Answer
$a_1$=$1$
$a_2$=$-\frac{1}{3}$
$a_3$=$\frac{1}{5}$
$a_4$=$-\frac{1}{7}$
Work Step by Step
Substitute $n=1,2,3,4$ in the formula for $a_n$:
$a_1$ = $\frac{(-1)^2}{2-1}$ = $1$
$a_2$ =$\frac{(-1)^3}{4-1}$ = $-\frac {1}{3}$
$a_3$ =$\frac{(-1)^4}{6-1}$ = $\frac{1}{5}$
$a_4$ = $\frac{(-1)^5}{8-1}$ = $-\frac{1}{7}$
