Given the function f (x) = LG [(A2-1) x2 + (a + 1) x + 1] (1) if the domain of F (x) is r, find the value range of real number a; (2) if the domain of F (x) is r, find the value range of real number a

(1) When A2-1 = 0, a = - 1, a = 1 does not hold. When A2-1 ≠ 0, A2 − 1 ＞ 0 △ = (a + 1) 2 − 4 (A2 − 1) ＜ 0, a ＞ 53 or a ＜ - 1 is obtained. In conclusion, a ＞ 53 or a ＜ - 1 (2) when A2-1 = 0, a = 1, a = - 1 does not hold

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