AMorris you genius... i remembered your estimated mark in the other post (117), and im not so suprised now. the probability answer you gave is same as mine, yeh!
my answers to non-proof questions:
1d. 5/12
1e. pi/2 (simplified to tan(-1)2 + tan(-1)1/2)
3c. 2pi
4c. 2e - 1/2 - (e^2)/2
5ai. 0.36...