三阶行列式的定义 12 C1C22+a12221+a1 13021032 3022031 (1.4) 83 32 5 2021/2/202021/2/20 5 三阶行列式的定义 11 12 13 21 22 23 11 22 33 12 23 31 13 21 32 31 32 33 13 22 31 12 21 33 11 23 32 a a a a a a a a a a a a a a a a a a a a a a a a a a a = ++- - - 11 12 13 11 12 21 22 23 21 22 31 32 33 31 32 a a a a a a a a a a a a a a a - - - + + + (1.4) (1.5)