Sum of first two terms of a G.P. is 1 and every term of this series is twice of its previous term, t

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8. Sequences and Series

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The sum of first two terms of a $G.P.$ is $1$ and every term of this series is twice of its previous term, then the first term will be

A

$1/4$

B

$1/3$

C

$2/3$

D

$3/4$

Solution

(b) Given $a + ar + 1$ and $r = 2$

therefore $a + 2a = 1$

$ \Rightarrow $$a = \frac{1}{3}$.

Standard 11

Mathematics

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