Question

In a G.P. a = 1, S11 = 1 find r.​

Answer 1

Answer:

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Step-by-step explanation:

S3 = a(r^3 -1)/(r-1)

125= a(r^2 + 1 + r) ....(1)

Also, S6 = a(r^6 - 1)/(r-1)

152= a(r^3 +1)(r^3 - 1)/(r-1)

152 = a(r^3 + 1)(r^2 + 1 + r) ...(2)

(2)/(1) :

152/125 = r^3 + 1

r^3 = (152-125)/125

r = 3√(27/125)

= 3/5