n (t-x (3)Hn(x)=∮ dt 2 n+ dHn(x)n!,旦 (t-x dt 2丌 +1 2n(n-1) dt 2丌i =nhn(x)2 2 2 2 -( - ) 1 -( - ) 1 ! (3) ( ) 2 ( ) ! 2 2 x t x n n x t x n n n e H x dt i t dH x n e t dt l dx i t — — p p + + = ò \ = × ò 2 2 - ( - ) -1 2 ( - 1 ) ! 2 2 ( ) x t x n n n n e d t i t n H x — p = ò =