Question

Determine the 15th term of the sequence
1,-2,4​

Answer 1

16384

Explanation:

The sequence is 1, -2, 4, ...........

This is a geometric sequence with first term 1 and common ratio - 2.

Hence, the 15th term of the sequence is =
`1 * (- 2)^((15 - 1)) = (- 2)^(14) = 16384` (Answer)

The nth term of an G.P. with first term a and common ratio r is given by
`a* r^((n - 1))`