定义2 D =an41+a1242+…+amn4im nn Laplace 展开式 D=a1jA1j+a2jA2j+.+anj Ani定义2. n nn n a a a a D     1 11 1 = = ai1 Ai1 + ai2 Ai2 ++ ainAin , 1  = = n j aijAij D = a1j A1j + a2 j A2 j ++ anjAnj . 1  = = n i ijAij a Laplace 展开式