Alg 2
posted by franey .
The first term of a geometric sequence is 25, and the fourth term is 1\5.
(a) Find the common ratio r.
r =
Find the fifth term.
a5 =
(b) Find the partial sum of the first eight terms.
S8 =

r^3 = (1/5)/25 = 1/125
so, r = 1/5
An = 5*(1/5)^(n1) = 125/5^n
S8 = 25(1  (1/5)^8)/(1  1/5) = 97656/3125
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