\documentclass{homework}
\usepackage{kotex}
\title{Test}
\author{Group 4}
\begin{document}
\maketitle

\exercise[2-1]

$$
\eta_k(x)=\operatorname{Pr}(Y=k | \boldsymbol{X}=\boldsymbol{x})
$$

$$
=(2 \pi)^{-\frac{d}{2}}|\Sigma|^{\frac{1}{2}} \exp \left(-\frac{1}{2}\left(\boldsymbol{x}-\boldsymbol{\mu}_k\right)^T \boldsymbol{\Sigma}^{-1}\left(\boldsymbol{x}-\boldsymbol{\mu}_k\right)\right)
$$

어떻게 해결해야 할까요?