%indent
$$$
\vec H = \left(\! \ffd{1}{4 \pi} \!\right)
\int\! \ffd{dq(\vec r - \vec r \,')}{|(\vec r - \vec r \,')|^3}
$$$
$$$
\vec H = \ffd{1}{4 \pi}
\int\! \ffd{\vec r - \vec r \,'}{|\vec r - \vec r \,'|^3} dq
$$$
$$$
\vec H = \ffd{1}{4 \pi}
\int\!\! \ffd{\vec r - \vec r \,'}{|\vec r - \vec r \,'|^3}\, dq
$$$
$$$
a \times b = \sum_{i = 1}^a \sum_{j = 1}^b 1 = \sum_{j = 1}^b \sum_{i = 1}^a 1 = b \times a
$$$
$$$
\sum_{i = 1}^a \sum_{j = 1}^b 1
$$$
$$$
\begin{array}{l}
x^2 + 25x - 144
\\ =\left(x-\ffd{25-\sqrt{1201}}2\right)\left(x-\ffd{25+\sqrt{1201}}2\right)
\end{array}
$$$
$$ abcdefghijklmnopqrstuvwxyz $$
$$ abc dx dy $$
$$ \iro[ak]{c\tau} $$
$$ \iro[ak]{ct} $$
$$ \iro[ao]{vt} $$
$$ \iro[ak]{(c\tau)^2} = \iro[ak]{(ct)^2} - \iro[ao]{(vt)^2} $$
$$ c\tau = \sqrt{c^2 - v^2}\sx t $$
$$ \tau = \sqrt{1 - \ffd{v^2}{c^2}}\sx t $$
![[PukiWiki]](image/NekoPunch.png "[PukiWiki]")
