Missing `]' shell error
Brackets in if condition: why am I getting syntax errors without whitespace?
Dubai (UAE) visa requirements when staying in the airport for a French citizen? Change pivot or local origin of an object If $p$ is prime, then $(x+y)^p=x^p+y^p$ holds in any field of characteristic $p$. However all the proofs I have seen use induction and some relatively nasty algebra despite how fundamental this fact seems.  What is the nicest, "highest level proof" you know? If for two suitable matrices $B$ and $C$, $AA^TB=AA^TC$ can we conclude that $A^TB=A^TC$? Let $A$ be a $m\times n$ real matrix. If for two suitable matrices $B$ and $C$, $$AA^TB=AA^TC$$ can we conclude that $A^TB=A^TC$?  I know $AA^T$ is a symmetric matrix. Every real symmetric matrix is diagonalizable. But I am not sure how to use this information. Thanks for reading and helping me out with hints. What's the best blog post/video/tweet/whatever to explain how the Stack Exchange system works to regular people? I am trying to gauge interest for a new Stack Exchange site, but I want to explain it to people as best (and preferably) as visually as I can. Any YouTube clips breaking it down?  anyone?  Note: I am fully aware of , but mine is about Stack Exchange, not Stack Overflow.  Most people think I'm describing traditional forum software, which they know sucks. Is there some way to describe the magic of how the design of the Stack Exchange system actually produces useful results very quickly? I can describe generally that it is a Q&amp;A site that users vote on the answers, but Stack Overflow feels like so much more. Am I perhaps thinking too big about this? Moderncv package - cventry date width I am writing my CV using moderncv package, everythig is nice but I have a problem with \cventry command. I have something like this:   (it means 2010 - now)  I would want to have this in one line, rather than in two lines. I tried looking into the moderncv style files but with no success. What can I do to achieve the effect I want? How to send emails and avoid them being classified as spam? This is a  about how to handle email sent from your server being misclassified as spam.  For additional information you may find these similar questions helpful:                    Sometimes I want to send newsletters to my customers. The problem is, that some of the emails get caught as spam messages. Mostly by Outlook at the client (even in my own Outlook 2007).  Now I want to know what should be done to create "good" emails. I know about reverse lookup etc., but (for example), what about a unsubscribe link with an unique ID?  Does that increase a spam rating? How to find $\partial\chi^2/\partial a$ where $\chi^2=\sum_{i=1}^N\dfrac{D(x_i)-a-b(x_i)^2}{\sigma_i^2}$?  My attempt: \begin{align} \dfrac{\partial}{\partial a}\sum_{i=1}^N\dfrac{D(x_i)-a-b(x_i)^2}{\sigma_i^2} &amp;= \dfrac{\partial}{\partial a}\sum_{i=1}^N\dfrac{D(x_i)-b(x_i)^2}{\sigma_i^2}-\sum_{i=1}^N\dfrac{-a}{\sigma_i^2}\\ &amp;=\sum_{i=1}^N\dfrac{D(x_i)-b(x_i)^2}{\sigma_i^2}-\dfrac{\partial}{\partial a}\sum_{i=1}^N\dfrac{-a}{\sigma_i^2}\\ &amp;=\sum_{i=1}^N\dfrac{D(x_i)-b(x_i)^2}{\sigma_i^2}-\dfrac{1}{\sigma_i^2}\cdot\dfrac{\partial}{\partial a}\sum_{i=1}^N-a\\ &amp;=\sum_{i=1}^N\dfrac{D(x_i)-b(x_i)^2}{\sigma_i^2}-\dfrac{1}{\sigma_i^2}\cdot\dfrac{\partial}{\partial a}a^N\\ &amp;=\sum_{i=1}^N\dfrac{D(x_i)-b(x_i)^2}{\sigma_i^2}-\dfrac{1}{\sigma_i^2}\cdot N\cdot a^{N-1}\\ \end{align}  Is this correct?  