Javelin question

[chickenpop]

Stuck on this one 

A javelin is thrown by a competitor on level ground. At time t in seconds measured from release of javelin, position vector of tip of javelin given by

r(t) = (19.5t) i + (pi/2)t - [4sin((t x pi)/8)] j + (2 + 19.5t - 5t^2) k

where i is a unit vector in the east direction, j a unit vector in the north and k a unit vector vertically up. Origin at ground level, displacement measured in metres

let P be point javelin tip hits ground

- tip of javelin reaches P in 4 seconds
- tip of javelin hits ground 78 metres from origin

What angle, to the nearest tenth of a degree, does path of javelin's tip make with ground at P?

[98.40_for_sure]

Do you have the answer? I'm not gonna post up the solution and risk looking like an idiot if it's wrong

[itolduso]

you don,t trust your own work

[98.40_for_sure]

Latexing this is gonna take me HOURS... i might as well go scan my scrap paper lol
hurry up with the answer!

[chickenpop]

This is going to sound really stupid, but I can' figure out where I got this exam from. I always print double sided, and never print the front covers, blank pages or formula sheet. It's not a VCAA one, since I've searched throughout 2002 to 2009 and still can't find it <_<

[98.40_for_sure]

Oh jeez... no markings on the corners or anything?

[chickenpop]

Oh jeez... no markings on the corners or anything?

It just says 'SPECMATH EXAM 2' :S

[98.40_for_sure]

Well what i did was angle = arctan(k component/magnitude of i and j component).
To get the numbers i did yadda yadda diffing and subbing numbers etc

SPECMATH2 is a VCAA EXAM!
im looking at an exam next to me right now and it says 2009 SPECMATH EXAM 2

[chickenpop]

I've got a feeling that this might be a VCAA exam before 2002, hence why I can't find it

[chickenpop]

oh, I think I've got it thanks guys