in=2时 (2) (t-1)(t-2)at 2×O!×(2-0)! 4J【(-2)2+(t-2)dt [(t-2)+(t-2)2 同理可得<(2) v(2)6 1 6 4 6 1 ( 2) ] 2 1 ( 2) 3 1 [ 4 1 [( 2) ( 2)] 4 1 ( 1)( 2) 2 0! (2 0)! ( 1) 2 (2) 2 (2) 1 2 0 3 2 2 0 2 2 0 2 0 (2) 0 = = = − + − = = − + − − −   − − = =   − C C t t t t dt C t t dt n 同理可得 ， 当 时