Answer
$-\frac{1}{25}$
Work Step by Step
To calculate $a_n$, we plug in $n$ to the general formula.
To calculate the result, we use PEMDAS (parentheses, exponentation, multiplication, division, addition, subtraction) to determine which operation is applied first.
$a_{19} = \frac{(-1)^{19}}{19+6} = \frac{-1}{19+6} = -\frac{1}{25}$
