Question

Find the nth term an of the geometric sequence described below, where r is the common ratio? Help please I'm use too when the problem gives at least 5 sets?

A4= -8. r= -2

An=?

Answer 1

`n^(th) term = (-2)^(n-1)`

Explanation:

nth term of G.P (geometric progression) is given by `color(green)(Ar^(n-1))` where `color(blue)A` is the first term and `color(red)r` the common ratio.

`A4=A*r^(4-1)`
Given A4 = -8 & r = -2.
`-8=Ar^3=A*(-2)^3=(-8)A`
`A=(-8)/(-8)=1`

`n^(th) term = A*r^(n-1)=1*(-2)^(n-1)=(-2)^(n-1)`