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Question
Answer the following:
For a G.P. if t2 = 7, t4 = 1575 find a
Solution
Given, t2 = 7, t4 = 1575
tn = arn–1
∴ t2 = ar
∴ ar = 7
∴ r = `7/"a"` ...(i)
Also, t4 = ar3
∴ ar3 = 1575
∴ `"a" xx (7/"a")^3` = 1575 ...[From (i)]
∴ a2 = `7^3/1575`
∴ a2 = `49/225`
∴ a = `7/15`
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