Asked by Anonymous
Evaluate this geometric series:
7 + 14 + 28 + ... + 3584
7 + 14 + 28 + ... + 3584
Answers
Answered by
Count Iblis
S = 7 + 14 + 28 + ... + 3584
2 S = 2 (7 + 14 + 28 + ...1792 + 3584) =
2*7 + 2*14 + +...+ 2* 1792 + 2*3584 =
14 + 28 + ...+ 3584 + 7168 =
S - 7 + 7168 = S + 7161
2S = S + 7161 --------->
S = 7161
2 S = 2 (7 + 14 + 28 + ...1792 + 3584) =
2*7 + 2*14 + +...+ 2* 1792 + 2*3584 =
14 + 28 + ...+ 3584 + 7168 =
S - 7 + 7168 = S + 7161
2S = S + 7161 --------->
S = 7161