Find the sum of the series `2+6+18++4374`

Explanation

Given`2+6+18+....+4374`


Above sequence is a GP with common ratio` =3`
`∴ r=3 and a=2`

Last term `=4374=``ar^(n−1)`

`S_n​=(a(r^n−1)/(r-1))`
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=`((ar^n−a)/(3-1))`

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