b b ∑l(x)y)tx=∑叮J”1(x) b (b-a∑l l, ()dxf(xi) b (b-a∑C("f( 因此就归结为求权 X-x 4, ()dx b i=0            = = = = = − − − = − = = − − = − = = b a n i j i j i i b a j n j j n j n j j n j b a j j n j b a j b a n j j j b a n dx x x x x b a l x dx b a C b a C f x l x dx f x b a b a L x dx l x y dx l x dx y 0 ( ) 0 ( ) 0 0 0 1 ( ) 1 ( ) ( ) ( ) ] ( ) 1 ( ) [ ( ) ( ( ) ) [ ( ) ] 因此就归结为求权