.


(Not sure of year)   Specialized Rockhopper Currently has 26x2.25 tyres, desperately need replacing though,  Mostly used on roads or grass, but trails occasionally   I'm not a professional, I just like riding my bike

We often get questions on bicycles.stackexchange about fitting wider or narrower tires to bicycles. We have a large number of these with answers suiting the specific bike or style of bicycle in question, but I have been unable to find one that provides a generic answer covering off all things that need to be considered. For most bicycles, the answer is the same regardless of the specific style and sizes of tires in question.   This is intended as a canonical question that we can point closed questions to.


Hello is there any way to edit html tag class name from script? For example: html: <div id="ThisIsId" class= "ThisIsName"> ... </div>  Script: <script> document.getElementById("ThisIsId").changeClassName("thisIsNewClassName")  </script>

How can I change the class of an HTML element in response to an onclick or any other events using JavaScript?


I remember back in 2012, when I tried to upgrade to Oneric using Software Updater, I got something called a partial upgrade and it was a mess to deal with.  Is there any way to avoid that from happening now that I want to upgrade to Bionic?  I have safety measures such as having backups, and separate home partition.

I have Ubuntu 12.04 with Unity and for the last 3 months or so it's been offering me a partial upgrade. The only things that cannot be upgraded are the kernel and dropbox. I'm still on the 3.2.0-37-generic-pae kernel. On my another machine (12.04 with MATE) I had the same problem but it disappeared on its own. What should I do to go on with normal life?


Over the years, I have had several cases where either an SD card, a USB stick or any other removable storage medium has had a physical defect, and after some use, or a certain amount of formatting, it becomes a Read only drive no matter what OS or means of formatting it you use, including the dd utility. In most of these cases, everything I have read says that this is almost 100% of the time a hardware failure and/or a defective storage medium, which I would agree with. In my case, I am not trying to fix a damaged USB, or SD card, but instead, trying to write files to it, and then physically modify it (and do "targeted damage"), so that after I have the files on it that I want, it is impossible for any software whatsoever to modify it, and it is impossible to put it back into RW mode again. Does anyone know of any way to permanently alter, or intentionally damage, an SD card or USB stick, so that It will forever be stuck in read only mode? I can't  find any sort of starting point anywhere on the internet, so even links, blogs, or articles involving this subject matter would be helpful. If you have the expertise to provide direct instructions for a task such as this, a writeup would be even better!

I have a 1.5TB USB drive with many important files that I want to give to a friend (they have Windows7) for reading only purposes.  appears to flip a registry switch but it seems to be on the local pc only.  UPDATE:  Are you aware of any USB drives that have such functionality built into their firmware?


Question: How do I show that $c_0$, which is shorthand for $C_0(\mathbb{N})$, is closed in $l_\infty$?  I've tried to work with the fact that if $(f_n)$ is a sequence in $c_0$ converging to $f \in l_\infty$, $|f(k)|\leq|f(k) - f_n(k)| + |f_n(k)|$ and that I can choose n so that $|f(k) - f_n(k)|$ is small independent of k. However, I don't get very far..  Thanks in advance!

Define $c_0$ to be the space of real sequences in $\ell^\infty$ that converge to $0$ and $\ell^\infty$ be the set of all bounded sequences. Show that $c_0$ is closed in $\ell^\infty$.   I am reading in the solution in  and I don't understand how we define $$x^{k}_n - \omega_n$$  Because $(x_n^k) = ( \{x^1_1,x_2^1,\dots \}, \{x_1^2, x_2^2,\dots \}, \dots)$ and $(\omega_n) = (\omega_1, \omega_2, \dots)$  The objects in $(x_n^k)$ are sequences (sets) and the objects in $\omega_n$ are real numbers, how can you subtract a number from a set?


Why do angular momentum of electrons in atoms are discrete value rather than being continuous ? I understand angular momentum needs to be fixed in a closed system but why I don't understand why they take value in accordance to the formula: $$L^2 = \ell(\ell+1)\hbar.$$ Why quantum mechanics allow only certain values of angular momentum? Is there any non mathematical explanation for it that can be visualized?

Why is it that unlike other quantum properties such as momentum and velocity, which usually are given through (probabilistic) continuous values, spin has a (probabilistic) discrete spectrum?


Which is the preferred way to check if a file exists and if not create it?

How do I check whether a file exists or not, without using the  statement?


I have been using Uploadify for several years to upload files onto our Intranet web site.  It is no longer actively being supported and even their so called HTML5 version uses a Flash SWF file.  Needless to say, Flash is dead.  I found several really nice Bootstrap / HTML5 uploaders.  I am having trouble picking one I can easily swap with Uploadify.  My site is still running Bootstrap 2 and I want to stay away from CSS3 for this site.  I am not only uploading a file but posting data back to a .NET ASHX handler to create a record in the database.  Can anyone recommend a good, basic replacement?  NOTE:  Dumping me to a question for 6 years ago is not helpful!  I already said I read all of this unhelpful information.

I would like to upload a file asynchronously with jQuery.     $(document).ready(function () {     $("#uploadbutton").click(function () {         var filename = $("#file").val();          $.ajax({             type: "POST",             url: "addFile.do",             enctype: 'multipart/form-data',             data: {                 file: filename             },             success: function () {                 alert("Data Uploaded: ");             }         });     }); });  File <input type="file" id="file" name="file" size="10"/> <input id="uploadbutton" type="button" value="Upload"/>     Instead of the file being uploaded, I am only getting the filename. What can I do to fix this problem?


I need to change the X glyphicon,glyphicon-remove from  to a check glyphicon,glyphicon-ok if the input email is valid. So my question is how to know if an email inputed and checked by keyup is valued.  var emailRegex = /^[A-Z0-9._%+-]+@[A-Z0-9.-]+.[A-Z]{2,4}$/i          document.getElementById("Email").addEventListener("keyup",          function() {             var email = document.getElementById("Email").value;             if (emailRegex.test(email)) {                 document.getElementById("EmailValidate").classList.remove('glyphicon,glyphicon-remove');                 document.getElementById("EmailValidate").classList.add('glyphicon,glyphicon-ok');             }         });

Is there a regular expression to validate an email address in JavaScript?


Let $\mathbb R$ be the set of real numbers and $f: \mathbb R \rightarrow \mathbb R$ be such that for all $x$ and $y$ in $\mathbb{R}$, $$|f(x)-f(y) |\leq |x-y|^3.$$ Prove that $f(x)$ is a constant.    This is a new type of problem for me and I feel I am missing some trick to simplify the given expression. Any help??

Suppose $f:(a,b) \to \mathbb{R} $ satisfy $|f(x) - f(y) | \le M |x-y|^\alpha$ for some  $\alpha >1$ and all $x,y \in (a,b) $. Prove that $f$ is constant on $(a,b)$.   I'm not sure which theorem should I look to prove this question. Can you guys give me a bit of hint? First of all how to prove some function $f(x)$ is constant on $(a,b)$? Just show $f'(x) = 0$?


I am trying to load a library in python in Windows 10 (x64).  The cpp file used to generate the library for testing is:  extern "C" int check() {   return(1); }   Then I generate the dll with the commands (in x64 Native Tools Command Prompt):  cl /c mylib.cpp link /dll /machine:x64 mylib.obj   The file mylib.dll is generated. Then in python, which initializes showing the following string:  Python 3.7.4 (default, Aug  9 2019, 18:34:13) [MSC v.1915 64 bit (AMD64)] :: Anaconda, Inc. on win32   I run the following commands:  import ctypes lib=ctypes.CDLL("mylib.dll") lib.check.restype=(ctypes.c_int,)   and the last command fails, saying that doesn't recognize check. I also tried lib._check and using a test C file instead of cpp, with the same result, and also tried using ctypes.WinDLL instead of ctypes.CDLL.  What's wrong? Python is x64 as well as the library mylib.dll...  If I do:  ctypes.windll.msvcrt.getchar()   the functions works ok… Here I use the MSVCRT library, which is automatically accessible when I load ctypes.  Should I compile my library differently?

I'd like a simple example of exporting a function from a C++ Windows DLL.  I'd like to see the header, the .cpp file, and the .def file (if absolutely required).  I'd like the exported name to be undecorated. I'd like to use the most standard calling convention (__stdcall?). I'd like the use __declspec(dllexport) and not have to use a .def file.  For example:    //header   extern "C"   {    __declspec(dllexport) int __stdcall foo(long bar);   }    //cpp   int __stdcall foo(long bar)   {     return 0;   }   I'm trying to avoid the linker added underscores and/or numbers (byte counts?) to the name.   I'm OK with not supporting dllimport and dllexport using the same header. I don't want any information about exporting C++ class methods, just c-style global functions.  UPDATE  Not including the calling convention (and using extern "C") gives me the export names as I like, but what does that mean? Is whatever default calling convention I'm getting what pinvoke (.NET), declare (vb6), and GetProcAddress would expect? (I guess for GetProcAddress it would depend on the function pointer the caller created).  I want this DLL to be used without a header file, so I don't really need the a lot of the fancy #defines to make the header usable by a caller.  I'm OK with an answer being that I have to use a *.def file.


i want to show that $(n+1)!(n+1)+(n+1)! = (n+2)!$   i put it into wolfram and it showed this to be true, but im not sure why.  I need to show this as a part of a induction proof.

I have an equation containing factorials  here  $$(k+1)!+(k+1)(k+1)!$$  yet I am having a hard time understanding how to simplify it using algebra. A simple search on wolfram gets me a reduced form of   $$(k + 2)! $$  This would be a great refresher to such problems, sadly I don't know the elementary operations to reduce it.


