用给定的多项式，如y=x3-6x2+5x-3，在[-1，1]上等间隔产生20组数据(xi,yi，i=1,2,…,n),再在yi上添加随机干扰(可用rand产生(-5,5)均匀分布随机数)。请

(1)对xi和添加了随机干扰的yi作3次多项式拟合，与原系数比较。

-With the given polynomial, such as y=x3-6x2+5x-3, [-1, 1] intervals of 20 sets of data (Xi, Yi, i=1,2,... , n), and then add the random interference in Yi (available on rand (-5,5) uniformly distributed random number). Please

(1) on the Xi and add a stochastic disturbance for Yi 3 polynomial fitting, compared with the original coefficient.