Thanks very much indeed for the replies, I think I understand it. I don't have a pen and paper to hand right now so as soon as I get the opportunity I'll go through the explainations thoroughly with a diagram. Re FFF A level maths bit, I reckon it might involve dividing each side by cosA which eliminates the cosA on the RHS and creates tanA on the left in one of the terms (sinA/cosA=tanA as I'm sure you all remembered
), but that kinda creates a mess with the 120 term, I'll explore that one with my pen and paper again! Thanks KW as well, looks like you've cracked it from where I'm standing, I'll let you know if I've any further probs or questions. Thanks again all of you.