<img class=jc-formula data-tex=行列式\quad \begin{ vmatrix } a \begin{ matrix } b c \end{ matrix } \\ d \begin{ matrix } e f \end{ matrix } \\ a \begin{ matrix } b c \end{ matrix } \end{ vmatrix }=0 src=https://huaweicloudobs.ahjxjy.cn/C87E34DE6102091E6EA6E6BA2DE1A9FA.png style=vertical-align: middle;/>