(2)复数式 f(x)=∑Cn ne Cn f(se inds 21 n丌 a n 1,0,1,2 △on=0n+1-0n=(跳跃)ï ï î ï ï í ì = = - - ¥ = -¥ ò å x x w x w f e d l Cn f x Cne n n i l l n i x ( ) 2 1 ( ) (2) 复数式 (跳跃） , ..., 3, 2 , 1,0 ,1,2 ,... 1 l n l n n n n n p D w w w p w \ = - = = = - - - +