Simplify i^31

$i^{31}$

Rewrite $i^{31}$ as ${(i^{4})}^{7} (i^{2} \cdot i)$ .

Factor out $i^{28}$ .

$i^{28} i^{3}$

Rewrite $i^{28}$ as ${(i^{4})}^{7}$ .

${(i^{4})}^{7} i^{3}$

Factor out $i^{2}$ .

${(i^{4})}^{7} (i^{2} \cdot i)$

Rewrite $i^{4}$ as $1$ .

Rewrite $i^{4}$ as ${(i^{2})}^{2}$ .

${({(i^{2})}^{2})}^{7} (i^{2} \cdot i)$

Rewrite $i^{2}$ as $- 1$ .

${({(- 1)}^{2})}^{7} (i^{2} \cdot i)$

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

$1^{7} (i^{2} \cdot i)$

One to any power is one.

$1 (i^{2} \cdot i)$

Multiply $i^{2} \cdot i$ by $1$ .

$i^{2} \cdot i$

Rewrite $i^{2}$ as $- 1$ .

$- 1 \cdot i$

Rewrite $- 1 i$ as $- i$ .

$- i$