$$\displaystyle\int{ \frac{ { x }^{ 3 } }{ \sqrt{ { x }^{ 2 } + { x }^{ 2 } } } }d x$$
$\int \frac{\sqrt{2}x^{3}}{2|x|}\mathrm{d}x$
$\frac{\sqrt{2}x^{3}}{2|x|}$
