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Question
Determine whether the sum to infinity of the following G.P.s exist, if exists find them:
9, 8.1, 7.29, ...
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Solution
Here, a = 9, r = 0.9
Since l r l = | 0.9 | = 0.9 < 1, the sum to infinity of this G.P. exist and
S = `"a"/(1 - "r")`
= `9/(1 - 0.9)`
= `9/0.1`
= 90.
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