Consider an infinite G.P. with positive first term a and common ratio r=−31. Let Rn be the remainder after the first n terms are summed. What is the sign of Rn when (i) n is even and (ii) n is odd?
a) Positive for both even and odd n
b) Positive for even n and negative for odd n
c) Negative for even n and positive for odd n
d) Negative for both even and odd n