*https://medemanabu.net/latex/horizontal-space/
\quad
===[https://ja.wikipedia.org/wiki/%E2%88%82 ∂]===
----
\partial
<math>\partial</math>
===ギリシャ文字===
----
<math>a_{i_j}</math>
===ベクトル===
----
u=\left(\begin{array}{c}u_1\\u_2\\u_3\end{array}\right)
<math>u=\left(\begin{array}{c}u_1\\u_2\\u_3\end{array}\right)</math>
====内積====
{a}\cdot{b}
{a}\times{b}
<math>{a}\times{b}</math>
===[https://cognicull.com/ja/mojgoomv Σによる総和]===
----
\sum_{k=1}^{n} k=\frac{n(n+1)}{2}
<math>\sum_{k=1}^{n} k=\frac{n(n+1)}{2}</math>