Math Help - Calculate the integral.

1. Calculate the integral.

Calculate

$\int_{0}^{2a}\frac{\sqrt[4]{\sin (3a-x)}}{\sqrt[4]{\sin(3a-x)}+\sqrt[4]{\sin (a+x)}}dx$

where $0 < a < \pi/3$.

2. An old case of symmetric trick, let $x\to2a-x.$