Question

The explicit formula for the geometric sequence 10,30,90,180

Answer 1

Answer:

$a_{n}$ = 10 $(3)^{n-1}$

Step-by-step explanation:

The n th term of a geometric sequence is

$a_{n}$ = a $(r)^{n-1}$

where a is the first term and r the common ratio

Here a = 10 and r = 30 ÷ 10 = 3, thus

$a_{n}$ = 10 $(3)^{n-1}$

Answer 2

Answer:

nth term =  10(3)^(n-1).

Step-by-step explanation:

General form is a1 r^(n-1)  where a1  is the first term and r is the common ratio and n is the term number.

For this sequence a1 = 10 and r = 30/10 = 3.

The explicit formula is  nth term =  10(3)^(n-1)