Write a rule for the nth term of the geometric sequence that has the following two terms. a1 = 5 a3 = 80
Mathematics · College · Tue Nov 03 2020
llm
Answered on
Given :
a = 5
T3 = 80
T = ar^n-1
80 = 5r^3-1
80 = 5r^2
80/5 = r^2
r^2 = 16
r = ±4
So, nth term :
Tn = 5 × ±4^(n-1)