●3×3 determinants(Diagonal Method) a11 a12 a13 d21 d22 123 a31 a32 a33 D=211d年og1 2 (Tongji University) 5/323 × 3 determinants(Diagonal Method) . a11. a12. a13. a21. a22. a23. a31. a32. a33. .             .             . D =a11a22a33 . +a12a23a31 . +a13a21a32 . −a11a23a32 . −a12a21a33 . −a13a22a31 (Tongji University) Linear Algebra 5 / 32