Given the function f (x) = ax-b / x-2lnx, f (1) = 0 (1) If the tangent slope of function image at x = 1 is 0, and a (n + 1) = f '{1 / [a (n) - N + 1]} - n ^ 2 + 1, we know that a (1) = 4, and prove that a (n) is not less than 2n + 2 (2) Under the condition of (1), the relationship between sum (from 1 to n) 1 / [1 + a (I)] and 0.4 was compared

Given the function f (x) = ax-b / x-2lnx, f (1) = 0 (1) If the tangent slope of function image at x = 1 is 0, and a (n + 1) = f '{1 / [a (n) - N + 1]} - n ^ 2 + 1, we know that a (1) = 4, and prove that a (n) is not less than 2n + 2 (2) Under the condition of (1), the relationship between sum (from 1 to n) 1 / [1 + a (I)] and 0.4 was compared

F (1) = 0 = > A-B = 0 = > A = B (1) f '(x) = a + B / x ^ 2-2 / X f' (1) = k = 0 = > A + B-2 = 0 = > A = b = 1 = > F (x) = 1-1 / x-2lnx f '(x) = 1 + 1 / x ^ 2-2 / x = (1-1 / x) ^ 2A (n + 1) = f' (1 / (a (n) - N + 1)) - n ^ 2 + 1 = (a (n) - n) ^ 2-N ^ 2 + 1 = a (n) ^ 2-2na (n) + 1 prove a (n) > =... By mathematical induction