Let $f: \mathbb{R} \to \mathbb{R}$ and $g: \mathbb{R} \to \mathbb{R}$ be continuous functions. Suppose that for all rational numbers $r$, $f(r) = g(r)$. Show that $f(x) = g(x)$ for all $x$.

Akhil showed that the  is the same as the continuum, using as a step the observation that continuous functions that agree at rational points must agree everywhere, since the rationals are dense in the reals.  This isn't an obvious step, so why is it true?


Is it possible to create a regex that retrieves all capturing groups matching that type of html input:  word1 word2 word3 prefix: word4 word5 word6 word7   That matches  word4 word5   I have tried with Lookahead and Lookbehind Zero-Length Assertions but with no success.  Here is my try    But I do know how to make groups repeating on every next occurence following my 'prefix: '  Thanks a lot,  Julien

I want to match a portion of a string using a  and then access that parenthesized substring:  var myString = "something format_abc"; // I want "abc"  var arr = /(?:^|\s)format_(.*?)(?:\s|$)/.exec(myString);  console.log(arr);     // Prints: [" format_abc", "abc"] .. so far so good. console.log(arr[1]);  // Prints: undefined  (???) console.log(arr[0]);  // Prints: format_undefined (!!!)   What am I doing wrong?    I've discovered that there was nothing wrong with the regular expression code above: the actual string which I was testing against was this:  "date format_%A"   Reporting that "%A" is undefined seems a very strange behaviour, but it is not directly related to this question, so I've opened a new one, .    The issue was that console.log takes its parameters like a printf statement, and since the string I was logging ("%A") had a special value, it was trying to find the value of the next parameter.


I searched within the site but none where addressing exactly my question, So I ask it here:  Which one of these structures for a user-friendly url is the best with regards to search engines and user experience:   http://www.example.com/category/sub-category/sub-sub-category/article/ID   or   http://www.example.com/ID/category/sub-category/sub-sub-category/article   or perhaps:   http://www.example.com/category/ID/sub-category/sub-sub-category/article   In another word, Is it better to place id at the end of url or at the beginning, or maybe somewhere in the middle of it?  And another question: is it better to add a trailing slash to the end of the url?  To guess how long would be such the url the number of words in each section of the url are:   Category-name: 2 words  sub-category-name: 1 word su-sub-category-name: 1-4 words (average 2 words) article-namae: Average: 4 words   Thank you very much

I would like to know what's the best location for an ID in a SEO optimized URL:   http://www.example.com/123/slug-title  http://www.example.com/slug-title-123


I want to find a recursive formula to determine the amount of different words that you can build by taking n letters from the set {a,b,c}. Also, there needs to be atleast on occurence of two consecutive a's in the word. For example, baac is a valid word, but abac is not. How would you approach this?

I know this problem is familiar to "the number of binary strings of length $n$ with no consecutive zeros" but still it is a way different problem. But in that question the alphabet is set to $\{0,1\}$ and here:  Q:  Let $A=\{0,1,2\}$ be an alphabet, what is the the number of possible strings of length $n$ with no consecutive zeros in it?


Given this code:  public class Test {     public T Get1<T>()     {         return Activator.CreateInstance<T>();     }      public T Get2<T>() where T : new()     {         return new T();     }     }   both methods produce exactly the same method body making use of System.Activator, namely:  .method public hidebysig instance !!T Get1<T> () cil managed  {     .maxstack 8      call !!0 [mscorlib]System.Activator::CreateInstance<!!T>()     ret }  .method public hidebysig instance !!T Get2<.ctor T> () cil managed  {     .maxstack 8      call !!0 [mscorlib]System.Activator::CreateInstance<!!T>()     ret }     Why does code using the new() constraint not compile to the fictional code below?  .method public hidebysig instance !!T Get2<.ctor T> () cil managed {     .maxstack 1      newobj instance void !!0::.ctor()     ret }   Does not the constraint <.ctor T> mean that there has to be a parameterless constructor on the type T, therefore should not it be okay to just call it as shown above?    Aforementioned behavior occurs when compiled for .NET Framework 4.8 as well as .NET Core (x64) and with the latest (23 Sep 2019) Roslyn compiler.

When you have code like the following:   static T GenericConstruct<T>() where T : new() {     return new T(); }   The C# compiler insists on emitting a call to Activator.CreateInstance, which is considerably slower than a native constructor.   I have the following workaround:  public static class ParameterlessConstructor<T>     where T : new() {     public static T Create()     {         return _func();     }      private static Func<T> CreateFunc()     {         return Expression.Lambda<Func<T>>( Expression.New( typeof( T ) ) ).Compile();     }      private static Func<T> _func = CreateFunc(); }  // Example: // Foo foo = ParameterlessConstructor<Foo>.Create();   But it doesn't make sense to me why this workaround should be necessary.


Got my code here  \documentclass{book} \usepackage{lipsum} \usepackage{marginnote} \begin{document} Some text \marginnote{\lipsum[1-4]}  \end{document}   How can I avoid marginnote to go down beyond the red line in the picture? P.S: Regarding the previous question, I'm sorry, I badly explained myself, @egreg & @Cristian, thanks a lot for your answer!

Is there a way to do this in LaTeX 3?  I looked at , and I am not sure that it addresses my question, but I belive it states that this is not possible in LaTeX 2e.  This is most common for me when I have a marginpar that is tied to text that happens to fall out near the bottom of a page. This also happens if I use marginnote instead.  If someone has ideas for how to post a MWE, let me know and I'll post one.


It is known that sample proportions are normally distributed according to central limit theorem. A common rule of thumb for central limit theorem to work is the sample size should be greater than 30. However, for sample proportions to be normally distributed there are additional conditions which are $np>5$ and $n(1-p)>5$.   Why there are two additional rule of thumbs for CLT to work for sample proportions? Why the rule of thumb $n>30$ is not enough for CLT to work for sample proportions?

Nearly every text book which discusses the normal approximation to the binomial distribution mentions the rule of thumb that the approximation can be used if $np\geq5$ and $n(1-p)\geq 5$.  Some books suggest $np(1-p)\geq 5$ instead.  The same constant $5$ often shows up in discussions of when to merge cells in the $\chi^2$-test.  None of the texts I found gives a justification or reference for this rule of thumb.  Where does this constant 5 come from?  Why not 4 or 6 or 10?  Where was this rule of thumb originally introduced?


My friends in South Africa are purchasing a round trip plane ticket for me in December 2015. I'll be flying from London to Durban and back to London and their travel agent wants to see my Passport. I live in the UK. Is this normal procedure?  I am fully aware that the ticket must bear the exact same name as my passport - I am just very cautious about giving this type of information ad lib.    I would appreciate your advice on this matter.

It is not uncommon for travel or holiday accommodation companies to ask for a scan of your passport by email. Sometimes local laws require them to keep a record of the passport numbers of all visitors. I'm happy to provide that information but you usually have to send it in an unsecured email, which may have consequences .  Could these companies be more responsible, and provide a public cryptographic key at least?  Are there other steps you should take to protect yourself, if you do send by unsecured email?


There is a base such $A$ and $B$ are both upper triangular on these base, and if $A$ and $B$ are diagonalizable, then $A$ and $B$ are diagonalizable simultaneously.   For the first I have no idea. To the second one I am trying to show something like: Iv $v$ is an eigenvector for $A$ then $Bv$ is an eigenvector for $A$.  To the second I proceeded as:  $$v \in \ker (A - \lambda * Id)$$ for same $\lambda \neq 0$, then  $$Bv = B\frac{1}{\lambda}Av = \frac{1}{\lambda}BAv = \frac{1}{\lambda}ABv$$  Then  $$A(Bv) = \lambda Bv$$ and then $Bv$ is an eigenvector for $A$ also with eigenvalue $\lambda$.  But I am stuck here. I mean, I don't know what to do with this.  I do appreciate any hint or answer.

Prove two commutative linear transformations on a finite-dimensional vector space $V$ over an algebraically closed field can be simultaneously triangularized.  It is equivalent to show if $AB=BA$, then there exists a basis $X$ such that both $[A:X]$ and $[B:X]$ are triangular, where $A$ and $B$ are both linear transformations.  Hint: Find a subspace $W$ of $V$ that is invariant under both by $A$ and $B$, with this in mind, consider any proper value $λ$ of $A$ and examine the set of all solutions of $Ax=λx$ for the role of $W$.  Notation:Let $A$ be a linear transformation on an $n$-dimensional vector space, and let $X={x_1,x_2,...,X-n}$ be a basis in that space, then $[A]=[A:X]=(a_{ij})$ be the matrix of $A$ in the coordinate system $X$, so that  $$Ax_{j}=\sum_{i}a_{ij}x_{i}$$.  Source: Halmos, Finite dimensional vector spaces, section 56 Triangular form exercise #2.  Could anyone please help, I have not idea how to do this. Any help is appreciated. Thanks a lot.


How would one go about such a classification and is there anything interesting that can be said about their corresponding Lie groups?

