Solve for a3 a_3=-1(1/3)^(3-1)

$a_{3} = - 1 {(\frac{1}{3})}^{3 - 1}$

Subtract $1$ from $3$ .

$a_{3} = - 1 {(\frac{1}{3})}^{2}$

Apply the product rule to $\frac{1}{3}$ .

$a_{3} = - 1 \frac{1^{2}}{3^{2}}$

One to any power is one.

$a_{3} = - 1 \frac{1}{3^{2}}$

Raise $3$ to the power of $2$ .

$a_{3} = - 1 (\frac{1}{9})$

Rewrite $- 1 (\frac{1}{9})$ as $- (\frac{1}{9})$ .

$a_{3} = - \frac{1}{9}$

The result can be shown in multiple forms.

Exact Form:

$a_{3} = - \frac{1}{9}$

Decimal Form:

$a_{3} = - 0.\overline{1}$