For the following geometric sequence, find the explicit formula.
{1, -3, 9, }

the explicit formula for given geometric sequence {1,-3,9,..} is

Step-by-step explanation:

We are given the series

1,-3,9,...

the common ratio is:

-3/1 = -3

9/-3 = -3

So, the common ratio in the series is -3

a₁ = 1

The formula used for geometric series is:

Putting values of a₁ and r

So, the explicit formula for given geometric sequence {1,-3,9,..} is