I am trying to find all 1- or 2- dimensional Lie Algebras "a" up to isomorphism. This is what I have so far:  If a is 1-dimensional, then every vector (and therefore every tangent vector field) is of the form $cX$. Then , by anti-symmetry, and bilinearity:  $$[X,cX]=c[X,X]= -c[X,X]==0$$  I think this forces a unique Lie algebra because Lie algebra isomorphisms preserve the bracket.  I also know Reals $\mathbb{R}$ are the only 1-dimensional Lie group, so its Lie algebra ($\mathbb{R}$ also) is also 1-dimensional. How can I show that every other 1-dimensional algebra is isomorphic to this one? Do I use preservation of bracket?  For 2 dimensions, I am trying to use the fact that the dimension of the Lie algebra g of a group $G$ is the same as the dimension of the ambient group/manifold $G$. I know that all surfaces (i.e., groups of dimension 2) can be classified as products of spheres and Tori, and I think the only 2-dimensional Lie group is $S^1\times S^1$, but I am not sure every Lie algebra can be realized as the Lie algebra of a Lie group ( I think this is true in the finite-dimensional case, but I am not sure).  I know there is a result out there that I cannot yet prove that all 1- and  2-dimensional Lie algebras are isomorphic to Lie subalgebras of $GL(2,\mathbb{R})$ (using matrix multiplication, of course); would someone suggest how to show this last? Thanks.


since the android screen is small to show a table with 10+ columns  so, I was wondering what is the best approach to show this kind of table according to material design guidlines The data from website that should be shown in android looks like this:

If I've 12 - 14 columns in a table to show on a page but there's not enough space to show all columns (let's say, there's only enough space to show 7 columns of the table), what is the solution for this?  I can make the page scroll horizontally but it's ugly and the last resort. Shrinking the font size of the table data only has rooms for 1  - 2 more columns at best.


I was using Windows 7 and in My Computer I had 2 local disks C: and D:.  On Elementary I only see a File System (if i'm not mistaken).  Has Linux combined these 2 into one called File System?

Can anyone explain why Linux is designed as a single directory tree?  Whereas in Windows we can have multiple drives like C:\, and D:\, there is a single root in Unix. Any specific reason there?


How do I put a decorative separator (like three asterisks or other symbols) in a text document so as to separate two sections of text, but not in a way that depends on LateX \section commands?  Such symbols used to be relatively common in books, but seem less common now.  NOTE: The proposed duplicate says "I would like to use a symbol", and the answers mostly reflect that. But I don't care if the decorative separator is a single symbol; in fact, it is better if it isn't. So, this question is more general than that one.

I have been trying to find a way to easily drop a nice horizontal rule into a LaTeX document.  \hline just makes a line across the page.  It would seem that some package must provide something that is maybe half a page wide, with little bedknobs on the ends or something to act as a nice section marker for paragraphs.  Any ideas?  Or am I boned, and need to come up with my own macro to create such a beast?


list=[endpoint.av.GrisoftAV.activescan,endpoint.as.KasperskyAS.activescan, endpoint.fw.ATTFW.description, endpoint.av["360SafeAV"].activescan, endpoint.av["H+BEDV"].description]   I need to build a regex to extract the values in third octet  The output needs to be:  GrisoftAV KasperskyAS ATTFW 360SafeAV H+BEDV

I don't really understand regular expressions.  Can you explain them to me in an easy-to-follow manner?  If there are any online tools or books, could you also link to them?


I have Kubuntu 18.04.01 installed on my PC.  I'm a computer tech, but I have extremely limited knowledge of Linux.  Everything is running fine, but I can no longer update the system.    sudo command doesn't work in the terminal and the Software Center fails to update.  I am entering the correct password, but the system fails to update.  The Software Center does successfully find the package to update.  I get an error message from the Software Center, but it is a light grey background with dark grey text. I'm unable to read it before it shuts off.    Below is the text from the terminal after the root login fails.    sudo apt-get update [sudo] password for glen:  Hit:1 repo.steampowered.com/steam precise InRelease Hit:2 us.archive.ubuntu.com/ubuntu bionic InRelease                                                                 Get:3 security.ubuntu.com/ubuntu bionic-security InRelease [83.2 kB]                                                Get:4 downloads.plex.tv/repo/deb public InRelease [3,408 B]                                                        Ign:5 dl.google.com/linux/chrome/deb stable InRelease                                                               Hit:6 us.archive.ubuntu.com/ubuntu bionic-updates InRelease                                          Hit:7 us.archive.ubuntu.com/ubuntu bionic-backports InRelease                                       Hit:8 dl.google.com/linux/chrome/deb stable Release                                                 Err:4 downloads.plex.tv/repo/deb public InRelease                              The following signatures couldn't be verified because the public key is not available: NO_PUBKEY 97203C7B3ADCA79D Reading package lists... Done W: GPG error: downloads.plex.tv/repo/deb public InRelease: The following signatures couldn't be verified because the public key is not available: NO_PUBKEY 97203C7B3ADCA79D E: The repository 'downloads.plex.tv/repo/deb public InRelease' is not signed. N: Updating from such a repository can't be done securely, and is therefore disabled by default. N: See apt-secure(8) manpage for repository creation and user configuration details.

I added some extra repositories with the Software Sources program. But when I reload the package database, I get an error like the following:     W: GPG error:  trusty InRelease: The following signatures couldn't be verified because the public key is not available: NO_PUBKEY 8BAF9A6F   I know I can fix it using apt-key in a terminal, according to the official Ubuntu documentation. But I would have liked to do it graphically. Is there a way to do this without using a terminal?


I have a requirement where I need to group records. For example I have 150 records and I need to get them in 5 groups, 30 records in each group.  Can anyone let me know how can I accomplish this?  Thanks in advance.

Is there a nice way to split a collection into n parts with LINQ? Not necessarily evenly of course.  That is, I want to divide the collection into sub-collections, which each contains a subset of the elements, where the last collection can be ragged.


I'm creating a commenting system for signed in users. It is very simple, I just want the user's username and the comment posted on the page and then stored in my user_comments table.       I have two db tables I am working with users and user_comments. All of the username info is stored in my users table. I want the comments to be stored into the user_comments section and post from there. Then I want the user's username to be echod next to the comment and then stored in with the user_comments after submitted. I can't figure out how to sync all of this together. As of now this posts and the comment stores into my user_comments.   How would I get the user's username to post and then be stored into the user_comments table?  <form action="communitySignedIn.php" method="POST">     Comment     <textarea cols="15" name="comment" placeholder="Message" class="messageinput" rows="5" maxlength="1000" required></textarea>
      <input type="hidden" name="token" value="<?php echo Token::generate(); ?>">     <input id="signinButton" name="submit" type="submit" value="Comment"> </form>

  <?php     if(isset($_POST['submit'])){          $comment = trim( $_POST['comment'] );;          $okay = true;             if( strlen($comment) < 2 ) {              echo "Please enter another character
";              $okay = false;          }          // you would do other validation here if other fields          if ( $okay ) {              $con = mysqli_connect("localhost", "root", "", "bfb");              $q = mysqli_query($con,"INSERT INTO user_comments (id, comment) VALUES ('', '$comment')")                  or die("Could not INSERT: " . mysql_error());              echo "Your comment was successfully posted.

";          }      } ?> <?php     $con = mysqli_connect("localhost", "root", "", "bfb");     $run = mysqli_query($con,"SELECT * FROM user_comments ORDER BY id DESC");     $numrows = mysqli_num_rows($run);     if($numrows > 0){         while($row = mysqli_fetch_assoc($run)){             $dbname = $row['name'];             $dbcomment = $row['comment'];             echo 'escape($user->data()->username)';             echo "Comment: $dbcomment

";         }     }     else         echo "No Comments Found..."; ?>

If user input is inserted without modification into an SQL query, then the application becomes vulnerable to , like in the following example:  $unsafe_variable = $_POST['user_input'];   mysql_query("INSERT INTO `table` (`column`) VALUES ('$unsafe_variable')");   That's because the user can input something like value'); DROP TABLE table;--, and the query becomes:  INSERT INTO `table` (`column`) VALUES('value'); DROP TABLE table;--')   What can be done to prevent this from happening?


How can I get the exact coordinates of the handle point?   For reference its the coordinates of the blue points at the end of the handles I am interested in.

When I move cursor on an anchor point, Illustrator shows me the coordinates of the anchor. But how can I find the [x, y] coordinates of the handles (in red circles)?


I have just installed MiKTex 2.9 in Windows 7. I had  and fixed it by deleting the .fndb files.  The first time I try to compile a "hello world" .tex file , a window pops up titled Package Installation telling me that a file is missing and I need to install the package cmap.   I click Install and it shows, after downloading the package, Unfortunately, the package cmap could not be installed.Please check the log file: C:/Users/Matt/AppData/Local/MiKTeX/2.9/miktex/log/pdflatex.log.  The log file contains:  2015-09-08 23:55:22,798+1200 INFO  pdflatex - installing package cmap triggered by tex\latex\cmap\cmap.sty 2015-09-08 23:55:25,488+1200 INFO  pdflatex - mpm: starting package maintenance... 2015-09-08 23:55:25,488+1200 INFO  pdflatex - mpm: installation directory: "F:\Prog\MiKTeX 2.9" 2015-09-08 23:55:25,488+1200 INFO  pdflatex - mpm: package repository: http://mirror.aut.ac.nz/CTAN/systems/win32/miktex/tm/packages/ 2015-09-08 23:55:25,728+1200 INFO  pdflatex - mpm: lightweight database digest: fd7a40a42ed2f1e70be3b6bdb1baccf2 2015-09-08 23:55:25,738+1200 INFO  pdflatex - mpm: going to download 7251 bytes 2015-09-08 23:55:25,738+1200 INFO  pdflatex - mpm: going to install 14 file(s) (1 package(s)) 2015-09-08 23:55:25,738+1200 INFO  pdflatex - mpm: downloading http://mirror.aut.ac.nz/CTAN/systems/win32/miktex/tm/packages/cmap.tar.lzma... 2015-09-08 23:55:25,908+1200 INFO  pdflatex - mpm: 7251 bytes, 41.65 KB/Sec 2015-09-08 23:55:25,918+1200 INFO  pdflatex - mpm: extracting files from cmap.tar.lzma... 2015-09-08 23:55:25,938+1200 FATAL pdflatex - Windows API error 87: The parameter is incorrect.   I have found that if I close TeXworks and open the MiKTex Package Manager, I can enter cmap and install the package successfully.  But then when I reopen TeXworks and build my file again, the exact same thing happens but with babel-english instead of cmap.  I have no idea how many packages it is going to need and this could be very time-consuming...  Is there a way to fix the auto package download?  I tried installing package ms as suggested  but that did not fix the problem.    Update: I discovered that if I run the Package Manager while TexWorks is still open, then the package installation for babel-english fails with the same Windows API error 87: The parameter is incorrect. but it gives extra information:  Data: C:\ProgramData\MiKTeX\2.9\miktex/data/le\0830eb7b3437d95b9288750893206d6f.fndb   So I wonder if this problem is related to or in fact the exact same problem as .

