F (x) = x ^ 2 - ax + ln (x + 1), a belongs to R F extremum when a = 2 If the function f (x) always has f prime (x) greater than x in the interval (0,1), find the value range of real number a

F (x) = x ^ 2 - ax + ln (x + 1), a belongs to R F extremum when a = 2 If the function f (x) always has f prime (x) greater than x in the interval (0,1), find the value range of real number a


(1) When a = 2, f (x) = x & sup2; - 2x + ln (x + 1)
The derivation is: F '(x) = 2x-2 + 1 / (x + 1)
Let f '(x) = 0, we can get x = = √ 2 / 2 or - √ 2 / 2
The extreme point is (√ 2 / 2,1 / 2 - √ 2 + ln (√ 2 / 2 + 1)) (- √ 2 / 2,1 / 2 + √ 2 + ln (- √ 2 / 2 + 1))