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प्रश्न
Find the 20th and nthterms of the G.P. `5/2, 5/4 , 5/8,...`
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उत्तर
The given G.P. is `5/2, 5/4, 5/8, ....`
Here, a = First term = `5/2`
r = Common ratio = `4/5 = 1/2`
a20 = `ar^(20 - 1) = 5/2(1/2)^19` = `5/((2)(2)^19)` = `5/(2)^20`
an = `ar^(n - 1) = 5/2(1/2)^(n - 1)` = `5/((2)(2)^(n - 1))` = `5/(2)^n`
20th term = `5/2^20`
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