How to integrate inverse cos:
y = cos<sup>-1</sup>(sqrt(x))
cos y = sqrt(x)
x = cos^2 y
then integrate it from 0 to pi/2 :)
Me, and a friend got pi/4, for both the approximation questions. So i'm sure that's the right answer..
AHHHHHHHHHHHHHHHHHHHH
lost one mark over forgetting...