Question

what is the nth term of the geometric sequence 4, 8, 16, 32, ... ?

Answer 1

formula:

a_n = a1 r^(n-1)

a1 is the first term = 4
r = common ratio = 8/4 = 2

so,
a_n = 4 (2)^(n-1)
or
a_n = 2 (2)^n