Problem:
A geometric sequence has a nonzero first term, distinct terms, and a positive common ratio. If the second, fourth, and fifth terms form an arithmetic sequence, find the common ratio of the geometric sequence.
Problem:
A geometric sequence has a nonzero first term, distinct terms, and a positive common ratio. If the second, fourth, and fifth terms form an arithmetic sequence, find the common ratio of the geometric sequence.
Solution:
Let be the first term and the common ratio of the geometric sequence. Since the second, fourth, and fifth terms form an arithmetic sequence,
Since the geometric sequence has distinct terms and a positive common ratio, the only possible value of the common ratio is .