∫nf(x)d≈JL(x)t b ∑a(x)f(x)a ∑| b a1(x)dtx∫(x1) i=0 ∫R,(xk=」 ∫m+() n+1 (x) a (n+ 1)0 ( ) ( ) n b i i a i a x f x dx =   =       0 ( ) ( ) n b i i a i a x dx f x =   =      = Ai ( ) ( ) b b n a a f x dx L x dx    ( ) b n a R x dx  1 1 1 ( )( ) ( ) ( )! n b n a f x dx n  + =  + + 