Find the sum of the first 20 terms of the series. 1+3+9+27+...

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tiburtius | High School Teacher | (Level 2) Educator

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This is geometric series with first term `a_1=1` and ratio `r=3`.

Sum of the first `n` terms of geometric series is

`S_n=a_1 (r^n-1)/(r-1)`

Hence sum of the first 20 terms is ` `


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