On the limit problems of Higher Mathematics If the real number B satisfies | B | 1, LIM (1 + B + B ^ 2... + B ^ (n-1)) / b ^ n =? If sequence {an} 1 / N ^ 2 1 ≤ n ≤ 1000 n ^ 2 / (n ^ 2-2n) n ＞ 1001, then {an} limit value A. 0b, 1C, 0or1d, not present Thank you The second point is that the two cases are divided into braces

On the limit problems of Higher Mathematics If the real number B satisfies | B | 1, LIM (1 + B + B ^ 2... + B ^ (n-1)) / b ^ n =? If sequence {an} 1 / N ^ 2 1 ≤ n ≤ 1000 n ^ 2 / (n ^ 2-2n) n ＞ 1001, then {an} limit value A. 0b, 1C, 0or1d, not present Thank you The second point is that the two cases are divided into braces

1. The formula of the sum of molecules by equal ratio: LIM (1 + B + B ^ 2... + B ^ (n-1)) / b ^ n n n → ＋∞ = LIM (1-B ^ n) / [(1-B) · B ^ n] n → ＋∞ = LIM (1 / b ^ n-1) (1-B) n → ＋∞| B | > 1  0 ＜ 1 / | B | 1} (1 / b) ^ n = 1 / b ^ n → 0, n → ＋∞ original limit = (0-1) / (1-B) = 1 / (B-1) 2