I frequently get this with no way to go on:   This is pdfTeX, Version 3.14159265-2.6-1.40.19 (MiKTeX 2.9.6730 64-bit) entering extended mode (C:/Users/Eckert/Documents/texzeta.txt ! Undefined control sequence. l.1 \documentclass                   {article} ?     I thought the \documentclass{article} was a mandatory first line?
Very new to Tex. Trying to get the most basic doc to work. Not matter what I do I always get an "Undefined control sequence" at line 1 of my document. As of now, I am only trying to build the following:  \documentclass{article} \begin{document} This is a test of the article \end{document}   Full error is:  This is pdfTeX, Version 3.1415926-2.5-1.40.14 (TeX Live 2013)  restricted \write18 enabled. entering extended mode (./example.tex ! Undefined control sequence. l.1 \documentclass                   {article} ?   I have tried many other variations, including \usepackage directives that people mentioned - nothing every varies.
Why isn’t the definite article used in "The commission commanded that work [...] should cease"? In this sentence:     The commission commanded that work on the building should cease.   Why isn't the used before the word work? It seems that the work is specified by on the building.  Another example is,     Construction of the building will start next week.   I understand construction here is something like putting up the building, and so the construction isn’t general in meaning. But the definite article isn’t used here, either.  I’ve asked about this several times, but none gave me a good answer. ACPI PPC Probe failed. Starting version 219 NVIDIA How to force the user to download a file, not to view it? Why is $\alpha \rightarrow \forall x(\alpha)$ not generally correct in first-order logic? Why is $\alpha \rightarrow \forall x(\alpha)$ not generally correct in first-order logic?  i.e., when there are free occurrences of $x$ in $\alpha$, and, on the same point, why is the formula scheme correct when there are no free occurrences of $x$ in $\alpha$? Finding determinant of matrix without expanding What is a terminal? How do I open a terminal window? How do I use the terminal? Add new item in existing array in c#.net How to add new item in existing string array in C#.net?  I need to preserve the existing data. I know standing in line to get a visa is never fun, but was wondering if any Americans had experience getting a standard tourist "L" visa in Hong Kong.   I'm leaving on a RTW trip in less than two weeks and I plan on being in China around June. So I either need to get a 6 or 12 month multi-entry visa before I leave the USA - which would entail booking all my flights and accommodation and securing an invitation letter in the next few days - or just fly to Hong Kong before going to China in June.   Hong Kong seems like the simplest answer, but China usually doesn't allow Americans to get visas outside of their home country (HK seems to be an exception). I just wanted to know if any Americans had done it successfully.  Update: The Chinese Visa Office in HK currently has this notice on their website: "If you don't reside or work in Hong Kong permanently, you are required to apply Chinese visa from the Embassy or Consulate-General of Peoples' Republic of China in your resident country." It seems practices may have changed. Any Americans with experience care to contradict this?  Link: Cann I use a 19.5V 4.62A laptop charger for 19V 4.74A laptop? I host am ExpressionEngine based website on a single Amazon EC2 instance in the US East (Virginia) region. I use Ubuntu.    The website allows members to post their content, and displays it for other members and for users who are not logged in.   Goal: I need to begin serving the same website across the globe, equally fast to Hong Kong, New York, and Los Angeles.   I considered two solutions:  1.Setting up three separate EC2 instances for three regions: Virginia, Oregon, and Singapore. Use Amazon Rot53 Geo Location to direct traffic to instances based on the browser's IP address.   Pro: the website will load fast for the region.   Contra: these will be essentially three separate websites. Unless I am mistaken?   Setting up one instance in a region equally remote from all three locations: (Ireliand), and boost the server to the highest performance available.    Pro: It will be the same website for all regions.   Contra: it will cost a lot to make it fast enough.   My challenges:   a) I do not know a way to sync server settings, database, and content between multiple Ubuntu instances in real time. If a knowledgeable person could explain to me how to do that, I would be most grateful.   