Lecture 12

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LaTex -- the ultimate "wordprocessor" for technical writing

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• MOTIVATION: The advantages of LaTex become huge whenever your documents become large, or you change your text often: indexing, citations, figure placements, and all this are completely automated. Same if you have to produce a whole bunch of similar documents with the same layout, but slightly different details. Moreover, the typographical qualities of documents produced by LaTeX is infinitely higher than what you get from Word. Of course, you can change the document templates in Word, but that will keep you busy for a while. Another example: student thesis writing. On average, the Word people spend *at least* two months more on the final work of their thesis than the LaTeX people, for the simple reason that towards the end, you change your text a lot, and you want an index, and you have to get your bibliography right, etc. In addition, when preparing their presentations, the Word people typically will go for PowerPoint, which adds another week or two to their time schedule... Another disadvantage of Word: it is not an open standard, and you have problems exchanging documents even between different versions of Word. And compare the file sizes of comparable documents in Word or LaTeX... LaTex requires a bit more time to learn, but it forces you to learn a good approach to making documents.



• So, LaTex is a sophisticated document preparation system, compatable with UNIX. A latex file is a program: in that sense, it is akin to C++. To produce a document, such a PDF file, you will need to compile the source.
  
  
• Here is an example of a typical LaTex input file:

   
  %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
  %%%%% The very basic LaTex document        %%%%%%%
  %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
  
  % specify what kind of document
  \documentclass[12pt]{article}
  
  % upload color fonts
  \usepackage{color}
  
  % use PDF compatable font: looks great on screen
  \usepackage{times}
  
  \begin{document}
  
  The foundations of the rigorous study of \emph{analysis}
  were laid in the nineteenth century, notably by the
  mathematicians Cauchy and Weierstrass. Central to the
  study of this subject are the formal definitions of
  \emph{limits} and \emph{continuity}.
  
  Let $D$ be a subset of $\bf R$ and let
  $f \colon D \to \mathbf{R}$ be a real-valued function on
  $D$. The function $f$ is said to be \emph{continuous} on
  $D$ if, for all $\epsilon > 0$ and for all $x \in D$,
  there exists some $\delta > 0$ (which may depend on $x$)
  such that if $y \in D$ satisfies
  
  \begin{equation}
  |y - x| < \delta 
  \label{eq1}
  \end{equation}
  
  then
  
  
  \textcolor{red}{
  \begin{equation}
  |f(y) - f(x)| < \epsilon. 
  \label{eq2}
  \end{equation}
  }
  
  The above inequalities \ref{eq1} and \ref{eq2} can be used to  
  verify that if $f$ and $g$ are continuous
  functions on $D$ then the functions $f+g$, $f-g$ and
  $f.g$ are continuous. If in addition $g$ is everywhere
  non-zero then $f/g$ is continuous. 
  
  \vspace{0.1in}
  
  Ok,  how about a table? 
  
  \begin{tabular}{|r|r|}
  \hline
  $n$&$n!$\\
  \hline
  1&1\\
  2&2\\
  3&6\\
  4&24\\
  5&120\\
  6&720\\
  7&5040\\
  8&40320\\
  9&362880\\
  10&3628800\\
  \hline
  \end{tabular}
  
  
  
  \end{document}
  
  

• Copy and paste the above into a file try.tex To compile the code (to see it in a "normal" way), do latex try.tex and then again latex try.tex . Now do either xdvi try or dvipdf try to produce PDF file try.pdf which can be opened using acroread or xpdf
  
  
• Anything inside $ $ is treated as "math mode". Math symbols are envoked with \ , e.g. \delta will show up as Greek letter "delta". This one Sum_{i=1}^N is the summation symbol from 1 to N . Here is the integral \int and the square root of 5x: \sqrt{5x} .
  
  
• Anything inside { } is treated as one indivisible entity. Useful for making long sub- or super- scripts.
  
  
• Notice special environment for equations.
  
  
• TABLES: In this example the format specification {|r|r|} after \begin{tabular} specifies that the table should consist of two columns of right-justified text, with vertical lines to the left and to the right of the table, and between columns. Within the body of the table, the command \hline produces a horizontal line; this command can only be placed between the format specification and the body of the table (to produce a line along the top of the table) or immediately after a row separator (to produce a horizontal line between rows or at the bottom of the table). In a tabular environment, the format specification after \begin{tabular} should consist of one or more of the following, enclosed within braces { and }:

      l specifies a column of left-justified text
      c specifies a column of centred text
      r specifies a column of right-justified text
      p{width} specifies a left-justified column of the given width
      | inserts a vertical line between columns
      @{text} inserts the given text between columns
  
  

  Here is more: A short LaTex primer
  
  You can also consider installing a GUI-based helper application such as TEXMAKER (free, works under Linux, Windows or Mac) or WinEdit (Just for Windows. I believe it is not free - as is everything windows related -- but a 30 day trial version is). If you want to run LaTex under windows, you will need to install MikTex .

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