How do you tell whether the sequence with the terms #a_3=21, a_5=27, a_12=48# is arithmetic?
1 Answer
Mar 9, 2017
It is an arithmetic series. See details below.
Explanation:
In an arithmetic series we can find common difference between two terms
Here we can get three values of

#(a_5a_3)/(53)=(2721)/2=6/2=3# 
#(a_12a_5)/(125)=(4827)/7=21/7=3# and 
#(a_12a_3)/(123)=(4821)/9=27/3=3#
As we get