Answer
$\frac{1}{i}$
Work Step by Step
In Section 7.7, we derived that $i^{4}=1$. Therefore, we can use this fact to write the equation in terms of $i^{4}$ and find the desired power of i.
$i^{-13}=\frac{1}{i^{13}}=\frac{1}{(i^{4})^{3}\times i^{1}}=\frac{1}{(i^{4})^{3}\times i^{1}}=\frac{1}{1^{3}\times i}=\frac{1}{i}$
