is not injective because the points and (for example) yield the same value of . It is, however, surjective, as every point in is hit. It's not bijective because both aren't satisfied.
isn't injective, because, for example, and both yield the same value. It isn't surjective either, because the only points in that are hit are vectors of length , which certainly don't compose all of 3-space.
PS: Make sure that the way I interpreted your functions is correct.