(x2sinx)C(x)(sin.x)) k=0 -C(x2)(sinx)+C(x2)(sinx)+C(x2)"(sinx) =s+n孕+a-2xsmx+a-经+2mx+a-2受2 ( ) ( sin ) n x x ( ) 0 2 ( ) (sin ) ( ) k n k k n C x x n k =  −  = 2 ( ) 1 2 ( 1) 2 2 ( 2) ( )(sin ) ( ) (sin ) ( ) (sin ) − − − − = +  +  n n n n n n n n Cn x x C x x C x x ] 2 sin[ ( 2) 2 ( 1) ] 2 ) 2 sin[ ( 1) 2 sin( 2    + − − = + +  + − + x n n n x x n n x x n