I installed a new hard drive on my computer this summer and I'm trying to install MiKTeX on it now. There were no problems when I was using my old hard drive. My OS is Windows 8.1. I'm trying to compile the following very basic file with pdfLaTeX:  \documentclass{article} \begin{document}   hi   \end{document}   Here's the first error I get:  Sorry, but "MiKTeX Configuration Utility" did not succeed.     The log file hopefully contains the information to get MiKTeX going again:   C:/Users/Tyler/AppData/Local/MiKTeX/2.9/miktex/log/initexmf.log  You may want to visit the MiKTeX project page (http://miktex.org), if you need help.   With the following errors in the log:  2015-09-03 22:23:51,625-0400 INFO  initexmf - starting: MiKTeX Configuration Utility 2.9.5700 (MiKTeX 2.9 64-bit)    2015-09-03 22:23:51,631-0400 FATAL initexmf - Windows API error 32: The process cannot access the file because it is being used by another process. 2015-09-03 22:23:51,631-0400 FATAL initexmf - Info: C:\Users\Tyler\AppData\Local\MiKTeX\2.9\miktex/data/le\1e0c0e04cb3be262fbb8e6e7ace14b67.fndb 2015-09-03 22:23:51,631-0400 FATAL initexmf - Source: Libraries\MiKTeX\Core\win\winFile.cpp 2015-09-03 22:23:51,631-0400 FATAL initexmf - Line: 520   The second error:  Sorry, but C:\Program Files\MiKTeX 2.9\miktex\bin\x64\miktex-pdftex.exe did not succeed. The log file hopefully contains the information to get MiKTeX going again:   C:/Users/Tyler/AppData/Local/MiKTeX/2.9/miktex/log/miktex-pdftex.log  You may want to visit the MiKTeX project page (http://miktex.org), if you need help.   with the following errors in the log:  2015-09-03 22:16:18,715-0400 INFO  miktex-pdftex - running 'initexmf --quiet --update-fndb' to refresh the file name database 2015-09-03 22:16:18,746-0400 FATAL miktex-pdftex - The operation failed for some reason. 2015-09-03 22:16:18,746-0400 FATAL miktex-pdftex - Info: C:\Program Files\MiKTeX 2.9\miktex\bin\x64\initexmf.exe 2015-09-03 22:16:18,746-0400 FATAL miktex-pdftex - Source: Libraries\MiKTeX\Core\Process.cpp 2015-09-03 22:16:18,746-0400 FATAL miktex-pdftex - Line: 290   Things I've tried:   Uninstalling and reinstalling MiKTeX Downloading all packages whose name starts with miktex (which is a solution that worked for someone else in a different thread) Having nothing open but TeXworks when trying to compile Looking for processes that may be related to MiKTeX in the task manager (I didn't find any)   How can I stop these errors? I apologize if my formatting is bad; this is my first stackexchange question. Thank you for your help.


I want the user to be able to run a script which looks like this now:  # script.sh export PASSPHRASE=123   and then be able to do this in the same terminal as that in which the script was evoked:  $ echo $PASSPHRASE 123   In other words, I want the variable in the script to be available to the user after the script has been run. How do I do that?

I'm trying to write a shell script that, when run, will set some environment variables that will stay set in the caller's shell.  setenv FOO foo   in csh/tcsh, or  export FOO=foo   in sh/bash only set it during the script's execution.  I already know that   source myscript   will run the commands of the script rather than launching a new shell, and that can result in setting the "caller's" environment.  But here's the rub:  I want this script to be callable from either bash or csh.  In other words, I want users of either shell to be able to run my script and have their shell's environment changed.  So 'source' won't work for me, since a user running csh can't source a bash script, and a user running bash can't source a csh script.  Is there any reasonable solution that doesn't involve having to write and maintain TWO versions on the script?


In the definition of C* algebra there is a Banach algebra together with a map, called involution map, which obey some properties. We denote the map by sending x to x*, called adjoint of x. Now my question is if there is one such involution map in a Banach algebra obeying those properties, then how many such map exist to make the Banach algebra a C* algebra. that is what can we say about the number of involutions if one exist.

indication please  Let $A$ be a C*-algebra. Suppose that there exists on $A$ another involution $x\rightarrow x^{\#}$ such that $\|xx^{\#}\|=\|x\|^2$, for all $x\in A$. Prove that $x^{\ast}=x^{\#}$, for all $x \in A$.


Does anyone know of a "glitch text" font available in LaTeX? I'm not even sure this is what this type of writing is technically called, but it's used on twitter by accounts like @glitchr_. Here's an example of some text, as generated from  (apologies for obscuring some of the question text):  T̷̝̗̰̞̙̞̖̱̥̯̙̖̯̲̜̜͙̪̀̑̀̍̀͑̀͊͒̃͊͊̌̓̍̒ͅh̴̨͔̫̜̮̖̑͑̎͗͠i̵̧̡͍̣̳̻̥̙̬̲̪̪̦̮̻̩̦̭̫̣͙̦̱͍̼̒̊̆̽̋́̈͂̓́̄̆̂̓̉̇̉̃̃͒̌̓̾̆̒̚͜͝͝ͅs̵̢̢̧̜͚̝̯̮̼̟͍̗̞̘̙̍̋̈̿̇̾́̐ͅ ̷̨̨͕̳̝̰̭̞̱͎̖̞̤̘̯̪̮̺͇̙̃͜͠ͅͅi̶̧͖͓͎̫̲̗͇̳̞̬̞͔͖͉̅̌̿̏̐͝s̶̢̨̮̤̺̼̖̰͓̣̗̦̲͎̠̰͗̊̒̑͛̓̔͒̑̒̔̔͂̆̽̑̇̾̐̇͗́͊̀̀͊͑̓̕̕̚̕ ̵̛͓̯̦̯̞̩̀̓̈́̄͐͑͗̑͌̈́͂́̑̓̓͌̈́͗͑̈́̉̐̓͊̐͘̚͜͝ä̵̛̛͚̰̹̣́̒̈̈́̍͛̂̄͊̀͂̆̐̈́̓̔̎͑͗̈̋͂̓̃́́̽̽͘̕͠͝n̷̨̨̛̛̛͈̖͕̭̺̦̞̹̅̽̂̀̂̑͆̆̔̽̋̐̈́͒͑̓̉̀͑̈́̂̒̇̎̍͐̉͊͘͜͠͠ ̵̢͇͚͔̲̂́͊̅͒͑̕ȇ̷̢̡̛̩̦̫̝̙͚̱̲̳̗̠̫̜͓͙̘̹̩͖̹̪͔̙̘̹̻̟̜̰͚̄͊͐̓͂̂̂͌̈́̓͒̚͝x̷̨̬̄̂͂̈͐̾̋̐̕̚͠͝ͅả̵̧̨̰̣̳̖͕̞͙̗̳̝̬͎̯̫̘̫̝̼͍̩̜͎̭̹̘͈̮̎͐͛̓̽̋̏̈̌̈̊̓̅͐̈́̂̋̊̏̆̊̐̈́̽͛͌͛̀̅͘͜͝ͅḿ̸̡̡̛̛̞̜̮͈̤̮̬̦̯̪̪̜͇͇͈̬̞̞̯̟͕̠̻͈̬͔͚̋̎̉͌̏̈́̈̀͒̈́̀̈́̄̆̚͜ͅͅp̸̢̨̨̢̢̛̮̹͙̜̟̜͕̩͉͍̜̠̮̲̤̹̬̙̯͕͖̜͉͚̘͇͒̌́̉̾̓̀͊̎̔͛́̽́̾ͅl̵̢̠̱̲̗̯̹̼͔̳̘̫̯͑è̷̯̗̩̹͓̲͍͚̫͜ ̴̖̖͙̙͙͇̝͉̽̐͋͐̑͂̋̾̒̉̈́̋͊̎̈̉̉͒͂̆̕̚͝͝͝o̵̢͈͍͍̹͓͓͖̝̙̥͒͌͗́͋̌͛͊̐̈́̈́̍̌̈͋̏̅̆͛̈́͐̎̇͂̍̚͘͠͠͠ͅf̵̢̢̰̼̗̯̝̮͈̲͓͙̲̩̰͎̙͎̟͚̅́̍̑͒́̕͝͠ ̸̨̨̛̹̪̳̹͇̼̹̻̺̥͉̰̙͓̣͙̙̜̫̫̼̣̣̘͍͕͙̭͚̄̍̆̏̉̀̋̏̑̑͊͝ͅğ̷̤̬̜̼͕̇̈́͝ḽ̴̢̮̥̬̟͖̻̓̒̊͒̀͑̐̇͆̿̔́̓̚͠͝i̷̡̧͚͔̻̖̬̺̰̬̬̗̮̙̥̤͕̩̜̻̩̪̙̯̳̅̓̓̀̑̇͗̉̑̽̔͊̂̈́̑̓̀̄͑̀̓̓̋̈́̄̄́̊̕͘͝͝ͅt̸̨̝̺͉̥̗͇͍̤̦̂c̵̡͇̜̠͍͇͖̯͕͇̝͎̬͕͑̒͆͗̆͛̍̀͛͊̈́h̴͈̭͔͎̭͚̱̼̾͂ ̷̢͔͓̭̥̠͈͚͈͕͈̳̜͙̤̲̥̮̳̞̱̰̱̇̍̍̔͂̃̐͑̊̾͘͘͘͜͜t̶̡̧̧̯̺̖͖͎͉̦̫̯͇̠͖͉͉̮͎͕̫͍̯̖̘͖̱͔͉̹͎͙̔̈́̈͑̉̑̇̎̓̓̑͛̒̄̄̑͐̅̑͊̎̿̔̐̅́̄̿͒̕̚̚̕̚͜e̶̡̡̨̩̤͓͔̪͙̥̫͍̍̐̀̂͛͜ͅx̴̡̨͓͎̼̞͚̬̀̅̈́̓͒͊̑̾̒̈̅̄̈́̽̃̏̆̋͑͊͑̒̌̕̚͠t̸̛̛̹͔͎̻̜̫̰̪̟͉̩̩̹͆̅̔͛̋͐̆͛͋̀̾̒̌́́͌͝͝͝

