Lower boundary = 2sqrt2

upper boundary = 4

(sqrt(x^2 - 4)) / x

So far i've set x = 2 sectheta

dx = 2 (sec theta) (tan theta)

From here i'm having problems what I should do next

I know I have to place new boundaries.

The new lower boundary is gonna pi / 4

the upper boundary i'm having trouble figuring out. what is the sec theta when it equals 2?