Hey guys

I don't know how to do this really hard last question in the attached file.

I kinda need help especially for 2) 3) and 4)

for 2) I know that t = | r x f | <- cross product, So you can find a general formula for the position vector R, in terms of alpha and theta, but then what do I use for the F vector?

and for 3) and 4) I just have no idea -.-

Thanks!