Answer:
A n+1 / A n the ratio of successive terms will be less than 1 if A is between -1 and 1 so successive terms will have a ratio less than 1 and can be determined
If A n+1 / A n > 1 then successive values of the given ratio will not approach a constant value
If you write the value of the nth term as L = a r^(n - 1) one can see that r^(n - 1) approaches a fixed value if r between -1 and 1 but not if | r | > 1