Answer
$\sqrt [4] {xy^2}$
Work Step by Step
Simplify. $\sqrt {\sqrt {xy^2}}$
Since, $\sqrt[n] {p^m}=p^{\frac{m}{n}}$
Thus,
$\sqrt {\sqrt {xy^2}}=\sqrt {(xy^2)^{\frac{1}{2}}}=((xy^2)^{\frac{1}{2}})^{\frac{1}{2}}$
or, $=(xy^2)^{\frac{1}{4}}$
ore, $=\sqrt [4] {xy^2}$
