Question

What is the 20th term for the following sequence?
3,-9, 27,-81, ...

Answer 1

Answer: -3486784401

Explanation:

This is a geometric progression and the formula to use to find the nth term will be: = ar^(n-1)

where,

a = 3

r = -9/3 = -3

n = 20

Therefore, ar^(n-1)

= 3 × -3^19

= 3 × -1162261467

= -3486784401