Geometric Sequences and Series

Question

Write the first five terms of the geometric sequence.

an= 3an-1, a1=1

Answer 1

1,3,9,27,81, ...

a5 = a1r^4 = 1(3)^4 = 81

an = a1r^(n-1) a1=1, r=3

a1 = 1(3^0)= 1

a2 = 3^1 = 3

a3 =3^2 = 9

a4 = 3^3 = 27

a5 = 3^4 = 81