the two dots above a letter represents two derivative of varible t.
My method:
\documentclass[UTF8]{ctexart}
\usepackage{amsmath}
\usepackage{amssymb}
\usepackage{graphicx}
\usepackage{epstopdf}
\usepackage{inputenc}
\begin{equation}
\"{o}
\mathaccent{o}
\end{equation}
However,the latex says in the math environment ,I must use the \mathaccent
. So I replace \"
by \mathaccent
, but it shows the warning information: Missing number, treated as zero
I am a starter, I want to know how to revise it? Can someone help me? Thanks sincerely!!
$\dot x$
for the first derivative,\ddot x
for the second,\dddot x
for the third,\ddddot x
for the fourth.\^{u}
cannot achieve that effect in the math enviroment.$\hat{u}$
....