Find the $9^{\text {th }}$ term in the following sequence whose $n^{\text {th }}$ term is $a_{n}=(-1)^{n-1} n^{3}$
Find the $9^{\text {th }}$ term in the following sequence whose $n^{\text {th }}$ term is $a_{n}=(-1)^{n-1} n^{3}$
Substituting $n=7,$ we obtain
$a_{9}=(-1)^{9-1}(9)^{3}=(9)^{3}=729$
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