# Find the 9th term in the following sequence whose nth term is

Question:

Find the 9th term in the following sequence whose nth term is $a_{n}=(-1)^{n-1} n^{3} ; a_{9}$

Solution:

Substituting n = 9, we obtain

$a_{9}=(-1)^{9-1}(9)^{3}=(9)^{3}=729$