In addition to the align* environment shown in the main lesson,
amsmath has several other display math constructs, notably gather
for multi-line displays that do not need alignment, and multline for
splitting a larger single expression over multiple lines, aligning the
first line to the left, and the last to the right. In all cases the *
form omits the equation numbers by default.
\documentclass[a4paper]{article}
\usepackage{amsmath}
\begin{document}
Gather
\begin{gather}
P(x)=ax^{5}+bx^{4}+cx^{3}+dx^{2}+ex +f\\
x^2+x=10
\end{gather}
Multline
\begin{multline*}
(a+b+c+d)x^{5}+(b+c+d+e)x^{4} \\
+(c+d+e+f)x^{3}+(d+e+f+a)x^{2}+(e+f+a+b)x\\
+ (f+a+b+c)
\end{multline*}
\end{document}
The amsmath alignment environments are designed to take pairs of
columns with the first column of each pair aligned to the right and
the second aligned to the left. This allows multiple equations to be
shown, each aligned towards its relation symbol.
\documentclass{article}
\usepackage{amsmath}
\begin{document}
Aligned equations
\begin{align*}
a &= b+1 & c &= d+2 & e &= f+3 \\
r &= s^{2} & t &=u^{3} & v &= w^{4}
\end{align*}
\end{document}
In addition there are variants of the display environments ending
in ed that make a subterm of a larger display for example, aligned and
gathered.
\documentclass{article}
\usepackage{amsmath}
\begin{document}
Aligned:
\[
\left.\begin{aligned}
a&=b\\
c&=d
\end{aligned}\right\}
\Longrightarrow
\left\{\begin{aligned}
b&=a\\
d&=c
\end{aligned}\right.
\]
\end{document}
aligned takes a positional optional argument similar to tabular.
This is often useful to align an inline math formula on its top row;
compare the items in the list in the following example.
\documentclass{article}
\usepackage{amsmath}
\begin{document}
\begin{itemize}
\item
$\begin{aligned}[t]
a&=b\\
c&=d
\end{aligned}$
\item
$\begin{aligned}
a&=b\\
c&=d
\end{aligned}$
\end{itemize}
\end{document}
Standard LaTeX has two methods to give bold symbols in math. To make
an entire expression bold, use \boldmath before entering the
expression. The command \mathbf is also available to set individual
letters or words in upright bold roman.
\documentclass[a4paper]{article}
\begin{document}
$(x+y)(x-y)=x^{2}-y^{2}$
{\boldmath $(x+y)(x-y)=x^{2}-y^{2}$ $\pi r^2$}
$(x+\mathbf{y})(x-\mathbf{y})=x^{2}-{\mathbf{y}}^{2}$
$\mathbf{\pi} r^2$ % bad use of \mathbf
\end{document}
If you want to access bold symbols (as would be used by \boldmath)
within an otherwise normal weight expression, then you can use the
command \bm from the bm package. Note that \bm also works with
symbols such as = and Greek letters. (Note that \mathbf has no effect
on \pi in the example above.)
\documentclass[a4paper]{article}
\usepackage{bm}
\begin{document}
$(x+\mathbf{y})(x-\mathbf{y})=x^{2}-{\mathbf{y}}^{2}$
$(x+\bm{y})(x-\bm{y}) \bm{=} x^{2}-{\bm{y}}^{2}$
$\alpha + \bm{\alpha} < \beta + \bm{\beta}$
\end{document}
The package mathtools loads amsmath and adds several additional
features, such as variants of the amsmath matrix environments that
allow the column alignment to be specified.
\documentclass[a4paper]{article}
\usepackage{mathtools}
\begin{document}
\[
\begin{pmatrix*}[r]
10&11\\
1&2\\
-5&-6
\end{pmatrix*}
\]
\end{document}
As will be seen in Lesson 14, there are variant TeX
engines that use OpenType fonts. By default, these engines still use
classic TeX math fonts but you may use the unicode-math package
to use OpenType Math fonts. The details of this package are beyond
this course and we refer you to the
package documentation.
However, we give a small example here.
% !TEX lualatex
\documentclass[a4paper]{article}
\usepackage{unicode-math}
\setmainfont{TeX Gyre Pagella}
\setmathfont{TeX Gyre Pagella Math}
\begin{document}
One two three
\[
\log \alpha + \log \beta = \log(\alpha\beta)
\]
Unicode Math Alphanumerics
\[A + \symfrak{A}+\symbf{A}+ \symcal{A} + \symscr{A}+ \symbb{A}\]
\end{document}