b) I am not thoroughly familiar with all Amazon AWS resources. Does AWS has a built-in method that would allow me to achieve my goal of serving a single PHP / MySQL based membership website across the globe equally fast in all three chosen locations? On September 29th, I created the  tag for  Today, while checking the tag description, I saw that the  seems to be .  Why is that? Why has the Community user "stolen" the spot as author of the tag? The new Top-Bar does not show reputation changes from Area 51. Is it true that for algebraic sets $V,W$ we have $I(V \times W ) =I(V) + I(W)$? This is a follow up question to my previous question  Let $k$ be a field and $V \subseteq \Bbb{A}^n$ and $W \subseteq \Bbb{A}^m$ be algebraic sets. Then it should be true that $I(V \times W ) = I(V) + I(W)$ where by $I(V)$ here we mean the extension of $I(V)k[x_1,\ldots,x_{m+n}]$. Now I believe I have proven this (see the proof at the bottom of my question) but when I look at Martin's answer , it is instead claimed that we  actually have  $$I(V \times W )= \sqrt{I(V) + I(W)},$$  and for $I(V) + I(W)$ to be a radical ideal we need $k$ to be algebraically closed.           My question is: What's going on here? I believe my claim is true even without the assumption that $k$ is algebraically closed.           Here's a proof user Sanchez told me of, which I have simplified:       First it is clear that we always have $I(V) + I(W) \subseteq I(V \times W)$. For the reverse inclusion consider a polynomial $f \in I(V \times W)$. Then we can always write $$f = \sum_{i=1}^n f_ig_i$$ where $f_i \in k[x_1,\ldots,x_n]$ and $g_i \in k[x_{n+1},\ldots,x_{m+n}]$. Now take any $b' \in W$. If for all $i$ we have $g_i(b') = 0$ then since $b'$ is arbitrary, $g_i \in I(W)$ for all $i$. Then $f \in I(W) \subseteq I(V ) + I(w)$ and we are done. Otherwise suppose there exists $b \in W$  and $i$ such that $g_i(b) \neq 0$. Then wlog we may suppose that  $g_1(b) \neq 0$.   Next, $\sum f_ig_i(b) = 0 $ on all of $V$ by assumption of $f \in I(V \times W)$. So $\sum f_i g_i(b) = p$ for some $p \in I(V)$. Now write $$f_1 = \frac{ p - g_2(b) f_2 + \ldots g_n(b)f_n}{g_1(b)}.$$  Substituting this for $f_1$ in $\sum f_ig_i$, followed by taking things mod $I(V)$ we get an  expression with only $n-1$ terms $\mod{I(V)}$. Continuing this process we will finally get an expression with $0$ terms $\mod{I(V)}$ so that $f \in I(V)$. This shows $I(V \times W) \subseteq I(V) + I(W)$ which completes the proof. Where does Minecraft for Windows 10 store its data? Is Dexterity overpowered compared to Strength? count() returns a different amount than a simple select For QA workstations preparation (Windows-based PCs) our IT department uses typical batch deployment tools. I'm not at all interested in the details of such process, but IT guys ask me:  What typical set of software you need for everyday manual testing tasks? We could include these in our deployment so that you guys could save more time for testing, not for environment prep &amp; tuning.  Sure thing we do test various range of projects, from web applications to standalone solutions, and each application requires its own set of tools for manual testing, e.g.:  Browsers Virtualization utilities DB clients Screens capturing tools FTP clients XML editors etc.  However, and that's for sure - there's a list of tools every QA MUST have installed on its PC, regardless of project types under testing. My area of experience is mostly standalone / complex web apps, that's why my vision on the task is a bit subjective. So, your suggestions of what are tools / software an average QA specialist can't live without will be highly appreciated. 2 assumptions:  Manual testing is a point of interest. Let's limit the list to not more than 15 (better 10) items.  Thanks in advance! Evaluate the limit of $\lim_{n\to\infty}\frac{1}{n^2}\left(\frac{2}{1}+\frac{9}{2}+\frac{64}{9}+\cdots+\frac{(n+1)^{n}}{n^{n-1}}\right)$ How can I change the default date format? When I paste a date into Excel 2010 in the format "2012-12-07 00:00:00.000" I'd like it to be displayed by default as "2012-12-07", but it is actually displayed as "00:00.0".   I know I can work around this by prepending a ' or changing the cell format, but I'm interested in changing the default format.  An approach that almost works is going to Control Panel->Region and Language->Long Time format and changing it to something like "h". This results in Excel displaying the dates I paste in as "2012-12-07 00:00:00.000", but screws up times displayed outside of Excel.  The dates I'm pasting in are from SQL Server. sort() and reverse() functions do not work