OK I'm writing some 3D Math routines for my game engine and I've come across something that's annoying me. I looked up some vector math in a 3D programming book and it gives this forumla to calculate the dot product of two vectors: u . v = ux * vX + uY * vY + uZ * vZ but just down the page it describes it as this: u . v = (Magnitude of u) * (Magnitude of v) * cos Angle between u and v And I can't see how those two are the same. Maths isn't my strong point so any help here would be much appreciated.

They are indeed the same. Read the section on the proof of the geometric interpretation in the wikipedia article about the dot product for an explanation. You can read the entire article for a generally better understanding of it, too.

Ooo thank you. I shall read that article. Now I've gotta fix these compile errors. Hmm shame they don't do exams on 3D Maths like this in GCSEs... I might be able to get a few extra marks if they did :P

Basically there are two representations of vectors (can also be applied to complex numbers), rectangular and polar. rectangular is simply a set of coordinates, where polar represents the vector based on its length (magnitude) and direction (angle).