FAQ
1.how to write equations without numbering?
A: use \[ ...\]. note: no empty line before \].
2.how to write text among equations?
A: \text{...} or \mbox{...}
example: \[ \frac{dx_k}{dt}=p_k/m_k \quad \text{for k=1,..,N} \]
Here \quad is for two spacing, \qquad gives more spacing3.how to write matrix?
A: need \usepackage{amsmath};
examples: \begin{matrix}0 & 1\\1 & 0\end{matrix}
0 1
1 0
\begin{bmatrix}0 & 1 \\ 1 & 0 \end{bmatrix}
[0 1]
[1 0]
\begin{pmatrix}0 & 1 \\ 1 & 0 \end{pmatrix}
(0 1)
(1 0)
\begin{vmatrix}0 & 1 \\ 1 & 0 \end{vmatrix}
|0 1|
|1 0|
\begin{Vmatrix}0 & 1\\ 1 & 0 \end{Vmatrix}
||0 1||
||1 0||