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

2-2+2-2+2

a1=2 and r=-1

Step-by-step 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!