级数展开 ∑ E E E (0)(0 (0) 0 E ()、(y-p) 8.C (y-1) m m n)=∑Wn mn n级数展开 1,2,3,..... 0 ( ) ( ) ( 1) 0 ( ) (0) (0) (0) ( ) ( ) = − = − = = = − −  =                      n m m m n m n m m m n n E c c W c E c c E E c c