$$\lim _\limits{n \rightarrow \infty}\left(\frac{(n+1)(n+2) \ldots 3 n}{n^{2 n}}\right)^{1 / n}$$ is equal to

If $$X \phi(x)=\int_\limits5^x 3 t^2-2 \phi(t) d t, x>-2$$ and $$\phi(0)=4$$, then $$\phi(2)$$ is

The value of $$\int\limits_0^{\pi / 2} \frac{d x}{1+\tan x}$$ is