How do you find $a_1$ for the geometric series with $r=3$ and $s_6=364$ ?

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Answer 1 · 2014-08-12T09:14:41

Can be done quite easily using the standard definition of a Geometric Series.

If the first term of the series is some $a$ , then the equation we have is,

$a\times r^5=364$
$a\times 243=364$ (substitute $r=3$ )
$a=\frac{364}{243}$

How do you find a_1a_1 for the geometric series with r=3r=3 and s_6=364s_6=364?