For a sequence ,a_1 = 2 and frac{a_{n+1}}{a_n | vedclass

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(B) The given sequence is a Geometric Progression $(G.P.)$ because the ratio of consecutive terms is constant.
Here,the first term $a = a_1 = 2$ and

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$3\left( 1 - \frac{1}{3^{20}} \right)$

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(B) The given sequence is a Geometric Progression $(G.P.)$ because the ratio of consecutive terms is constant.
Here,the first term $a = a_1 = 2$ and the common ratio $r = \frac{1}{3}$.
The sum of the first $n$ terms of a $G.P.$ is given by the formula $S_n = \frac{a(1 - r^n)}{1 - r}$.
For $n = 20$,we have:
$S_{20} = \frac{2(1 - (1/3)^{20})}{1 - 1/3}$
$S_{20} = \frac{2(1 - 1/3^{20})}{2/3}$
$S_{20} = 2 	imes \frac{3}{2} 	imes (1 - \frac{1}{3^{20}})$
$S_{20} = 3 \left( 1 - \frac{1}{3^{20}} ight)$.

For a sequence $,a_1 = 2$ and $\frac{a_{n+1}}{a_n} = \frac{1}{3}.$ Then $\sum_{r=1}^{20} a_r $is

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