[.] is the greatest integer function, then

$$ \int_0^{2 \pi}[|\sin x|+|\cos x|] d x= $$

If $f$ is defined on $R$ such that $f(x) f(-x)=9$, then $$ \int_{-23}^{23} \frac{d x}{3+f(x)}= $$

$$ \int_0^4| | x-2|-x| d x= $$

If $\int_{-a}^a f(x) d x=\int_0^a f(x) d x+\int_0^a g(x) d x$, then $g(x)=$