Question

Given the series 2+ 6 + 18+

*
use an appropriate formula to find S12.

Please put full solution.

Answer 1

S₁₂ = 531440

Explanation:

There is a common ratio between consecutive terms, that is

r = 6 ÷ 2 = 18 ÷ 6 = 3

This indicates the sequence is geometric with sum to n terms

`S_(n)` =
`(a(r^n-1))/(r-1)` ( r ≠ 1 )

where a is the first term and r the common ratio

Here a = 2 and r = 3 , then

S₁₂ =
`(2(3^(12)-1) )/(3-1)`

=
`(2(531441-1))/(2)`

= 531441 - 1

= 531440

Answer 2

Answer: Samsung Galaxy S12