EDIT: As per the accepted answer, this is how I got my final partial derivative. \begin{align}             \dfrac{\partial}{\partial a}\sum_{i=1}^N\dfrac{D(x_i)-a-b(x_i)^2}{\sigma_i^2} &amp;= \dfrac{\partial}{\partial a}\Bigg[\sum_{i=1}^N\dfrac{D(x_i)-b(x_i)^2}{\sigma_i^2}-\sum_{i=1}^N\dfrac{-a}{\sigma_i^2}\Bigg]\\             &amp;=\dfrac{\partial}{\partial a}\Bigg[\sum_{i=1}^N\dfrac{D(x_i)-b(x_i)^2}{\sigma_i^2}\Bigg]-\dfrac{\partial}{\partial a}\Bigg[\sum_{i=1}^N\dfrac{-a}{\sigma_i^2}\Bigg]\\             &amp;= 0-\dfrac{\partial}{\partial a}\Bigg[\dfrac{-a}{\sigma_1^2}+\dfrac{-a}{\sigma_2^2}+\cdots+\dfrac{-a}{\sigma_N^2}\Bigg]\\             &amp;= -\Bigg[\dfrac{\partial}{\partial a}\Bigg[\dfrac{-a}{\sigma_1^2}\Bigg]+\dfrac{\partial}{\partial a}\Bigg[\dfrac{-a}{\sigma_2^2}\Bigg]+\cdots+\dfrac{\partial}{\partial a}\Bigg[\dfrac{-a}{\sigma_N^2}\Bigg]\Bigg]\\             &amp;= -\Bigg[\dfrac{-1}{\sigma_1^2}\cdot\dfrac{\partial}{\partial a}[a]+\dfrac{-1}{\sigma_1^2}\cdot\dfrac{\partial}{\partial a}[a]+\cdots+\dfrac{-1}{\sigma_N^2}\cdot\dfrac{\partial}{\partial a}[a]\Bigg]\\             &amp;= -\Bigg[\dfrac{-1}{\sigma_1^2}+\dfrac{-1}{\sigma_2^2}+\cdots+\dfrac{-1}{\sigma_N^2}\Bigg]\\             &amp;= \sum_{i=1}^{N}\dfrac{1}{\sigma_i^2}\\         \end{align} How to prove that $\lim\limits_{h \to 0} \frac{a^h - 1}{h} = \ln a$ In order to find the derivative of a exponential function, on its general form $a^x$ by the definition, I used limits.  $\begin{align*} \frac{d}{dx} a^x &amp; = \lim_{h \to 0} \left [ \frac{a^{x+h}-a^x}{h} \right ]\\  \\ &amp; =\lim_{h \to 0} \left [ \frac{a^x \cdot a^h-a^x}{h} \right ] \\  \\  &amp;=\lim_{h \to 0} \left [ \frac{a^x \cdot (a^h-1)}{h} \right ] \\  \\ &amp;=a^x \cdot \lim_{h \to 0} \left [\frac {a^h-1}{h} \right ] \end{align*}$  I know that this last limit is equal to $\ln(a)$ but how can I prove it by using basic Algebra and Exponential and Logarithms properties? Thanks So a company decides to raise money by selling shares of its stock. The stock is offered at an initial price of their determination. The stock is then traded in a market where forces of supply and demand, as well as speculation, affect its price.  When a company performs well (or makes decisions that will likely increase the company's earnings in the future), more people want to buy that stock than do people wanting to sell it. This creates demand for that stock which causes its sell/bid prices rise. When a company performs poorly, the opposite occurs; more people want to sell the stock than want to buy. This creates a surplus that causes sell/bid prices to fall.  Understanding this, people speculate over company performance to determine the future behavior of a stock, and attempt to "buy low, sell high" or "borrow high, return low" in order to make a profit.  But my question is regarding the first part of that process. What is it about company performance that causes the perceived value of its stock to rise? This is especially perplexing since I would guess that most people don't exercise their voting rights, and many stocks don't pay dividends.  It's not like a shareholder has any direct financial gains from increased company earnings (speculative stock pricing notwithstanding).  What is the intrinsic value of the stock?  It seems to me that all participants in a stock market tacitly agree that stock price will have a direct correlation with company performance. So another way of asking the question is, would an opposite agreement hold? What financially (this isn't a question about logistics, communication, or feasibility) stops all participants in a market from agreeing to value a particular company's stock inversely with respect to the company's performance?  Since I feel like I can't quite nail down my question, another form of it would be, why is stock market behavior driven by company performance? How to replace ${} placeholders in a text file? I want to pipe the output of a "template" file into MySQL, the file having variables like ${dbName} interspersed. What is the command line utility to replace these instances and dump the output to standard output? Is $C[0,1]$ a Banach space for the $L^1$ norm? Is $C[0,1]$ a Banach space with respect to the norm $\|f\| = \int\limits_0^1|f(t)| \, dt$?   People keep telling me it is, but lets consider: $f_n(x) = x^n$. This function defines a Cauchy sequence, yet the limit clearly isn't a continuous function! How to create a page like this? I'm a LaTeX newbie. I want to create a page layout like in the picture below on every page.  