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f o r m a t h T e X Click for: mathTeX homepage download mathTeX |
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f o r m a t h T e X Click for: mathTeX homepage download mathTeX |
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| L a T e X P r a c t i c e B o x |
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Enter any LaTeX math markup you like in the top box. Then press Submit to see it rendered. I've started you out with a little example already in the box. Or you can Click any example image in this tutorial to place its corresponding markup in the box. |
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Now click "Submit" to see your expression
rendered below... |
LaTeX is a word processing programpurists will tell you it's a typesetting system, but for our purposes that's a distinction without a difference that lets you easily write documents containing complicated math. It's the math fragment of LaTeX's markup syntax that we'll briefly review here. Only the most basic features are discussed. And to keep the discussion short, examples sometimes illustrate features not explicitly explained in the text. Use the practice box above to try out anything you think I'm trying to tell you. The references below provide more complete information.
This tutorial accompanies mathTeXit also accompanies
http://www.forkosh.com/mimetex.html for users who can't install
LaTeX on their servers,
a program that uses LaTeX to facilitate
writing math on the web. You write familiar html markup to format
your text, and you write <img> tags containing LaTeX
markup in query strings to format your math. For example,
<img src="/cgi-bin/mathtex.cgi?\sqrt{a^2+b^2}">align="absmiddle" typically gives the best vertical alignment
displays
\small\sqrt{a^2+b^2}
wherever you put that tag.
Many ordinary keyboard characters are rendered just like you'd expect.
For example, typing
a...z,0...9,+-*/=()[]
in LaTeX (or in a mathTeX query string) just renders
\small a...z,0...9,+-*/=()[]
.
But some characters have special LaTeX significance. For
example, underscore b_i introduces a subscript,
rendering
b_i
,
and carat a^n introduces a superscript,
rendering
a^n
.
These and some other special LaTeX characters are discussed
in more detail below.
In particular, the backslash character \ always
introduces special LaTeX symbols like
\alpha,\beta,\gamma...\omega (which renders
\small\alpha,\beta,\gamma...\omega
),
or introduces special Latex commands like
\frac 12 \sqrt \pi (which renders
\small\frac12\sqrt\pi
).
When you want to see a displayed backslash,
type \backslash .
LaTeX special symbols and commands always begin with a
backslash \,
almost alwaysThere's one occasional exception to these rules.
A few LaTeX symbols consist of a backslash followed by a single
non-alphabetic character. Among other keyboard characters,
$,%,& have special LaTeX significance, so to display
them you have to type \$,\%,\& instead,
which renders $,%,&.
followed by one or more
alphabetic characters a-z,A-Z. The symbol or command
is always terminated by a space or by any non-alphabetic character.
For example, \frac2x can be typed without
a space between the \frac and the 2,
correctly rendering
\small\frac2x
.
And \frac\pi2 correctly renders
\small\frac\pi2
.
But \fracx2 is incorrectly interpreted as the
non-existent command \fracx followed by 2, so a space
is mandatory and you must type \frac x2
to render
\small\frac x2
.
As illustrated above, \frac takes two arguments,
and \sqrt takes oneActually, \sqrt accepts an optional
argument in the form, e.g., \sqrt[3]\pi, which renders
the cube root of pi. Several LaTeX commands accept one or more
optional arguments, but that's beyond the scope of this tutorial.
.
Similarly, subscripts
b_i and superscripts a^n
each take one argument. Some commands take no arguments. When needed,
each LaTeX argument is always the next single character following
the command. But any expression enclosed in curly braces is treated
as a single character, and the curly braces are not displayed.
For example, \frac1{\sqrt{a^2+b^2}} renders
\small\frac1{\sqrt{a^2+b^2}}
.
Curly braces must always appear in properly balanced pairs.
Unnecessary pairs of curly braces usually do no harm, so use
them when in doubt. For example, \sqrt{\frac12}
renders
\small\sqrt{\frac12}
.
To display curly braces, type \lbrace...\rbrace
which renders
\lbrace...\rbrace
.
Besides our preceding examples, note that symbols may be
simultaneously subscripted and superscripted. For example,
A_{u,v}^k renders
A_{u,v}^k
.
Also note that sub/superscripts may themselves be
sub/superscripted to any level (though you may want
to reconsider your notation after two levels). For example,
A_{u_i,v_j}^{k_m^n} renders
A_{u_i,v_j}^{k_m^n}
.
