$$ \int_{-1}^1 x|x| d x= $$

$$ \int_{-\pi / 2}^{\pi / 2} \sin ^2 x \cos ^2 x(\sin x+\cos x) d x= $$

If $\int_0^3\left(3 x^2-4 x+2\right) d x=k$, then an integer root of $3 x^2-4 x+2=3 k / 5$ is

$$ \int_0^\pi \frac{x \cos ^2 x}{1+\sin x} d x= $$