Example: {1,2<span>,4,8,...} The </span>sequence<span> starts at 1 and doubles each time, so. a=1 (</span>the first term); r=2<span> (the "common ratio" between terms is a doubling). And we </span>get: {a, ar, ar2, ar3, ... } = {1, 1×2, 1×<span>22</span>, 1×<span>23</span><span>, ... } = {1, </span>2<span>, 4, 8, ... } But be careful, r should not be 0: When r=0, we </span>get<span> the </span>sequence<span> {a,0,0,...} which is not </span>geometric<span> ...</span>
