Why arctan(n) goes to pi/2 as n goes infinite?

[Teachme]

I posted the picture of this question I am just wondering. Why does arctan(n) as n → ∞ go to ∏/2? How would you show that part more in depth?
Also what would arccos(n) and arcsin(n) go to as n goes to infinite?

 

[Dick]

I posted the picture of this question I am just wondering. Why does arctan(n) as n → ∞ go to ∏/2? How would you show that part more in depth?

y=arctan(n) then tan(y)=n. Sketch a graph of tan(y) for y between -pi/2 and pi/2. What value must y approach so tan(y) approaches infinity?