Origin of FRW cosmology in slow - roll inflation from noncompact Kaluza - Klein theory

Using a recently introduced formalism we discuss slow-roll inflation from Kaluza-Klein theory without the cylinder condition. In particular, some examples corresponding to polynomic and hyperbolic φ-potentials are studied. We find that the evolution of the fifth coordinate should be determinant for both, the evolution of the early inflationary universe and the quantum fluctuations .