There are many question about rendering unicode in latex that are subject to interpretation, I would like to ask how to properly render Zalgo text with lualatex (or any other tex; just to specify a focus), that is i want to have this:  T̸̙̖͕͕̣̥͕̙̓̋ͯ̇ͨ̎́̀̚o͎̤͍̠̯̣̦̖̔̈́̚͝ ̗̭͚̲̮͎̝͓ͨͫ̿̍̔͟͠i̳̙̪̙͎̗̠͌͐̃͛̈́ͅn̥͚͇̪̽̅̈́͌͌̀͞v̴͎͖̝̝̯̦̣̪ͩͧ̓ͥ̽̔̎͑͒o͙ͦͭ̀͝k̗̯̥̅̏̈́͑ͪ̋͞e͛ͩ҉̨҉̖͚̙ ̴͕̰̮̲̤͎̬̼ͥ̽̽ͬ̆͆͟t͕̳͈͖̪͍̞̭̐̊ͯͯͩ̇̊́h̰̅ͤ͒̂̄́e̵̯͙̓̾͑̀́ ̢̻͍̣̟͈̍̽͆̑̆ḥ̠̞̺̯ͥ̽̉ͥ̊̃ͨì̡̼̯̹̭̙͉̪̰̄ͤ́v̤̦ͦ̅̽̚͡ͅe̦̯̙̲̪̐̄̅͛ͫ̀̄̇͟͢-̡̘̭̓ͪ͒̄̽m̵̲̺͔̩̅̅̉̓͌̌ị̲̣̮̦͕̝͇̂̉̌ͩ̒̎̊͞n̰̮̦̪͈̩̄͐ͬ̋̈́͂̕͠ͅd̮̪̰ͮͧ̊̐͜ ̡͚͇͈̙͕̣̲͇ͯͣr̖̎̾͜͝e͑̊̎̈ͧ͌҉̤̫̥p̃̓́͂̈́̈҉̠̻̙̞͓̮̮̙̪r̴̦̭̺̝̤̪̪̗͒ͦͨ͊̆̎̚͘e̶̬͕͗ͭs͍͓̩͊̊̇̾ͬê̴̯̩͈̟̮͈̥ͅn͚̜̗͈̫̠̖̗͆͛͡ţ̠̳̩̻̭̿̊̒ͣ͘͢i͚̺̬̳͛̏̉͆ͣ͋̀͞ͅņ̝ͮ̄̕͟ǵ̡̟͈͉̭ͮ̈́̔̆ͣͬ̚͟ ̮̱̯ͮ̌̔̓̈̂ͪͯ̀c̵̵̶͇̙̟͚̪̤͍͖̖̄̃͒͐̃̊ȟ̬̬̦̲̖͙̫̔ͮ̍́a͙̖̒̍ͣ̑͂ͭo̢̖͔̞̫̩͚̗̝ͬ̍̌ͧ͆ͨͨ́s̜͍͈͓̲̞̦̥̾ͩ̀̅͐͗ͧͭ.̳̥̱̋̃̊̅̕͘ ̸̢͕̽͗̀ͣ̄̎͆ͨ͞I̢̟̪͎͔̜̥̙̥̬͛ͤͯ͐ǹ̀҉͎͎̜v̷̦̼̙̱̍̋̚o̵̢̪̥͐͛k̸̺͙̲͌́ͅi̛̞̹̹̞̤̭ͬ͛̾̍͑ͥ̑̕͜n̡͖͋͂̿́̕͞ǵͤ͂ͤ̇҉̜͔̱͓̮̜ ̵̴̼̞̟̬͒̽̈́̔̍̎͋̈͗t̡̺͔͚̖̼̺̞̍̔̔̈́̽͟͝h̲́̈̏̃̋͢ę̹̭ͦ̽ͤͭͦͅ ̪͔̜̞̺͓ͤͯͤ́͢͝f͓̮͕͇̼͆ͧ̈́̓͝e̛͍̮͙̼̰͍̜̜̾̂ͭ̀̅͋̈́̓̕e̢̩̫͆͊͟l̵̢̟̥̥̰͓̪̖ͮ̔͋ỉͧ̿̒̿ͩ҉̼͕̫͈n̗͔̩̗͖̳͍̺̱͗̇͗̏͑ͦ̐g̶̥͍̺̰͉͇̘̈ͫ͑̀͡ ̧̹̳̬͇͓̮̜͉͌̊̆͐̈́͊o̩͖̖ͧͩ̔̓̏̇ͨ͒ͩ͘͘f͎̺ͪͨ͊͆͗͒̇ͮ͡ ̨̼̘̭͓̪̉͌̒͒̔͐ͨͅc͕̼͕͂́ḫ̶̮̹̖͙̋̄̑̆̇̉͜͝a̷͕̻̩͉̘͎͑͋̒̕ȏ̢͙͚ͬ͂̿ͭ̎̋̄s̡̍ͫ͐̓̽̀ͨͬ̕҉̹̬̳͉͓̗͔͉̫.̟̙̯̍̈͒ͯ͝ ̠̻̓ͦͪ̀W͙͆̍ͮ̂͆̀̚i̓̄ͦ̋͟͞҉̩͉͚̖t͛̍̾͒ͨͦ̅҉͉̼́h͖͈̲͈̟͚͗̂͋ͤ́͢ ̙͚̙̄͊͝ͅǫ̷̲̖̖̘͋́̈́ù͉̫͔͓͇̇̌͒͒̈ͪ͜t̴̪̀̓ͦ̾̿͘͜ ̰̹͙ͤ͢o̝̝̬̮̥̟̳̍̀̋̇̑ͭͅr̯̟̝̠͍͇̭̤͚ͨͯ̿ͬ̔ͤd̵̘̮͎̖̯͇ͪ̀̐͠e̲̭̲̺̥͍̰͎͆ͫr̡̛̭ͣͦ̋̕.̫͓̯͎ͧ̐̌͑̕͠ ̧̢͚̩̪̦̮̏̍̇ͮ̒T̴̼̼̮̝̉ͬ̍ͤͥ̃̍͡h̴̠̣̙͎͋͐̀̚͠ḛ̛̦͖̻̱͒͌̍̈́͐͑̆̿͌ ̴̛͈͚͔̊ͨ̀ͩ͝Ņ̸̥͎̄ͧ̚͞e̺͚͈͖̠̘̤̽ͬ̎ͧ́ͭ̚͞z̼̫͓̺̹̮̝̮͗̚͡p̧̨̪̘͛̾̂̿̿ͫͦ̍ę̴͔͓̥̦͔͚̬̔ͧ͌͌ͨ̈́̊ͧͧr̾̈́ͥ͐̄̒̋͐҉̝̮͓̜̕d̷͕͈̥̦̺͔̳̊i̶͙͎̯̜̦̻͊̿̏ͩ͛ã̦̾̓͒̉̚͠ͅn̬̘͙͓̣̓̐̓̈̽̈͐̿ͅ ̷͈̣̲̻̍͒ͣ̉ͩ̔ͩ͘h̴͔̫̲̤͙͚̣͉͇̾͌͐ị̳͓͙͖̟̊ͩ́̀v̛͈̜́͗̒̊ͣ̒̋ͬ͟͠ȩ̻̲̺͚̪̹̔̑̇͗ͮͭ̀͝ͅ-̸͎͔̮͈͙̻̝̳̎̈́ͬ͋͋̏̒ͯ̉͢m̳̈̾͋̑ͭ̑̆ͬị̷͕̯ͤ̀͝͡n̯̲͓͂ͪͨ̀ͧ͑͠d̦̤̗̲͈̖̗̹̔ͅ ̨̪̗̣̝͎̺͛͛ͬ̿́̾̅͞o̘̣͇̜̗̞̱͍̓ͅf̲̗̳̟̣́͊͞ ̛͚͙͇̞̱̠ͧͫ̋ͨ͌͌̈́ͭċ̴̨͈͑ͤͣ̐̂͞h͙̃͐ͧ̿͆̂̈̅a͙̲͇͎͈̋̌͐̾ǒ̴̫̯̭̖͎̄̉̈́͛̄́s̗͍͈͙͕̺̲͍̋ͮ͟.̢͙ͭͭͫ͆͞ ͓̼̹ͬͨ͆͂̽̅ͯ͝Ż̸̴̲̯̤̟͈̘̈́̏ͭ͐̓͑̒̀à́͒ͅl̴̛͈̋͌͊̕g͕̤̖̮̾ͪ̏̊͐̎ͦ͘o̧̙̥̤̣ͮ̑̍̆̿̓.̢̙̠͗͌͋͝ͅ ̩̩̲̘͕̣̥͙ͦ̓̄͌ͯ̉̌̉͝͠ ̻̤̰͇̪̈͌͆̽̏ͣ̂̿͟͡H̺̽͌̈́ͣ͌̄e̗̜̜͒͋̂ͮ̉̑̈́̀̚͠ ̻̼͍͎ͧ̈́͝͠w̸̮̺̟̬̎ͫ̄̈́ͤ͂̌ͬ̓͝h̷͈̯̬̪̿̆̈͌͌̊̔̀̚o̻̟̜̱̙͆̈́̀ͩ͞͠ ̴̹̻̪̯̭̦͕͉̌̆̽͘W̧̧͔̺̦̯̙͕̾̒ͤ̑̇͞a̡̪̣̺̐͗̅ͩ̋̈́ͦͨ͢ȉ̉͞҉̢̝͉̻̩̹̰̤t̵̛̬̺͖̳̗͉̝̭͍̾̑̿́ͬͪ̂ͤs̴̫̱ͭͫ̆ͨ̈́ ̮͖̲̠̘̩̍̿́̚͡B̢͍̮̬̱̤̫̃ͬ̕ę̣̣̹̑͐̉ͪ̒ͧͅh̶͓̼̘ͭͨͯ̑̅͜ȋ̯͖̦́ͯͣ̿̒̐nͮͣͪͣ̏҉̹̮̩̭d͍̤̦̱͓̹̲͚̄̾̄̏͑̕ͅ ̠̤̿̿̉̍ͫṬ̡̼͚̾ͯͅh̶̹̠͈̗̋ͭͤͅe̘̫͍̮̥ͣͣ̐̂͐ͭ́ ̸͔̲͈̩̟̖̗͖̈̐͞ͅW̴̫̘̺̤̝͈̜̙ͤ̅̔ͩ̈́̑̊a̟̲͖ͤ̈́̂ͦͧͫl̷̥̺̙͎̝̬ͪͦͨ̐̔ͭ̓͐͞l̷̶̟̜̤̤̯̞̦̋ͬ̚.̸̵̜̩̄ͧͪͦ ̵̼͎̺̼̑̒͑̋ͅͅZ̡̘̤̮͇̞̪͉̞͐̏ͬͤͭͤͧ̀́Ḁ̪͖͚̫̼͔̼̆̐ͧ̓ͥ̓̓͝L̷͖͈ͪ͂̔̏̆̓̚͜Ģ̵̶̩̔̒ͦ̂̑͋̈́ͅO͊ͯ҉̟̮͇͔̬͉̣͡͡ͅ!̫̭̈́̅̌ͪ̃ͩ̚  in a pdf.  Just copypasting it inside a document does not work. Two possible kind of solution i can imagine would be:   an environment or a package that allow complex composing characters or a way to input a text codepoint by codepoint   In this context i don't care whether symbols like emoticon or flags would work; just really weird looking text.


