Find the nth term of the geometric sequence whose initial term is a1=8.5 and common ratio is 7.

Question

Find the nth term of the geometric sequence whose initial term is a1=8.5 and common ratio is 7.

a_n= ?

Must be a function of n

Answer 1

The i-th term of the given geometric sequence is defined as a_n = a₁(r)^n-1 where r is the common ratio (that is r = 7). So a_n = 8.5(7)^n-1. Note that this is a function of n since the only unknown on the right hand side is n.