Write the rule and find the 15th term 3 1 5 9 2 6 18 54 Sol

Write the rule and find the 15th term. -3, 1, 5, 9, .... 2, 6, 18, 54, ....

Solution

7. It is an arithmetic series with the first term -3 and a common difference of 4. The 15^th term is -3+(15-1)*4 = -3+56 = 53.

8. It is a geometric series with the first term 2 and common ratio of 3. The 15^th term is 2*(3)^15-1 = 2*3¹⁴ = 2*4782969 = 9565938.