Is there an appropriate word for the antonym of "full-stack", as in programming? Someone who knows a lot of things just as a full-stack programmer, but without mastering them.

I'm asking about someone who's employed by a company and does different jobs (both a qualified and unqualified person). Who knows; maybe in English those two are two different words? What are they called in English?  All I know is a navvy but that usually means physical work.  Let me just try a few things here. These are just wild guesses, nothing more.    odd job man/worker   shiftman   (unskilled) labourer


Before going to Hogwarts young wizard and witches must have either gone to Muggle school or been home schooled. Probably not every pair of wizard parents wants or has the time to home school their children. So if they went to Muggle school, how could they be so ignorant about the Muggle society when they are surrounded by it almost every day of their lives? It would be impossible not to learn how to use daily things like computers and electric lights if they were exposed to that type of environment. The only alternative is that wizard and witch children have no education at all up until the age of eleven...but to not have any experience with school and then be sent away to boarding school for ten months? That is inconceivable to me. Any ideas?

Most of the wand-carriers that come from a non-Muggle family seem fairly uneducated when it comes to interacting with Muggles.  This implies that they don't go to any type of Muggle school before entering into their education at Hogwarts (or whichever Wizarding school they go to), or else they would at least understand some Muggle culture.  What do children from magical families do before going to Hogwarts if they don't go to a traditional school?  Is there any evidence that they're homeschooled?


I can see that there are example codes online where an api call - [HttpPost] public async Task<users> GetUsers() {   // api call to retrieve users }  Isn't it supposed to be HttpGet - and what is the reason for HttpPost? Does it hide details from the url?

What's the difference when using GET or POST method? Which one is more secure? What are (dis)advantages of each of them?  ()


I am building a PCB with some ICs. To sum up, I have a global 3.6V supply and I need to have an 1.8V reference for some IOs.  I know the right way to do it is to use a voltage translator circuit (generally an IC), but I was wondering why not to do it with two similar resistors ?  Thanks

When would you use a voltage regulator vs a resistor voltage divider?  Are there any uses for which a resistor divider is particularly bad?


I get tons of meaningless (for me) exception when run this code. Not sure where I could make a mistake... Basically I want my producer to puts alpha chars in the buffer and consumers to  get them from a buffer and print. I just started to learn multithreading and I have no idea what could be the potential problem in this code. I tried to implement in-class example. I really apologize if it is a dumb question...  public class Driver {     public static void main(String[] args) {         new Consumer("Consumer1");         new Consumer("Consumer2");         new Consumer("Consumer3");         new Producer("Producer1");     }    } public class Producer implements Runnable{      private Buffer buf = null;      public Producer(String name){         buf = Buffer.getInstance();         new Thread(this, name).start();     }      public void run(){         char character = 'A';          for(; character < 'Z'; character ++){             buf.put(character);             System.out.println("Producer " + Thread.currentThread().getName() + " puts " + character);         }          Consumer.done = true;     } } public class Buffer {      private static Buffer instance = null;     private boolean full = false;     private boolean empty = true;      private char[] arr;     private int i;      private Buffer(){         arr = new char[26];         i = 0;     }      public static synchronized Buffer getInstance(){         if(instance != null){             instance = new Buffer();         }         return instance;     }      public synchronized void put(char c){         while(full){             try{                 wait();             }catch(Exception e){}         }          arr[i++] = c;         empty = false;         if(i == 25){             full = true;             notifyAll();         }else{             full = false;         }     }      public synchronized char get(){         while(empty){             try{                 wait();             }catch(Exception e){}         }          if(--i == 0){             empty = true;         }else{             notifyAll();         }         full = false;         return arr[i];     }  }  public class Consumer implements Runnable{      private Buffer buf = null;     public static boolean done = false;      public Consumer(String name){         buf = Buffer.getInstance();         new Thread(this, name).start();     }      public void run(){               while(!done){             System.out.println("Producer " + Thread.currentThread().getName() + " gets " + buf.get());         }     } }    Exception in thread "Consumer2" Exception in thread "Consumer3" Exception in thread "Consumer1" Exception in thread "Producer1" java.lang.NullPointerException     at Producer_consumer.Consumer.run(Consumer.java:15)     at java.lang.Thread.run(Thread.java:745) java.lang.NullPointerException     at Producer_consumer.Consumer.run(Consumer.java:15)     at java.lang.Thread.run(Thread.java:745) java.lang.NullPointerException     at Producer_consumer.Producer.run(Producer.java:16)     at java.lang.Thread.run(Thread.java:745) java.lang.NullPointerException     at Producer_consumer.Consumer.run(Consumer.java:15)     at java.lang.Thread.run(Thread.java:745)

What are Null Pointer Exceptions (java.lang.NullPointerException) and what causes them?  What methods/tools can be used to determine the cause so that you stop the exception from causing the program to terminate prematurely?


Software remediation of the Meltdown and Spectre problems slows performance. If and when non-problematic processor models come to market, or microcode updates fix installed processors, will kernels and applications need flags or recompilation to avoid the slowdown due to software-based remediation?   ref:

Because of the current Intel CPU security hole issue, there is a patch expected which slows down the system performance.  How can I make sure that this patch will not be installed on my Ubuntu system?


When I search on CodeReview.StackExchange.com for "[f#]" (so the tag F#), I get a captcha page. After the captcha I get redirect to the search result page. This now has the query string "f#", so it lost the square brackets - suddenly I'm searching for text, not for a tag.  When I search for "[f#]" and I don't get a captcha it works as expected.