Limits (lower and upper bounds) are written just like subscripts and superscripts. For example,
To make sure limits are displayed directly below and above the operator, begin your expression with \displaystyleA lengthier discussion involving the several LaTeX directives \displaystyle, \textstyle, \limits and \nolimits is beyond the scope of this tutorial. . For example,
Enclosing terms in ordinary parentheses doesn't always look good. For example,
Instead, the LaTeX commands \left( ... \right) automatically size parentheses, and other delimiters, to match the enclosed term. For example,
Ordinary parentheses (...) don't have to be balanced, but \left(...\right) must always appear in properly balanced pairs. And any number of \middle| commands may appear between a \left(...\right) pair, to size contained delimiters similarly (see the third and fourth examples below). Besides \left(...\middle|...\right), the following delimiters can also be automatically sized:
| Delimiter | example... | ...renders |
| \left( ... \right) | \left( \frac1{1-x^2} \right)^2 |
|
| \left[ ... \right] | \left[ \frac1{\sqrt2}x-y \right]^2 |
|
| \left\{ ... \right\} | \left\{ x \in \mathbb{R} \middle| x \geq \frac12 \right\} |
|
| \left\langle ... ... \right\rangle |
\left\langle \varphi \middle| \hat{H} \middle| \phi \right\rangle |
|
| \left| ... \right| | \left| \begin{matrix} a_1 & a_2 \\
b_1 & b_2 \end{matrix} \right| |
|
| \left\| ... \right\| | \left\| x^2-y^2 \right\| |
|
| \left\{ ... \right. | y = \left\{
{\text{this}\atop \text{that}} \right. |
|
| \left. ... \right\} | \left.
{\text{this}\atop \text{that}} \right\} = y |
|
Note the last two examples. Any left delimiter can be balanced with a matching \right. and any right delimiter can be balanced with a preceding \left. The . delimiter balances its mate but displays nothing, which lets you format math expressions like the last two illustrated above. The \text{ } and { \atop } commands from those examples are discussed below.
Use the LaTeX "math accent" \vec{ }
to write vectors. For example, \vec{v}
renders \vec{v}
.
Some accents have a wide counterpart, used when its
argument contains more than a single character.
Among the accents LaTeX recognizes are the following:
| Accent | example... | ...renders |
| \vec{ } | \vec{x} |
|
| \hat{ } | \widehat{ABC} |
|
| \tilde{ } | \widetilde{ABC} |
|
| \dot{ } | \dot{\omega} |
|
| \ddot{ } | \ddot{\omega} |
|
Note that accents can be composed, e.g.,
\dot{\vec{x}}
renders \dot{\vec{x}}
.
While not strictly accents, the following one-argument commands are also very useful. They have no wide counterparts: \not{ } accepts only a single-character argument, whereas \cancel{ }, \sout{ }, \overline{ } and \underline{ } all accept one or more characters.
| Command | example... | ...renders |
| \not{ } | a \not= b |
|
| a \not\in \mathbb{Q} |
| |
| \cancel{ } | \cancel{ABC} |
|
| \sout{ } | \sout{$ABC$} |
|
| \overline{ } | \overline{ABC} |
|
| \underline{ } | \underline{ABC} |
|
While also not accents, the following two-argument commands are similarly useful. Note that \overbrace{ }^{ } requires a carat ^ between its two arguments, whereas \overset{ }{ } doesn't. Similarly, \underbrace{ }_{ } requires an underscore _, whereas \underset{ }{ } doesn't.
| Command | example... | ...renders |
| \overbrace{ }^{ } | \overbrace{a,...,a}^{\text{k a's}} |
|
| \underbrace{ }_{ } | \underbrace{b,...,b}_{\text{l b's}} |
|
| \overset{ }{ } | a \overset{\text{def}}{=} b |
|
| \underset{ }{ } | c \underset{\text{def}}{=} d |
|
You can usefully combine
\overbrace{ }^{ } and
\underbrace{ }_{ } so that, for example,
\underbrace{\overbrace{a...a}^{\text{k a's}},
\overbrace{b...b}^{\text{l b's}}}_{\text{k+l elements}}
renders
\underbrace{\overbrace{a...a}^{\text{k a's}},
\overbrace{b...b}^{\text{l b's}}}_{\text{k+l elements}}
.
Writing sin^2\theta+cos^2\theta renders
sin^2\theta+cos^2\theta
, whereas
\sin^2\theta+\cos^2\theta renders
\sin^2\theta+\cos^2\theta
.
Several dozen common function names are recognized by LaTeX as
backslashed commands, and rendered in a roman font that's more
typical mathematical notation. And some of these function name
commands like \lim render subscripts more
typically, too. For example, \lim_{x\to\infty}\frac1x=0
renders
\lim_{x\to\infty}\frac1x=0
.
