$$\text{y = f (}{\rm X}\text{,}\Sigma \text{,}\nu \text{)=}\frac{{\left|{\rm X}\right|}^{\left(\text{(}\nu \text{d 1})/2\right)}{e}^{\left(\text{- - - - - -}\frac{1}{2}\text{跟踪}\left({\Sigma }^{-1}{\rm X}\right)\right)}}{{\text{2}}^{\text{(}\nu \text{d) / 2}}{\pi }^{\text{(d (d 1)) / 4}}{|\sum |}^{\nu /2}\Gamma \left(\nu /2\right)\mathrm{\dots }\Gamma \text{(}\nu \text{- (d 1)) / 2}}$$

$$\Sigma =\left(\begin{array}{cc}1& 5\\ 5& 2\end{array}\right)$$