应用拉格朗日定理求证|arctanx1-arctanx2|小于或等于|x1-x2|_百度知 ...答:使得 f'(P)(max{x1,x2}-min{x1,x2})=f(max{x1,x2})-f(min{x1,x2})1/(1+P^2)*(max{x1,x2}-min{x1,x2})=f(max{x1,x2})-f(min{x1,x2})f(max{x1,x2})-f(min{x1,x2})<=(max{x1,x2}-min{x1,x2})所以|arctanx1-arctanx2|<=|x1-x2| ...