Question

Write the explicit formula for the nth term of the given geometric sequence.
1, 5, 25, 125, . . .

5n

5n – 1

5n – 1

5n

1 + (n – 1)5

Answer 1

The nth term is a_n = a1 * r^(n-1) = 1 * 5^(n-1). So the explicit formula is a_n = 5^(n-1).