Assume that $x$ is a [positive](https://artofproblemsolving.com/wiki/index.php/Positive) [real number](https://artofproblemsolving.com/wiki/index.php/Real_number). Which is equivalent to $\sqrt[3]{x\sqrt{x}}$?
$\mathrm{(A)}\ x^{1/6}\qquad\mathrm{(B)}\ x^{1/4}\qquad\mathrm{(C)}\ x^{3/8}\qquad\mathrm{(D)}\ x^{1/2}\qquad\mathrm{(E)}\ x$
$\sqrt[3]{x\sqrt{x}}=\sqrt[3]{\sqrt{x^3}}=\sqrt[6]{x^3}=x^{3/6}=x^{1/2}\ \boxed{(D)}$