I clicked a tag from a user profile on a site where I don't have an account. The address was:        It then took me to the "nocaptcha" page which I passed (with flying colors) by clicking the magic checkbox. I was then redirected to the search, but with brackets that surrounded the tag removed:        Clearly the brackets should be retained through this captcha detour.


I asked this previously for my Earth project but it was never given an answer and was marked as a dupe which it wasn't as the question it was linked to was about textures being controlled by light, not the emission of an object. The effect would be somewhat the same however it shouldn't affect visibility but emission so that the objects emission fades when going dark.  For the atmosphere I'm using 2 spheres. One to act as the atmospheric distance you see where it gets more hazed the further away you look, and another which is the glow itself. For the glow I've found it works best with a volumetric material and have it emit light. The question I would like answered is, how would I control the emission of the volume material with the sun lamp in the scene? I have a strong feeling that nodes can make this happen but I have no clue on what ones would work.  I am working in Blender Render as I haven't figured out a better way to make a good looking Earth in Cycles yet.

showed in one of  how to use a white material node in the Blender internal render to get the brightness of a point and assign the texture accordingly.   In this case: Point is bright: assign daylight texture; Point is dark: assign night light texture  Is there anyway to reproduce that in cycles?


I'm very new to using SSH and my server has been hacked, someone has gone onto a website of mine and made modifications. I have the time which they did it (29/07/2013 18:14:30), but cannot see how they go into the website.  I have tried tail /var/log/messages and tail /var/log/secure but cannot see any activity at this time.  I just want to know if they came via control panel/ssh/ftp so that I can change the passwords and perhaps ports to stop them.  Any help is greatly appreciated.  Thank you

This is a  about Server Security - Responding to Breach Events (Hacking)   See Also:                  Canonical Version I suspect that one or more of my servers is compromised by a hacker, virus, or other mechanism:   What are my first steps? When I arrive on site should I disconnect the server, preserve "evidence", are there other initial considerations? How do I go about getting services back online? How do I prevent the same thing from happening immediately again? Are there best practices or methodologies for learning from this incident? If I wanted to put a Incident Response Plan together, where would I start? Should this be part of my Disaster Recovery or Business Continuity Planning?   Original Version       2011.01.02 - I'm on my way into work at 9.30 p.m. on a Sunday because our server has been compromised somehow and was resulting in a    attack on our provider. The servers access to the Internet   has been shut down which means over 5-600 of our clients sites are now   down. Now this could be an FTP hack, or some weakness in code   somewhere. I'm not sure till I get there.      How can I track this down quickly? We're in for a whole lot of   litigation if I don't get the server back up ASAP. Any help is   appreciated. We are running Open SUSE 11.0.            2011.01.03 - Thanks to everyone for your help. Luckily I WASN'T the only person responsible for this server, just the nearest. We managed   to resolve this problem, although it may not apply to many others in a   different situation. I'll detail what we did.      We unplugged the server from the net. It was performing (attempting to   perform) a Denial Of Service attack on another server in Indonesia,   and the guilty party was also based there.      We firstly tried to identify where on the server this was coming from,   considering we have over 500 sites on the server, we expected to be   moonlighting for some time. However, with SSH access still, we ran a   command to find all files edited or created in the time the attacks   started. Luckily, the offending file was created over the winter   holidays which meant that not many other files were created on the   server at that time.      We were then able to identify the offending file which was inside the   uploaded images folder within a  website.      After a short cigarette break we concluded that, due to the files   location, it must have been uploaded via a file upload facility that   was inadequetly secured. After some googling, we found that there was   a security vulnerability that allowed files to be uploaded, within the   ZenCart admin panel, for a picture for a record company. (The section   that it never really even used), posting this form just uploaded any   file, it did not check the extension of the file, and didn't even   check to see if the user was logged in.      This meant that any files could be uploaded, including a PHP file for   the attack. We secured the vulnerability with ZenCart on the infected   site, and removed the offending files.      The job was done, and I was home for 2 a.m.            The Moral   - Always apply security patches for ZenCart, or any other CMS system for that matter. As when security updates are released, the whole   world is made aware of the vulnerability.   - Always do backups, and backup your backups.   - Employ or arrange for someone that will be there in times like these. To prevent anyone from relying on a panicy post on Server   Fault.


If $G=\left<a\right>$ is cyclic of order $n$, then $a^k$ is also a generator iff $(k,n)=1$. Conclude that the number of generators of $G$ is $\phi(n)$.   I think it's easy but I'm just stuck in both directions in the first part. I've tried to use Bezout's Lemma and the division algorithm but getting nowhere.  Can someone give some hint? Thanks in advance

I need to find how many generators has a cyclic group $G=<g>$ of order $n$. I know that I have to prove that if $G$ is a cyclic group with order $n$, then the number of generators of $G$ is $\phi(n)$. But I don't know how can I prove that.  I already know that $<g^k>=<g^{gcd(k,n)}>$, so the generators of $G$ will be $g^k$ where $gcd(k,n)=1$


How to delete these Warehouse.jpg names from the list? I want to pack extra files, but get errors because these files don't exist  I use X sign, but no result

I'm creating a model for a 3D game that will eventually be exported using a custom Python script. This model makes heavy use of UV textures.  However, the project now references a bunch of images that are not used by any objects in the project. Example:    I don't want the first two, or the red_bubble.png image. However, I have no idea how to remove them from the project. Selecting one of them reveals that there are "2 users of the data" although I am not using it anywhere.  How can I get rid of these excess images?


Are there any proof of the speed of light in vacuum being constant? All I hear is that light in vacuum travels at a constant speed because that's an observation and that it fits in a coherent theory with all sorts of other detailed observations. Is there no like mathematical proof or something or is it just purely based on observations/measurements and why is the speed the same for all observers? Please, try to give simple and meticulous explanations since I'm not the best at physics and might have a hard time understanding what you mean otherwise.

asks why and how the speed of light is constant. I would like to ask a related, almost converse question:  Given that the speed of light is constant, how could I explain to a young-earth-creationist who is still a proponent of the disgraced Barry Setterfield  that the $c$-decay theory contradicts observed physical reality, as described and understood by all scientists, including those in the Physics and Astronomy fields?  Surely a variable speed of light would throw a monkey wrench into all sorts of fundamental laws or systems in physics? Surely it would be measurable on instruments today, if there was even a miniscule change in the  speed of light relative to a continuous cold caesium fountain atomic clock?  The fact that there is no observable change in any recent trustworthy data, is the beginning, middle, and end of the scientific argument. Am I correct?  My physics education ended at Grade 12. So I'm asking for a high-school level explanation.  I also wonder if $c$-decay theorists are contradicting themselves, or have sawn off the branch upon which they themselves sit; For example,  I wonder this; Would we have to modify our expectations of what the doppler effect (red shift) would look like, as light comes towards us from distant stars, if the speed of light is variable? Would we not have to throw all our doppler data out, and all the distances themselves, if the speed of light is variable in some undefined way, and thus unknown and unknowable?  The $c$-decay theory was spawned because redshift data indicates that the stars are too far away for their light to have reached us in the mere 6000 years the universe has existed.  In short, if $c$-decay theory exists to explain distant stars to young earth creationists and help them breathe a sigh of relief, wouldn't it be slightly-less-scientifically-bogus, to just dispute the doppler effect and the distance of those stars?


In Avengers: Endgame, Tony Stark and Steve Rogers go to...     ...the Shield base in New Jersey, on a specific date in 1970.  Tony says it's a date that he knows that his father and Hank Pym will both be working there.   Why did Tony pick that day?  Picking the year seems obvious, but why that day?  I had guessed that perhaps...     ...that is Tony's birthday, and he knows that his father had been at work right before he was born.   But I don't know if there's any way to verify that inside the MCU.  Edited to add: I'm not concerned with why they would go there (that seems obvious, and the other question addresses it); I'm asking about the specific month and day Tony chose.

The main plan of Avengers: Endgame for solving what Thanos did in Avengers: Infinity War involves the      Time Heist.   As part of the plan Tony misplaces      the Tesseract   and so he and Cap have to go looking for it elsewhere. They decide to go back to      a SHIELD base in 1970 where both the Tesseract is stored and Hank Pym is based working on the Pym Particle. Whilst there Tony also bumps into his father, Howard Stark, working on the base.   Tony and Cap have a conversation in hushed tones about choosing it and it seems to be that they both know about it. Is there anything special about this place and time and how did they both know about it?


Let $\{a_n\}$ be a sequence for $n\geq 1$ and let $E$ denote the set of subsequential limits of $\{a_n\}$. Suppose that ${b_n}$ (for $n\geq 1$) is a subsequence in the intersection $E \cap \mathbb{R}$ so that $\lim_{x\to\infty} b_n$ exists in $R = \mathbb{R}\cup \{\pm \infty\}$. Prove that $\lim_{x\to\infty} b_n \in E$. I am quite new to real analysis and have no idea how to go about approaching this problem. Any assistance is appreciated.

