n为简便起见取节点为等分 b-a h x1=a+jhj=0,1, ■现在关键是求 cb f(xdx= Ln(x)dx+R(xb◼ 为简便起见,取节点为等分 ◼ 现在关键是求 x a j h j n n b a h j , = + = 0,1,2,..., − = f x dx L x dx R x dx b a n b a b a   n  ( ) = ( ) + ( )