Can someone help please? Thanks. What happens when you run out of movement while jumping? What's in an Eclipse .classpath/.project file? What's the main difference between Intel processor generations? What are the main differences between each processor generation of Intel processors/chipsets? Is there a performance difference?  I've already seen processors from first to sixth generation, however I don't know/understand the exact differences. Can somebody help me with the execute commands in Minecraft? Recently, Minecraft had removed the /testfor command, which broke these sets of commands that I was trying to execute today.  /testfor @p[r=10] {SelectedItem:{id:"minecraft:feather",tag:{display:{Name:"Roc's Feather",Lore:[Jump higher using this feather.]}}}}`   Now normally, from Minecraft 1.13 onwards, the new /execute command would've been the replacement for the /testfor command, but as I soon found out, the command failed to detect my Roc's Feather and thus could not execute an /effect command that gave me a Jump Boost, for 1 second, at level 3.  I tried remaking my feather from scratch with this command here:  /give @p minecraft:feather{display:{Name:"{\"text\":\"Roc's Feather\",\"color\":\"light_purple\",\"bold\":true,\"italic\":true,\"underlined\":false,\"strikethrough\":false,\"obfuscated\":false}",Lore:["{\"text\":\"Jump higher using this feather.\",\"bold\":false,\"italic\":true,\"underlined\":false,\"strikethrough\":false,\"obfuscated\":false}"]}} 1   But the execute command I placed did not detect this type of uniqueness.  /execute if entity @p[distance=10,nbt={SelectedItem:{id:"minecraft:feather",Count:1b,tag:{display:{Name:"{\"text\":\"Roc's Feather\",\"color\":\"light_purple\",\"bold\":true,\"italic\":true,\"underlined\":false,\"strikethrough\":false,\"obfuscated\":false}",Lore:["{\"text\":\"Jump higher using this feather.\",\"bold\":false,\"italic\":true,\"underlined\":false,\"strikethrough\":false,\"obfuscated\":false}"]}}}}] run effect give @s minecraft:jump_boost 1 3 true   Can somebody tell me what I'm doing wrong here because I cannot even tell what's the issue. What's the difference between using black and white mode in-camera, and converting in post? For black and white photography, will there be any quality difference between using the built-in black and white mode, or shooting in color initially and then removing the color later using Photoshop (or similar application)?  I have a high-end compact camera, the . Chat Feature-Request: Thumbs-Up Add an additional form of "I agree" besides starring or pinning (since pinning is restricted to a smaller subset to begin with) or something that we can use to not clog up the right hand star bar.  This is because sometimes you want to say "I agree" but you don't want to star it because ... let's face it, that's not star-worthy, and you don't want to clutter the stream with fifty thousand "like totes for sure, hella right!" because then it becomes one big back-patting party and you lose all semblance of conversation.  So I would propose a fourth "flag" for chat, that allows us to say "I {agree with|like|am of the same opinion as} this comment" and that it would only be useful in the live-chat (and maybe but not really in the transcript) and that it have no other useful semantics (no badges, no list of's [unless the list is of comments you've upthumbed]). Solving multiple congruences by CRT = Chinese Remainder Theorem How do I get the solution given by CRT to match another solution, e.g. the least positive? For example say I have X = 1234. I choose mi as 5, 7, 11, 13. This satisfies the simple requirements of . More precisely given in my example k = n = 4, and the product of any k - 1 is smaller then X how come simply computing the remainder of each won't give equations that solve to X = 1234. In the case of the example, x = 4 mod 5 x = 2 mod 7 x = 2 mod 11 x = 12 mod 13  Which resolves to  (won't CRT produce the smallest?) Any hints?  Below is the solution linked to on &quot;Math Celebrity&quot; (cached to avoid link rot).