The most common LaTeX function name commands are listed below.
Those that treat subscripts like \lim are
followed by an underscore, e.g., \lim_.
| \arccos | \arcsin | \arctan | \arg | \cos |
| \cosh | \cot | \coth | \csc | \deg |
| \det_ | \dim | \exp | \gcd_ | \hom |
| \inf_ | \ker | \lg | \lim_ | \liminf_ |
| \limsup_ | \ln | \log | \max_ | \min_ |
| \Pr_ | \sec | \sin | \sinh | \sup_ |
| \tan | \tanh |
The easiest way to write a matrix in LaTeX is
\begin{matrix} a&b\\c&d \end{matrix}
which renders
\begin{matrix} a & b \\ c & d \end{matrix}
.
Surround it with \left( ... \right)
to obtain
\left(\begin{matrix} a & b \\ c & d \end{matrix}\right)
.
Alternatively, \begin{pmatrix} ... \end{pmatrix}
automatically surounds the rendered matrix with parentheses.
Matrices are written row-wise, with \\ at the end of each row. Within a row, columns are separated by &. A general m x n matrix is therefore written in the form
| \begin{matrix} | |||||||
| a1,1 | & | a1,2 | & | . . . | & | a1,n | \\ |
| a2,1 | & | a2,2 | & | . . . | & | a2,n | \\ |
| . . . | . . . | . . . | . . . | . . . | . . . | . . . | \\ |
| am,1 | & | am,2 | & | . . . | & | am,n | |
| \end{matrix} |
Each component ai,j can contain
any valid LaTeX markup whatsoever, even another matrix.
If you write & &,
the corresponding component is left blank. For example,
\begin{pmatrix} a&\\&b \end{pmatrix}
renders the diagonal 2 x 2 matrix
\left(\begin{matrix} a & \\ & b \end{matrix}\right)
.
You can terminate a row with \\ anytime,
so the preceding a&\\&b can
been written a\\&b.
And you can write (lower left) triangular matrices without
strings of empty & & &'s.
More general than \begin{matrix}......\end{matrix} illustrated above is the alternative \begin{array}{lcr}......\end{array} which requires that extra {lcr}-style argument specifying how to center elements in each column. The three one-letter choices stand for left or center or right, and you supply one letter for each column in your array. Thus, \begin{array}{lcr}......\end{array} specifies a three-column array, any number of rows, with elements in the first column left-justified, elements in the second centered, and elements in the third column right-justified. Note that \begin{matrix}......\end{matrix} is equivalent to \begin{array}{ccc...}......\end{array}, with enough c's to accommodate your array.
Suppose you want to display four simultaneous equations. That can be done with a four-row, three-column {rcl} array whose second column always contains an = sign, first column the left-hand side of an equation, and third column the right-hand side. For example,
| \begin{array}{rcl} | ||||
| a + b + c + d | & | = | & | 4 \\ |
| 2a - d | & | = | & | b + c \\ |
| 2b | & | = | & | c + d - a \\ |
| c - d | & | = | & | b - 2a |
| \end{array} |
renders
Or, for another example, to illustrate some simple algebra you can leave the first column empty after the first row, rendering (hover over or click the image to see its markup)
LaTeX provides various additional methodsFor example, \begin{align}......\end{align} more readily aligns multi-line equations than \begin{array}{rcl}......\end{array} illustrated above. to display array-type data that you may find useful. But a lengthy discussion is beyond the scope of this tutorial.
LaTeX does its own spacing, and spaces that you type yourself
are never displayed. For example, (abcd),
(a bcd), (a b cd)
and (a b c d)
all render the same
(a b c d)
.
To explicitly embed displayed space, LaTeX provides several commands
including
\, \: \; \quad \qquad,
and also a backslashed blank
\backslash\underline{\ }
(i.e., a \ followed by a blank).
These commands take no arguments. For example,
(a\,b\:c\;d\ e\quad f\qquad g)
renders
(a\,b\:c\;d\ e\quad f\qquad g)
.
For arbitrary embedded space, the
command \hspace{ } takes a single
numerical argument that specifies the width of the embedded space
(in "points").
For example, (ab\hspace{9pt}cd\hspace{25pt}ef)
renders
(ab\hspace{9pt}cd\hspace{25pt}ef)
.
