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Question
For the following G.P.s, find Sn
0.7, 0.07, 0.007, .....
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Solution
a = 0.7 = `7/10`, r = `0.07/0.7 = 1/10 < 1`
Sn = `("a"(1 - "r"^"n"))/(1 - "r")`, for r < 1
= `(7/10[1 - (1/10)^"n"])/(1 - 1/10)`
= `7/9 (1 - 1/10^"n")`
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