Question

Find an explicit formula that generates a sequence whose first four terms are: 24, 36, 54, 81

Answer 1

7 is the right answer to the question

Answer 2

see explanation

Explanation:

These are the first 4 terms of a geometric sequence with n th term

`a_(n)` = a₁
`(r)^(n-1)`

where a₁ is the first term and r the common ratio

r = 36 ÷ 24 = 54 ÷ 36 = 81 ÷ 54 = 1.5 and a₁ = 24, hence

`a_(n)` = 24
`(1.5)^(n-1)` ← explicit formula