If $f(x)=\int \frac{\sin 2 x+2 \cos x}{4 \sin ^2 x+5 \sin x+1} d x$ and $f(0)=0$, then $f(\pi / 6)=$

$\int_{-2}^2 x^4\left(4-x^2\right)^{\frac{7}{2}} d x=$

$$ \int_0^{\pi / 2} \frac{x \tan x \sec ^2 x}{\tan ^4 x+1} d x= $$

$$ \int_3^6 \frac{\sqrt{x}}{\sqrt{9-x}+\sqrt{x}} d x= $$