) 中图学技术大荸学系 University of Science and Technology of China DEPARTMENT OF MATHEMATICS ●二次插值 X-XIx-xX 2 0 X (x-x1)( (x-x0)(x-x2) X (x1-x0)(x1-x2) l2(x) (x-x0)(x-x1) (x2-x0)(x2-x1) L2(x)=f(x0)0(x)+f(x1)1(x)+f(x2)l2(x)数 学 系 University of Science and Technology of China DEPARTMENT OF MATHEMATICS ⚫二次插值 ( )( ) ( )( ) ( ) ( )( ) ( )( ) ( ) ( )( ) ( )( ) ( ) 2 0 2 1 0 1 2 1 0 1 2 0 2 1 0 1 0 2 1 2 0 x x x x x x x x l x x x x x x x x x l x x x x x x x x x l x − − − − = − − − − = − − − − = 2 0 0 1 1 2 2 L x f x l x f x l x f x l x ( ) ( ) ( ) ( ) ( ) ( ) ( ) = + +