In the known sequence {an}, a1 + a3 = 10, A4 + A6 = 54, find the sum of the fourth term and the first five terms

In the known sequence {an}, a1 + a3 = 10, A4 + A6 = 54, find the sum of the fourth term and the first five terms

Let the common ratio be q According to the known results, a1 + a1q2 = 10a1q3 + a1q5 = 54 (3 points) ② A1 (1 + Q2) = 10a1q3 (1 + Q2) = 54 (5 points) ② △ ① get & nbsp; Q3 = 18, that is, q = 12 (7 points) substituting q = 12 into (1) to get A1 = 8 (8) A4 = a1q3 = 8 × (12