Question

What are the geometric series of a1 and r of the geometric series?

2-2+2-2+2

Answer 1

a1=2 and r=-1

Explanation:

Given

geometric series= 2-2+2-2+2

geometric sequence has a constant ratior r and is given by

an=a1r(r)^(n-1)

where

an=nth term

r=common ratio

n=number of term

a1=first term

In given series:

r= a(n+1)/an

= a(2)/a1

= -2/2

=-1

so a1=2 and r=-1 !