Question

What is the explicit formula for this gemoetric sequence 8 4 2 1

Answer 1

an = 8·(1/2)^(n-1)

Explanation:

The first value is a1 = 8 and the common ratio is r = 1/2, so the formula is ...

an = a1·r^(n-1)

an = 8·(1/2)^(n-1)

an = 2^(4-n) . . . . . . more compact version