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

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

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

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

Evaluate the exponent.

$a_{1} = \frac{- 1}{1^{2}}$

One to any power is one.

$a_{1} = \frac{- 1}{1}$

Divide $- 1$ by $1$ .

$a_{1} = - 1$