Question

#1: Given the geometric sequence 3, 9, 27, 81...
• write the explicit formula. Determine the 20th term of the sequence

Answer 1

Answer:

3486784401

Step-by-step explanation:

a=3, r = T2/T1 = 9/3=3

Tn = ar^(n-1)

T20 = ar^(20-1)

T20 = ar^19

T20 = 3×(3^19]

T20 = 3486784401

Answer 2

Answer:

The given geometric series is:

3,9,27,81

Step-by-step explanation:

common ratio: r = ($a_n +1/ a_n$)

                        r = 3

20th term of geometric series is that :

$3^{1} =3\\3^2=9\\3^3=27\\3^4=81\\3^5=243\\.\\.\\.\\.\\.\\3^20 = 3486784401$