Typing abcdef renders
abcdef
in LaTeX's default math font. To intersperse explanatory text,
\text{abc def} or
\mbox{def ghi}
renders
\small\mbox{abc def}
in non-mathematical roman font. Note that embedded spaces
are respected. For example,
LaTeX commands that select font size are \tiny, \small, \normalsize (the usual default), \large, \Large, \LARGE, \huge and \Huge. But these commands are usually not permitted within math markup. MathTeX permits these font size commands by moving them outside the math markup. For example,
| \tiny\sqrt{a^2+b^2} | renders |
|
| \small\sqrt{a^2+b^2} |
| |
| \normalsize\sqrt{a^2+b^2} |
| |
| \large\sqrt{a^2+b^2} |
| |
| \Large\sqrt{a^2+b^2} |
| |
| \LARGE\sqrt{a^2+b^2} |
| |
| \huge\sqrt{a^2+b^2} |
| |
| \Huge\sqrt{a^2+b^2} |
|
These size directives affect the entire expression. There's no easy way to render a single expression at several different sizes, e.g., \frac {\small a}{\large b} won't work.
Here are several examples further demonstrating LaTeX features and usage. Some of the illustrated features haven't been discussed in this tutorial, and you'll have to consult the references for an explanation. To see how the examples are done, Click any one of them to place its corresponding markup in the Practice Box above. Then press Submit to re-render it, or you can edit the markup first to suit your own purposes.
You've already seen several LaTeX symbols like \alpha, \beta and \omega, and several LaTeX commands like \frac, \sqrt and \sum. The Comprehensive LaTeX Symbol List illustrates over 4,900 symbols supported by LaTeX. Some of the basic math symbols and operators are illustrated in the following tables.
Simply typing a-z,A-Z renders characters
a-z,A-Z
in LaTeX's default math font, while typing
\mathbf{a-z,A-Z} renders
\mathbf{a-z,A-Z}
in bold math font. And typing \text{a-z,A-Z}
renders characters
\text{a-z,A-Z}
in roman font. Spaces inside \text{ }
are rendered exactly as typed, for example,
\text{this is a test} renders
\text{this is a test}
.
LaTeX supports many useful fonts besides math and roman. Among these are
| Blackboard bold: | \mathbb{A-Z} | renders |
|
| Calligraphic: | \mathcal{A-Z} |
| |
| Script: | \mathscr{A-Z} |
|
You'd typically type only one character at a time in these fonts.
For example,
x\in\mathbb{R}_+ renders
x\in\mathbb{R}_+
.
But, just like \text{ }, any number of
characters is permitted between the { }'s.
Characters from the Greek alphabet supported by LaTeX.
Some operatorsBesides \int illustrated here, similarly
promoted operators include \oint, \iint, \sum,
\prod, \coprod, \oplus, \otimes,
\odot, \uplus, \wedge, \vee,
\cup, \cap, and \sqcup.
shown below
are automatically "promoted" to a larger size in
LaTeX's \displaystyle mode. For example,
f(x)=\int_{-\infty}^x e^{-t^2}dt renders
\textstyle f(x)=\int_{-\infty}^x e^{-t^2}dt
,
whereas
\displaystyle f(x)=\int_{-\infty}^x e^{-t^2}dt
renders
\displaystyle f(x)=\int_{-\infty}^x e^{-t^2}dt
.
The arrangement of symbols in the tables will be improved in a future version of this tutorial.
This tutorial discusses LaTeX's mathematical markup capabilities, ignoring the preparation of documents containing formatted text. Most references explain LaTeX's mathematical markup, but emphasize the preparation of complete documents. The TeX Users Group provides lists of online resources and book resources that you may find useful.
Among the online resources, the two pages Latex Math I and Latex Math II comprise another short LaTeX math tutorial. And The not so Short Introduction to LaTeX is a good general online LaTeX reference.
If you're only interested in LaTeX for online mathematical markup (and not for document preparation), then you may not want to invest the time and money that books entail. But in case you do want a book, try to browse as many as you can, and then choose the one or two you personally like best. Among the book resources, here are a few you might want to look at:
Intermediate: A Guide to LaTeX2e, 4th ed. is authoritative and easy to read, with a good math discussion.
Advanced: at 1100 pages it's not a suitable tutorial or first book, but the most comprehensive LaTeX reference available is, The LaTeX Companion, 2nd ed., Frank Mittelbach and Michel Goossens, Addison-Wesley 2004, ISBN 0-201-36299-6 ($59.99).
Math: Math into LaTeX, 3rd ed., George Gratzer, Birkhauser Boston 2000, ISBN: 0-8176-4131-9 emphasizes math. Portions of the first edition are available online.
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email: john@forkosh.com |
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