Find the sum of the following geometric progression: 1,3,9,27,… to 8 terms.

Explanation

We know that, sum of GP for n terms = `(a(r^n – 1))/(r – 1)`

Given:` a = 1, r = 3/1 = 3, n = 8`

Now let us substitute the values in `(a(r^n – 1))/(r – 1)`

= `(3^8 – 1)/(3 - 1)`

=` (3^8 – 1)/2 `

= `(6561 – 1)/2 `

`= 3280`