Sorry if the title is vague. But I don't really know the terms I'm looking for ( Nor do I know any tags that go with it). I usually end up being confused with the little( and perhaps trivial things ) in math. The following for example:
What are the rules that demand it's a.b / ||a||||b|| and not ||a||||b|| / a.b ?
Perhaps this is a silly question. But, What are the rules when moving from one side of the equation to the other?