Question

Find an explicit formula for the arithmetic sequence -11, -3, 5, 13, ...

Answer 1

`a_(n)` = 8n - 19

Explanation:

The explicit formula for an arithmetic sequence is

`a_(n)` = a₁ + (n - 1)d

where a₁ is the first term and d the common difference

Here a₁ = - 11 and d = - 3 - (- 11) = - 3 + 11 = 8, thus

`a_(n)` = - 11 + 8(n - 1) = - 11 + 8n - 8 = 8n - 19

Answer 2

`a_(n) = 8n-19`

Explanation:

Explicit formula is :

`a_(n) = a_(1) + d(n-1)`

Where
`a_(1)` is the first element i.e. -11

and d is the difference between the elements i.e. 8

`a_(n) = -11 + (8)(n-1)`

`a_(n) = -11 + 8 (n-1)`

`a_(n) = -11+8n-8\\`

`a_(n) = 8n-19`