杜兰德法则 Let the values of a function f(x) be tabulated at points x_i,equally spaced by h=x_(i+1)-x_i. so f_1=f(x_1), f_2=f(x_2), ..., f_n=f(x_n)(Durand's Rule Let the values of a function f(x) be tabulated at points x_i,equally spaced by h=x_(i+1)-