(1)若令 H(x) k 则e k=0 1 -(t-x d t 27i H(x)=.n!=f, d t 2 问:Hn(x)有无微分式?J(x呢?2 2 2 2 2 2 -( - ) 0 -( - ) 1 -( - ) 1 ( ) (1) ! 1 2 ! ( ) ! 2 ( ) ( ) k k x t x k k k x t x k l k x t x n n l n n n H x a k e a t e a dt i t n e H x a n dt i t H x J x — — 若令 ： 有 微分式？ 呢？ p p ¥ = + + = = å \ = ò \ = × = ò 则 问 无