How do you find the explicit formula for the following sequence 12,24,48,...?

1 Answer
Mar 22, 2016

# 12.(2)^(n-1) #

Explanation:

This is a geometric sequence

The standard sequence has terms

a,ar,#ar^2,ar^3,ar^4, ...................... , ar^(n-1)#

where a is the 1st term and r , the common ratio.

# r = a_2/a_1 = a_3/a_2 = ............ = a^n/a^(n-1) #

the nth term of the sequence is : # ar^(n-1) #

For this sequence a = 12 , #r =24/12 = 48/24 = 2 #

the nth term formula is therefore : # 12.(2)^(n-1) #