Question

How do you find the first four terms of the geometric sequence for which a1=4 and r=3?

Answer 1

If the first term is 4 and the common ratio (r) is 3, t

Explanation:

If the first term is 4 and the common ratio (r) is 3, then the second term must be 3 times the first time, since a geometric series is a repeated multiplication. Alternatively, you can use the formula for the nth of a geometric series, which will benefit when you're dealing with very large numbers such as finding `t_26` (the 26th term).

The following solution solves this problem using the formula:

`t_n` = a • `r^(n - 1)`

`t_4` = 4 • `3^(4 - 1)`

`t_4` = 4 • 27

`t_4` = 108

The 4th term is 108, and by logical deduction the 3rd term is 36, the second term 12 and the first term 4.

`t_1` = 4
`t_2` = 12
`t_3` = 36
`t_4` = 108