For each geometric sequence, find a recursive rule by finding the common ratio by calculating the ratio of consecutive terms. find an explicit rule for the sequence by finding each term as the product of the first term and a power of the common ratio. n 1 2 3 4 5 an 50 25 12.5 6.25 3.125 the recursive rule is a1 = and an = an − 1 for n ≥ . the explicit rule is an = ()n − 1.