Question

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

Answer 1

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}`