Answer:
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 !
