答案1
这样就可以了。
\documentclass{article}
\usepackage[utf8]{inputenc}
\usepackage{amsmath} % used for cases environment only
\begin{document}
\begin{equation}
I_{i,j}=\frac{(I_{i,j}-\bar{I}_i)}{\sigma_i}
\end{equation}
\begin{equation}
I_{input}=X_{i,j}
\end{equation}
\begin{equation}
O_{inception}=concatenate(L_A,L_B,L_C,L_D)
\end{equation}
\begin{equation}
\sigma(X_i)=\frac{e^{Z_i}}{\Sigma_{j=1}^{K=2}e^{Z_j}}
\end{equation}
\begin{equation}
O(X_{i,j})=
\begin{cases}
1, & X_{i,j}^1 > X_{i,j}^0 \\
0, & otherwise
\end{cases}
\end{equation}
\begin{equation}
Recog.=\frac{TP+TN}{TP+TN+FP+FN}
\end{equation}
\end{document}