Find the First Term a_n=(-1)^(n+1)n^2

$a_{n} = {(- 1)}^{n + 1} n^{2}$

Substitute in the value of $n$ to find the $n$ th term.

$a_{1} = {(- 1)}^{(1) + 1} {(1)}^{2}$

Add $1$ and $1$ .

$a_{1} = {(- 1)}^{2} {(1)}^{2}$

Raise $- 1$ to the power of $2$ .

$a_{1} = 1 {(1)}^{2}$

Multiply ${(1)}^{2}$ by $1$ .

$a_{1} = {(1)}^{2}$

One to any power is one.

$a_{1} = 1$