(adsbygoogle = window.adsbygoogle || []).push({}); 1. The problem statement, all variables and given/known data

The sum of an infinite geometric sequence is 13^{1}/_{2}, and the sum of the first three terms is 13. Find the first term.

2. Relevant equations

S_{ā}= a/(1-r)

Sn = a-ar^{n}/(1-r)

3. The attempt at a solution

a/(1-r) = 13^{1}/_{2}

a-ar^{3}/(1-r) = 13

2a = 27-27r ........................ 1

a-ar^{3}= 13-13r..... 2

I'm stuck.

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# Homework Help: First term of an infinite geometric sequence

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