Help on Math question

Question

Derive the general term formula for geometric sequence.

Answer 1

an = a1(r)^(n-1) where a1=1st term and r=the common ratio for a geometric sequence

for example:

1,2,4,8,... has common ratio =2, a1 =1

an=r^(n-1)

a4 =(2)^(4-1) = 2^3 = 8