I wanted to prove this claim but I'm not sure if this proof is okay. Please let me know what you think! 🌻  Let $\{a_n\}_{n=1}^{\infty}$ be a sequence, and let the set of its partial limits be $PL(a_n)=A=\{a|\exists a_{n_j}\rightarrow a\}$.  Let $a_0$ be an accumulation point of A, so, exists a sequence $\{x_n\}\subset A=PL(a_n)$ such that $x_n\rightarrow a_0$. But $\{x_n\}$ is a sequence of $a_n$'s accumulation points, (Edit) so for any $\epsilon>0$ There are infinitely many terms of $a_n$ in $(x_j-\epsilon,x_j+\epsilon)$, for any $j\in \Bbb N$.   Also, for any $\epsilon>0$,  exists $J\in \Bbb N$ such that for every $j\ge J$, $x_j$ is in the $\epsilon$ neighborhood of $a_0$, so and there is an infinite number of $a_n$'s terms in $(a_0-\epsilon, a_0+\epsilon)$.   It follows that (Edit) for any $\epsilon$ exists $\epsilon '$ such that $(x_j-\epsilon', x_j+\epsilon')\subseteq(a_0-\epsilon,a_0+\epsilon)$ so there are infinitely many of $a_n$'s terms in the $\epsilon$ neighborhood of $a_0$. This goes to show that $a_0$ is a limit point of $x_n$, so $a_0\in PL(a_n)$ so it is closed.


I was checking my reputation on Stack Overflow when something surprised me.        I don't understand why my quarter reputation is above my total reputation. I would like to know if this is a bug, or if there is something I've just misunderstood on this page.

When I went to the  to see my ranking in the reputation league, I saw this. Is this an error? My total reputation is less than my monthly reputation.


Let's say you're playing Mercy and your Pharah damages herself with her rockets until she's almost dead. Then, once the round starts, you start healing her. Does it help you build up ult charge?

Certain characters can damage themselves during the pre-game countdown, notably Junkrat and Pharah. If Mercy heals that damage before the game starts, she doesn't gain ultimate charge (so I've heard). However, does that hold true if she waits for the game to start before healing? Can you just have a Pharah and a Mercy in a corner taking an explosion bath and building ult?


I'm trying to start nginx on my Mac OS X using the command sudo nginx  It fails with the following error  nginx: [emerg] bind() to 0.0.0.0:8080 failed (48: Address already in use) nginx: [emerg] bind() to 0.0.0.0:8080 failed (48: Address already in use) nginx: [emerg] bind() to 0.0.0.0:8080 failed (48: Address already in use) nginx: [emerg] bind() to 0.0.0.0:8080 failed (48: Address already in use) nginx: [emerg] bind() to 0.0.0.0:8080 failed (48: Address already in use) nginx: [emerg] still could not bind()   I try to stop the Apache service by using sudo apachectl stop  This throws me the following error  launchctl: Error unloading: org.apache.httpd   According to  it most likely means that Apache is already not running  Then I tried to figure what is running on the Port 80 using sudo lsof -i:80  This outputs to this  Google    441 jaskaran   68u  IPv4 0xa3f4d891ed1a8373      0t0  TCP 192.168.1.45:50993->www.google:http (ESTABLISHED) Google    441 jaskaran  143u  IPv4 0xa3f4d891ed054b5b      0t0  TCP 192.168.1.45:51017->www.scorecardresearch.com:http (ESTABLISHED) Google    441 jaskaran  150u  IPv4 0xa3f4d891eb9a1b5b      0t0  TCP 192.168.1.45:51018->www.scorecardresearch.com:http (ESTABLISHED) Google    441 jaskaran  152u  IPv4 0xa3f4d891ed1a4373      0t0  TCP 192.168.1.45:51019->www.scorecardresearch.com:http (ESTABLISHED) Google    441 jaskaran  156u  IPv4 0xa3f4d891ed071b5b      0t0  TCP 192.168.1.45:51020->www.scorecardresearch.com:http (ESTABLISHED)   The output to this command keeps on changing with time.  How do I get nginx to work?

I can't make lighttpd listen to port 80.   ~# /etc/init.d/lighttpd start Starting web server: lighttpd2013-03-16 23:15:02: (network.c.379) can't bind to port:  80 Address already in use  failed!   Actually I have apache2 installed on my server, too (listening to port 80) but it is not active.   I used netstat /  netstat -npl but it wasn't helpful  How can I figure out what is using the port?


We have the following use case scenario with a client: - Whenever a new Order is created/registered in Sales Cloud, they want to inject the Client (Business Account) into the journey. There's a few implications to this:  The Order object (standard in SFDC) is the one that should trigger the journey because after the creation of a new Order the Client should be injected into the journey. The problem we have is that we cannot actively choose the Client (Business Account) into the journey, as it does not show up as an option in the "Select WHO enters the journey" list. There is only a "Person Account" option.   We have already tried selecting the "AccountID (PersonAccount)", "CompanyAuthorizedByID (User)" and "OwnerID (User)" options. None yields the results we look for. Choosing "OwnerID (User)" inserts the actual record Owner in SFDC. The other options show 0 Contacts processed/injected. We have already met several times with SF's own CSG (Customer Success) team, and they are investigating on their end. The reason behind using this instead of just an API Event is because the client needs to be able to easily create and configure journeys for different scenarios using Salesforce Data. Creating an API Event for all of their scenarios would be costly and time consuming for them. We are also experimenting with MC Connect Triggered Sends, but that's another story. Anyone's help would be greatly appreciated! Perhaps the almighty MC MVPs could chime in :)

I use as an entry source Salesforce Data. In case i want to target leads, i choose Lead ID everything works properly. Now, i want a journey for Accounts that i have in Salescloud.I tried everything but nothing worked.    I tried also selecting Contact by using Account ID ( PersonAccount)


My Window positions and sizes are never saved. When I open programs like:  Chromium, Code Blocks, XChat, Thunderbird, Skype and others. Set them in a correct location on one of my screens (I have 2x24' monitors), but when I close and open any of the apps again, apps will appear in a default location, with default size. Program that I use the most: Code Blocks. I set up window locations inside of it, set it up as I like, but when I re-run it - everything is reset to default:  Image:   Image:   And this happens to all of the apps.  Please advise how this can be dealt with.

I want my windows to be a specific size (not full screen) and to be in the middle of the screen by default. When I close the application and re-open it, it will be the dimensions I want it to be by default. Is there an easy way to do that? I'm using Ubuntu 11.10 and the Unity desktop enviroment.


Suppose $x$ and $y$ are points on the unit circle such that the line through $x$ and $y$ intersects the real axis. Show that if $z$ is the point where this line intersects the real axis, then  $z = \dfrac{x+y}{xy+1}$.   How should I go about attempting this problem? I am currently struggling to find a starting point (and going through with the entire proof).  Any help is appreciated!

(a) Suppose $p$ and $q$ are points on the unit circle such that the line through $p$ and $q$ intersects the real axis. Show that if $z$ is the point where this line intersects the real axis, then $z = \dfrac{p+q}{pq+1}$.  (b) Let $P_1 P_2 \dotsb P_{18}$ be a regular 18-gon. Show that $P_1 P_{10}$, $P_2 P_{13}$, and $P_3 P_{15}$ are concurrent.  I have gotten nowhere on this problem, but I have a hint:  One of those three segments is more interesting than the other two. Which one, and why? And how can you use that fact to make part (a) relevant?  Any help is appreciated!


If one was to reduce a creature, making them smaller and then casting Otiluke's  around them, what would happen when reduce has ended?  Would the creature get crushed by the sphere due to becoming big again, or would the sphere enlarge itself? If they would take damage, how much and what type?

Let's say that a Medium-size creature is targeted with the reduce part of the  spell, and therefore reduced to a Small size, before being locked inside a container only just about large enough to fit them. What happens to them & the container when the spell ends?  The rules are pretty clear on what happens if you Enlarge into an area that is too small, but not on what happens when a Reduce wears off. If it was adjudicated the same way it effectively gives Reduce an infinite duration, which doesn't seem right.


Even though that there are many recommended personal reading orders about Isaac Asimov's series, novels and short stories, is there any specific chronological order which was specified by Isaac Asimov about his books?

I believe that Asimov himself recommended reading them in chronological order, however I read them in the order that they were published and think that this is the best way to do it.  What is the correct order?


Suppose that $h$ is continuous on $[a,b]$, differentiable on $(a,b)$, and that $c \in (a,b)$. Suppose also that $\lim_{x \to c} h'(x)$ exists. Prove that $h'$ is continuous at $c$.   I have found this answer here  but can't follow the process. Any help/detailed explanations would be REALLY appreciated! I'd rather use L'Hospital Rule instead of the Mean Value Theorem, but I can't follow how to go from one step to the other... Thank you!

Assume that $f$ be continuous on $\mathbb{R}$, $f'(x)$ exists for all $x\neq 0$, and $\lim_{x\rightarrow 0} f'(x)=1$. We need to show $f'(0)$ exist and is equal to $1$.  $f'(0)=\lim_{x\rightarrow 0}\frac{f(x)-f(0)}{x}$, $\lim_{x\rightarrow 0}f'(x)=1\Rightarrow\lim_{x\rightarrow 0}\lim_{h\rightarrow 0}\frac{f(x+h)-f(x)}{h}=1$...am I going in the right direction? Please help.


Here is some code that I got from another website, but I am not able to understand what the <> sign does.  Can someone please explain it?     Dim FldrPicker As FileDialog     Application.ScreenUpdating = False    Application.EnableEvents = False    Application.Calculation = xlCalculationManual     Set FldrPicker = Application.FileDialog(msoFileDialogOpen)     With FldrPicker        .Title = "Select folder:"        .AllowMultiSelect = False        If .Show <> -1 Then GoTo NextCode        myPath = .SelectedItems(1) & "\"    End With

I have seen this before in SQL and VB, I am now reverse engineering an Excel speadsheet and have come across the following formula:   =IF(D23<>0,"Insufficent",0)   I am converting it to ActionScript:    var result:String = [condition] ? 0 : "Insufficient";    but I am unsure of what D23 <> 0 means, is it simply "not equal"?