利用导数定义 l x→>0△x △J 则可以利用均差 来估计导数 △x Table 4.16 The first and second divided differences estimate the first and second derivatives respectively First Second Data divided difference divided difference y1 y2 2-X1 y3-y2y2-y1 x3-x2x2-x1 x2 2 y3-y2 x3-x2 3 y3利用导数定义： 则可以利用均差 来估计导数 0 lim x dy y dx x  →  =  y x  