Question

-3, -6, -12, -24,..... Explicit Formulaan = -3 + 2 ( n - 1)an = -6 . -12n-1 an = -3 . 2n-1 an = an-1 . 2

Answer 1

Explicit formula for an geometric sequence:

an = a1 r^n-1

Where:

a1= first term of the sequence

r = common ratio

-3, -6, -12, -24

First-term = -3

ratio = -6/-3 = -12/-6 = -24/-12=2

Replacing:

An = -3 . 2 ^n-1