1. In the arithmetic sequence {an}, the fourth term is 10 and the eighth term is 22, find its tenth term 2. The third and fourth terms of an equal ratio sequence are 12 and 18 respectively. Find the first and second terms of it

1. In the arithmetic sequence {an}, the fourth term is 10 and the eighth term is 22, find its tenth term 2. The third and fourth terms of an equal ratio sequence are 12 and 18 respectively. Find the first and second terms of it

Solution: 1. If d = (22-10) / (8-4) = 3, then A10 = A4 + 3 (10-4) = 28
2. If q = 18 / 12 = 3 / 2, A1 = A3 / Q ^ 2 = 16 / 3, A2 = A1 * q = 8