The positive number 9/8,p,1/2,...form a G.S.
(a)Find the value of p
(b)Express th nth term in the terms of n.
(c)Find the sum of infinity.
Maths
2012-04-08 8:40 am
回答 (1)
2012-04-08 3:12 pm
✔ 最佳答案
(a) Common Ratio = p/(9/8) = (1/2)/pso p^2 = (9/8)(1/2) = 9/16
p = 3/4.
(b)
Common Ratio, r = p/(9/8) = (3/4)/(9/8) = 24/36 = 2/3.
So nth term = ar^(n - 1) = (9/8)(2/3)^(n - 1).
(c)
Since r < 1
So sum to infinity = (9/8)/[1 - (2/3)] = (9/8)/(1/3) = 27/8.
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