Answer
$-i$
Work Step by Step
Using $i^2=-1$ and the laws of exponents, the given expression $
i^{11}
,$ is equivalent to
\begin{array}{l}\require{cancel}
i^{10}\cdot i
\\\\=
(i^{2})^5\cdot i
\\\\=
(-1)^5\cdot i
\\\\=
(-1)\cdot i
\\\\=
-i
.\end{array}