[题目]设函数f x)在闭区间[0,1]上连续,在开区间-|||-(0,1)内可微,且 f(0)=f(1)=0 ,f(1/2)=1, 证明:-|||-(1)存在 in in (dfrac (1)(2),1), 使得 (xi )=5;-|||-(2)存在 in (0,g), 使得 '(n)=f(n)-n+1,